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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-02-25  8:51 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-02-25  8:51 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of February 18 to 25,
2020.

Table of Contents
─────────────────

Dune 2.3.0
What's the OCaml equivalent for HLint?
Training Sessions for "Expert OCaml" in Paris
OCaml 4.10 released
Old CWN


Dune 2.3.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-3-0/5184/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune team, I'm proud to announce the 2.3.0 release of
  dune. This release is particularly relevant for users of coq that use
  dune to build their theories, developers of coq that use dune to build
  their favorite theorem prover. I'd like to thank @ejgallego for all
  the hard work to improve dune in this regard.

  I'd also like to point out the `(strict_package_deps)' option that is
  now available in project files. This option will now ask dune to
  validate the package dependencies specified in the `package' stanzas
  in your dune-project files.

  Here's the full change list, and as always, happy hacking!


2.3.0 (15/02/2020)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Improve validation and error handling of arguments to `dune init'
    (#3103, fixes #3046, @shonfeder)

  • `dune init exec NAME' now uses the `NAME' argument for private
    modules (#3103, fixes #3088, @shonfeder)

  • Avoid linear walk to detect children, this should greatly improve
    performance when a target has a large number of dependencies (#2959,
    @ejgallego, @aalekseyev, @Armael)

  • [coq] Add `(boot)' option to `(coq.theories)' to enable bootstrap of
    Coq's stdlib (#3096, @ejgallego)

  • [coq] Deprecate `public_name' field in favour of `package' (#2087,
    @ejgallego)

  • Better error reporting for "data only" and "vendored" dirs. Using
    these with anything else than a strict subdirectory or `*' will
    raise an error. The previous behavior was to just do nothing (#3056,
    fixes #3019, @voodoos)

  • Fix bootstrap on bytecode only switches on windows or where `-j1' is
    set.  (#3112, @xclerc, @rgrinberg)

  • Allow `enabled_if' fields in `executable(s)' stanzas (#3137, fixes
    #1690 @voodoos)

  • Do not fail if `ocamldep', `ocamlmklib', or `ocaml' are absent. Wait
    for them to be used to fail (#3138, @rgrinberg)

  • Introduce a `strict_package_deps' mode that verifies that
    dependencies between packages in the workspace are specified
    correctly. (@rgrinberg, #3117)

  • Make sure the `@all' alias is defined when no `dune' file is present
    in a directory (#2946, fix #2927, @diml)


What's the OCaml equivalent for HLint?
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/whats-the-ocaml-equivalent-for-hlint/5167/3>


Continuing this thread, Stéphane Lavergne said
──────────────────────────────────────────────

  Aside from Mascot and `ppx_js_style', it seems that [ocp-lint] is
  actively maintained by the folks at OcamlPro. I personally only use
  `ocamlformat' so I can't vouch for it, but it seems promising.


[ocp-lint] <https://github.com/OCamlPro/typerex-lint>


Training Sessions for "Expert OCaml" in Paris
═════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-02/msg00032.html>


Laurène Gibaud announced
────────────────────────

  OCamlPro organizes a cross-company training in French for developers
  who already use OCaml. The "Expert OCaml" training mixes theory and
  practice and will allow you to master OCaml's advanced features such
  as its type-system, OCaml's open source tools and libraries, and how
  to write compact and efficient code.

  When? The next session is scheduled for March 3-4, 2020, the second
  will be on April 7-8, 2020.

  Where? Paris 14, at our office

  If interested, contact us at contact@ocamlpro.com or register on:
  <http://www.ocamlpro.com/forms/preinscriptions-formation-ocaml/>.  We
  can also organize custom and on-site sessions upon request.

  More info on: <http://www.ocamlpro.com/training-ocamlpro/>


OCaml 4.10 released
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-10-released/5194/1>


octachron announced
───────────────────

  We have the pleasure of celebrating the birthday of Francis Ronalds by
  announcing the release of OCaml version 4.10.0.

  Some of the highlights in this release are:

  • A new best-fit allocator for the major heap which reduces both GC
    cost an memory usage.
  • Some preliminary runtime work for OCaml multicore
  • Immutable strings are now enforced at configuration time
  • User-defined indexing operators for multidimensional arrays
  • Coming soon: statmemprof, a new statistical memory profiler.  The
    external API will be release next version.
  • Various improvements to the manual
  • More precise exhaustiveness check for GADTs
  • Many bug fixes

  Merlin, the OCaml editor service, is not yet available for this
  release.  We will publish a follow-up announcement when Merlin is
  ready.

  This release is (or soon will be) available as a set of OPAM switches,
  and as a source download here:

  <https://caml.inria.fr/pub/distrib/ocaml-4.10/>

  Editor note: please follow the archive link for the full changelog


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-07-26 17:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-07-26 17:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of July 19 to 26,
2022.

Table of Contents
─────────────────

Help w. my first GADT : unwrapping Sqlite3.Data.t
DocuLib 3.1.2 and MetaDB 1.0.2 now on OPAM
dune 3.4.0
OCaml 5.0, first normal alpha release
Other OCaml News
Old CWN


Help w. my first GADT : unwrapping Sqlite3.Data.t
═════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/help-w-my-first-gadt-unwrapping-sqlite3-data-t/10202/1>


Philippe Strauss asked
──────────────────────

  I would like to convert sqlite3-ocaml returns from Sqlite3.Data.t
  array to plain ocaml types in a tuple. I guess unwrapping the Data.t
  can be done using a GADT, here's my very very first attempt:

  ┌────
  │ (* simulate Sqlite3.Data.t *)
  │ 
  │ type t =
  │ | NONE
  │ | NULL
  │ | INT of int64
  │ | FLOAT of float
  │ | TEXT of string
  │ | BLOB of string ;;
  │ 
  │ (* a simple GADT to unwrap Sqlite3.Data.t *)
  │ 
  │ type _ dbval =
  │     | INT : int64 -> int64 dbval
  │     | FLOAT : float -> float dbval
  │     | TEXT : string -> string dbval
  │     | BLOB : string -> string dbval
  │     | NONE | NULL ;;
  │ 
  │ let unwrap_data : type a. a dbval -> a = fun dbval ->
  │     match dbval with
  │     | INT x -> x
  │     | FLOAT x -> x
  │     | TEXT str -> str
  │     | BLOB str -> str ;;
  │ 
  │ let tuple_of_array4 (arr: t array) =
  │     assert (Array.length arr = 4) ;
  │     (unwrap_data arr.(0), unwrap_data arr.(1), unwrap_data arr.(2), unwrap_data arr.(3)) ;;
  └────

  Compilation fails with this typing error:

  ┌────
  │ File "database.ml", line 233, characters 17-24:
  │ 233 |     (unwrap_data arr.(0), unwrap_data arr.(1), unwrap_data arr.(2), unwrap_data arr.(3)) ;;
  │ 		       ^^^^^^^
  │ Error: This expression has type t but an expression was expected of type
  │ 	 'a dbval
  └────

  What am I doing wrong? I need to make type t compatible with type 'a
  dbval.  Thanks in advance.


octachron replied
─────────────────

  You cannot make the type `t' and `'a dbval' compatible, there are
  different types.

  A very important point to keep in mind with GADTs is that one cannot
  create type-level information from dynamical values. In other words,
  there are no functions of type ~ x : t -> f(x) dbval~that will infer
  the type of its return from the value of its argument in OCaml.

  Thus the type of the final result must come from your code source
  rather than from the dynamical data.  For instance, you can define
  constructor from the type `t' to the right `dbval' type:
  ┌────
  │ exception Type_error
  │ 
  │ let int: t -> _ dbval = function
  │ | INT x -> INT x
  │ | _ -> raise Type_error
  │ 
  │ let float: t -> _ dbval = function
  │ | FLOAT x -> FLOAT x
  │ | _ -> raise Type_error
  └────
  Then if you know the type of the tuple, you can write it as:
  ┌────
  │ let tuple_of_array4 (arr: t array) =
  │     assert (Array.length arr = 4) ;
  │     int arr.(0), int arr.(1), int arr.(2), int arr.(3)
  └────
  or possibly as
  ┌────
  │ let int4 = int, int, int, int
  │ let tuple (a,b,c,d) arr =
  │   assert (Array.length arr = 4) ;
  │   a arr.(0), b arr.(1), c arr.(2), d arr.(3)
  └────
  There are more complex alternatives based on type witness, that allow
  to implement a form of static matching over the dynamical type of
  data, but the core idea that the types are always present in the
  source code in some way is the same.


Philippe Strauss then said
──────────────────────────

  Oh I didn't noticed it would be dynamical typing! I'm too used to ppx
  (and previously camlp4) written db abstraction layer!

  I'm simply replacing sqlexpr by plain sqlite3-ocaml in some existing
  code of mine. sqlexpr quick doco:

  <https://github.com/mfp/ocaml-sqlexpr>

  But I can live with a Data.t array!


Yawar Amin then added
─────────────────────

  Everybody has their favourite way of wrapping SQLite. Here's mine (no
  PPX): <https://github.com/yawaramin/ocaml_sql_query>

  It has a little data translation layer to convert from `Data.t' array
  to the desired return type.


DocuLib 3.1.2 and MetaDB 1.0.2 now on OPAM
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/doculib-3-1-2-and-metadb-1-0-2-now-on-opam/10204/1>


nguermond announced
───────────────────

  I'm pleased to announce the release of `doculib' and `metadb', now
  available on OPAM.

  *DocuLib* is a GUI for document management, particularly for all the
  textbooks and articles you've accumulated but know you'll never read
  :thinking:. The idea of DocuLib is to keep track of metadata of files
  stored across multiple libraries on your file system in such a way
  that you can move, reorganize, or rename a file without losing your
  metadata. You can additionally lookup metadata on `openlibrary.org' or
  `semanticscholar.org'. DocuLib will also warn about missing and
  duplicate files. Stored metadata presently includes author, title,
  year, tags, and DOI/ISBN.

  <https://global.discourse-cdn.com/standard11/uploads/ocaml/original/2X/f/fa064cd32bce6e52722d30047d8e0ef21fa09684.png>

  For more screenshots and details:
  <https://github.com/nguermond/doculib>

  *Metadb* is the JSON database for manipulating file metadata
  underlying DocuLib, in hopes that it may be useful somewhere
  else. Data is stored in the following way:
  ┌────
  │ path/to/library
  │ |- .metadata
  │    |- ./foo.txt.json
  │    |- ./blah/bar.pdf.json
  │    |- ./foobar.pdf.json
  │ |- ./foo.txt
  │ |- ./blah/bar.pdf
  │ |- ./foobar.pdf
  └────
  For documentation: <https://github.com/nguermond/metadb>


dune 3.4.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-4-0/10211/1>


Etienne Millon announced
────────────────────────

  On behalf of the dune team, I’m pleased to announce the release of
  version 3.4.0.

  Bug fixes, a couple new features, better hints and error messages - I
  won't restate what's in the changelog below.  Thanks to everyone
  involved in this release!

  • Make `dune describe' correctly handle overlapping implementations
    for virtual libraries (#5971, fixes #5747, @esope)

  • Building the `@check' alias should make sure the libraries and
    executables don't have dependency cycles (#5892, @rgrinberg)

  • [ctypes] Add support for the `errno' parameter using the
    `errno_policy' field in the ctypes settings. (#5827, @droyo)

  • Fix `dune coq top' when it is invoked on files from a subdirectory
    of the directory containing the associated stanza (#5784, fixes
    #5552, @ejgallego, @rlepigre, @Alizter)

  • Fix hint when an invalid module name is found. (#5922, fixes #5273,
    @emillon)

  • The `(cat)' action now supports several files. (#5928, fixes #5795,
    @emillon)

  • Dune no longer uses shimmed `META' files for OCaml 5.x, solely using
    the ones installed by the compiler. (#5916, @dra27)

  • Fix handling of the `(deps)' field in `(test)' stanzas when there is
    an `.expected' file. (#5952, #5951, fixes #5950, @emillon)

  • Ignore insignificant filesystem events. This stops RPC in watch mode
    from flashing errors on insignificant file system events such as
    changes in the `.git/' directory. (#5953, @rgrinberg)

  • Fix parsing more error messages emitted by the OCaml compiler. In
    particular, messages where the excerpt line number started with a
    blank character were skipped. (#5981, @rgrinberg)

  • env stanza: warn if some rules are ignored because they appear after
    a wildcard rule. (#5898, fixes #5886, @emillon)

  • On Windows, XDG_CACHE_HOME is taken to be the
    `FOLDERID_InternetCache' if unset, and XDG_CONFIG_HOME and
    XDG_DATA_HOME are both taken to be `FOLDERID_LocalAppData' if unset.
    (#5943, fixes #5808, @nojb)


Etienne Millon then added
─────────────────────────

  This broke 32-bit cygwin installations, so 3.4.1 was released with a
  fix.


OCaml 5.0, first normal alpha release
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-5-0-first-normal-alpha-release/10216/1>


octachron announced
───────────────────

  The stabilisation of OCaml 5.0 has been progressing well during the
  last month.  We have thus released a first normal alpha release of
  OCaml 5.0.0 to help fellow hackers join us early in our bug hunting
  and opam ecosystem fixing fun (see below for the installation
  instructions).

  You can follow the progress in stabilising the opam ecosystem on

  <https://github.com/ocaml/opam-repository/issues/21526>

  If you find any bugs, please report them here:

  <https://github.com/ocaml/ocaml/issues>

  Compared to the zeroth alpha release, this alpha release restores the
  support for the bytecode debugger, and integrates a change of type in
  the FFI API that might trigger some warnings in FFI code.

  We also have a change in the installed files: the compiler distributes
  now its own META files rather than relying on either findlib or dune
  to provide those files. This should simplify the tasks of both tools
  in future version.

  Note there are still some changes expected in the Effect module before
  the next candidate release. Generally, both the Effect and Domain
  modules are still experimental and might change API even during the
  beta releases.

  If you are interested by the ongoing list of bug fixes, the updated
  change log for OCaml 5.0.0 is available at:

  <https://github.com/ocaml/ocaml/blob/5.0/Changes>

  A short summary of the changes since the zeroth alpha release is also
  available below.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands on opam 2.1:
  ┌────
  │ opam update
  │ opam switch create 5.0.0~alpha1
  └────
  For previous version of opam, the switch creation command line is
  slightly more verbose:
  ┌────
  │ opam update
  │ opam switch create 5.0.0~alpha1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to test this version, it is strongly advised to install
  the alpha opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git+https://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  You can check that the alpha repository has been correctly installed
  with

  ┌────
  │ $ opam repo
  │ 
  │ <><> Repository configuration for switch 5.0.0~alpha1 <><><><><><><><><><><><><>
  │  1 alpha   git+https://github.com/kit-ty-kate/opam-alpha-repository.git
  │  2 default https://opam.ocaml.org
  └────

  This alpha repository contains various fixes in the process of being
  upstreamed which vastly increases the number of opam packages
  currently compatible with OCaml 5.0.0 .

  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:
  ┌────
  │ opam update
  │ opam switch create <switch_name> ocaml-variants.5.0.0~alpha1+options <option_list>
  └────

  where `option_list' is a comma separated list of `ocaml-option-*'
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 5.0.0~alpha1+flambda+nffa ocaml-variants.5.0.0~alpha1+options ocaml-option-flambda
  │ ocaml-option-no-flat-float-array
  └────
  The command line above is slightly more complicated for opam version
  anterior to 2.1:
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.5.0.0~alpha1+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────

  In both cases, all available options can be listed with `opam search
  ocaml-option'.

  The source code for the alpha is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/5.0.0-alpha1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-5.0/ocaml-5.0.0~alpha1.tar.gz>


Changes since the zeroth alpha release:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Runtime system:
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#11400]: Runtime events counters fixes Fixes mismatch between OCaml
    and C APIs, removes events from 4.x that are not present in the 5.0
    GC and adds some missing probes.  (Sadiq Jaffer, review by Gabriel
    Scherer, Florian Angeletti)

  • [#11368]: Runtime events buffer size OCAMLRUNPARAMS fix The runtime
    events buffer size can now be set via the 'e' OCAMLRUNPARAM.  This
    is previously mistakenly enabled/disabled tracing instead.  (Sadiq
    Jaffer, review by KC Sivaramakrishnan, David Allsopp, Damien
    Doligez)

  • [#11304]: Fix data race on Windows file descriptors (Olivier Nicole
    and Xavier Leroy, review by Xavier Leroy, David Allsopp, and Sadiq
    Jaffer)

  • *breaking change* [#11337]: pass 'flags' metadata to root scanners,
     to optimize stack scanning in the bytecode interpreter. Changes the
     interface of user-provided root-scanning hooks. (Gabriel Scherer,
     review by Xavier Leroy, Guillaume Munch-Maccagnoni, Sadiq Jaffer
     and Tom Kelly)

  • [#11144]: Restore frame-pointers support for amd64 (Fabrice Buoro,
    review by Frederic Bour and KC Sivaramakrishnan)

  • *breaking change* [#11255]: in the C interface, `&Field(v, i)' now
     has type `volatile value *' instead of `value *' in OCaml 4.  This
     makes the memory model for mixed OCaml/C code better defined, but
     can cause warnings or type errors in user C code. (KC
     Sivaramakrishnan, review by Xavier Leroy, Gabriel Scherer and
     Guillaume Munch-Maccagnoni, additional discussions with Stephen
     Dolan and Luc Maranget)


[#11400] <https://github.com/ocaml/ocaml/issues/11400>

[#11368] <https://github.com/ocaml/ocaml/issues/11368>

[#11304] <https://github.com/ocaml/ocaml/issues/11304>

[#11337] <https://github.com/ocaml/ocaml/issues/11337>

[#11144] <https://github.com/ocaml/ocaml/issues/11144>

[#11255] <https://github.com/ocaml/ocaml/issues/11255>


Standard library:
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#10867], +[#11345]: Remove deprecated values: …, the infix operator
    (.[ ]<-). (Nicolás Ojeda Bär, review by Damien Doligez)

  • [#11309], [#11424], [#11427]: Add
    Domain.recommended_domain_count. (Christiano Haesbaert, Konstantin
    Belousov, review by David Allsopp, KC Sivaramakrishnan, Gabriel
    Scherer, Nicolas Ojeda Bar)


[#10867] <https://github.com/ocaml/ocaml/issues/10867>

[#11345] <https://github.com/ocaml/ocaml/issues/11345>

[#11309] <https://github.com/ocaml/ocaml/issues/11309>

[#11424] <https://github.com/ocaml/ocaml/issues/11424>

[#11427] <https://github.com/ocaml/ocaml/issues/11427>


Tools:
┄┄┄┄┄┄

  • [#11065]: Port the bytecode debugger to 5.0, adding support for
    effect handlers. (Damien Doligez and fabbing, review by fabbing and
    Xavier Leroy)

  • [#11382]: OCamlmktop use a new initialization module
    "OCamlmktop_init" to preserve backward-compatibility with
    user-module provided modules that install toplevel printers.
    (Florian Angeletti, review by Gabriel Scherer and David Allsopp)


[#11065] <https://github.com/ocaml/ocaml/issues/11065>

[#11382] <https://github.com/ocaml/ocaml/issues/11382>


Installation:
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#11007], [#11399]: META files for the stdlib, compiler-libs and
    other libraries (unix, dynlink, str, runtime_events, threads,
    ocamldoc) are now installed along with the compiler. (David Allsopp,
    Florian Angeletti, Nicolás Ojeda Bär and Sébastien Hinderer, review
    by Daniel Bünzli, Kate Deplaix, Anil Madhavapeddy and Gabriel
    Scherer)


[#11007] <https://github.com/ocaml/ocaml/issues/11007>

[#11399] <https://github.com/ocaml/ocaml/issues/11399>


Bug fixes:
┄┄┄┄┄┄┄┄┄┄

  • [#10768], [#11340]: Fix typechecking regression when combining first
    class modules and GADTs. (Jacques Garrigue, report by François
    Thiré, review by Matthew Ryan)

  • [#10790]: don't drop variance and injectivity annotations when
    pretty printing `with' constraints (for example, `with type +!'a t =
    ...'). (Florian Angeletti, report by Luke Maurer, review by Matthew
    Ryan and Gabriel Scherer)

  • [#11289], [#11405]: fix some leaks on systhread termination (Fabrice
    Buoro, Enguerrand Decorne, Gabriel Scherer, review by Xavier Leroy
    and Florian Angeletti, report by Romain Beauxis)

  • [#11314], [#11416]: fix non-informative error message for module
    inclusion (Florian Angeletti, report by Thierry Martinez, review by
    Gabriel Scherer)

  • [#11358], [#11379]: Refactor the initialization of bytecode
    threading, This avoids a "dangling pointer" warning of GCC
    12.1. (Xavier Leroy, report by Armaël Guéneau, review by Gabriel
    Scherer)

  • [#11387], module type with constraints no longer crash the compiler
    in presence of both shadowing warnings and the `-bin-annot' compiler
    flag. (Florian Angeletti, report by Christophe Raffalli, review by
    Gabriel Scherer)


[#10768] <https://github.com/ocaml/ocaml/issues/10768>

[#11340] <https://github.com/ocaml/ocaml/issues/11340>

[#10790] <https://github.com/ocaml/ocaml/issues/10790>

[#11289] <https://github.com/ocaml/ocaml/issues/11289>

[#11405] <https://github.com/ocaml/ocaml/issues/11405>

[#11314] <https://github.com/ocaml/ocaml/issues/11314>

[#11416] <https://github.com/ocaml/ocaml/issues/11416>

[#11358] <https://github.com/ocaml/ocaml/issues/11358>

[#11379] <https://github.com/ocaml/ocaml/issues/11379>

[#11387] <https://github.com/ocaml/ocaml/issues/11387>


Other OCaml News
════════════════

From the ocaml.org blog
───────────────────────

  Here are links from many OCaml blogs aggregated at [the ocaml.org
  blog].

  • [Tarides is on the Wavestone Radar!]


[the ocaml.org blog] <https://ocaml.org/blog/>

[Tarides is on the Wavestone Radar!]
<https://tarides.com/blog/2022-07-19-tarides-is-on-the-wavestone-radar>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-07-19  8:58 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-07-19  8:58 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of July 12 to 19,
2022.

Table of Contents
─────────────────

Gopcaml-mode and Gopcaml-mode merlin (0.0.6) - Phoenix release (Support for OCaml 4.14.0!)
Sandmark Nightly - Benchmarking as a Service
OCamlFormat Web Configurator
Jane Street is Hiring Front End Engineers
BAP 2.5.0 Release
Why I used OCaml to developed a utility to download Jira items
Liquidsoap 2.1.0
Vim now highlights types, feedback welcome
Other OCaml News
Old CWN


Gopcaml-mode and Gopcaml-mode merlin (0.0.6) - Phoenix release (Support for OCaml 4.14.0!)
══════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-gopcaml-mode-and-gopcaml-mode-merlin-0-0-6-phoenix-release-support-for-ocaml-4-14-0/10164/1>


Kiran Gopinathan announced
──────────────────────────

  Like the *phoenix*, /Gopcaml-mode/ *rises* again from the ashes!…

  …this time with support for OCaml 4.14.0 and OCaml 4.13.0 (by popular
  demand)

  See the [original release post ] for detailed instructions on how you
  can install it.


[original release post ]
<https://discuss.ocaml.org/t/introducing-gopcaml-mode-structural-ocaml-editing/5310>

Screenshots (if you haven't seen them before)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  <https://global.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/abc1ff0b5dbbefe2beb150f2c09148cb5472ece2.gif>

  <https://global.discourse-cdn.com/standard11/uploads/ocaml/original/2X/1/1d43e0f42cc17a30053ee4c71460e70e4061f711.gif>


Video
╌╌╌╌╌

  <https://www.youtube.com/watch?v=KipRuiLXYEo>


What's next?
╌╌╌╌╌╌╌╌╌╌╌╌

  • Support for OCaml 5.0
  • Better ergonomics for piping (i.e `_ |> _')
  • … you decide! (feature requests/pull requests welcome!)


Sandmark Nightly - Benchmarking as a Service
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-sandmark-nightly-benchmarking-as-a-service/10174/1>


Shakthi Kannan announced
────────────────────────

  Tarides is happy to announce Sandmark Nightly benchmarking as a
  service. tl;dr OCaml compiler developers can now point development
  branches at the service and get sequential and parallel benchmark
  results at <https://sandmark.tarides.com>.

  [Sandmark] is a collection of sequential and parallel OCaml
  benchmarks, its dependencies, and the scripts to run the benchmarks
  and collect the results. Sandmark was developed for the Multicore
  OCaml project in order to (a) ensure that OCaml 5 (with multicore
  support) does not introduce regressions for sequential programs
  compared to sequential OCaml 4 and (b) OCaml 5 programs scale well
  with multiple cores. In order to reduce the noise and get actionable
  results, Sandmark is typically run on [tuned machines].  This makes it
  harder for OCaml developers to use Sandmark for development who may
  not have tuned machines with a large number of cores.

  To address this, we introduce Sandmark Nightly service which runs the
  sequential and parallel benchmarks for a set of compiler /variants/
  (branch/commit/PR + compiler & runtime options) on two tuned machines:

  • Turing (28 cores, Intel(R) Xeon(R) Gold 5120 CPU @ 2.20GHz, 64 GB
    RAM)
  • Navajo (128 cores, AMD EPYC 7551 32-Core Processor, 504 GB RAM)

  OCaml developers can request their development branches to be added to
  the nightly runs by adding it to [sandmark-nightly-config]. The
  results will appear the following day at
  <https://sandmark.tarides.com>.

  Here is an illustration of sequential benchmark results from the
  service:

  <https://i.imgur.com/Mn7VZky.png>

  You should first specify the `number of variants' that you want for
  comparison, and then select either the `navajo' or `turing'
  hostnames. The dates for which benchmark results are available are
  then listed in the `date' column. If there are more than one result on
  a given day, then the specific variant name, SHA1 commit and date are
  displayed together for selection. You need to choose one of the
  variants as a baseline for comparison. In the following graph, the
  `5.1.0+trunk+sequential_20220712_920fb8e' build on the `navajo' server
  has been chosen as the baseline, and you can see the normalized time
  (seconds) comparison for the various Sandmark benchmarks for both
  `5.1.0+trunk+sequential_20220713_c759890' and
  `5.1.0+trunk+sequential_20220714_606abe8' variants. We observe that
  the `matrix_multiplication' and `soli' benchmark have become 5% slower
  as compared to the July 12, 2022 nightly run.

  <https://i.imgur.com/7b0yS0h.png>

  Similarly, the normalized MaxRSS (KB) graph for the same baseline and
  variants chosen for comparison is illustrated below:

  <https://i.imgur.com/SfMbEiu.png>

  The `mandelbrot6' and `fannkuchredux' benchmarks have increased the
  MaxRSS (KB) by 3% as compared to the baseline variant, whereas, the
  metric has significantly improved for the `lexifi-g2pp' and
  `sequence_cps' benchmarks.

  The parallel benchmark speedup results are also available from the
  Sandmark nightly runs.

  <https://i.imgur.com/uKFDXCv.png>

  <https://i.imgur.com/24BGXVZ.png>

  We observe from the speedup graph that there is not much difference
  between `5.1.0+trunk+parallel_20220714_606abe8' and the
  `5.1.0+trunk+decouple_20220706_eb7a38d' developer branch results. The
  x-axis in the graph represents the number of domains, while the y-axis
  corresponds to the speedup. The number in the parenthesis against each
  benchmark refers to the corresponding running time of the sequential
  benchmark. These comparison results are useful to observe any
  performance regressions over time. It is recommended to use the
  `turing' machine results for the parallel benchmarks as it is tuned.

  If you would like to use Sandmark nightly for OCaml compiler
  development, please do ping us for access to the
  [sandmark-nightly-config] repository so that you may add your own
  compiler variants.


[Sandmark] <https://github.com/ocaml-bench/sandmark>

[tuned machines]
<https://github.com/ocaml-bench/ocaml_bench_scripts#notes-on-hardware-and-os-settings-for-linux-benchmarking>

[sandmark-nightly-config]
<https://github.com/ocaml-bench/sandmark-nightly-config>


OCamlFormat Web Configurator
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamlformat-web-configurator/10103/6>


Louis Roché announced
─────────────────────

  Thanks to [Pomba Magar] we now have a code editor with
  highlighting. It hopefully should also solve the lack of monospace
  font on safari.

  <https://global.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/9/96fb3536409c5553926228f097812d5b63bd6db8_2_1380x798.jpeg>


[Pomba Magar] <https://github.com/pjmp>


Jane Street is Hiring Front End Engineers
═════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/jane-street-is-hiring-front-end-engineers/10183/1>


Matt Russell announced
──────────────────────

  Jane Street is looking to hire Front End Engineers that want to design
  and build our next-generation of browser-based tools for operating our
  trading infrastructure (in OCaml).  We’re building tools for expert
  users, and want to maintain a high UX bar while building tools that
  are powerful and flexible, so it’s a challenging domain.

  Ron Minsky wrote a bit more about the role here:
  <https://twitter.com/yminsky/status/1541605410691596289?s=20&t=yyrhGx7TnNwPIwdZoArpGw>

  And you can find a link to the job descriptions and the application
  page here:

  • NYC: [Front End Software Engineer: Experienced: Jane Street]
  • LDN: [Front End Software Engineer: Experienced: Jane Street]


[Front End Software Engineer: Experienced: Jane Street]
<https://www.janestreet.com/join-jane-street/position/6184529002/>

[Front End Software Engineer: Experienced: Jane Street]
<https://www.janestreet.com/join-jane-street/position/6236002002/>


BAP 2.5.0 Release
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-bap-2-5-0-release/10185/1>


Ivan Gotovchits announced
─────────────────────────

  We are proud to announce the 2.5.0 release of the Carnegie Mellon
  University Binary Analysis Platform (CMU BAP). This is one of the
  biggest releases of BAP with lots of new [features and bug fixes]. In
  this release, we significantly improved BAP performance (in some use
  cases by a factor of three) and reduced memory consumption (up to a
  factor of two). In addition, we devised a new method for representing
  floating-point operations that is scalable and efficient and now we
  enable floating-point lifters for all x86 binaries with little to no
  extra overhead. The floating-point support for other targets is
  coming! We also rewrote the ABI specifications and now support dozens
  of different ABI.  The new ABIs support calling conventions for
  structures and floating-point values and the `bap-c` library was
  significantly expanded with lots of new functions and types to
  describe C types and C object layouts.

  You can install bap with

  ┌────
  │ opam install bap.2.5.0
  └────

  Do not forget to `opam update' before that.


[features and bug fixes]
<https://github.com/BinaryAnalysisPlatform/bap/releases/tag/v2.5.0>


Why I used OCaml to developed a utility to download Jira items
══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/why-i-used-ocaml-to-developed-a-utility-to-download-jira-items/10186/1>


Willem Hoek announced
─────────────────────

  Not a technical post – but my notes on why I decided to used OCaml to
  develop a small utility that download Jira items to SQLite
  [https://whoek.com/b/jira-to-sqlite-with-scrumdog]

  The Hacker News comments here
  [https://news.ycombinator.com/item?id=32109461]


[https://whoek.com/b/jira-to-sqlite-with-scrumdog]
<https://whoek.com/b/jira-to-sqlite-with-scrumdog>

[https://news.ycombinator.com/item?id=32109461]
<https://news.ycombinator.com/item?id=32109461>


Liquidsoap 2.1.0
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-liquidsoap-2-1-0/10192/1>


Romain Beauxis announced
────────────────────────

  Liquidsoap `2.1.0' was just released, some `10 months after the
  initial release of the ~2.0.x' release cycle!

  The release is available here:
  <https://github.com/savonet/liquidsoap/releases/tag/v2.1.0> and should
  be coming through `opam' pretty soon.


🤔  What is liquidsoap?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Liquidsoap is a statically-typed, type-inferred, functional scripting
  language equipped with specialized operators to build audio and video
  stream automation.

  The liquidsoap language offers all the flexibility and expressivity of
  a fully featured programming language to help build your media
  streams.

  Using liquidsoap, one can very quickly stand up a media streaming
  platform that can rotate files from playlists, accept live DJ input,
  mux audio and video, encode (or not!) and send the resulting data to
  youtube, icecast, HLS and more..


:white_check_mark: Why liquidsoap?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  While there are many tools that offer competing features, the real
  difference with liquidsoap is its scripting language.

  Setting up tools using configuration files is often easier and more
  straight forward, however, when it comes to the finer details, such as
  inserting jingles between shows, defining crossfades between tracks
  and more, potentially, each project has its own set of expectations,
  and this is where liquidsoap becomes really useful!


:zap:️ What's new in Liquidsoap 2.1.0?                              :zap:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Lots of things have been brewing since the `2.0.0' release. This new
  release branch is intended to bring up some of the breaking changes
  that were introduced while we keep working on more exciting future
  changes that we have on our [roadmap]

  Some noticeable changes include:


[roadmap] <https://github.com/savonet/liquidsoap/blob/main/ROADMAP.md>

Improved JSON parsing
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  You should now be able to do:
  ┌────
  │ let json.parse ({
  │   foo,
  │   bla,
  │   gni
  │ } : {
  │   foo: string,
  │   bla: float,
  │   gni: bool
  │ }) = '{ "foo": "aabbcc", "bla": 3.14, "gni": true }'
  └────
  For any one who has ever tried to parse json in their liquidsoap
  scripts, this is gonna be a game changer. We have a detailed article
  [here]


[here] <https://www.liquidsoap.info/doc-dev/json.html>


Regular expressions are now first-class entities.
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  This should be familiar to anyone used to working with Javascript's
  regular expression. So, now, instead of doing:

  ┌────
  │ string.match(pattern="\\d+", s)
  └────

  You will now do:

  ┌────
  │ r/\d+/.test(s)
  └────

  There's a detailed description of this new feature [here].


[here]
<https://www.liquidsoap.info/doc-dev/language.html#regular_expressions>


Vim now highlights types, feedback welcome
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/vim-now-highlights-types-feedback-welcome/10198/1>


Maëlan announced
────────────────

  [A patch] just made its way to [the community-maintained Vim files for
  OCaml] (not propagated to the [official Vim distribution], yet), that
  tries to highlight types. IMHO the patch is large and hacky so you may
  want to try it cautiously, and *feedback would be appreciated*. :-)

  The former behavior was to highlight identifiers that happened to be
  the name of a builtin type (such as `int' or `list'), regardless of
  where they appeared. Now, in principle, all type expressions can be
  highlighted, and be so only when in a type context. By default, only
  builtin types are highlighted, but you can unleash the full power of
  the new linter:

  ┌────
  │ " put this in ~/.vim/after/syntax/ocaml.vim for instance:
  │ hi link ocamlTypeConstr   Type
  │ hi link ocamlTypeBuiltin  Type
  │ hi link ocamlTypeVar      Type
  │ hi link ocamlTypeAnyVar   Type
  └────

  or fancier (if you like excess :rainbow:):

  ┌────
  │ " 112 = light green (the color of the “Type“ hl group with my theme)
  │ hi ocamlTypeConstr       ctermfg=112
  │ hi ocamlTypeBuiltin      ctermfg=112 cterm=bold
  │ hi ocamlTypeVar          ctermfg=112 cterm=italic
  │ hi ocamlTypeAnyVar       ctermfg=112 cterm=bold
  └────

  Even if you don’t care about highlighting types, allowing the linter
  to discriminate between types and exceptions has some tangential
  benefits.


[A patch] <https://github.com/ocaml/vim-ocaml/pull/76>

[the community-maintained Vim files for OCaml]
<https://github.com/ocaml/vim-ocaml>

[official Vim distribution]
<https://github.com/vim/vim/tree/master/runtime>


Other OCaml News
════════════════

From the ocaml.org blog
───────────────────────

  Here are links from many OCaml blogs aggregated at [the ocaml.org
  blog].

  • [Faster Incremental Builds with Dune 3]


[the ocaml.org blog] <https://ocaml.org/blog/>

[Faster Incremental Builds with Dune 3]
<https://tarides.com/blog/2022-07-12-faster-incremental-builds-with-dune-3>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-07-12  7:59 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-07-12  7:59 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 17052 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of July 05 to 12,
2022.

Table of Contents
─────────────────

Dune how to define custom build task
Timedesc 0.8.0 - modern date time handling
containers 3.9
OBazl 2.0.0-alpha-1 (Building OCaml SW with Bazel)
QCheck 0.19
Opam-cross-windows now supports OCaml 4.14.0!
Other OCaml News
Old CWN


Dune how to define custom build task
════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/dune-how-to-define-custom-build-task/10092/1>


cnmade explained
────────────────

  dune has very powerful extensions, but the documentation doesn't tell
  you directly. Today I'll share a specific example of how we can make
  dune do many things with a dune configuration.

  For example

  • Publish compiled documents to our documentation server
  • Sending email notifications to email groups
  • Sending SMS notifications to administrators
  • Build a document and open a browser to preview the document page

  Let's start with an example, we create a dune file in the root
  directory of our project, which you may not have originally, you have
  to create a new one, we enter the following

  ┌────
  │ ; now we tell you how to define a custom rule
  │ ; rule start with (rule )
  │ (rule
  │ ; (alias is point  the command name , so you can run this rule by call  dune build @docopen
  │  (alias docopen)
  │  ; following line is very important, it tell dune do not cache this build command, so it will running every call
  │ without any cache
  │  (deps (universe))
  │  ; action  (system  to told system run command by `sh` in your Linux/MacOS, windows user may running cmd.exe
  │  ; cd ../.. is change the base directory of the running command ,or the default directory will be _build/default
  │  (action (system "cd ../.. && pwd &&  dune build @doc && open _build/default/_doc/_html/index.html" ))
  │ )
  │ ; end of one piece of rule
  │ 
  │ ; and we define more and more rule as we want
  │ (rule
  │   (alias whoami)
  │   (deps (universe))
  │   (action (system "uname -a;whoami"))
  │ )
  └────

  In this example, we define two rules, the rules are the tasks that
  dune can recognize, in dune, it is called rules

  Because it is a custom build command, we use alias to take a unique
  and non-repeating alias.

  The first build command is to build the document and open the browser
  preview.

  Our alias is docopen

  Then deps we add universe to tell dune that you don't want to cache
  and give me a new build every time. If you don't add this line, dune
  will only give you one build, and then because of the cache, you won't
  be able to execute it later.

  action following by system here, action is the command to start,
  system means to use the system shell (windows is cmd, linux macos is
  sh) to give you the execution of the code you specify.

  You can see the first we are first change the directory to the project
  root directory [because the default directory is _build/default], and
  then we perform the build document generation, and then open open the
  generated html page.

  The first build command is this, if you want to perform the first
  build task, you can type

  `dune build @docopen'

  Then our second build command, relatively simple, with reference to
  the first, we can add a lot of build commands we want to add inside
  this dune configuration file.

  We just need to specify different alias aliases for them, no
  duplication.

  The official documentation also specifies some other available
  commands, I won't go into them one by one. Since I prefer to use shell
  scripts, I really only need the system to execute my shell scripts for
  me.


Timedesc 0.8.0 - modern date time handling
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-timedesc-0-8-0-modern-date-time-handling/10138/1>


Darren announced
────────────────

  I'm pleased to announce the release of Timedesc 0.8.0.

  Timedesc is a very comprehensive date time handling library with good
  support of time zone.

  [Homepage]


[Homepage] <https://github.com/daypack-dev/timere>

Features
╌╌╌╌╌╌╌╌

  • Timestamp and date time handling with platform independent time zone
    support
    • Subset of the IANA time zone database is built into this library
  • Supports Gregorian calendar date, ISO week date, and ISO ordinal
    date
  • Supports nanosecond precision
  • ISO8601 parsing and RFC3339 printing


Main changes since 0.6.0
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Significantly reduced size of time zone database by using a custom
    compression scheme
    • Many thanks to @glennsl for the proposed scheme at issue [#46]
    • This yields reduction of roughly 82% for same date period. The
      exact range of years included has been tuned slightly as well and
      I've lost track of the exact size after compilation.
  • Significantly reduced the number of dependencies, and moved JS, JSON
    code into separate packages
    • Removed dependencies: `fmt', `containers', `oseq'
      • Introduced `sexplib' dependency for sexp handling consequently
        as previously containers `CCSexp' was used
    • Moved JSON code into `timedesc-json' package along with Yojson
      dependency
    • Moved `tzlocal' and `tzdb' stuff into their own separate packages
      (`timedesc-tzlocal' and `timedesc-tzdb' respectively)
    • Moved JS tzlocal backend into `timedesc-tzlocal-js' (along with JS
      specific dependencies)


[#46] <https://github.com/daypack-dev/timere/issues/46>


Quality of life changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Updated string conversion functions based on pretty printers which
    raise `Date_time_cannot_deduce_offset_from_utc' to raise the
    exception instead of returning `None'
    • This simplifies the handling as return type is now simply just
      `string'
    • And for serious stuff users are expected to use only unambiguous
      date times anyway, which would not trigger this exception
  • Added ISO8601 printing facilities to `Timestamp' module for
    consistency
    • They are just aliases to the RFC3339 printers


containers 3.9
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-containers-3-9/10140/1>


Simon Cruanes announced
───────────────────────

  I'm happy to announce that containers 3.9 has just been
  released. Containers is a lightweight, modular extension of the stdlib
  that tries to remains compatible with it.

  Containers is starting to sprout some serialization primitives: it now
  has codecs for Bencode and CBOR. This release also contains a revamp
  of the testlib system (bye qtest) and the use of ocamlformat, for
  potential contributors who enjoy that. Containers should also be
  compatible with OCaml 5.0.


OBazl 2.0.0-alpha-1 (Building OCaml SW with Bazel)
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/obazl-2-0-0-alpha-1-building-ocaml-sw-with-bazel/10142/1>


Gregg Reynolds announced
────────────────────────

  I've tagged alpha versions of OBazl [rules_ocaml] and [tools_opam].
  The best way to start exploring is via [demos_obazl], which contains
  over 100 mostly simple demo/test programs, many of which are
  commented.  Three simple commands get you configured and then `bazel
  test test' runs all the tests.

  Tested on MacOS 12.4 and Ubuntu 20.

  Documentation is still in progress but there is useful info at [The
  OBazl Book].

  Lot's of things to say about this version but I'll stick to one point
  of interest.  The four basic OCaml compilers are modeled by Bazel's
  platforms and toolchains mechanisms.  Two of the compilers are
  actually cross-compilers (e.g.  `ocamlc.opt' runs on the system arch
  but targets the OCaml vm), so to pick a compiler you tell OBazl which
  buildhost and targethost platforms you want.  I've predefined
  configurations in [.bazelrc]; for example:

  ┌────
  │ build:bcnc --host_platform=@opam//tc/host/build:bc
  │ build:bcnc --platforms=@opam//tc/host/target:nc
  └────
  which means to select the `ocamlopt.byte' (cross-)compiler, pass
  `--config=bcnc'.

  Kinda cool IMHO. Maybe overkill for the basic compilers, but the
  mechanism is essential to support remote builds, custom compiler
  implementations and genuine cross-compilers.

  Feedback welcome.


[rules_ocaml] <https://github.com/obazl/rules_ocaml>

[tools_opam] <https://github.com/obazl/tools_opam>

[demos_obazl]
<https://github.com/obazl/demos_obazl/blob/main/rules_ocaml/README.adoc>

[The OBazl Book] <https://obazl.github.io/docs_obazl/>

[.bazelrc]
<https://github.com/obazl/demos_obazl/blob/main/rules_ocaml/.bazelrc>


QCheck 0.19
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-qcheck-0-19/10149/1>


Jan Midtgaard announced
───────────────────────

  I'm happy to share the release of QCheck 0.19 - a library for
  property-based testing in OCaml in the style of Haskell's QuickCheck.

  • GitHub repo: <https://github.com/c-cube/qcheck>
  • Documentation: <https://c-cube.github.io/qcheck/0.19/>

  The 0.19 release brings a range of new features and improvements
  detailed below and combines the effort of several individual
  contributors.

  It is now available on opam.

  Release notes:

  • new features and feature extensions
    • add optional `debug_shrink' parameters in alcotest interface and
      expose default `debug_shrinking_choices' in test runners
    • add missing `?handler' parameter to `Test.check_cell_exn'
    • add an option `retries' parameter to `Test.make' et al. for
      checking a property repeatedly while shrinking.  This can be
      useful when testing non-deterministic code.
    • add `tup2' to `tup9' for generators
    • add `Test.make_neg' for negative property-based tests, that are
      expected not to satisfy the tested property.
    • add environment variable `QCHECK_LONG_FACTOR' similar to
      `QCHECK_COUNT'
    • rename `Gen.opt' to `Gen.option' but keep the old binding for
      compatibility.
    • shrinker changes
      • recursive `list' shrinker with better complexity
      • `string' shrinker reuses improved `list' shrinker and adds
        `char' shrinking
      • function shrinker now shrinks default entry first and benefits
        from `list' shrinker improvements
      • replacing the linear-time `char' shrinker with a faster one
        reusing the bisecting `int' shrinker algorithm
      • add `Shrink.char_numeral' and `Shrink.char_printable'
      • add shrinking for `char arbitrary~s ~char', `printable_char',
        and `numeral_char'

  • bug fixes
    • fix function generation affecting reproducability
    • fix distribution of `QCheck2.printable' which would omit certain
      characters
    • use `Float.equal' for comparing `float~s in the ~Observable'
      module underlying function generators.

  • documentation updates:
    • clarify upper bound inclusion in `Gen.int_bound' and
      `Gen.int_range'
    • clarify `printable_char' and `Gen.printable' distributions
    • add missing `string_gen_of_size' and `small_printable_string'
      documentation
    • document `QCheck_alcotest.to_alcotest'
    • fix documented size distribution for `arbitrary' generators
      `string_gen', `string', `printable_string', `numeral_string',
      `list', and `array'
    • fix exception documentation for `check_result', `check_cell_exn',
      and `check_exn'
    • fix documentation for the distribution of `Gen.printable' and
      `printable_char'
    • fix documentation for the shrinking behaviour of
      `QCheck2.printable'

  • internal and test suite changes
    • add additional expect and unit tests and refactor expect test
      suite
    • add a shrinker performance benchmark
    • remove `--no-buffer' option on `dune runtest' to avoid garbling
      the test output
    • make test suite run on 32-bit architectures


Opam-cross-windows now supports OCaml 4.14.0!
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/opam-cross-windows-now-supports-ocaml-4-14-0/10159/1>


Romain Beauxis announced
────────────────────────

  Bit of a late announcement but the `opam-cross-windows' project now
  supports the OCaml compiler version `4.14.0':
  <https://github.com/ocaml-cross/opam-cross-windows>

  The `opam-cross-windows' project is part of an initiative started by
  @whitequark to provide cross-compilation support to existing `opam'
  packages. This allows users to compile binaries for windows but also
  android and ios on a linux or macos host.

  Support for packages is a on best-effort basis and is always looking
  for more contributors. Adding a package can be a little tricky at
  times but, if your package uses `dune', the cross-compilation support
  there is pretty wonderful and makes it pretty easy to add
  cross-compiled packages.


Other OCaml News
════════════════

>From the ocaml.org blog
───────────────────────

  Here are links from many OCaml blogs aggregated at [the ocaml.org
  blog].

  • [The Magic of Merlin]
  • [Thales Cyber@Station F Selection]
  • [Team Tarides Visits a 17th Century Chateau]
  • [Functional Conf 2022]
  • [OCaml 5 Alpha Release]
  • [Adding Merkle Proofs to Tezos]
  • [OCaml Matrix: A Virtual World]
  • [Tarides Sponsors 12th Annual Journées Franciliennes]
  • [OCaml.org Reboot: User-Centric Design & Content]
  • [Lightning Fast with Irmin: Tezos Storage is 6x faster with 1000 TPS
    surpassed]
  • [Tarides Partners with 50inTech!]
  • [What's New in MirageOS 4!]


[the ocaml.org blog] <https://ocaml.org/blog/>

[The Magic of Merlin]
<https://tarides.com/blog/2022-07-05-the-magic-of-merlin>

[Thales Cyber@Station F Selection]
<https://tarides.com/blog/2022-06-28-thales-cyber-station-f-selection>

[Team Tarides Visits a 17th Century Chateau]
<https://tarides.com/blog/2022-06-23-team-tarides-visits-a-17th-century-chateau>

[Functional Conf 2022]
<https://tarides.com/blog/2022-06-21-functional-conf-2022>

[OCaml 5 Alpha Release]
<https://tarides.com/blog/2022-06-15-ocaml-5-alpha-release>

[Adding Merkle Proofs to Tezos]
<https://tarides.com/blog/2022-06-13-adding-merkle-proofs-to-tezos>

[OCaml Matrix: A Virtual World]
<https://tarides.com/blog/2022-06-09-ocaml-matrix-a-virtual-world>

[Tarides Sponsors 12th Annual Journées Franciliennes]
<https://tarides.com/blog/2022-06-02-tarides-sponsors-12th-annual-journ-e-francilienne>

[OCaml.org Reboot: User-Centric Design & Content]
<https://tarides.com/blog/2022-05-02-ocaml-org-reboot-user-centric-design-content>

[Lightning Fast with Irmin: Tezos Storage is 6x faster with 1000 TPS
surpassed]
<https://tarides.com/blog/2022-04-26-lightning-fast-with-irmin-tezos-storage-is-6x-faster-with-1000-tps-surpassed>

[Tarides Partners with 50inTech!]
<https://tarides.com/blog/2022-04-19-tarides-partners-with-50intech>

[What's New in MirageOS 4!]
<https://tarides.com/blog/2022-04-14-what-s-new-in-mirageos-4>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-07-05  7:42 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-07-05  7:42 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 17974 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of June 28 to July
05, 2022.

Table of Contents
─────────────────

An amusing use of first-class modules: reading from plaintext and compressed files
TLS signature with opam:tls
Open Source tooling engineer at Jane Street
Dune how to define custom build task
Lwt.5.6.0 (and other Lwt packages)
Windows-friendly OCaml 4.12 distribution - Diskuv OCaml 0.1.0
OCamlFormat Web Configurator
Release of optiml-transport
Old CWN


An amusing use of first-class modules: reading from plaintext and compressed files
══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/an-amusing-use-of-first-class-modules-reading-from-plaintext-and-compressed-files/10073/9>


Continuing this thread, Maëlan asked and Simon Cruanes replied
──────────────────────────────────────────────────────────────

        You got me curious: what’s the reason for using a
        first-class module here instead of a record or an object?

  Of course!

  • compared to records, I find first-class modules to be a lot more
    convenient for this use case. I still use records for _data_, but a
    record-of-function is often less convenient. For example, modules
    allow you to use `include', they directly handle down-casting as a
    way to hide internal state (whereas for modules you need to close
    over values created before the record); module types are structural,
    so I don't need to worry about disambiguation, whereas records need
    more care there. In terms of performance both seem exactly the same,
    from my toy benchmarks.
  • compared to objects, first-class modules are a bit less convenient
    (no runtime-free cast, no true inheritance/mixin), but LSP and other
    tools are fragile. In addition, invoking an object method seems to
    be roughly twice as slow as a record/module field access — I suppose
    it's because the latter is just an access via offset. That's on a
    micro benchmark so in reality it might be worse.


TLS signature with opam:tls
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/tls-signature-with-opam-tls/9399/10>


Marcus Rohrmoser announced
──────────────────────────

  just implemented key generation
  <https://codeberg.org/mro/seppo/src/branch/develop/lib/as2.ml#L95>


Open Source tooling engineer at Jane Street
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-open-source-tooling-engineer-at-jane-street/10083/1>


Yaron Minsky announced
──────────────────────

  We're looking to hire someone to join our build-systems team with a
  focus on open-source tooling. We currently release almost a million
  lines of code of our internal libraries and tools, including things
  like Sexplib, Base, Core, Async, Incremental, Bonsai, Hardcaml,
  memtrace-viewer, and patdiff.

  We have internal tooling for moving code from our internal
  repositories to Github and for publishing to opam, and for ferrying
  information back from Github to our internal tools, so that developers
  can more easily and promptly respond to PRs and issues coming from the
  outside.

  We want to make open-sourcing our code better and faster, so it's
  easier for us to work with outside contributors, and improvements can
  get out to the community more quickly. Your work would be to make our
  releases delightfully easy and reliable!

  I wrote a bit more about it here:

  <https://twitter.com/yminsky/status/1536766031313739776?s=20&t=sCyUlHGHO1y3znBh4pl0Xw>

  If you're interested, go ahead and make an [ordinary application] to
  our software engineering role, and mention that you're interested in
  "open-source tooling". We're happy to hire for this role in both
  London and New York.


[ordinary application]
<https://www.janestreet.com/join-jane-street/apply/>


Dune how to define custom build task
════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/dune-how-to-define-custom-build-task/10092/1>


cnmade explained
────────────────

  dune has very powerful extensions, but the documentation doesn't tell
  you directly. Today I'll share a specific example of how we can make
  dune do many things with a dune configuration.

  For example

  • Publish compiled documents to our documentation server
  • Sending email notifications to email groups
  • Sending SMS notifications to administrators
  • Build a document and open a browser to preview the document page

  Let's start with an example, we create a dune file in the root
  directory of our project, which you may not have originally, you have
  to create a new one, we enter the following

  ┌────
  │ ; now we tell you how to define a custom rule
  │ ; rule start with (rule )
  │ (rule
  │ ; (alias is point  the command name , so you can run this rule by call  dune build @docopen
  │  (alias docopen)
  │  ; following line is very important, it tell dune do not cache this build command, so it will running every call
  │ without any cache
  │  (deps (universe))
  │  ; action  (system  to told system run command by `sh` in your Linux/MacOS, windows user may running cmd.exe
  │  ; cd ../.. is change the base directory of the running command ,or the default directory will be _build/default
  │  (action (system "cd ../.. && pwd &&  dune build @doc && open _build/default/_doc/_html/index.html" ))
  │ )
  │ ; end of one piece of rule
  │ 
  │ ; and we define more and more rule as we want
  │ (rule
  │   (alias whoami)
  │   (deps (universe))
  │   (action (system "uname -a;whoami"))
  │ )
  └────

  In this example, we define two rules, the rules are the tasks that
  dune can recognize, in dune, it is called rules

  Because it is a custom build command, we use alias to take a unique
  and non-repeating alias.

  The first build command is to build the document and open the browser
  preview.

  Our alias is docopen

  Then deps we add universe to tell dune that you don't want to cache
  and give me a new build every time. If you don't add this line, dune
  will only give you one build, and then because of the cache, you won't
  be able to execute it later.

  action following by system here, action is the command to start,
  system means to use the system shell (windows is cmd, linux macos is
  sh) to give you the execution of the code you specify.

  You can see the first we are first change the directory to the project
  root directory [because the default directory is _build/default], and
  then we perform the build document generation, and then open open the
  generated html page.

  The first build command is this, if you want to perform the first
  build task, you can type

  `dune build @docopen'

  Then our second build command, relatively simple, with reference to
  the first, we can add a lot of build commands we want to add inside
  this dune configuration file.

  We just need to specify different alias aliases for them, no
  duplication.

  The official documentation also specifies some other available
  commands, I won't go into them one by one. Since I prefer to use shell
  scripts, I really only need the system to execute my shell scripts for
  me.


Lwt.5.6.0 (and other Lwt packages)
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-lwt-5-6-0-and-other-lwt-packages/10077/2>


Raphaël Proust announced
────────────────────────

Lwt 5.6.1
╌╌╌╌╌╌╌╌╌

  Version 5.6.1 of the Lwt package has been released. This version
  contains a fix for a bug introduced in 5.6.0 whereby devnull file
  descriptor would be closed during some uses of `Lwt_process'.

  <https://github.com/ocsigen/lwt/releases/tag/5.6.1>


Windows-friendly OCaml 4.12 distribution - Diskuv OCaml 0.1.0
═════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-windows-friendly-ocaml-4-12-distribution-diskuv-ocaml-0-1-0/8358/21>


jbeckford announced
───────────────────

  The 0.4.0 release of Diskuv OCaml for Windows users is available! It
  is usable enough that I've let my school-age kids (elementary through
  high school) install it and go through some tutorials.

  <https://github.com/diskuv/dkml-installer-ocaml#readme>

  The links to the documentation are available from the above link as
  well.

  Here are the one-time inconveniences if you install this release:
  1. The built-in antivirus Windows Defender treats newly signed
     binaries like spam. There needs to be enough people who "Report
     this file as safe" before the binaries are trusted. /If you do
     nothing but mark it safe or install it on Windows, you are helping
     others!/
  2. The installer will automatically install the Visual Studio compiler
     if needed. But Visual Studio sometimes requires a reboot. The
     instructions will tell you if you need the reboot.
  3. The Visual Studio Code OCaml plugin defaults to expecting a legacy
     `ocamlenv' program on Windows. You have to search for `ocamlenv' in
     Visual Studio Code Settings and disable it. This should have a fix,
     but not in time for this release.


Windows parity with Unix
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  1. `opam' commands like `opam install' should work without any
     wrappers. But you should create new switches with `opam dkml init'
     (see `--help' for options).
  2. `dune' commands like `dune build' should work without any
     wrappers. The only hiccup is that aliases like `dune build
     @runtest' need to be escaped in PowerShell like:
     ┌────
     │ dune build `@runtest
     └────
  3. You have partial support if your home directory has spaces, since
     it is very common on Windows to have your username be `FirstName
     LastName'. So far I've configured/patched most things to work with
     spaces, but there could be common packages that were missed, and
     only NTFS drives work.
  4. OCaml 4.12.1. I'd like to upgrade to 4.13 or 4.14, but having
     support for Visual Studio Code debugging with [4.12-only
     ocamlearlybird] is more important, especially for traditional
     Windows users.
  5. Dune 2.9.3. I've bundled in support in 2.9.3 for fswatch/inotify so
     that `dune build --watch' works on Windows. Nothing is blocking an
     upgrade to 3.x except time (ie. not now) and a reason.
  6. Opam 2.1.2 plus some PRs that are pending the not-yet-released
     version 2.2.
  7. Git performance on Windows just sucks. It is like someone designed
     it for a Linux kernel 🤨. Apparently [Git FSMonitor in 2.37.0] can
     be enabled to speed things up, but I don't have real-world
     experience with it because it was just released yesterday.
  8. MSYS2, which can be accessed with `with-dkml bash', now uses the
     CLANG64 variant. There are thousands of up-to-date third-party
     libraries available and, unlike MinGW, they are ABI compatible with
     the dominant Windows compiler (MSVC). And if you are interested
     there is an [ocamlverse Help Wanted] to add the CLANG64 compiler as
     an alternative to the Administrator-requiring, reboot-needing MSVC
     compiler.

  Thanks to OCaml Software Foundation for sponsoring this!

  0.4.x will be the last minor versions of the "preview". I'll be
  shifting to closing out any show-stopping bugs, and updating the
  various Windows onboarding guides for OCaml to officially include
  Diskuv OCaml.


[4.12-only ocamlearlybird]
<https://github.com/hackwaly/ocamlearlybird/issues/38>

[Git FSMonitor in 2.37.0]
<https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a-file-system-monitor/>

[ocamlverse Help Wanted]
<https://ocamlverse.github.io/content/help_wanted.html>


OCamlFormat Web Configurator
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamlformat-web-configurator/10103/1>


Louis Roché announced
─────────────────────

  It is my pleasure to share with you the [ocamlformat configurator] as
  a web page.

  Ocamlformat is a great tool that really makes editing code a more
  pleasant experience. It has a bunch of different built in profiles and
  many additional options to fine tune how the code should look
  like. While I would encourage most people and new projects to use one
  of the default profiles, the many options are helpful when
  transitioning an existing codebase. Unfortunately it is not super easy
  to figure out which options to use and how to combine them.  There are
  [58 parameters]! I've spent a long time trying different combinations
  by changing an option in my .ocamlformat, running `dune build @fmt`,
  checking the code, going back to the first step… It is a tedious
  work. So I decided to make a simple web interface with all of the
  options available and a faster feedback loop.

  <https://global.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/2/24e891e9e1400d4a47debf9e34b3ea414bebf418_2_1380x826.jpeg>

  Thanks to js_of_ocaml the task was not too complicated. Ocamlformat
  can be compiled to javascript, there is nothing special to do. Which
  means everything can be done in the browser, the code won't leak to
  anyone, there is no need to maintain a server, and the result will be
  guaranteed to be identical as a formatting with the cli tool.

  The configuration can be set through text (just put the content of
  your `.ocamlformat` in the text box) and through a bunch of
  dropdown. They will be combined together. The dropdown takes
  precedence over the textual configuration if an option is set in both.

  The project has been started as part of the "open source day" at
  Ahrefs (we try to dedicate some time to open source projects that we
  use internally). It is still in its infancy. Please pardon the
  terrible style, I am not a web developer and didn't have time to make
  it look nicer yet. There are some annoying things to fix (no feedback
  when the code is invalid and can't be formatted), and many
  improvements to come (a way to download the configuration for
  example). But I think that it is already working well enough to be
  used by others.

  You can find the configurator at
  <https://ahrefs.github.io/ocamlformat/>
  The source code is on github at
  <https://github.com/ahrefs/ocamlformat/tree/ahrefs/web-ui/bin/web-ui>

  If you like ocaml and want to look for a job, we have some [positions
  available]


[ocamlformat configurator] <https://ahrefs.github.io/ocamlformat/>

[58 parameters]
<https://raw.githubusercontent.com/ocaml-ppx/ocamlformat/main/ocamlformat-help.txt>

[positions available] <https://ahrefs.com/jobs>


Release of optiml-transport
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-optiml-transport/10128/1>


Igarnier announced
──────────────────

  Hi! [optiml-transport] was just released on opam. This library binds
  C++ primitives to solve the [optimal
  transportation](<https://en.wikipedia.org/wiki/Transportation_theory_(mathematics)>)
  problem between finite weighted point clouds (i.e. finite
  measures). Concretely, this allows to lift any [metric] on a base
  space to a metric on finitely supported probability measures over that
  base space. (In fact, the library works with cost functions more
  general than that satisfying the metric axioms.) The library also
  outputs an optimal coupling between any two such measures. Optimal
  transportation has many applications in statistics, graphics,
  optimization, etc.

  The library consists in bindings to
  <https://github.com/nbonneel/network_simplex>


[optiml-transport] <https://github.com/igarnier/optiml-transport>

[metric] <https://en.wikipedia.org/wiki/Metric_space>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-06-28  7:37 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-06-28  7:37 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of June 21 to 28,
2022.

The mailing list mode of discuss.ocaml.org seems to have been down for a
few days, so I had to manually scrape the messages. My apologies if I
missed any.

Table of Contents
─────────────────

An amusing use of first-class modules: reading from plaintext and compressed files
Lwt.5.6.0 (and other Lwt packages)
Old CWN


An amusing use of first-class modules: reading from plaintext and compressed files
══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/an-amusing-use-of-first-class-modules-reading-from-plaintext-and-compressed-files/10073>


Chet_Murthy explained
─────────────────────

  I was recently trying to write a thing in Rust, and having problems,
  so I wrote the same thing in OCaml, just to make sure that it was
  doable. I thought I’d post about it, b/c maybe it’s an example of what
  we’ll find more tractable, once we have modular implicits.

  The problem: I have both compressed and plaintext files, and I want to
  run a function over the uncompressed contents. I’d like a combinator
  that I can apply to the filename and the function, that will do the
  work of opening the file, calling the function, closing the file, etc.

  This isn’t so hard.

  1. define a type of READER (and two instances for plaintext and
     gzipped). This is the equivalent of Rust’s “io::BufRead”.

     ┌────
     │ module type READER =
     │   sig
     │     type in_channel
     │     val open_in : string -> in_channel
     │     val input_char : in_channel -> char
     │     val close_in : in_channel -> unit
     │   end
     │ let stdreader = (module Stdlib : READER) ;;
     │ let gzreader = (module Gzip : READER) ;;
     └────

  2. then define a type of “in channel user” (“ICUSER”) and the generic
     version of it

     ┌────
     │ module type ICUSER = sig
     │   type in_channel
     │   val use_ic : in_channel -> unit
     │ end
     │ module type GENERIC_ICUSER = functor (R : READER) -> (ICUSER with type in_channel = R.in_channel)
     └────

  3. then define our function that takes a generic in_channel, and uses
     it – “Cat”

     ┌────
     │ module Cat(R : READER) : ICUSER with type in_channel = R.in_channel = struct
     │   type in_channel = R.in_channel
     │   let use_ic ic =
     │   let rec rerec () =
     │     match R.input_char ic with
     │       c -> print_char c ; rerec ()
     │     | exception End_of_file -> ()
     │   in rerec ()
     │ end
     └────

  4. And then write our “with_input_file” function, that takes a
     filename, the function from #3, and applies it to either a normal
     in_channel, or one produced from a gzip-reader.

     ┌────
     │ let with_input_file fname (module R : GENERIC_ICUSER) =
     │   let (module M : READER) =
     │     if Fpath.(fname |> v |> has_ext "gz") then
     │       gzreader
     │     else stdreader in
     │   let open M in
     │   let ic = M.open_in fname in
     │   let module C = R(M) in
     │   try let rv = C.use_ic ic in close_in ic ; rv
     │   with e -> close_in ic ; raise e
     └────

  And now we can use it:

  ┌────
  │ with_input_file "/etc/passwd" (module Cat) ;;
  │ with_input_file "foo.gz" (module Cat) ;;
  └────

  Easy-peasy. I don’t remember enough about the modular implicits
  proposal to remember if this can be cast in the supported language
  there, so I suppose I should get some version of that code (or the
  newer versions from others) up-and-running, and see if this can be
  made to work.


hyphenrf asked and Chet_Murthy replied
──────────────────────────────────────

        can’t we get rid of the `GENERIC_ICUSER' requirement and
        just ask for functions that take a packed module of type
        `READER'

        by that I mean the signature of `with_input_file' becomes
        `string -> ((module READER) -> 'a) -> 'a'

  It’s a good question, and as a newbie user of first-class modules, I
  don’t know the typing rules well enough to answer. But I did try:

  ┌────
  │ let with_input_file' fname f =
  │   let (module M : READER) =
  │     if Fpath.(fname |> v |> has_ext "gz") then
  │       gzreader
  │     else stdreader in
  │   let open M in
  │   let ic = M.open_in fname in
  │   f (module M : READER) ic
  └────

  and got

  ┌────
  │ File "ioabs.ml", line 96, characters 24-26:
  │ 96 |   f (module M : READER) ic
  │ 			     ^^
  │ Error: This expression has type M.in_channel
  │        but an expression was expected of type 'a
  │        The type constructor M.in_channel would escape its scope
  └────

  ETA: I remember in the modular implicits paper, that there was a lot
  of wrappering code in structs (that didn’t start off in structs). I
  wonder if that’s evidence that you really do have to “push up” code to
  the module level in order to make it work.


octachron then said
───────────────────

  You don’t need modular implicits to simplify your code. Your packed
  module type is equivalent to:

  ┌────
  │ type channel = { input_char: unit -> char; close_in: unit -> unit }
  │ type channel_generator = string ->  channel
  └────

  We could go fancy and manifest the type with an existential

  ┌────
  │ type 'a channel =
  │   { open_fn: string -> 'a; input_char: 'a -> char; close_in: 'a -> unit }
  │ type chan = Any: 'a channel -> chan
  └────

  but this has mainly the advantage to illustrate the fact that you are
  never using the non-existentially qualified `'a channel' which means
  that in the current version of your code, modular (explicits or)
  implicits is not a good fit: we are not selecting a module to provide
  functions for a type, we have an object (aka an existentially
  qualified record) with some hidden inner type that we never need to
  know.


c-cube later said
─────────────────

  I think it’s kind of counter-productive to want a `in_channel' type at
  all. This is what I’ve been doing, more and more:

  ┌────
  │ module type INPUT = sig
  │   val read_char : unit -> char
  │   val read : bytes -> int -> int -> int
  │   val close : unit -> unit
  │ end
  │ 
  │ type input = (module INPUT)
  │ 
  │ let open_file (filename:string) : input =
  │   let ic = open_in filename in
  │   (module struct
  │     let read_char() = input_char ic
  │     let read = input ic
  │     let close() = close_in ic
  │  end)
  │ 
  │ 
  │ let do_sth (module IN:INPUT) =
  │   IC.read_char ();
  │   IC.read …
  └────

  This behaves like classic objects in other languages and there’s no
  complicated typing going on (what with each implementation having its
  own channel type).


Lwt.5.6.0 (and other Lwt packages)
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-lwt-5-6-0-and-other-lwt-packages/10077>


raphael-proust announced
────────────────────────

  It is a real pleasure to announce the release of Lwt version 5.6.0 as
  well as Lwt-domain.0.2.0, Lwt-ppx.2.1.0 and Lwt-react.1.2.0. With this
  release Lwt is now compatible with OCaml version 5.

  <https://github.com/ocsigen/lwt/releases/tag/5.6.0>

  Thank you to the many contributors for the fixes, the improvements,
  and the OCaml5 compatibility! Check out the changelog for full details
  on each contribution.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-06-21  8:06 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-06-21  8:06 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 17329 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of June 14 to 21,
2022.

Table of Contents
─────────────────

OBazl Toolsuite - tools for building OCaml with Bazel
Job offer: 3 years compiler engineer at the French tax authority
OCaml 5.0, zeroth alpha release
Tezt, a framework for all your tests
OCaml Stdlib, Containers, Batteries, Base and F# core functions comparisons
Dune 3.3.0
Old CWN


OBazl Toolsuite - tools for building OCaml with Bazel
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/obazl-toolsuite-tools-for-building-ocaml-with-bazel/10021/1>


Gregg Reynolds announced
────────────────────────

  Version 2 of OBazl, a Bazel ruleset for building OCaml code, will soon
  be available.  I'm letting you know early because I'll be giving a
  presentation about the OBazl Toolsuite for the [Bazel Exchange]
  conference next Wed, 22 June, at 3:00 pm UDT (10:00 am CDT). It's a
  virtual conference so you can tune in from anywhere.  The talk will
  focus on some of the quirks of the OCaml build discipline and how I
  addressed them for the OBazl ruleset.

  The tools are usable now, they're just not yet properly documented and
  packaged, and in a few places there's a little more work to be done on
  the code. Nonetheless there is quite a bit of documentation (CAVEAT:
  some of it is outdated), with more on the way soon, and there are lots
  of demos available.  So if you're interested in using Bazel to build
  your OCaml code I welcome you to take a look:

  [The OBazl Book]

  Twitter handle is @obazldev Discord: [https://discord.gg/PHSAW5DUva]


[Bazel Exchange]
<https://skillsmatter.com/conferences/13682-bazel-exchange>

[The OBazl Book] <https://obazl.github.io/docs_obazl/>

[https://discord.gg/PHSAW5DUva] <https://discord.gg/PHSAW5DUva>


Gregg Reynolds lated added
──────────────────────────

  PS.  The conference organizers have provided this discount token:
  BAZEL-GR-20

  It should be good for 20% off, registration is at
  [https://events.skillsmatter.com/bazelx2022]


[https://events.skillsmatter.com/bazelx2022]
<https://events.skillsmatter.com/bazelx2022>


Job offer: 3 years compiler engineer at the French tax authority
════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-offer-3-years-compiler-engineer-at-the-french-tax-authority/10023/1>


Denis Merigoux announced
────────────────────────

  [En français parce que c'est une offre d'emploi dans l'administration]

  Bonjour à toutes et à tous,

  Vous aimez la programmation fonctionnelle et les compilateurs ? Vous
  en avez marre des offres d'emploi dans la blockchain ? Ça tombe bien,
  j'ai ce qu'il vous faut !

  Il y a deux ans, j'ai lancé un grand projet de modernisation du calcul
  informatique de calcul de l'impôt sur le revenu à la Direction
  Générale des Finances Publiques (DGFiP), en partenariat avec Inria:
  <https://www.inria.fr/fr/mlang-modernisation-calcul-impot-revenu>.

  Le logiciel au cœur de ce projet de modernisation est Mlang, un
  compilateur écrit en OCaml pour un couple de langages dédiés utilisés
  par la DGFiP pour encoder le calcul de l'impôt sur le revenu. Depuis
  deux ans, la DGFiP travaille à intégrer Mlang à l'infrastructure
  officielle de calcul de l'impôt sur le revenu pour remplacer des
  systèmes vieillissants. C'est donc un projet à très fort impact (80M€
  par d'impôts par an), et proche de la R&D (OCaml, libre, innovation) !
  Depuis un an, la DGFiP emploie la société OCamlPro sur le projet mais
  souhaite maintenant ré-internaliser ses compétences pour garder la
  souveraineté numérique sur son infrastructure de calcul.

  C'est là que cette offre d'emploi entre en jeu ! En effet la DGFiP
  vient d'ouvrir un poste en CDD de 3 ans pour un.e expert.e en
  compilation ! Les détails :

  • Bureaux à Noisy-le-Grand (+ jusqu'à 3 jours télétravail/semaine)
  • Salaire: À négocier selon expérience mais similaire à "Inspecteur
    des finances publiques". Selon le site du ministère de l'économie ça
    débuterait à 3k€ net/mois.
  • Tâches: Maintenance, évolution de Mlang et travaux annexes

  Et pour l'heureux.se recruté.e, la cerise sur le gâteau sera de
  pouvoir collaborer avec moi et l'équipe Prosecco d'Inria (ainsi que
  Raphaël Monat, ) :) Attention cependant : il faudra s'attendre à
  devoir également aider l'équipe de la DGFiP sur d'autres chantiers en
  fonction des priorités. De même, l'objectif est de partager la
  compétence en compilation au sein de la DGFiP, donc les profils
  évangélisateurs de la programmation fonctionnelle sont les bienvenus !

  Pour référence, voici l'offre officielle complète:
  <https://merigoux.ovh/assets/OffreDGFiP.pdf>. S'il vous plaît, pas
  d'autocensure à cause de ce qui est marqué dans ce PDF! Si vous avez
  un doute contactez-moi par retour de mail.

  Deadline pour les candidatures: 9 juillet. Prise de poste inconnue,
  sûrement aux alentours du 1er septembre mais j'imagine que c'est
  négociable.


Denis Merigoux later added
──────────────────────────

  Si vous êtes intéressé.e, envoyez votre CV et lettre de motivation à
  bureau.si-part-rh@dgfip.finances.gouv.fr et
  bureau.rh-mobilite-carriere-a-recrutementchoix@dgfip.finances.gouv.fr.


OCaml 5.0, zeroth alpha release
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-5-0-zeroth-alpha-release/10026/1>


octachron announced
───────────────────

  Five months after the initial merge of the multicore branch into the
  mainline OCaml and three months after the release of OCaml 4.14.0,
  OCaml 5.0.0 is starting to take shape.

  I am thus happy to announce an exceptional zeroth alpha release of
  OCaml 5.0.0 (see below for the installation instructions).

  This alpha release is expected to be rougher than an usual alpha
  release, due to the full rewrite of the OCaml runtime. In particular,
  the bytecode debugger will only be available in the next alpha
  release. Similarly, there will be some changes to the internal C
  runtime API and to the files installed by the compiler package in the
  next alpha release.

  Moreover, this zeroth alpha release is the occasion to remind everyone
  that OCaml 5.0 itself is expected to be a more experimental release
  than usual. Notably, the native compiler will only be available on the
  ARM64 and x86-64 architectures in this 5.0 release.

  Nevertheless, this zeroth alpha version is already stable enough for
  fellow hackers eager to join us in our early bug hunting and opam
  ecosystem fixing fun, or to venture in the new era of parallelism and
  (experimental) effects.

  You can follow the progresses in stabilising the opam ecosystem on

  <https://github.com/ocaml/opam-repository/issues/21526>

  A brief summary is that at least dune, merlin, ppxlib, utop,
  ocamlfind, and ocamlbuild work (potentially by using patches from the
  alpha opam repository).

  If you find any bugs, please report them here:

  <https://github.com/ocaml/ocaml/issues>

  In particular, any sequential OCaml 4 library or program should be
  valid in OCaml 5 (except for deprecated modules and functions). Please
  don't hesitate to report any compatibility bugs!

  If you are interested by the ongoing list of bug fixes, the updated
  change log for OCaml 5.0.0 is available at:

  <https://github.com/ocaml/ocaml/blob/5.0/Changes>


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
  The base compiler can be installed as an opam switch with the
  following commands on opam 2.1:
  ┌────
  │ opam update
  │ opam switch create 5.0.0~alpha0
  └────
  For previous version of opam, the switch creation command line is
  slightly more verbose:
  ┌────
  │ opam update
  │ opam switch create 5.0.0~alpha0 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:
  ┌────
  │ opam update
  │ opam switch create <switch_name> ocaml-variants.5.0.0~alpha0+options <option_list>
  └────
  where `<option_list>' is a comma separated list of `ocaml-option-*'
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 5.0.0~alpha0+flambda+nffa ocaml-variants.5.0.0~alpha0+options ocaml-option-flambda
  │ ocaml-option-no-flat-float-array
  └────
  The command line above is slightly more complicated for an opam
  version anterior to opam 2.1:
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.5.0.0~alpha0+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  In both cases, all available options can be listed with `opam search
  ocaml-option'.

  If you want to test this version, it is strongly advised to install
  the alpha opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This alpha repository contains various fixes in the process of being
  upstreamed.

  The source code for the alpha is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/5.0.0-alpha0.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-5.0/ocaml-5.0.0~alpha0.tar.gz>


Daniel Bünzli asked and octachron replied
─────────────────────────────────────────

        Does this mean we get [global warming] again ?

  Indeed! I should have mentioned that point! The normal development
  process can restart on the compiler development branch.

  I will also try to slowly go through the backlog of frozen PRs once
  the alpha releases settle down.


[global warming]
<https://discuss.ocaml.org/t/the-road-to-ocaml-5-0/8584#the-sequential-glaciation-3>


Tezt, a framework for all your tests
════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-tezt-a-framework-for-all-your-tests/10038/1>


rbardou announced
─────────────────

  Tezt (pronounced [/tɛzti/]) is a test framework for OCaml that has
  been developed and used at Nomadic Labs to test [Octez], an OCaml
  implementation of the Tezos blockchain. It has become quite mature and
  we feel it would benefit the OCaml community at large, so we are
  releasing it publicly as a standalone product.

  Tezt is well-suited for unit tests, integration tests, and regression
  tests in particular. It was designed with a focus on user experience,
  with colourful logs, various ways to select the tests to run from the
  command-line, and more. It integrates well into CI pipelines. And it
  cleans up after itself, deleting temporary files and killing external
  processes. Unless you tell it not to, of course.

  For a more in-depth tour of Tezt, see [our latest blog post entry].

  Tezt is available on opam:
  ┌────
  │ opam install tezt
  └────
  Have a look at the [API documentation] and the [source code].


[/tɛzti/] <http://ipa-reader.xyz/?text=t%C9%9Bzti>

[Octez]
<https://research-development.nomadic-labs.com/announcing-octez.html>

[our latest blog post entry]
<https://research-development.nomadic-labs.com/announcing-tezt.html>

[API documentation]
<https://tezos.gitlab.io/api/odoc/_html/tezt/Tezt/index.html>

[source code] <https://gitlab.com/tezos/tezos/-/tree/master/tezt/lib>


OCaml Stdlib, Containers, Batteries, Base and F# core functions comparisons
═══════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-stdlib-containers-batteries-base-and-f-core-functions-comparisons/10041/1>


Jp R announced
──────────────

  <https://github.com/Fourchaux/OCaml-Stdlib_Containers_Batteries_Base-and-FSharp--core-functions-comparisons>

  Comparisons (names/signatures) of the core functions used in:

  • OCaml Stdlib (v4.41.0)
  • Containers (v3.8)
  • Batteries (v3.5.1)
  • Base (v0.15.0)
  • F# (v6.0) as a bonus

  Note: F# provides an Array.Parallel module with some functions
   (choose, collect, init, iter, iteri, map, mapi, partition) which
   could be good candidates for OCaml 5.0.0…


Dune 3.3.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-3-0/10048/1>


Etienne Millon announced
────────────────────────

  On behalf of the dune team, I’m pleased to announce the release of
  version 3.3.0. This is the first version that supports the upcoming
  OCaml 5.0. It also improves safety by sandboxing more rules and
  enabling more warnings, and there's a bunch of new features on the coq
  side too. Full changelog follows.

  Note that as usual, dune works hard not to break existing packages. So
  even if it mentions that rules require precise dependencies, for
  example, this new safety net is only enabled for project that use
  `(lang dune 3.3)'.

  Happy hacking.


3.3.0 (17-06-2022)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Sandbox preprocessing, lint, and dialect rules by default. All these
    rules now require precise dependency specifications (#5807,
    @rgrinberg)

  • Allow list expansion in the `pps' specification for preprocessing
    (#5820, @Firobe)

  • Add warnings 67-69 to dune's default set of warnings. These are
    warnings of the form "unused X.." (#5844, @rgrinberg)

  • Introduce project "composition" for coq theories. Coq theories in
    separate projects can now refer to each other when in the same
    workspace (#5784, @Alizter, @rgrinberg)

  • Fix hint message for `data_only_dirs' that wrongly mentions the
    unknown constructor `data_only' (#5803, @lambdaxdotx)

  • Fix creating sandbox directory trees by getting rid of buggy
    memoization (#5794, @rgrinberg, @snowleopard)

  • Handle directory dependencies in sandboxed rules. Previously, the
    parents of these directory dependencies weren't created. (#5754,
    @rgrinberg)

  • Set the exit code to 130 when dune is terminated with a signal
    (#5769, fixes #5757)

  • Support new locations of unix, str, dynlink in OCaml >= 5.0 (#5582,
    @dra27)

  • The `coq.theory' stanza now produces rules for running
    `coqdoc'. Given a theory named `mytheory', the directory targets
    `mytheory.html/' and `mytheory.tex/' or additionally the aliases
    `@doc' and `@doc-latex' will build the HTML and LaTeX documentation
    repsectively. (#5695, fixes #3760, @Alizter)

  • Coq theories marked as `(boot)' cannot depend on other theories
    (#5867, @ejgallego)

  • Ignore `bigarray' in `(libraries)' with OCaml >= 5.0. (#5526, fixes
    #5494, @moyodiallo)

  • Start with :standard when building the ctypes generated foreign
    stubs so that we include important compiler flags, such as -fPIC
    (#5816, fixes #5809).


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-06-14  9:29 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-06-14  9:29 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of June 07 to 14,
2022.

Table of Contents
─────────────────

Lwt informal user survey
Tutorial: Full-Stack Web Dev in OCaml w/ Dream, Bonsai, and GraphQL
dkml-c-probe: Cross-compiler friendly definitions for C compiling
Htmx/hc web development approach
Engineer and postdoc positions in France (various labs) to work on a proof assistant for crypto protocols
Yojson 2.0.0
opentelemetry 0.2
omake-0.10.5
findlib-1.9.5
Old CWN


Lwt informal user survey
════════════════════════

  Archive: <https://discuss.ocaml.org/t/lwt-informal-user-survey/9666/3>


Continuing this thread, Raphaël Proust said
───────────────────────────────────────────

  Thanks to everyone who took the time to answer the polls above. I've
  now closed them.

  The first pull-request to come out of this poll is
  [<https://github.com/ocsigen/lwt/pull/947>](removing support for
  OCaml<=4.07). This was the cutoff in the poll. It removes a lot of
  `#if' preprocessing statements and a few workarounds to stay
  compatible with old Stdlib interfaces. Thanks to @hannes for
  contributing most of the commits on this pull-request.  If support for
  OCaml<=4.07 is important to you, please participate in the
  pull-request's discussion or on this thread.

  Stay tuned for more. (But also be patient.)


Tutorial: Full-Stack Web Dev in OCaml w/ Dream, Bonsai, and GraphQL
═══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/tutorial-full-stack-web-dev-in-ocaml-w-dream-bonsai-and-graphql/9963/20>


Continuing this thread, jerben asked and Daniel Bünzli replied
──────────────────────────────────────────────────────────────

        Very interesting, did you write somewhere about how it
        compares to htmx?

  Not really.

  As far as I can remember I liked the ideas but found their execution
  to be a bit lacking, sometimes ad-hoc in their attribute DSL, focusing
  more on the show off to convince single page application proponents of
  the approach than on a clear conceptual model (which `hc' tries to
  detail in the manual [here]).

  Two other things that come to mind are:

  1. AFAIR their examples relied a lot on unique `id' attributes for
     targeting request results. Unless you find a principled and
     automated way to generate these that's not compositional and
     brittle. In `hc' I [extended the CSS selector syntax] to allow to
     address your ancestors (peace be upon them). That's more
     compositional but now you become sensitive to structural changes in
     your markup – pick your poison[^1].
  2. I'm no longer sure about that, i.e. don't take my word for it, but
     I think their DSL allowed to spread the definition of an
     interaction among many elements which made it more difficult to
     understand what is happening. In `hc' all attributes defining the
     effects of an interaction are always located on a single element,
     the element that performs the request.

  Finally when things go wrong I prefer to have to understand [700 lines
  of ml] rather than [2800 lines of JavaScript] (note that they likely
  have better legacy browser support and more functionality).

  In any case there's a long list of todos in `hc' and it likely needs
  one or two more design rounds before getting to something decent – if
  that's even remotely possible on the web.

        Dang it @dbuenzli one day you’ll run out of letters and
        need to come up with an actual name for your libraries.

  Mind you I tried to use three letters once, but the whole experience
  turned out to be [extremely unpleasant] :–)

  [^1]: Using unique ids reifed in an OCaml EDSL could be a better idea.


[here] <https://erratique.ch/software/hc/doc/manual.html#request>

[extended the CSS selector syntax]
<https://erratique.ch/software/hc/doc/manual.html#selector>

[700 lines of ml]
<https://github.com/dbuenzli/hc/blob/master/src/hc_page.ml>

[2800 lines of JavaScript]
<https://github.com/bigskysoftware/htmx/blob/master/src/htmx.js>

[extremely unpleasant]
<https://github.com/dbuenzli/rel/commit/f95b6bad02a8080eb64f8d0123cd63d40b528e33>


dkml-c-probe: Cross-compiler friendly definitions for C compiling
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-dkml-c-probe-cross-compiler-friendly-definitions-for-c-compiling/9950/8>


jbeckford announced
───────────────────

  V3 is available. Its `C_abi' module has some big enhancements:
  • cleaner API (thanks @mseri!)
  • recognizes the BSD family: OpenBSD, FreeBSD, NetBSD and DragonFly on
    x86_64 hardware
  • integration testing now includes OpenBSD, FreeBSD and one
    cross-compiling toolchain (macOS x86_64 host that targets arm64)

  V3 also has a new module `C_conf' which occupies the same problem
  space as `findlib / ocamlfind' and `pkg-config':
  • Unlike `findlib' which is a specification+tool for 3rd party OCaml
    libraries, `C_conf' is a specification+tool for foreign C libraries
  • Unlike `pkg-config' which is a specification+tool for system (host
    ABI) C libraries, `C_conf' is a specification+tool for the multiple
    ABIs that are present when you cross-compile OCaml or C code
  • Unlike `pkg-config' which is designed for Unix, `C_conf' is designed
    for Windows and Unix where paths may have spaces, backslashes and
    colons
  • For now the specification is based on environment variables. If it
    proves useful the specification can be extended.

  Examples and doc links for V3 are available at
  [https://github.com/diskuv/dkml-c-probe#dkml-c-probe]


[https://github.com/diskuv/dkml-c-probe#dkml-c-probe]
<https://github.com/diskuv/dkml-c-probe#dkml-c-probe>


Marcello Seri asked and jbeckford replied
─────────────────────────────────────────

        Thanks a lot for the update! Can you say a bit more about
        how `C_conf' works?

  C_conf has a detailed problem statement and spec at
  <https://diskuv.github.io/dkml-c-probe/dkml-c-probe/Dkml_c_probe/C_conf/index.html>
  (which is linked to on the dkml-c-probe README).

  I probably shouldn't regurgitate the doc here, so I'll take a few key
  pieces from the doc and then post some things here that I didn't put
  on that doc page …

  1. Here is my configuration for locating the "gmp" library on my Apple
     Silicon host machine that cross-compiles to x86_64:

     ┌────
     │ CP_GMP_CC_DEFAULT                 = -IZ:/build/darwin_arm64/vcpkg_installed/arm64-osx/include
     │ CP_GMP_CC_DEFAULT_DARWIN_X86_64   = -IZ:/build/darwin_x86_64/vcpkg_installed/x64-osx/include
     │ CP_GMP_LINK_DEFAULT               = -LZ:/build/darwin_arm64/vcpkg_installed/arm64-osx/lib;-lgmp
     │ CP_GMP_LINK_DEFAULT_DARWIN_X86_64 = -LZ:/build/darwin_x86_64/vcpkg_installed/x64-osx/lib;-lgmp
     └────

     • The other direction may be more interesting, since the free
       GitHub Actions only supports x86_64. The scenario of taking a
       macOS x86_64 GitHub host and cross-compiling to Apple Silicon is
       [implemented and partially tested].
  2. I am using a C package manager (vcpkg) to give me cross-compiled
     libraries and the flags for the target ABI (in this case
     darwin_x86_64 is the target ABI). In general it doesn't matter
     where you get your target ABI compatible libraries from. Example:
     When I'm cross-compiling to Android on a Windows x86_64 host, the
     Android Studio environment gives me some libraries for an Android
     Emulator (host ABI) and also prebuilt libraries for 4 Android
     device ABIs:

     ┌────
     │ Directory: C:\Users\xxx\AppData\Local\Android\Sdk\ndk\23.1.7779620\prebuilt
     │ 
     │ Mode                 LastWriteTime         Length Name
     │ ----                 -------------         ------ ----
     │ d-----        10/20/2021   8:27 PM                android-arm
     │ d-----        10/20/2021   8:27 PM                android-arm64
     │ d-----        10/20/2021   8:27 PM                android-x86
     │ d-----        10/20/2021   8:26 PM                android-x86_64
     │ d-----        10/20/2021   8:27 PM                windows-x86_64
     └────
  3. The `CP_clibrary_CC_DEFAULT_abi' configuration relies on `abi' (the
     ocamlfind toolchain name) being standardized. The `gmp' library,
     for example, is used by many OCaml packages; I wanted one
     configuration for `gmp', not one configuration for each `(gmp,
     OCaml package)' combination. In fact, getting a consistent `abi'
     naming was one of my motivations for releasing `dkml-c-probe'. I
     don't think the prior art got this right … the very stale
     [opam-cross-android] project uses [`abi = "android"'] which is
     insufficient to differentiate the 5+ sets of libraries available in
     Android Studio.
  4. The "gmp" (etc.) configuration is done once in a familiar syntax
     (`-L, -I, -l'). However the `C_conf' library will parse and print
     the configuration in the appropriate C compiler syntax. When the
     MSVC compiler is used you get MSVC style linking:
     ┌────
     │ [
     │   "-LIBPATH:Z:/build/darwin_x86_64/vcpkg_installed/x64-osx/lib";
     │   "gmp.lib"
     │ ]
     └────
     MSVC and GCC conventions are supported today in `C_conf'.
  5. A real example of using `C_conf' is in my customization of [zarith
     library]. It checks `C_conf' first to see whether the user has the
     host/target ABI configuration; if it doesn't it falls back to
     pkg-config.

  The trend of using `pkg-config' in OCaml packages makes both native
  Windows and cross-compilation difficult. At the moment *we
  unintentionally shoot ourselves in the foot* because [Dune
  documentation encourages `pkg-config'] for understandable reasons. I
  hope `dkml-c-probe' can break that trend.


[implemented and partially tested]
<https://github.com/diskuv/dkml-c-probe/blob/2c1e90b4eea119348d6dae37d64949041ef9eaeb/.github/workflows/test.yml#L299-L379>

[opam-cross-android] <https://github.com/ocaml-cross/opam-cross-android>

[`abi = "android"']
<https://github.com/ocaml-cross/opam-cross-android#porting-packages>

[zarith library]
<https://github.com/jonahbeckford/Zarith/blob/a1bf6d55cd3c4b91dee0afb2309ef11271e9729b/discover.ml>

[Dune documentation encourages `pkg-config']
<https://dune.readthedocs.io/en/stable/dune-libs.html#configurator-1>


Htmx/hc web development approach
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/htmx-hc-web-development-approach/9993/11>


Vladimir Keleshev announced asked
─────────────────────────────────

  @cemerick, @yawaramin, @dbuenzli, and others who've used htmx/hc with
  OCaml back-end: what is your experience with templating? It seems that
  htmx/hc puts high requirements on a flexible HTML templating/DSL. What
  did you choose and is it working out for you?


Daniel Bünzli replied
─────────────────────

  I'm using OCaml and an absolutely [trivial HTML generation
  library]. If you want to see a real world example head to the
  `*_html.{ml,mli}' files in [this directory] (more on the structure
  found there [here])

  Works quite well for me but I'd say the problem is not really
  templating it's rather non-brittle URL management. For that I use
  [this module] which while I'm not entirely convinced by it yet, allows
  me to type them and avoid the stringly unchecked dependendencies so
  characteristic of the web development world.


[trivial HTML generation library]
<https://erratique.ch/software/webs/doc/Webs_html/index.html>

[this directory]
<https://github.com/dbuenzli/hyperbib/tree/master/src/service>

[here]
<https://github.com/dbuenzli/hyperbib/blob/master/DEVEL.md#cli-tool-and-backend>

[this module]
<https://erratique.ch/software/webs/doc/Webs_kit/Kurl/index.html>


Chas Emerick also replied
─────────────────────────

  Yeah, you're right on that point.

  I'm using tyxml for 99% of my HTML generation, specifically its jsx
  ppx. I am judicious about keeping the main logics of the project in
  OCaml proper; `.re' files exist exclusively to hold markup. The end
  result is a _very_ pleasant environment IMO. In the end, I dearly wish
  there was a way to get actual HTML syntax into `.ml' files (I am no
  fan of reason syntax outside of jsx, and I suspect the sorta-legacy
  jsx toolchain leftover from reasonml will end up being a tech risk
  over time), but as things stand, it's the best option I've found.


Yawar Amin also replied
───────────────────────

  I'm just using Dream's 'built-in' templating, 'Embedded ML (.eml)', it
  works reasonably well–each template or partial is just a function that
  you define to take some arguments and return some markup. It even
  auto-escapes to prevent injection attacks. E.g.,

  ┌────
  │ let card name =
  │   <div class="card"><%s name %></div>
  └────

  There are a couple of tricks to be aware of with the EML syntax but in
  general it works well.


Simon Cruanes also replied
──────────────────────────

  For the little webdev I do (internal tools mostly for myself), I've
  also been using server side html generation, with my own `wheels'
  tools and a bit of htmx.

  Here's an excerpt from a personal project, with my own httpd and html
  combinators; it adds a root to handle `/thy/<some string>':

  ┌────
  │ let h_thy (self:state) : unit =
  │   H.add_route_handler self.server
  │     H.Route.(exact "thy" @/ string_urlencoded @/ return) @@ fun thy_name req ->
  │   let@ () = top_wrap_ req in
  │   let thy = Idx.find_thy self.st.idx thy_name in
  │   let res =
  │     let open Html in
  │     [
  │       div[cls "container"][
  │ 	h3[][txtf "Theory %s" thy_name];
  │ 	Thy_file.to_html thy;
  │ 	div [
  │ 	  "hx-trigger", "load";
  │ 	  "hx-get", (spf "/eval/%s" @@ H.Util.percent_encode thy_name);
  │ 	  "hx-swap", "innerHtml"] [
  │ 	  span[cls "htmx-indicator"; A.id "ind"][
  │ 	    txt "[evaluating…]";
  │ 	  ]
  │ 	];
  │       ]
  │     ]
  │   in
  │   reply_page ~title:(spf "theory %s" thy_name) req res
  └────


Engineer and postdoc positions in France (various labs) to work on a proof assistant for crypto protocols
═════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/engineer-and-postdoc-positions-in-france-various-labs-to-work-on-a-proof-assistant-for-crypto-protocols/9999/1>


David Baelde announced
──────────────────────

  We are looking for engineers and postdocs to work on Squirrel, a proof
  assistant dedicated to proving cryptographic protocols. We have a
  broad range of projects in mind, ranging from pure OCaml development
  to involved protocol formalizations, with several theoretical
  questions in between. If you'd like to work on some of these aspects
  for one or more years, please get in touch with us!

  More details can be found here:

  <https://squirrel-prover.github.io/positions.pdf>


Yojson 2.0.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-yojson-2-0-0/10003/1>


Marek Kubica announced
──────────────────────

  This Friday, it is my pleasure to announce the release of Yojson
  2.0.0. You can get it [in your local OPAM repository].

  Key highlights include:

  • Fewer dependencies: Given Yojson is a common dependency we cut down
    on its dependencies so you have to install less and have less
    transitive dependencies
  • `Seq' interface: Since OCaml 4.14 deprecates `Stream' and 5.0
    removes it, this was a good time to change to this interface
  • `Buffer' interface: coming along with #1, we changed Yojson to use
    `Buffer' wherever it was using `Biniou' types before

  Thanks to everybody involved in this release!

  If Yojson sounds like an interesting project for you to contribute,
  [join us].

  Full changelog follows:


[in your local OPAM repository]
<https://opam.ocaml.org/packages/yojson/>

[join us] <https://github.com/ocaml-community/yojson>

2.0.0
╌╌╌╌╌

  *2022-06-02*


Removed
┄┄┄┄┄┄┄

  • Removed dependency on easy-format and removed `pretty_format' from
    `Yojson', `Yojson.Basic', `Yojson.Safe' and `Yojson.Raw'. (@c-cube,
    #90)
  • Removed dependency on `biniou', simplifying the chain of
    dependencies. This changes some APIs:
    ‣ `Bi_outbuf.t' in signatures is replaced with `Buffer.t'
    ‣ `to_outbuf' becomes `to_buffer' and `stream_to_outbuf' becomes
      `stream_to_buffer'
    (@Leonidas, #74, and @gasche, #132)
  • Removed `yojson-biniou' library
  • Removed deprecated `json' type aliasing type `t' which has been
    available since 1.6.0 (@Leonidas, #100).
  • Removed `json_max' type (@Leonidas, #103)
  • Removed constraint that the "root" value being rendered (via either
    `pretty_print' or `to_string') must be an object or
    array. (@cemerick, #121)
  • Removed `validate_json' as it only made sense if the type was called
    `json'.  (@Leonidas, #137)


Add
┄┄┄

  • Add an opam package `yojson-bench' to deal with benchmarks
    dependency (@tmcgilchrist, #117)
  • Add a benchmark to judge the respective performance of providing a
    buffer vs letting Yojson create an internal (#134, @Leonidas)
  • Add an optional `suf' keyword argument was added to functions that
    write serialized JSON, thus allowing NDJSON output. Most functions
    default to not adding any suffix except for `to_file' (#124,
    @panglesd) and functions writing sequences of values where the
    default is `\n' (#135, @Leonidas)


Change
┄┄┄┄┄┄

  • The `stream_from_*' and `stream_to_*' functions now use a `Seq.t'
    instead of a `Stream.t', and they are renamed into `seq_from_*' and
    `seq_to_*' (@gasche, #131).


Fix
┄┄┄

  • Avoid copying unnecessarily large amounts of strings when parsing
    (#85, #108, @Leonidas)
  • Fix `stream_to_file' (#133, @tcoopman and @gasche)


opentelemetry 0.2
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-opentelemetry-0-2/10005/1>


Simon Cruanes announced
───────────────────────

  It is my pleasure to announce the release of [ocaml-opentelemetry]
  0.2. This library provides a core instrumentation library, as well as
  exporters, for the [opentelemetry] standard for observability; it
  encompasses distributed tracing, metrics, and (more recently) log
  export. A lot of tools are compatible with opentelemetry these days,
  including Grafana, DataDog, jaeger, etc.

  This is still very early days for ocaml-opentelemetry, feedback and
  contributions are welcome.


[ocaml-opentelemetry]
<https://github.com/imandra-ai/ocaml-opentelemetry>

[opentelemetry] <https://opentelemetry.io/>


omake-0.10.5
════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-06/msg00012.html>


Gerd Stolpmann announced
────────────────────────

  I just released omake-0.10.5, the build utility, which fixes the
  broken installation of version 0.10.4 from last week.

  For docs and the download link see
  <http://projects.camlcity.org/projects/omake.html>. opam is underway.


findlib-1.9.5
═════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-06/msg00012.html>


Gerd Stolpmann announced
────────────────────────

  findlib-1.9.5 is out, fixing some scripting errors in the version
  1.9.4 from last week.

  For manual, download, manuals, etc. see here:

  <http://projects.camlcity.org/projects/findlib.html>

  An updated OPAM package will follow soon.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-06-07 10:15 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-06-07 10:15 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 23518 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of May 31 to June 07,
2022.

Table of Contents
─────────────────

carray.0.0.1
ML Family Workshop 2022: Final Call for Presentations
OCaml Users and Developers Workshop 2022
dkml-c-probe.2.0.0: Cross-compiler friendly definitions for C compiling
Full-Stack Web Dev in OCaml Tutorial w/ Dream, Bonsai, and GraphQL
Sketch.sh now supports multiple compiler versions, starting with 4.13.1
Explicit type binding and mutual recursion
findlib-1.9.4
omake-0.10.4
Old CWN


carray.0.0.1
════════════

  Archive: <https://discuss.ocaml.org/t/ann-carray-0-0-1/9938/6>


Deep in this threas, Fabian said
────────────────────────────────

  Note that you can, to a certain degree, build your own flat structures
  with the `Bytes' module. Compared to bigarrays, `Bytes.t' has less
  indirection, a lower constant memory overhead and can be allocated on
  the minor heap. The contents of `Bytes.t' are not scanned by the GC,
  just like bigarrays.

  For example, a more efficient `int32 Array.t':

  ┌────
  │ module Int32_array : sig
  │   type t
  │   val equal : t -> t -> bool
  │   val create : int -> t
  │   val length : t -> int
  │   val get : t -> int -> int32
  │   val set : t -> int -> int32 -> unit
  │   val sub : t -> int -> int -> t
  │   val to_list : bytes -> int32 list
  │ end = struct
  │   type t = Bytes.t
  │   let equal = Bytes.equal
  │   let create len = Bytes.create (4 * len)
  │   let length t = Bytes.length t / 4
  │   let get t i = Bytes.get_int32_le t (4 * i)
  │   let set t i x = Bytes.set_int32_le t (4 * i) x
  │   let sub t pos len = Bytes.sub t (4 * pos) (4 * len)
  │   let to_list t = List.init (length t) (get t)
  │ end
  └────

  A more efficient `(int * int)':

  ┌────
  │ module Point : sig
  │   type t
  │   val create : int -> int -> t
  │   val x : t -> int
  │   val y : t -> int
  │ end = struct
  │   external get_int64_unsafe : bytes -> int -> int64 = "%caml_bytes_get64u"
  │   external set_int64_unsafe : bytes -> int -> int64 -> unit = "%caml_bytes_set64u"
  │   type t = Bytes.t
  │   let create x y =
  │     let p = Bytes.create 16 in
  │     set_int64_unsafe p 0 (Int64.of_int x);
  │     set_int64_unsafe p 8 (Int64.of_int y);
  │     p
  │   let x t = Int64.to_int (get_int64_unsafe t 0)
  │   let y t = Int64.to_int (get_int64_unsafe t 8)
  │ end
  └────

  (making a more efficient `(int * int) Array.t' is left as an exercise
  to the reader)

  The downside compared to bigarrays is that it doesn't support `sub'
  without copying. Also, bytes can be moved by the GC (during minor GCs
  or compaction), and therefore you cannot release the runtime lock when
  passing them to C. The latter point is less relevant with the
  multicore extensions, especially since there is no compactor
  yet. There is some related discussion on the eio repository:
  <https://github.com/ocaml-multicore/eio/issues/140>


ML Family Workshop 2022: Final Call for Presentations
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ml-family-workshop-2022-final-call-for-presentations/9877/2>


Benoit Montagu announced
────────────────────────

ML Family Workshop 2022: DEADLINE EXTENSION
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  To increase your chances of submitting your work to the ML workshop,
  *the submission deadline is extended by a week*.  The new deadline is
  Friday 10th June (AoE).

  A quick reminder:
  • The workshop does not have proceedings, making it the perfect venue
    to run some ideas with the community or present some work in
    progress within a friendly environment.
  • The work load as an author is low: submissions are only 3 pages long
    (excluding references)
  • YOU have the power to make the ML workshop a success!
  • You have one more full week to submit to
    <https://ml2022.hotcrp.com/> (please register your submission
    early!)
  • All the details are here:
    <https://icfp22.sigplan.org/home/mlfamilyworkshop-2022#Call-for-Presentations>
  • The ML workshop is colocated with ICFP 2022
    <https://icfp22.sigplan.org/>


OCaml Users and Developers Workshop 2022
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-users-and-developers-workshop-2022/9726/4>


Matija Pretnar announced
────────────────────────

  To offer additional opportunities to contribute to the OCaml workshop,
  and to align with the [ML family workshop], to which you are also
  cordially invited, the submission deadline has been extended by a week
  to *Friday, June 10* (anywhere on Earth).


[ML family workshop]
<https://icfp22.sigplan.org/home/mlfamilyworkshop-2022#Call-for-Presentations>


dkml-c-probe.2.0.0: Cross-compiler friendly definitions for C compiling
═══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-dkml-c-probe-2-0-0-cross-compiler-friendly-definitions-for-c-compiling/9950/1>


jbeckford announced
───────────────────

  Summary: dkml-c-probe is a new package for maintainers who compile or
  link C code. Install it with `opam install dkml-c-probe'. Full docs
  are at [https://github.com/diskuv/dkml-c-probe#readme]


[https://github.com/diskuv/dkml-c-probe#readme]
<https://github.com/diskuv/dkml-c-probe#readme>

Problem
╌╌╌╌╌╌╌

  You are creating an OCaml package that has foreign C code. Perhaps you
  need special C headers or libraries when you are targeting Apple
  users, or perhaps you need to execute custom OCaml code for Android
  users. More generally you need a way to determine whether your OCaml
  or C code is compiling for a Linux AMD/Intel 64-bit, Android ARM
  32-bit, or any other ABI target.


Solution
╌╌╌╌╌╌╌╌

  A user of your OCaml package may, for example, be on a 64-bit
  AMD/Intel Linux machine using a 32-bit OCaml system compiled with `gcc
  -m32'; additionally they have a 32-bit Android ARM cross-compiler
  toolchain. `dkml-c-probe' will tell you the target operating system is
  `Linux' and the target ABI is `Linux_x86' except when the
  cross-compiler toolchain is invoked. With the cross-compiler toolchain
  `dkml-c-probe' will tell you the target operating system is `Android'
  and the target ABI is `Android_arm32v7a'.


How it works
╌╌╌╌╌╌╌╌╌╌╌╌

  `dkml-c-probe' uses C preprocessor definitions (ex. `#if
  TARGET_CPU_X86_64', `#if __ANDROID__', etc.) to determine which ABI
  the C compiler (ex. `ocamlopt -config | grep native_c_compiler') is
  targeting.

  This isn't a new idea. The pattern is used in Esy and Mirage code as
  well. `dkml-c-probe' just codifies the pattern for use in your own
  code.


Usage
╌╌╌╌╌

  In OCaml code you can use the /versioned/ module:

  ┌────
  │ module V2 :
  │   sig
  │     type t_os = Android | IOS | Linux | OSX | Windows
  │     type t_abi =
  │ 	Android_arm64v8a
  │       | Android_arm32v7a
  │       | Android_x86
  │       | Android_x86_64
  │       | Darwin_arm64
  │       | Darwin_x86_64
  │       | Linux_arm64
  │       | Linux_arm32v6
  │       | Linux_arm32v7
  │       | Linux_x86_64
  │       | Linux_x86
  │       | Windows_x86_64
  │       | Windows_x86
  │       | Windows_arm64
  │       | Windows_arm32
  │     val get_os : (t_os, Rresult.R.msg) result Lazy.t
  │     val get_abi : (t_abi, Rresult.R.msg) result Lazy.t
  │     val get_abi_name : (string, Rresult.R.msg) result Lazy.t
  │   end
  └────

  In C code you can use the [provided `dkml_compiler_probe.h' header]
  from within Dune or Opam. Here is a snippet that handles part of the
  Linux introspection:

  ┌────
  │ #elif __linux__
  │ #   if __ANDROID__
  │ #       ...
  │ #   else
  │ #       define DKML_OS_NAME "Linux"
  │ #       define DKML_OS_Linux
  │ #       if __aarch64__
  │ #           define DKML_ABI "linux_arm64"
  │ #           define DKML_ABI_linux_arm64
  │ #       elif __arm__
  │ #           if defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) ||
  │ defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) ||
  │ defined(__ARM_ARCH_6T2__)
  │ #               define DKML_ABI "linux_arm32v6"
  │ #               define DKML_ABI_linux_arm32v6
  │ #           elif defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) ||
  │ defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
  │ #               define DKML_ABI "linux_arm32v7"
  │ #               define DKML_ABI_linux_arm32v7
  │ #           endif /* __ARM_ARCH_6__ || ...,  __ARM_ARCH_7__ || ... */
  │ #       elif __x86_64__
  │ #           define DKML_ABI "linux_x86_64"
  │ #           define DKML_ABI_linux_x86_64
  │ #       elif __i386__
  │ #           define DKML_ABI "linux_x86"
  │ #           define DKML_ABI_linux_x86
  │ #       elif defined(__ppc64__) || defined(__PPC64__)
  │ #           define DKML_ABI "linux_ppc64"
  │ #           define DKML_ABI_linux_ppc64
  │ #       elif __s390x__
  │ #           define DKML_ABI "linux_s390x"
  │ #           define DKML_ABI_linux_s390x
  │ #       endif /* __aarch64__, __arm__, __x86_64__, __i386__, __ppc64__ || __PPC64__,
  │ __s390x__ */
  └────


[provided `dkml_compiler_probe.h' header]
<https://github.com/diskuv/dkml-c-probe#c-header>


Versioning and Contributing
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Whenever a new ABI is added, it goes into a new version (ex. `module
  V3'). Your existing code that uses `module V2' will be unaffected.

  But each new ABI needs to have its own maintainer because I don't have
  access to every hardware platform on the planet!

  For example, PowerPC (`ppc64') and Linux on IBM Z (`s390x') are
  supported in the C Header but not the OCaml module because there are
  no PowerPC and S390x maintainers.

  Please consider contributing, especially if you want others to have an
  easier compilation story for your favorite hardware platform.


Full-Stack Web Dev in OCaml Tutorial w/ Dream, Bonsai, and GraphQL
══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/full-stack-web-dev-in-ocaml-tutorial-w-dream-bonsai-and-graphql/9963/1>


Alexander (Sasha) Skvortsov announced
─────────────────────────────────────

  Hi everyone! I’ve written a tutorial blog series about full-stack web
  development in OCaml, and wanted to share it here.

  Last semester, I took Penn State's [CMPSC 431W], where our final
  project was to build a database-driven web application. Since I'm
  fairly familiar with web programming through my work on [Flarum] and
  past internships/side projects, I decided to use this opportunity to
  explore the OCaml web development ecosystem. I used [Dream] for the
  backend, and [Bonsai] for the frontend.

  While working on this project, I realized two things:

  • OCaml is very underrated for web development. In addition to all the
    language’s great features and safety guarantees, the ecosystem is
    pretty good! Dream near-perfectly coincides with my vision of
    backend webdev, and Bonsai has a great balance of
    flexibility/elegance and safety.
  • I couldn’t find realistic but accessible full-stack web projects in
    OCaml available for reference. I found [tutorials] for [bits] and
    [pieces], but nothing that connected all the dots.

  I really enjoyed writing an article series on [hardware design with
  OCaml], so I decided to do so for web development as well. In total, I
  wrote 7 articles that walk through my project’s:

  1. [Full-Stack WebDev in OCaml Intro]. This includes some background
     on the project, and instructions for accessing the [live demo].
  2. [Backend WebDev w/ Dream and Caqti].
  3. [Building GraphQL APIs with Dream]
  4. [Setting up Bonsai].
  5. [Understanding Bonsai]. I actually wrote the first draft of this
     before I decided to do a blog, while trying to, well, understand
     Bonsai. It goes over some underlying concepts (SPAs, Frontend State
     Management, Algebraic Effects, Monads), as well as Bonsai’s core
     design.
  6. [Using GraphQL in Bonsai].
  7. [Routing in Bonsai and Project Conclusion].

  Additionally, the [project’s README] has a comprehensive overview of
  the tech stack, folder structure, and usage instructions. It also
  includes some reflections on design decisions and my experience
  working with these libraries.

  I had a lot of fun writing these, and I hope they’re useful to anyone
  considering OCaml for web development. Would be happy to answer any
  questions or comments.


[CMPSC 431W]
<https://bulletins.psu.edu/university-course-descriptions/undergraduate/cmpsc/#:~:text=CMPSC%20431W%3A%20Database%20Management%20Systems>

[Flarum] <https://flarum.org/>

[Dream] <https://aantron.github.io/dream/>

[Bonsai] <https://github.com/janestreet/bonsai>

[tutorials] <https://github.com/paurkedal/ocaml-caqti>

[bits] <https://jsthomas.github.io/ocaml-dream-api.html>

[pieces]
<https://github.com/janestreet/bonsai/blob/master/docs/getting_started/counters.mdx>

[hardware design with OCaml]
<https://discuss.ocaml.org/t/hardcaml-mips-cpu-learning-project-and-blog/8088>

[Full-Stack WebDev in OCaml Intro]
<https://ceramichacker.com/blog/26-1x-full-stack-webdev-in-ocaml-intro>

[live demo] <https://cmpsc431.ceramichacker.com/>

[Backend WebDev w/ Dream and Caqti]
<https://ceramichacker.com/blog/28-2x-backend-webdev-w-dream-and-caqti>

[Building GraphQL APIs with Dream]
<https://ceramichacker.com/blog/29-3x-building-graphql-apis-with-dream>

[Setting up Bonsai]
<https://ceramichacker.com/blog/30-4x-setting-up-bonsai>

[Understanding Bonsai]
<https://ceramichacker.com/blog/31-5x-understanding-bonsai>

[Using GraphQL in Bonsai]
<https://ceramichacker.com/blog/32-6x-using-graphql-in-bonsai>

[Routing in Bonsai and Project Conclusion]
<https://ceramichacker.com/blog/33-77-routing-in-bonsai-and-project-conclusion>

[project’s README] <https://github.com/askvortsov1/nittany_market>


Alexander (Sasha) Skvortsov later added
───────────────────────────────────────

  Also, forgot to mention this originally, but I recommend accessing the
  demo with one of the emails from [this file] or [this file] (all
  passwords are still [here]), as those users can also demo
  create/update functionalities.


[this file]
<https://github.com/askvortsov1/nittany_market/blob/main/data/Local_Vendors.csv>

[this file]
<https://github.com/askvortsov1/nittany_market/blob/main/data/Sellers.csv>

[here]
<https://github.com/askvortsov1/nittany_market/blob/main/data/Users.csv>


Daniel Bünzli replied
─────────────────────

  People who are looking for more lightweight alternatives – and want to
  do web programming without bothering too much about front end insanity
  can have a look at [hc] (yes indeed: sending HTML over `fetch', web
  programming excels at running in circles).

  The front JavaScript for that [CRUD webapp] comes out at 132Ko
  uncompressed without even trying to tweak anything.


[hc] <https://erratique.ch/software/hc>

[CRUD webapp] <https://github.com/dbuenzli/hyperbib>


Sketch.sh now supports multiple compiler versions, starting with 4.13.1
═══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-sketch-sh-now-supports-multiple-compiler-versions-starting-with-4-13-1/9971/1>


Javier Chávarri announced
─────────────────────────

  The interactive OCaml sketchbook [sketch.sh] has now support to store,
  edit and run sketches in different versions of the OCaml compiler.


[sketch.sh] <https://sketch.sh/>

Support for 4.13
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Storing and running sketches using the compiler version 4.13.1 is now
  possible, this functionality has been added to the already existing
  support for version 4.06.1. The Reason parser and formatting tool
  refmt were also updated to a more recent version that supports 4.13.1.

  Here you can see a sketch showcasing the monadic let syntax, using the
  example from the official OCaml docs: [ZipSeq - Sketch.sh].


[ZipSeq - Sketch.sh] <https://sketch.sh/s/8cnNChTTq6IoGeFQarbvN2/>


Existing sketches and forks
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Previously existing sketches remain in 4.06.1, while newly created
  sketches will be on 4.13.1. For now, the only way to "migrate" a
  sketch to the newer version of the compiler is by copying its content
  and pasting it in a new sketch.

  Forked sketches inherit the compiler version of the forked sketch.


Future plans
╌╌╌╌╌╌╌╌╌╌╌╌

  In the future, there are plans to support version 4.14.0 of the
  compiler, and we are considering adding a way so that the version of
  the compiler can be chosen for a given sketch. We are also working on
  migrating the editor UI codebase to a more recent version of
  ReasonReact, and use JSX3 instead of JSX2.


Feature requests and bugs
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Please [let us know] in case you have a feature request, or if you
  encounter any issues or bugs. Also, don't hesitate to reach out via DM
  or any other means if you would like to contribute or participate in
  the project in some way.

  Thanks to [Ahrefs] for supporting an Open Source Day initiative, which
  allowed to allocate time to work on this improvement for sketch.sh,
  and for providing the infrastructure to run the sketch.sh service for
  the community. Thanks as well to the authors and maintainers of the
  OCaml compiler, js_of_ocaml, and ReScript, that sketch.sh relies upon.


[let us know] <https://github.com/Sketch-sh/sketch-sh/issues/new>

[Ahrefs] <https://ahrefs.com/>


Explicit type binding and mutual recursion
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/explicit-type-binding-and-mutual-recursion/9973/3>


Deep in this thread, octachron explained
────────────────────────────────────────

  For most use cases, if you want an explicit annotation for recursive
  function, it will be much simpler to use the `type a. ...' form:
  ┌────
  │ let rec foo: type a. a -> a = fun x -> x
  │ and bar: type a. a -> a = fun x -> foo x
  └────
  This form is a shortcut for both adding an explicit universal
  quantified and and a corresponding locally abstract type (in other
  words ~let f : 'a . …. = fun (type a) -> … ~).

  The root issue with

  ┌────
  │ let rec f (type a) (x:a) = f x
  └────
  is that the locally abstract type `a' is introduced after
  `f'. Moreover, without an explicit type annotation, a recursive
  function like `f' is monomorphic in its body and a monorphic function
  cannot be called on a type that was defined after the function.

  In other words, the issue is that in term of type scopes, the function
  `f' is equivalent to
  ┌────
  │ let f = ref Fun.id
  │ type t = A
  │ let x = !f A
  └────
  which also fails with
  ┌────
  │ Error: This expression has type t but an expression was expected of type 'a
  │        The type constructor t would escape its scope
  └────
  This is why the second solution proposed by @Gopiandcode
  works. Indeed, in

  ┌────
  │ let foo, bar = fun (type a) ->
  │   let rec foo (x: a) : a = x
  │   and bar (x: a) : a = foo x in
  │   foo, bar
  └────
  the type `a' is defined before the recursive functions `foo' and
  `bar', thus `foo a' does not break any scope constraint.


findlib-1.9.4
═════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-06/msg00004.html>


Gerd Stolpmann announced
────────────────────────

  findlib-1.9.4 is out. It mainly includes a change in the configuration
  script needed for OCaml-4-14.

  For manual, download, manuals, etc. see here:

  <http://projects.camlcity.org/projects/findlib.html>

  An updated OPAM package will follow soon.


omake-0.10.4
════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-06/msg00005.html>


Gerd Stolpmann announced
────────────────────────

  I just released omake-0.10.4, the build utility. This finally includes
  the fix for Apple Silicon, but also a couple of small changes (roughly
  everything since PR#100 to PR#146 on GitHub).

  For docs and the download link see
  <http://projects.camlcity.org/projects/omake.html>. opam is underway.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-05-31 12:29 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-05-31 12:29 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of May 24 to 31,
2022.

Table of Contents
─────────────────

carray.0.0.1
OCaml Users and Developers Workshop 2022
Old CWN


carray.0.0.1
════════════

  Archive: <https://discuss.ocaml.org/t/ann-carray-0-0-1/9938/1>


Danny Willems announced
───────────────────────

  I'm glad to announce the first (experimental) release of ocaml-carray,
  a library mocking the Array interface to work with contiguous C array.
  *Disclaimer*: this first version is experimental and must be used with
  caution. A restricted set of values are supported at the moment
  (custom block with no out-of-heap values). Depending on the demand,
  more values might be supported.  Feel free to use this thread to
  suggest ideas, make opinions, etc.

  Repository
        <https://gitlab.com/dannywillems/ocaml-carray>
  License
        [MIT]
  Release
        [0.0.1]
  Documentation
        <https://dannywillems.gitlab.io/ocaml-carray/carray/index.html>
  Nomadic Labs website
        <https://nomadic-labs.com>
  Tezos ZK-rollups repository
        <https://gitlab.com/nomadic-labs/privacy-team>


[MIT]
<https://gitlab.com/dannywillems/ocaml-carray/-/blob/0.0.1/LICENSE>

[0.0.1] <https://gitlab.com/dannywillems/ocaml-carray/-/tags/0.0.1>

Motivation
╌╌╌╌╌╌╌╌╌╌

  OCaml arrays are not always contiguous piece of memory, requiring
  accessing different chunks of memory when accessing individual
  elements. When requiring a value in memory, the CPU will fetch the RAM
  and load not only the particular value but a memory page (a contiguous
  piece of memory) and add it to its cache. The CPU will use its cache
  to load the values in its registers. It is not efficient with large
  OCaml arrays as the CPU will constantly fetch the RAM to load
  different memory pages in its cache.  Also, when using the C FFI, the
  user must know the memory representation of an array and use the non
  user-friendly low-level interface macro `Field'.


This work
╌╌╌╌╌╌╌╌╌

  This library provides a polymorphic interface mocking a subset of the
  `Array' interface to work with contiguous piece of memory. Using the
  library should be as easy as adding `module Array = Carray'.  A C
  macro `Carray_val' is also provided for developers writing bindings
  and requires to simply cast in the underlying C type.  It has also
  been observed sub arrays are sometimes used for read-only
  operations. However, `Array.sub' allocates a fresh copy of the
  requested sub part. `Carray' leverages this memory cost by providing
  noalloc variants, like `sub_noalloc'.


Performances
╌╌╌╌╌╌╌╌╌╌╌╌

  The concept has been tested and used in real world applications like
  the polynomial library used by Nomadic Labs to implement zk-rollups. A
  speed up of around 50% has been observed when using contiguous arrays
  compared to OCaml arrays to compute NTT/FFT.


Usage
╌╌╌╌╌

  This library is *experimental*. Use this library with caution. The
  interface might change in the future.

  ┌────
  │ opam install carray.0.0.1
  └────


OCaml Users and Developers Workshop 2022
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-users-and-developers-workshop-2022/9726/2>


Continuing this thread, Matija Pretnar announced
────────────────────────────────────────────────

  This is a reminder for anyone interested in contributing to OCaml
  Workshop 2022. The deadline has been slightly extended to Friday, June
  3 (anywhere on Earth), which means you have roughly *four days left*
  to prepare your submissions.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-05-24  8:04 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-05-24  8:04 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of May 17 to 24,
2022.

Table of Contents
─────────────────

ML Family Workshop 2022: Final Call for Presentations
Dune 3.2.0
Hardcaml MIPS CPU Learning Project and Blog
A tutorial on parallel programming in OCaml 5
Old CWN


ML Family Workshop 2022: Final Call for Presentations
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ml-family-workshop-2022-final-call-for-presentations/9877/1>


Benoit Montagu announced
────────────────────────

  We are happy to invite submissions to the *ML Family Workshop 2022*,
  to be held during the ICFP conference week on Thursday, September
  15th.

  The ML family workshop warmly welcomes submission touching on the
  programming languages traditionally seen as part of the “ML family”
  (Standard ML, OCaml, F#, CakeML, SML#, Manticore, MetaOCaml, etc.).
  The scope of the workshop includes all aspects of the design,
  semantics, theory, application, implementation, and teaching of the
  members of the ML family. We also encourage presentations from related
  languages (such as Haskell, Scala, Rust, Nemerle, Links, Koka, F*,
  Eff, ATS, etc), to exchange experience of further developing ML ideas.

  The workshop does not have proceedings, making it the perfect venue to
  run some ideas with the community or present some work in progress
  within a friendly environment. The PC has a broad expertise and
  submissions are 3 pages long: when in doubt, just submit!

  Currently, the workshop is scheduled to be an in-person event. We will
  give to the authors of accepted abstracts the opportunity to give
  their talks remotely if necessary, in case they could not travel.

  See the detailed CFP online on the ICFP website:
  <https://icfp22.sigplan.org/home/mlfamilyworkshop-2022#Call-for-Presentations>


Important dates
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Friday 3th June (any time zone): Abstract submission deadline
  • Tuesday 28th June: Author notification
  • Thursday 15th August: ML Family Workshop


Program committee
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Kenichi Asai (Ochanomizu University)
  • Arthur Azevedo de Amorim (Boston University)
  • Dariusz Biernacki (University of Wrocław)
  • Stephen Dolan (Jane Street)
  • Kavon Farvardin (Apple)
  • Armaël Guéneau (Inria)
  • Sam Lindley (University of Edinburgh)
  • Guido Martínez (CIFASIS-CONICET)
  • Keiko Nakata (SAP Innovation Center Potsdam)
  • Lionel Parreaux (Hong Kong University of Science and Technology)
  • Matija Pretnar (University of Ljubljana)
  • Mike Rainey (Carnegie Mellon University)
  • Yann Régis-Gianas (Nomadic Labs)
  • KC Sivaramakrishnan (IIT Madras and Tarides)
  • Ningning Xie (University of Cambridge)

  Chair: Benoît Montagu (Inria)


Submission details
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  See the online CFP for the details on the expected submission format.

  Submissions must be uploaded to the workshop submission website
  <https://ml2022.hotcrp.com/> before the submission deadline.


Dune 3.2.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-2-0/9892/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune team, I'm pleased to announce the availability
  of version 3.2.0. This release contains few new features, but is
  packed with bug fixes and usability improvements. In particular, I'd
  like to point out that we've continued to improve the user experience
  with the watch mode. I encourage you all to try it out if you haven't
  already.

  Happy Hacking.


3.2.0 (17-05-2022)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Fixed `dune describe workspace --with-deps' so that it correctly
    handles Reason files, as well as files any other dialect. (#5701,
    @esope)

  • Disable alerts when compiling code in vendored directories (#5683,
    @NathanReb)

  • Fixed `dune describe --with-deps', that crashed when some
    preprocessing was required in a dune file using `per_module'.
    (#5682, fixes #5680, @esope)

  • Add `$ dune describe pp' to print the preprocssed ast of
    sources. (#5615, fixes #4470, @cannorin)

  • Report dune file evaluation errors concurrently. In the same way we
    report build errors. (#5655, @rgrinberg)

  • Watch mode now default to clearing the terminal on rebuild (#5636,
    fixes, #5216, @rgrinberg)

  • The output of jobs that finished but were cancelled is now
    omitted. (#5631, fixes #5482, @rgrinberg)

  • Allows to configure all the default destination directories with
    `./configure' (adds `bin', `sbin', `data', `libexec'). Use
    `OPAM_SWITCH_PREFIX' instead of calling the `opam' binaries in `dune
    install'. Fix handling of multiple `libdir' in `./configure' for
    handling `/usr/lib/ocaml/' and `/usr/local/lib/ocaml'. In `dune
    install' forbid relative directories in `libdir', `docdir' and
    others specific directory setting because their handling was
    inconsistent (#5516, fixes #3978 and #5455, @bobot)

  • `--terminal-persistence=clear-on-rebuild' will no longer destroy
    scrollback on some terminals (#5646, @rgrinberg)

  • Add a fmt command as a shortcut of `dune build @fmt --auto-promote'
    (#5574, @tmattio)

  • Watch mode now tracks copied external files, external directories
    for dependencies, dune files in OCaml syntax, files used by
    `include' stanzas, dune-project, opam files, libraries builtin with
    compiler, and foreign sources (#5627, #5645, #5652, #5656, #5672,
    #5691, #5722, fixes #5331, @rgrinberg)

  • Improve metrics for cram tests. Include test names in the event and
    add a category for cram tests (#5626, @rgrinberg)

  • Allow specifying multiple licenses in project file (#5579, fixes
    #5574, @liyishuai)

  • Match `glob_files' only against files in external directories
    (#5614, fixes #5540, @rgrinberg)

  • Add pid's to chrome trace output (#5617, @rgrinberg)

  • Fix race when creating local cache directory (#5613, fixes #5461,
    @rgrinberg)

  • Add `not' to boolean expressions (#5610, fix #5503, @rgrinberg)

  • Fix relative dependencies outside the workspace (#4035, fixes #5572,
    @bobot)

  • Allow to specify `--prefix' via the environment variable
    `DUNE_INSTALL_PREFIX' (#5589, @vapourismo)

  • Dune-site.plugin: add support for `archive(native|byte, plugin)'
    used in the wild before findlib documented `plugin(native|byte)' in
    2015 (#5518, @bobot)

  • Fix a bug where Dune would not correctly interpret `META' files in
    alternative layout (ie when the META file is named `META.$pkg'). The
    `Llvm' bindings were affected by this issue. (#5619, fixes #5616,
    @nojb)

  • Support `(binaries)' in `(env)' in dune-workspace files (#5560, fix
    #5555, @emillon)

  • (mdx) stanza: add support for (locks). (#5628, fixes #5489,
    @emillon)

  • (mdx) stanza: support including files in different directories using
    relative paths, and provide better error messages when paths are
    invalid (#5703, #5704, fixes #5596, @emillon)

  • Fix ctypes rules for external lib names which aren't valid ocaml
    names (#5667, fixes #5511, @Khady)


Hardcaml MIPS CPU Learning Project and Blog
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/hardcaml-mips-cpu-learning-project-and-blog/8088/12>


Alexander (Sasha) Skvortsov announced
─────────────────────────────────────

  Hi everyone! Last fall, we completed our original plan for this
  project, rewriting the verilog MIPS CPU we had designed for a class
  into Hardcaml. A few weeks later, we got an invite to video-meet with
  the Hardcaml team to talk about our experience. They even sent us
  actual Arty A-7 FPGAs so we could test out our simulation on real
  hardware!

  Junior year ended up much busier than expected, and although we had
  gotten our code onto the FPGAs by January, we’ve only just now fully
  finished our project. Our blog now has 2 bonus installments:

  1. [Running Hardcaml on an actual FPGA]. Here, we lit up LEDs to
     display the output of a hardcoded program.
  2. [Hardcaml MIPS and I/O]. Here, we restructured our CPU so that
     programs can communicate with an external device using UART.

  With these changes, our full design is now a simplified but realistic
  processor that can run meaningful programs.

  Thank you very much to @andyman, @fyquah95, Ben Devlin, and the rest
  of the Jane Street FPGA team for creating Hardcaml, meeting with us,
  and answering our numerous questions throughout this process. Thank
  you also to @yaron_minsky and Jane Street for sending us the FPGAs to
  try out our code.

  This has been an incredibly interesting, challenging, and rewarding
  journey. We hope that our blog posts and sample project are useful for
  learning Hardcaml in the future, and welcome any questions or
  comments.


[Running Hardcaml on an actual FPGA]
<https://ceramichacker.com/blog/27-1312-running-hardcaml-on-an-actual-fpga>

[Hardcaml MIPS and I/O]
<https://ceramichacker.com/blog/34-1412-hardcaml-mips-and-io>


A tutorial on parallel programming in OCaml 5
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-tutorial-on-parallel-programming-in-ocaml-5/9896/1>


KC Sivaramakrishnan announced
─────────────────────────────

  I ran a hands-on tutorial on the new parallel programming primitives
  in the upcoming OCaml 5 at the Tarides off-site last week. It covers
  the low-level parallelism primitives exposed by the OCaml 5 compiler
  as well as high-level parallel programming using `domainslib'. I hope
  you like it and find it useful. Please feel free to open issues if you
  find anything amiss.

  <https://github.com/kayceesrk/ocaml5-tutorial>


Alain De Vos asked and Olivier Nicole replied
─────────────────────────────────────────────

        As it is not immediately clear for me, does it uses
        threads , green threads, processes , fibers ? And who is
        responsible for the scheduling ,the Ocaml application or
        the underlying operating system ?

  Each domain corresponds to one system thread. The scheduling between
  them is therefore performed by the operating system.

  The tutorial only covers domains, which are the way to perform
  /parallelism/ in OCaml 5. To use /concurrency/ (e.g.  having several
  IO-depending operations that run concurrently on the same core), the
  main mechanism is effects (which at the level of the runtime system,
  are implemented using small stack segments called fibers), as in the
  [eio library]. Effects allow such libraries to provide a form a
  lightweight threads (aka green threads) whose scheduling is
  implemented in the OCaml application using effect mechanisms.


[eio library]
<https://github.com/ocaml-multicore/eio#design-note-capabilities>


UnixJunkie then said
────────────────────

  Here is a very simple tutorial on parallel programming in OCaml: use
  parany !  <https://github.com/UnixJunkie/parany> For OCaml 5, use the
  right branch of parany:
  <https://github.com/UnixJunkie/parany/tree/domains>

  Happy hacking!


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-05-17  7:12 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-05-17  7:12 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 8480 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of May 10 to 17,
2022.

Table of Contents
─────────────────

Browsing OCaml source tree with VSCode/merlin?
release of prbnmcn-gnuplot 0.0.3
Call for Presentations for "Teaching Functional Programming in OCaml" as part of the OCaml Workshop 2022
Old CWN


Browsing OCaml source tree with VSCode/merlin?
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/browsing-ocaml-source-tree-with-vscode-merlin/9819/2>


Keigo Imai explained
────────────────────

  I managed to browse the OCaml source tree with VSCode with the
  following steps:

  1. Prepare `.merlin' file (attached below) referring to the all source
     directories in the tree
  2. Pin your ocaml-lsp-server at 1.8.3 by `opam pin ocaml-lsp-server
     1.8.3' (as it is the last version that support `.merlin')
  3. Clone OCaml repository and check out the same OCaml version as
     yours (e.g. `opam switch create 4.12.1; git checkout 4.12.1')
  4. Build OCaml (./configure && make world)
  5. Open the top folder of the source tree using VSCode (or restart the
     language server)
  6. Browse the code

  Cheers!

  content of `.merlin':
  ┌────
  │ S ./asmcomp/
  │ S ./boot/menhir/
  │ S ./bytecomp/
  │ S ./debugger/
  │ S ./driver/
  │ S ./file_formats/
  │ S ./lambda/
  │ S ./lex/
  │ S ./middle_end/
  │ S ./middle_end/closure/
  │ S ./middle_end/flambda/
  │ S ./middle_end/flambda/base_types/
  │ S ./ocamldoc/
  │ S ./ocamltest/
  │ S ./otherlibs/dynlink/
  │ S ./otherlibs/dynlink/byte/
  │ S ./otherlibs/dynlink/dynlink_compilerlibs/
  │ S ./otherlibs/dynlink/native/
  │ S ./otherlibs/str/
  │ S ./otherlibs/systhreads/
  │ S ./otherlibs/unix/
  │ S ./parsing/
  │ S ./stdlib/
  │ S ./tools/
  │ S ./tools/unlabel-patches/
  │ S ./toplevel/
  │ S ./toplevel/byte/
  │ S ./toplevel/native/
  │ S ./typing/
  │ S ./utils/
  │ B ./asmcomp/
  │ B ./asmcomp/debug/
  │ B ./boot/
  │ B ./bytecomp/
  │ B ./debugger/
  │ B ./driver/
  │ B ./file_formats/
  │ B ./lambda/
  │ B ./lex/
  │ B ./middle_end/
  │ B ./middle_end/closure/
  │ B ./middle_end/flambda/
  │ B ./middle_end/flambda/base_types/
  │ B ./ocamldoc/
  │ B ./ocamldoc/generators/
  │ B ./ocamltest/
  │ B ./otherlibs/bigarray/
  │ B ./otherlibs/dynlink/
  │ B ./otherlibs/dynlink/byte/
  │ B ./otherlibs/dynlink/dynlink_compilerlibs/
  │ B ./otherlibs/dynlink/native/
  │ B ./otherlibs/str/
  │ B ./otherlibs/systhreads/
  │ B ./otherlibs/unix/
  │ B ./parsing/
  │ B ./stdlib/
  │ B ./testsuite/tests/no-alias-deps/
  │ B ./tools/
  │ B ./toplevel/
  │ B ./toplevel/byte/
  │ B ./toplevel/native/
  │ B ./typing/
  │ B ./utils/
  └────


release of prbnmcn-gnuplot 0.0.3
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-prbnmcn-gnuplot-0-0-3/9840/1>


Igarnier announced
──────────────────

  [prbnmcn-gnuplot] is a declarative wrapper on top of
  [gnuplot]. Version 0.0.3 was just released.

  The API is not entirely set in stone but it's reasonably usable, at
  least for up to moderately sized plots. It proceeds by constructing
  self-contained gnuplot scripts from declarative specifications and
  deferring to gnuplot for execution.

  Here's the [documentation].

  Happy hacking!


[prbnmcn-gnuplot] <https://github.com/igarnier/prbnmcn-gnuplot>

[gnuplot] <http://www.gnuplot.info/>

[documentation] <https://igarnier.github.io/prbnmcn-gnuplot/>


Call for Presentations for "Teaching Functional Programming in OCaml" as part of the OCaml Workshop 2022
════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/call-for-presentations-for-teaching-functional-programming-in-ocaml-as-part-of-the-ocaml-workshop-2022/9847/1>


Yurug announced
───────────────

Special Session / Call for Presentations for "Teaching Functional Programming in OCaml" as part of the OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Workshop 2022

  • Abstract Submission: 6 June 2022
  • Author Notification: 7 July 2022
  • OCaml Workshop: 9 Sept 2022

  The OCaml Workshop 2022, co-located with ICFP 2022, will take place
  the 2022-09-16 and will be held at Ljubljana, Slovenia. This year, we
  would like to organize a special session on "Teaching Functional
  Programming in OCaml".

  Hence, we would like to encourage and invite submissions for
  presentations that highlight teaching practices and innovation that
  highlight how OCaml is taught around the globe and the wide range of
  tools and strategies that have been developed to teach effectively
  functional programming using OCaml. In particular, we are interested
  in automated program evaluation / grading tools / error analysis (both
  type and syntax errors) for OCaml programs, tools that provide
  assistance in practical lessons (such as pair programming for
  example), Jupiter notebooks like solutions to interactively introduce
  programming concepts, or full-featured web platforms. We are
  particularly seeking contributions and experience reports of the
  Learn-OCaml online programming environment which has been used by the
  OCaml teaching community for online but also for regular in-person
  classes. The goal is to share experiences, exchange ideas and tools,
  and promote best practices.

  Interested researchers are invited to submit and register a
  description of the talk (about 2 pages long) at
  <https://ocaml2022.hotcrp.com/providing> a clear statement of what
  will be provided by the presentation: the problems that are addressed,
  the solutions or methods that are proposed.

  LaTeX-produced PDFs are a common and welcome submission format. For
  accessibility purposes, we ask PDF submitters to also provide the
  sources of their submission in a textual format, such as ..tex
  sources. Reviewers may read either the submitted PDF or the text
  version.

  The OCaml workshop and this special session are informal meetings with
  no formal proceedings. The presentation material will be available
  online from the workshop homepage. The presentations may be recorded
  and made available at a later date.

  The main presentation format is a workshop talk, traditionally around
  20 minutes in length, plus question time, but we also have a poster
  session during the workshop - this allows us to present more diverse
  work and gives time for discussion. The program committee for the
  OCaml Workshop will decide which presentations should be delivered as
  posters or talks.

  • Simão Melo de Sousa (University of Beira Interior)
  • Brigitte Pientka (McGill University)
  • Yann Regis-Gianas (Nomadic Labs)
  • Xujie Si (McGill University)


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-05-10 12:30 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-05-10 12:30 UTC (permalink / raw)
  To: lwn, cwn, caml-list


[-- Attachment #1.1: Type: text/plain, Size: 1803 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of May 03 to 10,
2022.

Table of Contents
─────────────────

Multicore OCaml: March 2022
Old CWN


Multicore OCaml: March 2022
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-march-2022/9692/3>


Deep in this threal, KC Sivaramakrishnan announced
──────────────────────────────────────────────────

  The benchmarks from the "Retrofitting Effect handlers to OCaml" PLDI
  2022 paper (<https://arxiv.org/abs/2104.00250>) is available here:
  <https://github.com/prismlab/retro-concurrency/tree/master/bench>. See
  sections 6.2 and 6.3 in the paper.


He later added
──────────────

  I've moved the microbenchmarks alone to a separate repo:
  <https://github.com/prismlab/retro-concurrency-bench>. This repo also
  contains instructions to run the docker container that runs the
  benchmarks from the paper with the custom compiler variants.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-05-03  9:11 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-05-03  9:11 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of April 26 to May
03, 2022.

Table of Contents
─────────────────

ATD now supports TypeScript
pp_loc 2.0
Windows-friendly OCaml 4.12 distribution - Diskuv OCaml 0.1.0
V3.ocaml.org: we are live!
Remaking an Old Game in OCaml
Old CWN


ATD now supports TypeScript
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/atd-now-supports-typescript/9735/1>


Martin Jambon announced
───────────────────────

  [ATD] is a language for specifying typed interfaces for communicating
  across programming languages. It turns concrete type definitions
  ("schema") into code for each language. This code can read and write
  JSON safely, relieving the user of worrying about the structure of the
  JSON data.

  Starting from version 2.5.0, ATD provides `atdts', a single executable
  that turns a file `foo.atd' into `foo.ts'. See the [tutorial] for an
  introduction. The programming languages targeted by ATD are now:

  • Java
  • OCaml
  • Python + mypy
  • ReScript (BuckleScript)
  • Scala
  • TypeScript

  For an expert overview of the features that are currently supported,
  check out the test data:
  • [ATD input]
  • [TypeScript output]

  See also the [announcement for atdpy] that we made a month ago.


[ATD] <https://github.com/ahrefs/atd>

[tutorial] <https://atd.readthedocs.io/en/latest/atdts.html#tutorials>

[ATD input]
<https://github.com/ahrefs/atd/blob/master/atdts/test/atd-input/everything.atd>

[TypeScript output]
<https://github.com/ahrefs/atd/blob/master/atdts/test/ts-expected/everything.ts>

[announcement for atdpy]
<https://discuss.ocaml.org/t/atdpy-derive-safe-json-interfaces-for-python/9544>


pp_loc 2.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-pp-loc-2-0/9741/1>


Armael announced
────────────────

  Do you know how OCaml now displays errors by quoting back part of the
  source, highlighting the faulty part? For instance, with a single-line
  error location:
  ┌────
  │ File "foo.ml", line 1, characters 12-14:
  │ 1 | let foo x = yy + 1;;
  │                 ^^
  └────
  or a multi-line location:
  ┌────
  │ File "bar.ml", lines 3-5, characters 10-10:
  │ 3 | ..........function
  │ 4 |   | A -> 0
  │ 5 |   | B -> 1
  └────

  Do you have your own language/configuration file/… parser or
  typechecker, that could benefit from nice, user-friendly error
  messages?

  The [pp_loc] library provides an easy-to-use implementation of the
  same source-quoting mechanism that is used in the OCaml compiler. It
  provides a single function `pp' which will display the relevant part
  of the input given the location(s) of the error.

  ┌────
  │ val pp :
  │   ?max_lines:int ->
  │   input:Input.t ->
  │   Format.formatter ->
  │   loc list ->
  │   unit
  └────
  (As one can see from the signature, `pp' also supports displaying
  several locations at once on the same source snippet, for
  multi-location errors.)

  The full [documentation is available online], and the library is
  available on opam (`opam install pp_loc').

  This new version, thanks to the contribution of @c-cube, makes the
  `loc' type more flexible. It should now be easy to create source
  locations that can be passed to `pp', however you represent them in
  your parser (be it as (line,column) pairs, offsets, or any combination
  of those…). For more details, see the [Pp_loc.Position] module.

  I am completely open to more PRs or ideas for improving the library
  further, and displaying source locations in even nicer ways!

  Happy error-message printing!


[pp_loc] <https://github.com/Armael/pp_loc>

[documentation is available online]
<https://armael.github.io/pp_loc/pp_loc/Pp_loc/index.html>

[Pp_loc.Position]
<https://armael.github.io/pp_loc/pp_loc/Pp_loc/Position/index.html>


Windows-friendly OCaml 4.12 distribution - Diskuv OCaml 0.1.0
═════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-windows-friendly-ocaml-4-12-distribution-diskuv-ocaml-0-1-0/8358/18>


jbeckford announced
───────────────────

  A single `setup-*.exe' executable is now all that is necessary to
  install the Diskuv OCaml distribution on 64-bit Windows!

  Today you can use a prerelease of v0.4.0 which is available at
  <https://github.com/diskuv/dkml-installer-ocaml/releases/download/v0.4.0-prerel11/setup-diskuv-ocaml-windows_x86_64-0.4.0.exe>

  The prerelease:
  • is for *experienced Windows users only* because the prerelease is
    not signed! You will have to fight with your browser, operating
    system and anti-virus software to run the setup executable
  • is *not reproducible*. Because many Diskuv packages have not yet
    made it into Opam, the builds need several `opam pin' of unstable
    branches.
  • has not been incorporated into the
    <https://diskuv.gitlab.io/diskuv-ocaml> documentation site. But the
    [Beyond Basics] documentation should still be accurate.

  Once those items above are addressed, a real (non-prerelease) 0.4.0
  will be announced.

        Existing Diskuv OCaml users: Your existing Opam switches
        should be unaffected by the upgrade. But please make sure
        you can recreate your Opam switches (ie. use a `.opam'
        file) if something goes wrong.

  Release notes, including details of the migration to the Apache 2.0
  license, are at available at
  [https://github.com/diskuv/dkml-installer-ocaml/releases/tag/v0.4.0-prerel11]


[Beyond Basics]
<https://diskuv.gitlab.io/diskuv-ocaml/doc/BeyondBasics.html#beyondbasics>

[https://github.com/diskuv/dkml-installer-ocaml/releases/tag/v0.4.0-prerel11]
<https://github.com/diskuv/dkml-installer-ocaml/releases/tag/v0.4.0-prerel11>


V3.ocaml.org: we are live!
══════════════════════════

  Archive: <https://discuss.ocaml.org/t/v3-ocaml-org-we-are-live/9747/1>


Thibaut Mattio announced
────────────────────────

  I am thrilled to announce that <https://ocaml.org/> now serves version
  3 of the site! Here's an overview of the major features in this new
  version:

  • [Central OCaml package documentation], which contains the
    documentation of every version of every OCaml packages.
  • [OCaml job board], which lists job opportunities from the community.
  • [A syndicated blog], which links to blog articles from the community
    and offers original blog posts.
  • [OCaml success stories] which explore how major OCaml industrial
    users solved real-world challenges using OCaml.
  • [Resources for learning OCaml], which aggregates resources and
    tutorials to learn OCaml.
  • [An interactive OCaml playground] to try OCaml code directly in the
    browser.

  Version 2 remains accessible at <https://v2.ocaml.org/>, and older
  URLs to ocaml.org will be redirected to the v2 URL from now
  on. Similarly, v3.ocaml.org URLs will continue to work.

  Community feedback was instrumental and has been driving the direction
  of the project since day one. For instance, having a centralized
  package documentation site; or facilitating the hiring of OCaml
  developers and finding OCaml jobs were major concerns that were
  highlighted in the last [OCaml Survey]. They were what prompted us to
  work on the documentation site and the job board respectively.

  We've also listened to the community feedback we received along the
  way, and in particular, here's an overview of everything we've been
  doing to address the feedback we received after our last Discuss post:
  <https://hackmd.io/IniIM_p3Qs2UB74cuKK7UQ>.

  Given how critical your input is to drive the project, I am deeply
  grateful to every one who took the time to share insights, suggestions
  and bug reports. Some of the suggestions will need more work and
  couldn't happen before launch, but we've listened to every one and
  will keep working on improving OCaml.org to address pain points of the
  community.  Thank you, and keep the feedback coming!

  We're also starting to see a lot of contributions from external
  contributors. OCaml.org is open source, and contributions from anyone
  are extremely welcome! Never hesitate to open a PR if you see
  something you'd like to improve! You can read our [Contributing Guide]
  to learn how to contribute.


[Central OCaml package documentation] <https://ocaml.org/packages>

[OCaml job board] <https://ocaml.org/opportunities>

[A syndicated blog] <https://ocaml.org/blog>

[OCaml success stories] <https://ocaml.org/success-stories>

[Resources for learning OCaml] <https://ocaml.org/learn>

[An interactive OCaml playground] <https://ocaml.org/play>

[OCaml Survey]
<https://discuss.ocaml.org/t/ann-ocaml-user-survey-2020/6624>

[Contributing Guide]
<https://github.com/ocaml/ocaml.org/blob/main/CONTRIBUTING.md>

Ecosystem Contributions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  As the storefront of the OCaml ecosystem, we couldn't develop the next
  version of OCaml.org without contributing back! As a result, we've
  published several packages on opam that we're using for OCaml.org:

  • [dream-accept]: Accept headers parsing for Dream
  • [dream-encoding]: Encoding primitives for Dream.
  • [hilite]: Generate HTML ready for syntax-highlighting with CSS by
    parsing markdown documents.

  Other packages that are yet to be released are:

  • [code-mirror]: The code-mirror bindings
  • [js_top_worker]: An OCaml toplevel designed to run in a web worker

  We've also made contributions downstream:

  • odoc: [Support for HTML fragments in odoc]
  • river: [API changes and capability to fetch metadata from RSS post
    links]

  A huge thank you to the community for your constant effort in making
  OCaml such a great language to work with! In particular, here are some
  amazing community projects we are building upon: [Dream], [Brr] and
  [Omd] and [many more]


[dream-accept] <https://github.com/tmattio/dream-accept>

[dream-encoding] <https://github.com/tmattio/dream-encoding>

[hilite] <https://github.com/patricoferris/hilite>

[code-mirror]
<https://github.com/patricoferris/jsoo-code-mirror/tree/static>

[js_top_worker] <https://github.com/jonludlam/js_top_worker>

[Support for HTML fragments in odoc]
<https://github.com/ocaml/odoc/pull/842>

[API changes and capability to fetch metadata from RSS post links]
<https://github.com/kayceesrk/river/pull/6>

[Dream] <https://aantron.github.io/dream/>

[Brr] <https://github.com/dbuenzli/brr>

[Omd] <https://github.com/ocaml/omd>

[many more] <https://github.com/ocaml/ocaml.org/blob/main/ocamlorg.opam>


What's next?
╌╌╌╌╌╌╌╌╌╌╌╌

  Launching the website is the first step on our roadmap to improve
  OCaml’s online presence.

  As mentioned above, the immediate goal is to be ready for this OCaml
  5.00.0 release. With this in mind, we want to focus on improving the
  documentation and ensuring it includes good user pathways to learn
  about Domains, Effects, and generally how to write concurrent programs
  in OCaml.

  In addition to the documentation, some of the other projects on our
  roadmap are:

  • Toplevels for all the packages that compile to JavaScript.
  • Including OCaml Weekly News in the OCaml blog.
  • A better search through packages, documentation, and packages'
    documentation.

  This is an exciting time! Stay tuned!


Call for maintainers
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  There's a lot of ways to contribute if you'd like to help. Our
  [contributing guide] should be a good entry point to learn what you
  can do as a community contributor.

  We're also looking for maintainers. As we're completing the first
  milestone with the launch and will start working on new projects, now
  is a great time to get involved!

  If you'd like to help on the initiatives on our roadmap above (or
  others!), feel free to reach out to me by email at
  thibaut@tarides.com, or by replying to this post.


[contributing guide]
<https://github.com/ocaml/ocaml.org/blob/main/CONTRIBUTING.md>


Acknowledgements
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This project was a huge effort that started over a year ago, and the
  result of dozens of [contributors]. We want to thank every one who
  contributed to the site.

  In particular, for the groundwork on rethinking the sitemap, user
  flows, new content, design, and frontend and package docs, we thank
  Ashish Agarwal, Kanishka Azimi, Richard Davison, Patrick Ferris, Gemma
  Gordon, Isabella Leandersson, Thibaut Mattio and Anil Madhavapeddy.

  For the work on the package site infrastructure and UI, we thank Jon
  Ludlam, Jules Aguillon and Lucas Pluvinage. And for the work on the
  designs and bringing them to life on the frontend, we thank Isabella
  Leandersson and Asaad Mahmood.

  For the work on the new content and reviewing the existing one, we
  thank Christine Rose and Isabella Leandersson.

  For the contributions on the content for Ahrefs, Jane Street and
  LexiFi respectively, we thank Louis Roché, James Somers, Nicolás Ojeda
  Bär.

  We’d also like to thank the major funders who supported the work on
  revamping the website: grants from the Tezos Foundation, Jane Street
  and Tarides facilitated the bulk of the work. Thank you, and if anyone
  else wishes to help support it on an ongoing basis then donations to
  the OCaml Software Foundation and grants to the maintenance teams
  mentioned above are always welcomed.


[contributors] <https://github.com/ocaml/ocaml.org/graphs/contributors>


Remaking an Old Game in OCaml
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/remaking-an-old-game-in-ocaml/9760/1>


Yotam Barnoy announced
──────────────────────

  I've starting blogging about a [side-project of mine]. Hopefully I'll
  find the time to write some further entries in the series, including
  about reverse engineering a binary with IDA.


[side-project of mine]
<https://justabluddyblog.wordpress.com/2022/05/01/remaking-an-old-game-in-ocaml/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-04-26  6:44 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-04-26  6:44 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of April 19 to 26,
2022.

Table of Contents
─────────────────

Multicore OCaml: March 2022
OUPS meetup may 2022 (french only)
JFLA 2022: Call for Participation (in French)
Old CWN


Multicore OCaml: March 2022
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-march-2022/9692/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the March 2022 [Multicore OCaml] monthly report! This
  update along with the [previous updates] have been compiled by me,
  @ctk21, @kayceesrk and @shakthimaan.

  We have continued steadily towards making a stable OCaml 5.0 release,
  as you can see from the long list of fixes later – thank you for all
  your contributions! Platform configurations that were formerly
  supported in the 4.x branches for OpenBSD, FreeBSD, and NetBSD have
  now been re-enabled. ARM64 support (for macOS, Linux and the BSDs) is
  stable in trunk, and ARM CFI integration has been merged as a
  follow-up to facilitate debugging and profiling.  Notably, this also
  includes [memory model tests for ARMv8 and Power ports]. The Windows
  mingw64 port is also working again in trunk.

  An [effects tutorial] has also been contributed to the OCaml manual;
  feedback continues to be welcome even after it's merged in.  As you
  experiment with effects, please do continue to post to this forum with
  questions or comments about your learnings.

  The Sandmark benchmark project has added bytecode analysis to address
  any performance regressions. We have also been working on obtaining
  measurements for the compilation data points. The current-bench
  pipeline production deployments has significant UI changes, and now
  has alert notifications for the benchmark runs.

  As always, the Multicore OCaml open and completed tasks are listed
  first, which are then followed by the ecosystem tooling projects. The
  Sandmark, sandmark-nightly, and current-bench project updates are
  finally presented for your reference.

  /Editor’s note: please find the full changelog following the archive
  link above./


[Multicore OCaml] <https://github.com/ocaml-multicore/ocaml-multicore>

[previous updates] <https://discuss.ocaml.org/tag/multicore-monthly>

[memory model tests for ARMv8 and Power ports]
<https://github.com/ocaml/ocaml/pull/11004>

[effects tutorial] <https://github.com/ocaml/ocaml/pull/11093>


OUPS meetup may 2022 (french only)
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/oups-meetup-may-2022-french-only/9715/1>


zapashcanon announced
─────────────────────

  Le prochain OUPS aura lieu le *jeudi 12 mai* 2022. Le rendez-vous est
  fixé à *19h* en *salle 15-16 101* , *4 place Jussieu* , 75005 Paris.

  *L'inscription est obligatoire* pour pouvoir accéder au meetup ! Votre
  nom complet doit être disponible.  L'inscription s'effectue sur
  [meetup].

  Toutes les informations sont disponibles sur [le site du oups].

  J'aimerais aussi signaler que les slides et vidéos des exposés passés
  [sont maintenant disponibles] ! :partying_face:

  *Programme*


[meetup] <https://www.meetup.com/fr-FR/ocaml-paris>

[le site du oups] <https://oups.frama.io>

[sont maintenant disponibles] <https://oups.frama.io/past.html>

Gospel & Ortac - Clément Pascutto
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Gospel is a behavioural specification language for OCaml program. It
  provides developers with a non-invasive and easy-to-use syntax to
  annotate their module interfaces with formal contracts that describe
  type invariants, mutability, function pre-conditions and
  post-conditions, effects, exceptions, and [much more]!

  ortac: OCaml Runtime Assertion Checking.


[much more] <https://ocaml-gospel.github.io/gospel/>


MirageOS 4 - Romain Calascibetta
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  MirageOS 4 vient de sortir récemment et c'est l'occasion de
  (re)présenter ce projet permettant de construire des unikernels. Nous
  y présenterons les nouvelles features et possibilités et nous ferons
  une introspection de 3 ans de travail de l'équipe core.


Tezt: OCaml Tezos Test Framework - Romain Bardou
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Tezt is a test framework for OCaml. It is well suited for unit and
  regression tests and particularly shines for integration tests,
  i.e. tests that launch external processes. It was made with a focus on
  user experience. It allows you to easily select tests from the
  command-line and provides pretty logs. It also can run tests in
  parallel, automatically split the set of tests into several
  well-balanced batches to be run in parellel CI jobs, produce JUnit
  outputs, and more. It has been in use at Nomadic for the last 2 years
  and is thus quite battle-tested.


JFLA 2022: Call for Participation (in French)
═════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-04/msg00008.html>


Timothy Bourke announced
────────────────────────

  [ This message is intentionally written in French. It is a call for
  participation for the "Francophone Days on Functional Languages" to be
  held, finally and fingers crossed, at the end of June. Some of the
  articles are written in English. They are available online:
  <https://hal.inria.fr/JFLA2022/> ]

  *Merci de faire circuler : premier appel à participation*

  JFLA'2022 (<http://jfla.inria.fr/jfla2022.html>)

  Journées Francophones des Langages Applicatifs

  Saint-Médard-d'Excideuil - du 28 juin au 1er juillet 2022

  Les inscriptions aux JFLA 2022 - en présence ! - sont désormais
  ouvertes :

  <https://www.azur-colloque.fr/DR04/inscription/preinscription/203/fr>

  Ces journées réunissent concepteurs, utilisateurs et théoriciens ;
  elles ont pour ambition de couvrir les domaines des langages
  applicatifs, de la preuve formelle, de la vérification de programmes,
  et des objets mathématiques qui sous-tendent ces outils. Ces domaines
  doivent être pris au sens large : nous souhaitons promouvoir les ponts
  entre les différentes thématiques.

  L'inscription est un forfait qui comprend notamment l'hébergement en
  pension complète sur le site des journées :
  • participant·e plein tarif, chambre simple : 660 euros
  • étudiant·e orateur·ice, en chambre double : 0 euro

  Nous espérons que vous serez nombreux à participer à ces journées.
  Inscrivez-vous dès que possible ! En particulier, les étudiant·es
  orateur·ices sont invité·es à s'inscrire, même s'ils ne paient pas
  grâce à nos sponsors.

  Vous pouvez d'ores et déjà vous inscrire au salon de discussion
  framateam afin d'échanger ensemble :
  <https://framateam.org/signup_user_complete/?id=gnbebtncubnbpe96ok9kam8t9y>

  Tout le programme est à retrouver ici :
  <http://jfla.inria.fr/jfla2022.html>


Dates importantes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • 17 juin 2022 : date limite d'inscription aux journées
  • 28 juin au 1er juillet 2022 : journées


Cours invités
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Delphine Demange (IRISA, Université de Rennes 1) "Si2-FIP:
    Programmation Fonctionnelle en Licence 1 avec Scala"

  • Denis Mérigoux (Inria) "Rust pour le formaliste impatient"


Exposé invité
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Matthias Puech (INA GRM) Titre à venir - avec une surprise !


Articles acceptés
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  L'ensemble des articles acceptés est disponible sous forme d'une
  collection HAL : <https://hal.inria.fr/JFLA2022>


Comité de programme
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Chantal Keller LMF, Université Paris-Saclay (Présidente)
  • Timothy Bourke Inria, ÉNS de Paris (Vice-président)

  • Sandrine Blazy Irisa, Université Rennes 1
  • Frédéric Bour Tarides - Inria
  • Guillaume Bury OcamlPro
  • Stefania Dumbrava Samovar, ENSIIE, Télécom Sud Paris
  • Diane Gallois-Wong Nomadic Labs
  • Adrien Guatto IRIF, Université de Paris
  • David Janin LaBRI, Université de Bordeaux
  • Marie Kerjean LIPN, Université Paris 13
  • Luc Pellissier LACL, Université Paris-Est Créteil
  • Mário Pereira NOVA-LINCS, Universidade Nova de Lisboa
  • Alix Trieu Aarhus University
  • Yannick Zakowski LIP, Inria, ÉNS de Lyon


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-04-19  5:34 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-04-19  5:34 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of April 12 to 19,
2022.

Table of Contents
─────────────────

Lwt informal user survey
pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
Creating a library for use from JS with js_of_ocaml
ocaml-lsp-server 1.11.0
OCaml summer school in Spain, call for industry speakers
Dune 3.1.0
Old CWN


Lwt informal user survey
════════════════════════

  Archive: <https://discuss.ocaml.org/t/lwt-informal-user-survey/9666/1>


Raphaël Proust announced
────────────────────────

  In order to make some decisions relating to the maintenance of Lwt,
  I'd like to know a little bit more about how the library is used in
  the wild. Do not hesitate to respond to the poll and/or as a message
  in this thread, or even to contact me via other means in case discuss
  is not your jam.

  /Editor’s note: please follow the link above to reply to the survey./


pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-pyml-bindgen-a-cli-app-to-generate-python-bindings-directly-from-ocaml-value-specifications/8786/7>


Continuing this thread, Ryan Moore announced
────────────────────────────────────────────

  I wrote a [blog post] providing an introduction to `pyml_bindgen'.  It
  gives an intro in a slightly different style as compared to the [docs]
  and the [examples], and includes some of the latest features I've been
  working on.


[blog post]
<https://www.tenderisthebyte.com/blog/2022/04/12/ocaml-python-bindgen/>

[docs] <https://mooreryan.github.io/ocaml_python_bindgen/>

[examples]
<https://github.com/mooreryan/ocaml_python_bindgen/tree/main/examples>


Creating a library for use from JS with js_of_ocaml
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/creating-a-library-for-use-from-js-with-js-of-ocaml/9523/5>


Deep in this thread, threepwood said
────────────────────────────────────

  Cautionary note for anyone reading this in the future: dynamic imports
  are asynchronous, and initializing the jsoo runtime takes some
  milliseconds, so that if you just do:
  ┌────
  │ import("ocaml/export.bc.js");
  │ var x = mylib.myfunction();
  └────
  the second line will fail as `mylib' is not defined yet (at least this
  is what I think is happening). You need to guarantee the module is
  done initializing in some way or other.


Kim Nguyễn then said
────────────────────

  `import' should return a promise of the loaded module. So you can just
  `await' for it (if your current context allows you to write `await')
  or just :
  ┌────
  │  import("ocaml/export.bc.js").then ((_) => {
  │ 
  │  mylib.myfunction();
  │ 
  │ });
  └────


ocaml-lsp-server 1.11.0
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-lsp-server-1-11-0/9677/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the ocamllsp team, I'm excited to announce the
  availability of version 1.11.0. This release is an important milestone
  for the project because it introduces integration with our favorite
  build system. When you run dune in watch mode, you will now be able to
  see build errors in the diagnostics panel of your editor. It's all
  rather experimental for now, so your feedback and bug reports are
  appreciated.

  As usual, the full change log is below.

  Happy hacking.

  *1.11.0*


Features
╌╌╌╌╌╌╌╌

  • Add support for dune in watch mode. The lsp server will now display
    build errors in the diagnostics and offer promotion code actions.

  • Re-introduce ocamlformat-rpc (#599, fixes #495)


Fixes
╌╌╌╌╌

  • Fix workspace symbols that could have a wrong path in some cases
    ([#675])


[#675] <https://github.com/ocaml/ocaml-lsp/pull/671>


OCaml summer school in Spain, call for industry speakers
════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-summer-school-in-spain-call-for-industry-speakers/9685/1>


Roberto Blanco announced
────────────────────────

  Dear all, Ricardo Rodríguez and I are organizing an introductory OCaml
  course as part of the annual summer school of the University of
  Zaragoza in Spain. (This is the oldest summer university in the
  country, nearing its centennial anniversary!). The country's computing
  programs are quite excellent, although we have found them to generally
  not pay serious attention to modern functional programming. Our goal
  is to use OCaml to begin to address this dearth.

  In addition to the regular academic program we are planning a
  satellite event open to the general public. This is meant to introduce
  the OCaml ecosystem to a wider audience of students and academics, as
  well as professionals. As part of this, we would like to hold a round
  table discussion of industrial OCaml users to demonstrate the width
  and depth of practical uses of the language. There will be time for
  participants to present their work in more detail, if they wish to do
  so.

  If you may be interested in participating or have any questions, feel
  free to write to me here or send email to either of us. The course is
  currently in its planning stages; it is scheduled to take place in
  early to mid July, in all likelihood in the city of Zaragoza and in
  hybrid format. The OCaml Software Foundation is backing the initiative
  and we thank them for their generous support.

  Updated information about the course will be available on its website:
  <https://webdiis.unizar.es/evpf/>


Dune 3.1.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-1-0/9690/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune team, I'm pleased to announce version
  3.1.0. This release contains some small, but interesting features, and
  some important quality of life bug fixes. I encourage everyone to
  upgrade as soon as possible.

  Happy Hacking.

  *3.1.0 (15/04/2022)*

  • Add `sourcehut' as an option for defining project sources in
    dune-project files. For example, `(source (sourcehut
    user/repo))'. (#5564, @rgrinberg)

  • Add `dune coq top' command for running a Coq toplevel (#5457,
    @rlepigre)

  • Fix dune exec dumping database in wrong directory (#5544, @bobot)

  • Always output absolute paths for locations in RPC reported
    diagnostics (#5539, @rgrinberg)

  • Add `(deps <deps>)' in ctype field (#5346, @bobot)

  • Add `(include <file>)' constructor to dependency
    specifications. This can be used to introduce dynamic dependencies
    (#5442, @anmonteiro)

  • Ensure that `dune describe' computes a transitively closed set of
    libraries (#5395, @esope)

  • Add direct dependencies to $ dune describe output (#5412, @esope)

  • Show auto-detected concurrency on Windows too (#5502, @MisterDA)

  • Fix operations that remove folders with absolute path. This happens
    when using esy (#5507, @EduardoRFS)

  • Dune will not fail if some directories are non-empty when
    uninstalling.  (#5543, fixes #5542, @nojb)

  • `coqdep' now depends only on the filesystem layout of the .v files,
    and not on their contents (#5547, helps with #5100, @ejgallego)

  • The mdx stanza 0.2 can now be used with `(implicit_transitive_deps
    false)' (#5558, fixes #5499, @emillon)

  • Fix missing parenthesis in printing of corresponding terminal
    command for `(with-outputs-to )' (#5551, fixes #5546, @Alizter)


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-04-12  8:10 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-04-12  8:10 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of April 05 to 12,
2022.

Table of Contents
─────────────────

LexiFi is hiring!
Développeur principal à plein temps d'Alt-Ergo chez OCamlPro
Using an external JavaScript file in js_of_ocaml
diskuvbox: small set of cross-platform CLI tools
Old CWN


LexiFi is hiring!
═════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-fulltime-internship-paris-lexifi-is-hiring/9648/1>


Alain Frisch announced
──────────────────────

  📢 [LexiFi] is hiring!

  ✔️ Software Engineer (full-time): <https://lnkd.in/evhkxTg>

  ✔️ Software Development Internship: <https://lnkd.in/gb-bdDA9>

  LexiFi is a software editor, based in Paris. We have been happily
  using OCaml 🐪 for more than 20 years in our entire software stack,
  from backend components to UI (web & native) front-end, and we
  contribute back to the OCaml community (check out our blog post :
  <https://www.lexifi.com/blog/ocaml/ocaml-open-source/>)

  Don't hesitate to contact me directly if you want to learn more about
  the positions before applying!


[LexiFi] <https://www.lexifi.com>


Développeur principal à plein temps d'Alt-Ergo chez OCamlPro
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-fulltime-paris-developpeur-principal-a-plein-temps-dalt-ergo-chez-ocamlpro/9660/1>


Fabrice Le Fessant announced
────────────────────────────

  Alt-Ergo est l'un des solveurs SMT les plus efficaces pour la
  vérification formelle de code. Il est ainsi utilisé derrière des
  ateliers tels que Why3, Frama-C et Spark. Initialement développé par
  Sylvain Conchon au LRI, il est aujourd'hui maintenu par OCamlPro,
  grâce aux financements du Club Alt-Ergo (AdaCore, Trust-in-Soft,
  Thalès, MERCE, CEA List), à des contrats bilatéraux d'évolution et à
  des projets collaboratifs.

  OCamlPro souhaite aujourd'hui recruter un développeur principal à
  temps plein pour Alt-Ergo, pour compléter son équipe méthodes
  formelles et accélérer l'évolution d'Alt-Ergo.  Disposant d'une
  expérience dans les méthodes formelles, ses missions seront :

  • de découvrir le projet Alt-Ergo et tous ses composants (prouveur,
    interface graphique, etc.) et d'en comprendre le fonctionnement à
    travers l'exploration du code et la lecture d'articles
    scientifiques;
  • d'élaborer la roadmap de maintenance évolutive d'Alt-Ergo, en
    collaboration avec les membres du Club Alt-Ergo, et de proposer des
    améliorations qui pourront être financées au travers de contrats
    bilatéraux ou de projets collaboratifs;
  • de participer avec l'équipe à la maintenance corrective d'Alt-Ergo
    et de fournir du support aux membres du Club Alt-Ergo;
  • de participer à l'encadrement de stages et de thèses CIFRE autour
    d'Alt-Ergo et des solveurs SMT en général;
  • de suivre l'actualité des solveurs SMTs et des travaux scientifiques
    connexes, et de maintenir des collaborations avec les experts
    académiques du domaine;

  Intégré au sein de l'équipe Méthodes Formelles d'OCamlPro, il
  bénéficiera de leur expérience et leur fera bénéficier de son
  expertise croissante dans l'utilisation d'Alt-Ergo. Outre la
  maintenance d'Alt-Ergo, l'équipe Méthodes Formelles d'OCamlPro
  participe à diverses activités:

  • Développement d'outils open-source pour les méthodes formelles, tels
    que Dolmen, Matla, etc.
  • Expertises sur WhyML, TLA, Coq, et autres langages de spécification
    et de vérification;
  • Certification de logiciels pour les Critères Communs (EAL6 et plus)
  • Spécification et vérification formelle de smart contracts (Solidity,
    etc.)

  Les bureaux d'OCamlPro sont dans le 14ème arrondissement de Paris
  (Alésia). L'entreprise est connue pour son équipe sympathique, son
  excellence technique, sa productivité, ses valeurs et son éthique.

  Si ce poste vous intéresse, n'hésitez pas à envoyer votre CV à:

  contact@ocamlpro.com

  Pour plus d'informations sur OCamlPro:

  <https://www.ocamlpro.com/>

  Pour plus d'informations sur Alt-Ergo:

  <https://alt-ergo.ocamlpro.com/>

  Pour plus d'informations sur le Club Alt-Ergo:

  <https://www.ocamlpro.com/club-alt-ergo>


Using an external JavaScript file in js_of_ocaml
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/using-an-external-javascript-file-in-js-of-ocaml/9661/1>


John Whitington asked
─────────────────────

  I am a beginner at both Javascript and `js_of_ocaml', so I may be
  mixing up all sorts of mistakes and misconceptions here.

  I have compiled up an existing project, my command line PDF tools,
  using `js_of_ocaml', and all is well:

  ┌────
  │ $ node cpdf.js -info hello.pdf
  │ Encryption: Not encrypted
  │ Permissions:
  │ Linearized: false
  │ Version: 1.1
  │ Pages: 1
  └────

  Like magic! But I had to comment out the parts of my code which use
  external C code of course - that is zlib and some encryption
  primitives. So now I wish to bind javascript libraries for those. I am
  experimenting with a simple library of my own, first, which is given
  on the command line to `js_of_ocaml' as `foomod.js':

  ┌────
  │ foo = 42;
  └────

  I can get to this global variable easily from OCaml:

  ┌────
  │ let foo = Js.Unsafe.global##.foo
  └────

  But now I want to do things better, and I change `foomod.js' to:

  ┌────
  │ exports.foo = 42;
  └────

  How can I get to that? Giving `foomod.js' on the `js_of_ocaml' command
  line includes the contents of `foomod.js' in some way, but does not
  contain the string `foomod', so I'm not sure how to get to the
  foomod's variables and functions. How to I access them? In the node
  REPL, I can simply do:

  ┌────
  │ > foomod = require('./foomod.js');
  │ { foo; 42 }
  │ > foomod.foo;
  │ 42
  └────

  I have read the `js_of_ocaml' help page on how to bind JS modules:

  <https://ocsigen.org/js_of_ocaml/latest/manual/bindings>

  I imagine if I could get over this hump, all the rest of the
  information I need will be there.


Nicolás Ojeda Bär replied
─────────────────────────

  Not exactly what you asked, but if you just want to provide a JS
  version of some C primitive

  ┌────
  │ external foo : unit -> int = "caml_foo"
  └────

  you can do this by writing the following in your `.js' file:

  ┌────
  │ //Provides: caml_foo
  │ function caml_foo() {
  │   return 42;
  │ }
  └────

  Then `js_of_ocaml' will automatically replace calls to the external
  function by a call to its JS implementation.

  This is the same mechanism used by `js_of_ocaml' to implement its own
  JS version of the OCaml runtime, see eg

  <https://github.com/ocsigen/js_of_ocaml/blob/3850a67b1cb00cfd2ee4399cf1e2948062884b92/runtime/bigarray.js#L328-L335>


diskuvbox: small set of cross-platform CLI tools
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-diskuvbox-small-set-of-cross-platform-cli-tools/9663/1>


jbeckford announced
───────────────────

  *TLDR*:
  ┌────
  │ $ opam update
  │ $ opam install diskuvbox
  │ 
  │ $ diskuvbox copy-dir --mode 755 src1/ src2/ dest/
  │ $ diskuvbox copy-file --mode 400 src/a dest/b
  │ $ diskuvbox copy-file-into src1/a src2/b dest/
  │ $ diskuvbox touch-file x/y/z
  │ 
  │ $ diskuvbox find-up . _build
  │ Z:/source/_build
  │ 
  │ $ diskuvbox tree --max-depth 2 --encoding=UTF-8 .
  │ .
  │ ├── CHANGES.md
  │ ├── README.md
  │ ├── _build/
  │ │   ├── default/
  │ │   ├── install/
  │ │   └── log
  └────

  *Problem*: When writing cram tests, Dune rules and Opam build steps,
  often we default to using GNU binaries (`/usr/bin/*') available on
  Linux (ex. `/usr/bin/cp -R'). Unfortunately these commands rarely work
  on Windows, and as a consequence Windows OCaml developers are forced
  to maintain Cygwin or MSYS2 installations to get GNU tooling.

  *Solution*: Provide some of the same functionality for Windows and
  macOS that the GNU binaries in `/usr/bin/*' do in Linux.

  `diskuvbox' is a single binary that today provides an analog for a
  very small number of binaries that I have needed in the Diskuv Windows
  OCaml distribution. It is liberally licensed under Apache v2.0. *With
  your PRs it could emulate much more!*

  `diskuvbox' has CI testing for Windows, macOS and Linux. Usage and
  help are available in the diskuvbox README:
  <https://github.com/diskuv/diskuvbox#diskuv-box>

  *`diskuvbox' also has a OCaml library, but consider the API unstable
   until version 1.0.*

  Alternatives:
  • There are some shell scripting tools like [shexp] and [feather] that
    give you POSIX pipes in OCaml-friendly syntax. I feel these
    complement Diskuv Box.
  • Dune exposes `(copy)' to copy a file in Dune rules; theoretically
    more operations could be added.

  Internally `diskuvbox' is a wrapper on the excellent [bos - Basic OS
  interaction] library.


[shexp] <https://github.com/janestreet/shexp>

[feather] <https://github.com/charlesetc/feather>

[bos - Basic OS interaction]
<https://erratique.ch/software/bos/doc/Bos/index.html>

Acknowledgements
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The first implementations of Diskuv Box were implemented with the
  assistance of the [OCaml Software Foundation (OCSF)], a sub-foundation
  of the [INRIA Foundation].

  Two OCaml libraries ([bos] and [cmdliner]) are essential to Diskuv
  Box; these libraries were created by [Daniel Bünzli] (@dbuenzli) .


[OCaml Software Foundation (OCSF)] <http://ocaml-sf.org>

[INRIA Foundation] <https://www.inria.fr>

[bos] <https://erratique.ch/software/bos>

[cmdliner] <https://erratique.ch/software/cmdliner>

[Daniel Bünzli] <https://erratique.ch/profile>


Examples
╌╌╌╌╌╌╌╌

  The following are examples that have been condensed from the
  [diskuvbox README.md] …


[diskuvbox README.md] <https://github.com/diskuv/diskuvbox#diskuv-box>

Using in Dune cram tests
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  ┌────
  │ $ install -d a/b/c/d/e/f
  │ $ install -d a/b2/c2/d2/e2/f2
  │ $ install -d a/b2/c3/d3/e3/f3
  │ $ install -d a/b2/c3/d4/e4/f4
  │ $ install -d a/b2/c3/d4/e5/f5
  │ $ install -d a/b2/c3/d4/e5/f6
  │ $ touch a/b/x
  │ $ touch a/b/c/y
  │ $ touch a/b/c/d/z
  │ 
  │ $ diskuvbox tree a --max-depth 10 --encoding UTF-8
  │ a
  │ ├── b/
  │ │   ├── c/
  │ │   │   ├── d/
  │ │   │   │   ├── e/
  │ │   │   │   │   └── f/
  │ │   │   │   └── z
  │ │   │   └── y
  │ │   └── x
  │ └── b2/
  │     ├── c2/
  │     │   └── d2/
  │     │       └── e2/
  │     │           └── f2/
  │     └── c3/
  │         ├── d3/
  │         │   └── e3/
  │         │       └── f3/
  │         └── d4/
  │             ├── e4/
  │             │   └── f4/
  │             └── e5/
  │                 ├── f5/
  │                 └── f6/
  └────


Using in Opam `build' steps
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  ┌────
  │ build: [
  │   ["diskuvbox" "copy-file-into" "assets/icon.png" "assets/public.gpg" "%{_:share}%"]
  │ ]
  └────


Using in Dune rules
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  ┌────
  │ (rule
  │  (targets diskuvbox.corrected.ml diskuvbox.corrected.mli)
  │  (deps
  │   (:license %{project_root}/etc/license-header.txt)
  │   (:conf    %{project_root}/etc/headache.conf))
  │  (action
  │   (progn
  │    (run diskuvbox copy-file -m 644 diskuvbox.ml  diskuvbox.corrected.ml)
  │    (run diskuvbox copy-file -m 644 diskuvbox.mli diskuvbox.corrected.mli)
  │    (run headache -h %{license} -c %{conf} %{targets})
  │    (run ocamlformat --inplace --disable-conf-files --enable-outside-detected-project %{targets}))))
  └────


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-04-05 11:50 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-04-05 11:50 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of March 29 to April
05, 2022.

Table of Contents
─────────────────

v0.15 release of Jane Street packages
EmelleTV Show - 2022
Open source editor for iOS, iPadOS and macOS
The mysterious pointer in the runtime closure representation
Other OCaml News
Old CWN


v0.15 release of Jane Street packages
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-v0-15-release-of-jane-street-packages/9612/1>


Arseniy Alekseyev announced
───────────────────────────

  We are pleased to announce the v0.15 release of Jane Street packages!

  This release comes with 41 new packages, and a large number of fixes
  and enhancements. The documentation for the individual packages will
  soon be available on [v3.ocaml.org/packages], after some technical
  issues are fixed.

  The remainder of this e-mail highlights the main changes since the
  v0.14 release.


[v3.ocaml.org/packages] <https://v3.ocaml.org/packages>

Notable changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Re-structuring of `Core'.
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  The most noticeable breaking change is the re-structuring of `Core'.

  In 0.14, `Core' is somewhat bloated and includes many modules that are
  barely ever used, many of which are Unix-specific. In 0.15, many of
  those modules moved to separate libraries, most of them to
  package~core_unix~, and `core' is now much smaller and no longer
  contains unix-specific code.

  The mapping between the new libraries and the old modules can be
  summarized by the contents of `Core_compat' library v0.14:

  ┌────
  │ module Command_unix = Core.Command
  │ module Date_unix = Core.Date
  │ module Filename_unix = Core.Filename
  │ module Signal_unix = Core.Signal
  │ module Sys_unix = Core.Sys
  │ module Core_thread = Core.Thread
  │ module Time_unix = Core.Time
  │ module Time_ns_unix = Core.Time_ns
  │ module Core_unix = Core.Unix
  │ module Version_util = Core.Version_util
  │ 
  │ module Interval_lib = struct
  │   module Interval = Core.Interval
  │   module Interval_intf = Core.Interval_intf
  │ end
  │ 
  │ module Time_interface = Core.Time_common
  └────


Async: `Monitor.try_with'
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  `Monitor.try_with' and related functions changed the defaults for
  their `run' and `rest' parameters.  They used to default to
  `~~run:~Schedule ~rest:~Log~', but now they default to `~~run:~Now
  ~rest:~Raise~'.


Many other changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  There are many changes and additions across 130+ existing packages,
  and unfortunately we don't maintain a changelog to list them all.  The
  code for all of our packages is on our [github], and if you're
  interested in the details of what changed in a particular package, you
  can inspect the diff between branches v0.14 and v0.15.


[github] <https://github.com/janestreet>


New packages
╌╌╌╌╌╌╌╌╌╌╌╌

  [`abstract_algebra']: A small library describing abstract algebra
  concepts

  A library describing abstract algebra concepts. Currently, it includes
  Commutative_group and Vector_space.

  [`async_rpc_websocket']: Library to serve and dispatch Async RPCs over
  websockets

  Library to serve and dispatch Async RPCs over websockets.

  Rpc_websocket makes it easy to serve and send Async RPCs with
  HTTP+Websocket underlying the transport. It also provides a mechanism
  to share the RPC implementations between a vanilla TCP server and a
  HTTP server.

  On the server side, the library detects when a websocket connection is
  established, and routes to an optionally provided vanilla HTTP handler
  when non-websocket traffic occurs.

  [`bigdecimal']: Arbitrary-precision decimal based on Zarith

  A high-precision representation of decimal numbers as [mantissa *
  10^exponent], where the mantissa is internally a [Bigint.t] and the
  exponent is an [int].

  [`cohttp_async_websocket']: Websocket library for use with cohttp and
  async

  Websocket library for use with cohttp and async.

  Cohttp_async_websocket is a full-featured server-side websocket
  implementation, using Async as the concurrency library, and Cohttp for
  HTTP negotiation.

  It implements a large portion of RFC6445. The library has been
  hardened with many applications using it for several year, in
  conjunction with async-js and google-chrome.

  [`cohttp_static_handler']: A library for easily creating a cohttp
  handler for static files

  Single page handlers are handlers that serve user specified JavaScript
     and css files along with a generated index page that loads those
     files.

  [`core_compat']: Compatibility for core 0.14

  Compatibility wrapper to make it possible to have code compatible with
  both Core 0.14 and 0.15.

  [`env_config']: Helper library for retrieving configuration from an
  environment variable

  The Env_config library is a helper for retrieving library and program
  configuration from an environment variable. Its goal is to make it
  easy to override a configuration that is loaded from disk, computed,
  or embedded in a library.

  [`file_path']: A library for typed manipulation of UNIX-style file
  paths

  A library for typed manipulation of UNIX-style file paths.

  [`fuzzy_match']: A library for fuzzy string matching

  A library for fuzzy string matching

  [`fzf']: A library for running the fzf command line tool

  A library for running the fzf command line fuzzy matcher

  [`hardcaml_c']: Hardcaml C Simulation Backend

  A fast C-based simulation backend for Hardcaml circuits.

  The library transparently compiles a Hardcaml Circuit to C code, which
  is in turn compiled and linked into the running executable. The
  generated simulation object can be used like any other cyclesim
  simulation.

  [`hardcaml_circuits']: Hardcaml Circuits

  A small library of useful/interesting Hardcaml circuits.

  [`hardcaml_fixed_point']: Hardcaml fixed point arithmetic

  Signed and Unsigned fixed point operations, with a full complement of
  rounding and overflow functionality.

  [`hardcaml_of_verilog']: Convert Verilog to a Hardcaml design

  The opensource synthesis tool yosys is used to convert a verilog
  design to a JSON based netlist representation. This library can load
  the JSON netlist and build a hardcaml circuit.

  Code can also be generated to wrap the conversion process using
  Hardcaml interfaces.

  [`hardcaml_step_testbench']: Hardcaml Testbench Monad

  A monad for interacting with Hardcaml.Cyclesim based simulations.

  Allows multiple control threads to interact with a simulation module,
  all of which are synchronised to the system clock.

  [`hardcaml_verify']: Hardcaml Verification Tools

  Tools for verifying properties of Hardcaml circuits.

  Combinational circuits can be converted to 'conjunctive normal form'
  for input into SAT solvers via DIMAC files. Support for a few
  opensource solvers is integrated - minisat, picosat, Z3 - just ensure
  they are in your PATH.

  Circuits can also be converted to NuSMV format for advanced bounded
  and unbounded model checking tasks.

  [`hardcaml_verilator']: Hardcaml Verilator Simulation Backend

  Very fast verilator-based simulations of Hardcaml circuits.

  This library transparently compiles a verilator-based shared library,
  and links it back to the running executable to be used as a Cyclesim
  simulation.

  [`hardcaml_xilinx']: Hardcaml wrappers for Xilinx memory primitives

  The Hardcaml_xilinx library provides wrappers for Xilinx specific RAM
  and FIFO primitive blocks. In many cases a simulation model is
  provided.

  The `Synthesis' module implements various arithmetic and logical RTL
  components with Xilinx LUT primitives.

  [`hardcaml_xilinx_components']: Hardcaml Xilinx component definitions

  A tool for reading Xilinx VHDL Unisim and XPM component definitions
  from a Vivado installation and generating Hardcaml interfaces
  automatically.

  [`hex_encode']: Hexadecimal encoding library

  This library implements hexadecimal encoding and decoding

  [`hg_lib']: A library that wraps the Mercurial command line interface

  A library that wraps the Mercurial command line interface.

  [`int_repr']: Integers of various widths

  Integers of various widths.

  [`jsonaf']: A library for parsing, manipulating, and serializing data
  structured as JSON

  A library for parsing, manipulating, and serializing data structured
  as JSON.

  [`krb']: A library for using Kerberos for both Rpc and Tcp
  communication

  Jane Street's library for Kerberizing RPC connections so that
  • the server gets an authenticated principal (i.e. username) with
    every incoming connection, and
  • RPC communication may be encrypted, if necessary.

  [`magic-trace']: Easy Intel Processor Trace Visualizer

  Magic-trace makes it easy to record and visualize Intel Processor
      Trace data for debugging tricky performance issues.

  [`ocaml-embed-file']: Files contents as module constants

  Embed-file takes some files and generates code for an OCaml module
  defining string constants containing the contents of those files.

  [`ocaml_intrinsics']: Intrinsics

  Provides functions to invoke amd64 instructions (such as
       clz,popcnt,rdtsc,rdpmc) when available, or compatible software
       implementation on other targets.

  [`ocaml-probes']: USDT probes for OCaml: command line tool

  A tool for controlling user-space statically-defined tracing probes
  for OCaml.  Experimental.

  [`ppx_css']: A ppx that takes in css strings and produces a module for
  accessing the unique names defined within

  A ppx that takes in css strings and produces a module for accessing
  the unique names defined within.

  [`ppx_disable_unused_warnings']: Expands [@disable_unused_warnings]
  into [@warning \"-20-26-32-33-34-35-36-37-38-39-60-66-67\"]

  Part of the Jane Street's PPX rewriters collection.

  [`ppx_ignore_instrumentation']: Ignore Jane Street specific
  instrumentation extensions

  Ignore Jane Street specific instrumentation extensions from internal
     PPXs or compiler features not yet upstreamed.

  [`ppx_jsonaf_conv']: [@@deriving] plugin to generate Jsonaf conversion
  functions

  Part of the Jane Street's PPX rewriters collection.

  [`ppx_typed_fields']: GADT-based field accessors and utilities

  Part of the Jane Street's PPX rewriters collection.

  [`ppx_type_directed_value']: Get [@@deriving]-style generation of
  type-directed values without writing a ppx

  `Ppx_type_directed_value' is a ppx that does `[@@deriving]'-style
  generation of type-directed values based on user-provided modules. The
  user-provided modules tell `ppx_type_directed_value' how to compose
  type-directed values (for example, combine type-directed values of the
  fields of a record to form a type-directed value for the record
  itself).

  This allows a wide variety of PPXs such as `ppx_sexp_conv',
  `ppx_compare', `ppx_enumerate', etc. to be implemented with
  `ppx_type_directed_value', but with some runtime cost.

  This PPX currently supports deriving type-directed values for records,
  ordinary & polymorphic variants and tuples. It also supports custom
  user-defined attributes on record and variant fields.

  [`profunctor']: A library providing a signature for simple profunctors
  and traversal of a record

  This is a very small library which provides a signature for profunctor
  types and operations which can be used to traverse a record with them
  based on record_builder and the `ppx_fields' syntax extension.

  [`redis-async']: Redis client for Async applications

  A client library for Redis versions 6 and higher.

  Provides a strongly-typed API with transparent (de)serialization for
  application-defined types.

  Supports client tracking and internally uses the RESP3 protocol.

  [`sexp_diff']: Code for computing the diff of two sexps

  The code behind the [diff] subcommand of the Jane Street's [sexp]
  command line tool.

  [`sexp_grammar']: Sexp grammar helpers

  Helpers for manipulating [Sexplib.Sexp_grammar] values.

  [`sexp_string_quickcheck']: Quickcheck helpers for strings parsing to
  sexps

  This library provides quickcheck generators, helpers, and shrinkers
  for quickcheck-based tests that wish to exercise the concrete syntax
  of sexps, including escape sequences and comments.

  [`tracing']: Tracing library

  Utilities for creating and parsing traces in Fuchsia Trace Format.

  [`username_kernel']: An identifier for a user

  A string representation for a user, typically a UNIX username


[`abstract_algebra'] <https://github.com/janestreet/abstract_algebra>

[`async_rpc_websocket']
<https://github.com/janestreet/async_rpc_websocket>

[`bigdecimal'] <https://github.com/janestreet/bigdecimal>

[`cohttp_async_websocket']
<https://github.com/janestreet/cohttp_async_websocket>

[`cohttp_static_handler']
<https://github.com/janestreet/cohttp_static_handler>

[`core_compat'] <https://github.com/janestreet/core_compat>

[`env_config'] <https://github.com/janestreet/env_config>

[`file_path'] <https://github.com/janestreet/file_path>

[`fuzzy_match'] <https://github.com/janestreet/fuzzy_match>

[`fzf'] <https://github.com/janestreet/fzf>

[`hardcaml_c'] <https://github.com/janestreet/hardcaml_c>

[`hardcaml_circuits'] <https://github.com/janestreet/hardcaml_circuits>

[`hardcaml_fixed_point']
<https://github.com/janestreet/hardcaml_fixed_point>

[`hardcaml_of_verilog']
<https://github.com/janestreet/hardcaml_of_verilog>

[`hardcaml_step_testbench']
<https://github.com/janestreet/hardcaml_step_testbench>

[`hardcaml_verify'] <https://github.com/janestreet/hardcaml_verify>

[`hardcaml_verilator']
<https://github.com/janestreet/hardcaml_verilator>

[`hardcaml_xilinx'] <https://github.com/janestreet/hardcaml_xilinx>

[`hardcaml_xilinx_components']
<https://github.com/janestreet/hardcaml_xilinx_components>

[`hex_encode'] <https://github.com/janestreet/hex_encode>

[`hg_lib'] <https://github.com/janestreet/hg_lib>

[`int_repr'] <https://github.com/janestreet/int_repr>

[`jsonaf'] <https://github.com/janestreet/jsonaf>

[`krb'] <https://github.com/janestreet/krb>

[`magic-trace'] <https://github.com/janestreet/magic-trace>

[`ocaml-embed-file'] <https://github.com/janestreet/ocaml-embed-file>

[`ocaml_intrinsics'] <https://github.com/janestreet/ocaml_intrinsics>

[`ocaml-probes'] <https://github.com/janestreet/ocaml-probes>

[`ppx_css'] <https://github.com/janestreet/ppx_css>

[`ppx_disable_unused_warnings']
<https://github.com/janestreet/ppx_disable_unused_warnings>

[`ppx_ignore_instrumentation']
<https://github.com/janestreet/ppx_ignore_instrumentation>

[`ppx_jsonaf_conv'] <https://github.com/janestreet/ppx_jsonaf_conv>

[`ppx_typed_fields'] <https://github.com/janestreet/ppx_typed_fields>

[`ppx_type_directed_value']
<https://github.com/janestreet/ppx_type_directed_value>

[`profunctor'] <https://github.com/janestreet/profunctor>

[`redis-async'] <https://github.com/janestreet/redis-async>

[`sexp_diff'] <https://github.com/janestreet/sexp_diff>

[`sexp_grammar'] <https://github.com/janestreet/sexp_grammar>

[`sexp_string_quickcheck']
<https://github.com/janestreet/sexp_string_quickcheck>

[`tracing'] <https://github.com/janestreet/tracing>

[`username_kernel'] <https://github.com/janestreet/username_kernel>


EmelleTV Show - 2022
════════════════════

  Archive: <https://discuss.ocaml.org/t/emelletv-show-2022/9613/1>


David Sancho announced
──────────────────────

  I'm creating a post as a header from this season of *EmelleTV* in
  2020. Will use this post to share announcements, new shows, gather
  feedback and invite you to watch and follow
  [https://www.twitch.tv/emelletv]!

  For the ones who doesn't know us, It's a streaming show that will
  happen once per month and will try to interview and talk casually
  about OCaml, Reason, ReScript and their communities. Inviting
  interesting engineers and ask silly questions about literally
  anything.

  If can't attend live, we publish the VOD in youtube under
  [https://www.youtube.com/channel/UCvVVfCa7-nzSuCdMKXnNJNQ].  You can
  re-watch some of the 2021 interviews, they were a ton of fun for me.

  It's made by myself and @fakenickels.

  Feel free to share any feedback, propose any guest or make fun of us
  ^^


[https://www.twitch.tv/emelletv] <https://www.twitch.tv/emelletv>

[https://www.youtube.com/channel/UCvVVfCa7-nzSuCdMKXnNJNQ]
<https://www.youtube.com/channel/UCvVVfCa7-nzSuCdMKXnNJNQ>


Open source editor for iOS, iPadOS and macOS
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/open-source-editor-for-ios-ipados-and-macos/7624/21>


Nathan Fallet announced
───────────────────────

  Just released the app on the Play Store for Android: [Play Store]

  Feel free to give your feedback as well. I tried to make it like the
  iOS/macOS version. For now, the only missing feature is syntax
  highlighting, but I'm working on it (I still have a few bugs with it)


[Play Store]
<https://play.google.com/store/apps/details?id=me.nathanfallet.ocaml>


The mysterious pointer in the runtime closure representation
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/the-mysterious-pointer-in-the-runtime-closure-representation/9560/7>


Deep in this thread, Yue Li Picasso announced
─────────────────────────────────────────────

  Thanks for your replies @silene @zozozo !  Due to project interest I
  need to understand the runtime value representation. Now I released a
  little library for displaying runtime values in textual form:
  [OInspect].


[OInspect] <https://github.com/YueLiPicasso/OInspect>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [MirageOS 4 Released!]
  • [PhD Position at CEA LIST - LSL]
  • [All your metrics belong to influx]
  • [Secure Virtual Messages in a Bottle with SCoP]
  • [Research internships in our Tools and Compilers group]


[OCaml Planet] <http://ocaml.org/community/planet/>

[MirageOS 4 Released!]
<https://tarides.com/blog/2022-03-29-mirageos-4-released>

[PhD Position at CEA LIST - LSL]
<http://frama-c.com/jobs/2022-03-28-machine-learning-for-improving-formal-verification-of-code.html>

[All your metrics belong to influx]
<https://hannes.nqsb.io/Posts/Monitoring>

[Secure Virtual Messages in a Bottle with SCoP]
<https://tarides.com/blog/2022-03-08-secure-virtual-messages-in-a-bottle-with-scop>

[Research internships in our Tools and Compilers group]
<https://blog.janestreet.com/research-internships-tnc/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-03-29  7:42 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-03-29  7:42 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of March 22 to 29,
2022.

Table of Contents
─────────────────

pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
Tarides is hiring!
For Diversity and the OCaml Community: Outreachy Summer 2022
Caqti 1.8.0 and related news
First release of prbnmcn-dagger
MirageOS 4.0
OCaml 4.14.0 is released
ocaml-in-python.0.1.0: Effortless Python bindings for OCaml modules
Old CWN


pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-pyml-bindgen-a-cli-app-to-generate-python-bindings-directly-from-ocaml-value-specifications/8786/6>


Ryan Moore announced
────────────────────

New releases
╌╌╌╌╌╌╌╌╌╌╌╌

  Version 0.3.0 and 0.3.1 are now available on [GitHub].  0.3.0 has been
  merged into opam, and a PR for 0.3.1 has been opened.  The [change
  log] has more details about the changes.


[GitHub] <https://github.com/mooreryan/ocaml_python_bindgen/tags>

[change log]
<https://github.com/mooreryan/ocaml_python_bindgen/blob/main/CHANGELOG.md>


Binding tuples
╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  You can now bind tuples directly.  Here's a Python function that takes
  two lists of points (where each "point" is a tuple like `(x, y)') and
  adds them together

  ┌────
  │ def add(points1, points2):
  │     return [(x1 + y1, x2 + y2) for (x1, x2), (y1, y2) in zip(points1, points2)]
  └────

  And you could bind it using tuples from the OCaml side as well.

  ┌────
  │ val add : points1:(int * int) list -> points2:(int * int) list -> unit -> (int * int) list
  └────

  Note there are some restrictions regarding tuples, which you can read
  about [here], [here], or [here].


[here] <https://mooreryan.github.io/ocaml_python_bindgen/tuples/>

[here]
<https://github.com/mooreryan/ocaml_python_bindgen/blob/main/examples/README.md>

[here]
<https://github.com/mooreryan/ocaml_python_bindgen/blob/main/CHANGELOG.md#030-2022-03-18>


Attributes
╌╌╌╌╌╌╌╌╌╌

  You can use attributes on value specifications.  Currently the only
  one supported is `py_fun_name', which allows you to decouple the
  Python method name and the generated OCaml function name.

  As an example, take the following Python function, which adds to
  "things".

  ┌────
  │ def add(x, y):
  │     return x + y
  └────

  You could bind multiple OCaml functions to this single function now.

  ┌────
  │ val add_int : x:int -> y:int -> unit -> int
  │ [@@py_fun_name add]
  │ 
  │ val add_float : x:float -> y:float -> unit -> float
  │ [@@py_fun_name add]
  │ 
  │ val add_string : x:string -> y:string -> unit -> string
  │ [@@py_fun_name add]
  └────


Python magic methods
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  This is also nice for binding Python [magic methods]. For example, you
  don't have to use `__init__' as the name of the OCaml function you use
  to make instances of a Python class.  You can bind it to a more
  natural name like `create' or `make'.

  ┌────
  │ val create : name:string -> age:int -> unit -> t
  │ [@@py_fun_name __init__]
  └────


[magic methods]
<https://docs.python.org/3/reference/datamodel.html#specialnames>


Using Pytypes.pyobject directly
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Sometimes you may not want to bother converting Python types to normal
  OCaml types at all.  You can do that now in value specifications by
  using the `Pytypes.pyobject' and `Py.Object.t' types directly.


Fewer dependencies
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  `re' is now used instead of `re2', which drops the number of
  dependencies that need to be installed by about half.  Additionally,
  `core', `core_bench', and `bisect_ppx' don't need to be installed if
  you want to install `pyml_bindgen' directly from the git repository,
  which greatly cuts the required dependencies in this case.

  Thanks again to UnixJunkie for spurring many of these updates!


Tarides is hiring!
══════════════════

  Archive: <https://discuss.ocaml.org/t/tarides-is-hiring/9553/1>


Thomas Gazagnaire announced
───────────────────────────

  Following the recent announcement about Tarides (joining forces with
  [OCaml Labs] and [Segfault System]), we are now looking to expand our
  team with experienced software engineers, compassionate team leads and
  experts in software consulting services. Our ambition is to bring
  OCaml to a vast set of new developers and industries. We want to make
  developers more productive by spending less time on fixing bugs and
  more on writing new features. And we want the software industry to
  build more robust and performant systems that can last for decades.

  We are looking for:

  • Experienced [Software Engineer(s)] to take part in the development
    of Irmin. You will be part of the team that designs, builds and
    ships Irmin libraries and applications to our community and
    customers.
  • [Team Lead(s)] who cares about motivating their team members,
    supporting their growth and development and successfully delivering
    the team's objectives on time.
  • A [Head of Consulting Services] to diversify our technical teams and
    commercial services portfolio. You'll be the first hire for this
    brand new department and will have the opportunity to help us build
    our services structure from scratch, including our strategy,
    processes, tools, and team.

  We are always looking for great OCaml enthusiasts to join our team, so
  even if these job descriptions do not fit your profile precisely, you
  are welcome to send us [a spontaneous application]!


[OCaml Labs]
<https://tarides.com/blog/2022-01-27-ocaml-labs-joins-tarides>

[Segfault System]
<https://tarides.com/blog/2022-03-01-segfault-systems-joins-tarides>

[Software Engineer(s)]
<https://tarides.com/jobs/senior-software-engineer>

[Team Lead(s)] <https://tarides.com/jobs/team-lead-engineering>

[Head of Consulting Services]
<https://tarides.com/jobs/head-of-consulting-services>

[a spontaneous application]
<https://tarides.com/jobs/spontaneous-application>


For Diversity and the OCaml Community: Outreachy Summer 2022
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/for-diversity-and-the-ocaml-community-outreachy-summer-2022/9234/6>


Deep in this thread, Aya announced
──────────────────────────────────

  @pitag and I have resubmitted the PPX derivers project for this Summer
  2022 round: *Expand OCaml's library of standard derivers*! This is the
  same project I was the intern for this past Winter 2022 round, where
  the goal is to build up a [standard derivers] library, like
  `ppx_deriving', using the updated `ppxlib' API.

  I'm excited to be supporting @pitag with mentoring, and for the
  opportunity to stay involved now that my internship has ended :smiley:


[standard derivers] <https://github.com/ocaml-ppx/standard_derivers>


Caqti 1.8.0 and related news
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-caqti-1-8-0-and-related-news/9561/1>


"Petter A. Urkedal announced
────────────────────────────

  I am happy to announce the second release of [Caqti] this year. The
  reason for the quick succession is partly an adjustment to the [new
  API for request construction] and partly that [matchable error
  conditions] did not make it into the previous release.  You can see
  the full release notes below.

  I would also like to thank [OCaml Software Foundation] for sponsoring
  my efforts on the Caqti project this year, also including most of the
  work that went into the previous release.

  One [feature in progress] is a new driver based on the pure-OCaml
  [pgx] which should make it possible, with some additional changes to
  the way drivers are loaded, to target MirageOS. I am note sure if this
  can be done in a minor release or will require a Caqti 2 branch.


[Caqti] <https://github.com/paurkedal/ocaml-caqti>

[new API for request construction]
<https://paurkedal.github.io/ocaml-caqti/caqti/Caqti_request/Infix/index.html>

[matchable error conditions]
<https://github.com/paurkedal/ocaml-caqti/issues/72>

[OCaml Software Foundation] <https://ocaml-sf.org>

[feature in progress]
<https://github.com/paurkedal/ocaml-caqti/issues/38>

[pgx] <https://github.com/arenadotio/pgx>

Release Notes
╌╌╌╌╌╌╌╌╌╌╌╌╌

  New features:

  • A matchable representation of common causes of errors on the
    database side is now available, with limitations.  It focuses on
    conditions which seem most likely useful to handle.  At the moment
    we lack extended error codes from SQLite3 needed to make the cause
    fully precise.

  • Expose the underlying error details from database client libraries.
    This is meant to be use as a last resort, and requires directly
    linking with the relevant drivers.

  • A second set of request construction operators `->.', `->?', `->!',
    and `->*' were introduced after experience with converting existing
    code.  Given the parameter and result type they return a function
    which constructs a request directly from a query string.  Avoiding
    the need to compose with `@:-' simplifies local opens and usage with
    `List.map' etc.

  • Environment variables are now expanded in the debug log when using
    the new request constructors introduced in 1.7.0.

  • A new `?tweaks_version' connection parameter has been added to
    control when the client is ready to adapt to changes in database
    session parameters or other adjustments of the interaction with
    specific database systems. [[More details available in the
    documentation.]]

  • Enable foreign key constraint checks for SQLite3 starting at tweaks
    version 1.7.

  Fixes:

  • Fixed debug logging to pass the correct driver info to the query
    callback instead of a dummy driver info which would cause a failure
    if unsupported.

  Deprecations:

  • The `-->' operator was renamed to `-->!', with a deprecated alias,
    for consistency with the new `->!' operator.

  • The old convenience interface for creating requests has been
    deprecated in favour of the new infix operators and the new query
    template parser.

  • Documented-only deprecations of `Caqti_sql_io', `Caqti_lwt_sql_io',
    and `Caqti_async_sql_io' have been annotated.


[More details available in the documentation.]
<https://paurkedal.github.io/ocaml-caqti/caqti/tweaks.html>


First release of prbnmcn-dagger
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-prbnmcn-dagger/9311/2>


Igarnier announced
──────────────────

  I'm proud to announce the release of version 0.0.2 of
  [prbnmcn-dagger].

  This version adds Sequential Monte-Carlo, a.k.a. [particle
  filters]-based inference to the library.

  Here's the full changelog:
  • Dependency: `prbnmcn-stats.0.0.3' -> `prbnmcn-stats.0.0.4'
  • Add beta distribution to Gsl samplers
  • Refactor Cps monad
  • Add SMC inference
  • Simplify handler type, modularize effect definitions away from
    Cps_monad
  • Fix typo: bernouilli -> bernoulli (report by @nilsbecker)

  I also wrote the following article: [Applying Sequential Monte-Carlo
  to time series forecasting] It contains some use cases for the
  library, I hope some find it fun :)

  To conclude this post, and as a partial answer to @gasche 's
  [question] in an older thread, I believe that unlike some other
  inference techniques, single-shot continuations are enough to
  implement SMC. Without getting into the details, the implementation is
  very reminiscent of that of lightweight threading libraries. I look
  forward to experiment with a fibre-based implementation!


[prbnmcn-dagger] <https://github.com/igarnier/prbnmcn-dagger>

[particle filters] <https://en.wikipedia.org/wiki/Particle_filter>

[Applying Sequential Monte-Carlo to time series forecasting]
<http://probanomicon.xyz/blog/wind_power_forecast.html>

[question]
<https://discuss.ocaml.org/t/multi-shot-continuations-gone-forever/9072/5>


MirageOS 4.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-mirageos-4-0/9598/1>


Thomas Gazagnaire announced
───────────────────────────

  *On behalf of the MirageOS team, I am delighted to announce the
  release of MirageOS 4.0.0!* I'd like to send special thanks to
  @dinosaure and @Lortex who drove that release forward for multiple
  years.

  Since the first release of 2013, MirageOS has made steady progress
  toward deploying a self-managed internet infrastructure. The project’s
  initial aim was to self-host as many services as possible aimed at
  empowering internet users to securely deploy infrastructure to own
  their data and take back control of their privacy. MirageOS can
  securely deploy [static website hosting] with “Let’s Encrypt”
  certificate provisioning and a [secure SMTPstack] with security
  extensions. MirageOS can also deploy decentralised communication
  infrastructure like [Matrix], [OpenVPN servers], and [TLS tunnels] to
  ensure data privacy or [DNS(SEC) servers] for better authentication.

  The protocol ecosystem now contains [hundreds of libraries] and
  services millions of daily users. Over these years, major commercial
  users have joined the projects. They rely on MirageOS libraries to
  keep their products secure. For instance, the MirageOS networking code
  powers [Docker Desktop’s VPNKit], which serves the traffic of millions
  of containers daily. [Citrix Hypervisor] uses MirageOS to interact
  with Xen, the hypervisor that powers most of today’s public
  cloud. [Nitrokey] is developing a new hardware security module based
  on MirageOS. [Robur] develops a unikernel orchestration system for
  fleets of MirageOS unikernels. [Tarides] uses MirageOS to improve the
  [Tezos] blockchain, and [Hyper] uses MirageOS to build sensor
  analytics and an automation platform for sustainable agriculture.

  In the coming weeks, our blog will feature in-depth technical content
  for the new features that MirageOS brings, as well as a tour of the
  existing community and commercial users of MirageOS. Please reach out
  if you’d like to tell us about your story.


[static website hosting] <https://github.com/roburio/unipi>

[secure SMTPstack] <https://github.com/mirage/ptt>

[Matrix] <https://github.com/mirage/ocaml-matrix>

[OpenVPN servers] <https://github.com/roburio/openvpn>

[TLS tunnels] <https://github.com/roburio/tlstunnel>

[DNS(SEC) servers] <https://github.com/mirage/ocaml-dns>

[hundreds of libraries] <https://github.com/mirage/>

[Docker Desktop’s VPNKit]
<https://www.docker.com/blog/how-docker-desktop-networking-works-under-the-hood/>

[Citrix Hypervisor]
<https://www.citrix.com/fr-fr/products/citrix-hypervisor/>

[Nitrokey] <https://www.nitrokey.com/products/nethsm>

[Robur] <https://robur.io/>

[Tarides] <https://tarides.com/>

[Tezos] <https://tezos.com/>

[Hyper] <https://hyper.ag/>

Install MirageOS 4
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The easiest way to install MirageOS 4 is by using the opam version 2.1
  and `ocaml>=4.12.1`. Follow the [installation guide] for more details.

  ┌────
  │ $ opam update
  │ $ opam install 'mirage>4'
  └────

  /Note/: if you upgrade from MirageOS 3 you will need to manually clean
  the previous generated files (or call `mirage clean' before
  upgrading). You would also want to read [the full list of API
  changes].  You can see unikernel examples in [mirage/mirage-skeleton],
  [roburio/unikernels] or [tarides/unikernels].


[installation guide] <https://mirage.io/docs/install>

[the full list of API changes] <https://mirage.io/docs/breaking-changes>

[mirage/mirage-skeleton] <https://github.com/mirage/mirage-skeleton>

[roburio/unikernels] <https://github.com/roburio/unikernels>

[tarides/unikernels] <https://github.com/tarides/unikernels>


About MirageOS
╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  MirageOS is a library operating system that constructs unikernels for
  secure, high-performance, low-energy footprint applications across
  various hypervisor and embedded platforms. It is available as an
  open-source project created and maintained by the [MirageOS Core
  Team]. A unikernel can be customised based on the target architecture
  by picking the relevant MirageOS libraries and compiling them into a
  standalone operating system, which contains strictly the functionality
  necessary for the target. This minimises the unikernel’s footprint,
  increasing the security of the deployed operating system.

  The MirageOS architecture can be divided into operating system
  libraries, typed signatures, and a metaprogramming compiler. The
  operating system libraries implement various functionalities, ranging
  from low-level network card drivers, to full reimplementations of the
  TLS protocol, as well as the Git protocol to store versioned data. A
  set of typed signatures ensures that the OS libraries are consistent
  and work well in conjunction with each other. Most importantly,
  MirageOS is also a metaprogramming compiler that can input OCaml
  source code along with its dependencies, and a deployment target
  description in order to generate an executable unikernel, i.e., a
  specialised binary artefact containing only the code needed to run on
  the target platform. Overall, MirageOS focuses on providing a small,
  well-defined, typed interface with the system components of the target
  architecture.

  Read the full announcement on [mirage.io's blog].


[MirageOS Core Team] <https://github.com/orgs/mirage/teams/core/members>

[mirage.io's blog] <https://mirage.io/blog/announcing-mirage-40>


Anil Madhavapeddy then added
────────────────────────────

  For those curious about what some of the MirageOS libraries _are_,
  there is a raw Yaml list over at [mirage/mirage-repositories] listing
  most of them.  Conversion of this Yaml to HTML for the main mirage.io
  website would be a welcome contribution! :slight_smile:


[mirage/mirage-repositories]
<https://github.com/mirage/mirage-repositories/blob/main/repos.yml>


OCaml 4.14.0 is released
════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-14-0-is-released/9600/1>


octachron announced
───────────────────

  The OCaml team has the pleasure of celebrating the birthday of
  Alexander Grothendieck by announcing the release of OCaml version
  4.14.0.

  Some of the highlights in the 4.14.0 release are:

  • Integrated support for "go to definitions" in Merlin.
  • Standard library: new modules `In_channel' and `Out_channel', many
    new functions in Seq module, UTF decoding and validation support for
    strings and bytes.
  • Runtime optimisation: GC prefetching. Benchmarks show a speedup of
    around 20% in GC-heavy programs.
  • Improved error messages in particular for module-level error.
  • Deprecated functions and modules in preparation for OCaml 5.  In
    particular, the Stream and Genlex modules are now deprecated.
  • Type variables can be explicitly introduced in value and variant
    constructor declarations. For instance,
    ┌────
    │ val fold: ('acc -> 'elt -> 'acc) -> 'acc -> 'elt list -> 'acc
    │ type showable = Show: 'a * ('a -> string) -> showable
    └────
    can now be written as
    ┌────
    │ val fold: 'acc 'elt. ('acc -> 'elt -> 'acc) -> 'acc -> 'elt list -> 'acc
    │ type showable = Show: 'a. 'a * ('a -> string) -> showable
    └────
  • Tail-call with up to 64 arguments are now guaranteed to be optimized
    for all architectures.
  • Experimental tail modulo cons (TMC) transformation

  The full list of changes can be found in the changelog
  below. (/editor’s note: please follow the archive link for the full
  changelog/)

  Those releases are available as OPAM switches, and as a source
  download here:

  • <https://github.com/ocaml/ocaml/archive/4.14.0.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.14/ocaml-4.14.0.tar.gz>


ocaml-in-python.0.1.0: Effortless Python bindings for OCaml modules
═══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-in-python-0-1-0-effortless-python-bindings-for-ocaml-modules/9603/1>


Thierry Martinez announced
──────────────────────────

  I am happy to announce the first release of `ocaml-in-python': this is
  a Python package that exposes all OCaml modules as Python libraries,
  generating bindings on the fly. This can be seen as a dual of
  [`pyml_bindgen']: `pyml_bindgen' binds Python libraries in OCaml,
  while `ocaml-in-python' binds OCaml modules in Python.

  It is available from [GitHub] or *via* `opam': `opam install
  ocaml-in-python'

  Requirements: `OCaml' >= 4.13, `Python' >= 3.7.

  Once installed *via* `opam', the package should be registered in the
  Python environment:

  • either by registering the package with `pip' using the following
    command (requires Python >=3.8):
    ┌────
    │ pip install --editable "`opam var ocaml-in-python:lib`"
    └────
  • or by adding the following definition to the environment:
    ┌────
    │ export PYTHONPATH="`opam var share`/python/:$PYTHONPATH"
    └────

  Then, we can `import ocaml' in Python and use OCaml modules:
  ┌────
  │ Python 3.10.0 (default, Nov 10 2021, 19:16:14) [GCC 7.5.0] on linux
  │ Type "help", "copyright", "credits" or "license" for more information.
  │ >>> import ocaml
  │ >>> print(ocaml.List.map((lambda x : x + 1), [1, 2, 3]))
  │ [2;3;4]
  └────

  We can for instance compile an OCaml module on the fly from Python.
  ┌────
  │ >>> m = ocaml.compile('let hello x = Printf.printf "Hello, %s!\n%!" x')
  │ >>> m.hello('world')
  │ Hello, world!
  └────

  And we can require and use packages /via/ `findlib'.
  ┌────
  │ >>> ocaml.require("parmap")
  │ >>> from ocaml import Parmap
  │ >>> print(Parmap.parmap(
  │ ...   (lambda x : x + 1), Parmap.A([1, 2, 3]), ncores=2))
  │ [2;3;4]
  └────

  Details about the conversions are given in [`README.md'].

  Happy hacking!


[`pyml_bindgen']
<https://discuss.ocaml.org/t/ann-pyml-bindgen-a-cli-app-to-generate-python-bindings-directly-from-ocaml-value-specifications/8786>

[GitHub] <https://github.com/thierry-martinez/ocaml-in-python>

[`README.md']
<https://github.com/thierry-martinez/ocaml-in-python/blob/main/README.md>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'INRIA.

^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-03-22 13:01 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-03-22 13:01 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 14712 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 15 to 22,
2022.

Table of Contents
─────────────────

Friday 03/04 Intern presentations – open attendance!
Multicore OCaml: February 2022
OCaml 4.14.0, second release candidate
For Diversity and the OCaml Community: Outreachy Summer 2022
Understanding cancellation (in eio)
Atdpy: derive safe JSON interfaces for Python
Old CWN


Friday 03/04 Intern presentations – open attendance!
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/friday-03-04-intern-presentations-open-attendance/9429/8>


Continuing this thread, Aya announced
─────────────────────────────────────

  [Here is the link] to the video recording of the presentations! Thanks
  again to everyone who attended :pray: :tada:


[Here is the link]
<https://watch.ocaml.org/videos/watch/f3829e4b-e2cd-443e-8502-f406e893fe5f>


Multicore OCaml: February 2022
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-february-2022/9522/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the February 2022 [Multicore OCaml] monthly report! As with
  [previous updates], these have been compiled by me, @ctk21, @kayceesrk
  and @shakthimaan.

  Progress towards a stable OCaml 5.0.0 release have been moving forward
  at full steam, with most of the multicore OCaml work now happening
  directly within the main ocaml/ocaml repository. As a number of
  [deprecations] have happened in OCaml 5.0+trunk, it can be a little
  tricky in the immediate term to get a working development environment.
  You may find these resources helpful:
  • There is a [multicore monorepo] which is a 'fast clone and dune
    build' with a number of ecosystem libraries. (thanks @patricoferris)
  • There is an [alpha-opam-repository] which contains work-in-progress
    packages.  If a package you maintain is in there, now would be a
    good time to start releasing it to the mainline opam-repository.
    Remember that while we can propose changes, only the community
    maintainers of the relevant projects can do the actual release, so
    *your help with making OCaml 5.0-compatible releases of your
    projects would be very much appreciated*. (thanks @kit-ty-kate)

  For mainline development, the [compiler development newsletter] has an
  overview of what's been happening in the compiler.  From a multicore
  perspective:
  • the [ARM64 PR] has been merged, so your shiny Mac M1s will now work
  • we continue to work on the post-Multicore merge tasks for an
    upcoming 5.0.0+trunk release. The documentation efforts on the OCaml
    memory model, runtime system, and STW synchronization have also
    started.
  • The [eio project] is actively being developed which now includes UDP
    support with Eio's networking interface.  There has been [robust
    discussion] on several aspects of eio which is all influencing the
    next iteration of its design (thank you to everyone!). For those of
    you who do not wish to participate in public discussion, feel free
    to get in touch with me or @kayceesrk for a private discussion,
    particularly if you have a large OCaml codebase and opinions on
    concurrency. We'll summarise all these discussions as best we can
    over the coming months.
  • `Sandmark-nightly' and `Sandmark' have a custom variant support
    feature to build trunk, developer branches, or a specific commit to
    assess any performance regressions. The backend tooling with UI
    enhancements continue to drive the `current-bench' project forward.

  As always, the Multicore OCaml updates are listed first, which are
  then followed by the ecosystem tooling updates.  Finally, the
  sandmark, sandmark-nightly and current-bench project tasks are
  mentioned for your reference.

  /Editor’s note: please find the full update at the archive link
  above./


[Multicore OCaml] <https://github.com/ocaml-multicore/ocaml-multicore>

[previous updates] <https://discuss.ocaml.org/tag/multicore-monthly>

[deprecations] <https://github.com/ocaml/ocaml/blob/trunk/Changes>

[multicore monorepo]
<https://discuss.ocaml.org/t/awesome-multicore-ocaml-and-multicore-monorepo/9515>

[alpha-opam-repository]
<https://github.com/kit-ty-kate/opam-alpha-repository/tree/master/packages>

[compiler development newsletter]
<https://discuss.ocaml.org/t/ocaml-compiler-development-newsletter-issue-5-november-2021-to-february-2022/9459>

[ARM64 PR] <https://github.com/ocaml/ocaml/pulls/10972>

[eio project] <https://github.com/ocaml-multicore/eio>

[robust discussion] <https://discuss.ocaml.org/tag/effects>


OCaml 4.14.0, second release candidate
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-14-0-second-release-candidate/9528/1>


octachron announced
───────────────────

  The release of OCaml 4.14.0 is imminent.  As a last test that
  everything is in order, we are publishing a second release candidate
  for OCaml 4.14.0.

  We are directly jumping to the second release candidate due to a type
  system regression discovered during the release process of the first
  release candidate.

  Compared to the last beta, this release candidate includes a
  regression fix when typing recursive constraints, two backend fixes
  (one for the frame-pointer mode and the other one for the RISC-V
  architecture), one configuration fix for musl/arm64, and the manual
  chapter for the TMC transformation.

  If you find any bugs, please report them here:

  <https://github.com/ocaml/ocaml/issues>

  The full release of OCaml 4.14.0 is currently planned for next week.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.14.0~rc2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.14.0~rc2+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where `<option_list>' is a comma separated list of `ocaml-option-*'
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 4.14.0~rc2+flambda+nffa
  │ --packages=ocaml-variants.4.14.0~rc2+options,ocaml-option-flambda,ocaml-option-no-flat-float-array
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with `opam search ocaml-option'.

  The source code for the release candidate is also available at these
  addresses:

  • <https://github.com/ocaml/ocaml/archive/4.14.0-rc2.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.14/ocaml-4.14.0~rc2.tar.gz>


Changes since the last beta
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Type system regression fix
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#11101], [#11109]: A recursive type constraint fails on 4.14
    (Jacques Garrigue, report and review by Florian Angeletti)


[#11101] <https://github.com/ocaml/ocaml/issues/11101>

[#11109] <https://github.com/ocaml/ocaml/issues/11109>


Backend fixes
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#10688]: Move frame descriptor table from `rodata` to `data`
    section on RISC-V.  Improves support for building DLLs and PIEs. In
    particular, this applies to all binaries in distributions that build
    PIEs by default (eg Gentoo and Alpine). (Alex Fan, review by Gabriel
    Scherer)

  • [#11031]: Exception handlers restore the rbp register when using
    frame-pointers on amd64. (Fabrice Buoro, with help from Stephen
    Dolan, Tom Kelly and Mark Shinwell, review by Xavier Leroy)


[#10688] <https://github.com/ocaml/ocaml/issues/10688>

[#11031] <https://github.com/ocaml/ocaml/issues/11031>


Configuration fix
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [#11025], [#11036]: Do not pass -no-pie to the C compiler on
    musl/arm64 (omni, Kate Deplaix and Antonio Nuno Monteiro, review by
    Xavier Leroy)


[#11025] <https://github.com/ocaml/ocaml/issues/11025>

[#11036] <https://github.com/ocaml/ocaml/issues/11036>


Documentation
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • *updated entry* [#181], [#9760], +[#10740]: opt-in tail-modulo-cons
     (TMC) transformation
    ┌────
    │ let[@tail_mod_cons] rec map f li = ...
    └────
    (Frédéric Bour, Gabriel Scherer, Basile Clément, review by Basile
    Clément and Pierre Chambart, tested by Konstantin Romanov)


[#181] <https://github.com/ocaml/ocaml/issues/181>

[#9760] <https://github.com/ocaml/ocaml/issues/9760>

[#10740] <https://github.com/ocaml/ocaml/issues/10740>


For Diversity and the OCaml Community: Outreachy Summer 2022
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/for-diversity-and-the-ocaml-community-outreachy-summer-2022/9234/5>


Continuing this thread, Patrick Ferris said
───────────────────────────────────────────

  Thanks for the updates @pitag! For this summer's round I'll be
  mentoring a project to [Extend ocaml-geojson to support TopoJSON]
  which will likely be a separate package.  This is part of a larger
  effort I'm embarking on to provide better [geospatial libraries and
  tools in OCaml]!

  I'd be very happy to have a co-mentor if the project (or just the idea
  of Outreachy) interests anyone. Don't hesitate to reach out to me on
  discuss publicly or privately if you are interested or have more
  questions :camel:


[Extend ocaml-geojson to support TopoJSON]
<https://www.outreachy.org/apply/project-selection/#ocaml>

[geospatial libraries and tools in OCaml] <https://github.com/geocaml>


Understanding cancellation (in eio)
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/understanding-cancellation-in-eio/9369/45>


Deep in this thread, Simon Cruanes announced
────────────────────────────────────────────

  I still have reservations about the capabilities aspect of Eio, but
  the structured concurrency part looks very nice.  Just a few notes,
  for future reference to readers of this thread (if I haven't missed
  them being posted above already):

  Another interesting post about structured concurrency and
  cancellation: <https://250bpm.com/blog:71/>

  A structured concurrency library in python: [trio], which might be
  relatively similar to Eio's switches in concept (esp since @talex
  linked [this])?

  Companion post to the trio blogpost:
  <https://vorpus.org/blog/timeouts-and-cancellation-for-humans/> which
  is directly relevant to the current topic.


[trio] <https://trio.readthedocs.io/en/stable/index.html>

[this]
<https://vorpus.org/blog/notes-on-structured-concurrency-or-go-statement-considered-harmful/>


Atdpy: derive safe JSON interfaces for Python
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/atdpy-derive-safe-json-interfaces-for-python/9544/1>


Martin Jambon announced
───────────────────────

  On behalf of the ATD team, I'd like to announce atdpy, which is part
  of the release 2.3.x of the ATD tools. For now, the best installation
  method with via opam:

  ┌────
  │ $ opam install atdpy
  └────

  Atdpy is a new backend for [ATD]. It takes a collection of type
  definitions and derives Python classes with mypy type annotations that
  validate the JSON data.

  A [short introduction] is included in the documentation.

  Use cases:
  • Safe communication with another program that also uses an ATD
    interface. Other supported languages are OCaml (including
    Bucklescript), Java, and Scala.
  • Need for [mostly] type-safe Python methods via mypy.
  • Need for a good Python API to communicate with an OCaml executable
    or service.
  • Need for sum types (variants, algebraic data types, tagged
    unions). ATD sum types are ordinary types that include pure enums.

  Atdpy was developed as part of our work on [Semgrep] at [r2c]. Many
  thanks to @mseri for his massive help during the opam release of the 7
  ATD packages, and to the Ahrefs folks and @Khady in particular for
  supporting the project.


[ATD] <https://github.com/ahrefs/atd>

[short introduction] <https://atd.readthedocs.io/en/latest/atdpy.html>

[Semgrep] <https://semgrep.dev/>

[r2c] <https://r2c.dev/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-03-15  9:59 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-03-15  9:59 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 13917 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 08 to 15,
2022.

Table of Contents
─────────────────

Robur Reproducible Builds
OCaml TeXmacs plugin
Release of ocaml-sf/learn-ocaml:0.14.0
Tutorial: Roguelike with effect handlers
Awesome Multicore OCaml and Multicore Monorepo
ppx_viewpattern initial release
Old CWN


Robur Reproducible Builds
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-robur-reproducible-builds/8827/6>


Continuing this thread, Hannes Mehnert announced
────────────────────────────────────────────────

  The background article by @rand is now online
  <https://r7p5.earth/blog/2022-3-7/Builder-web%20visualizations%20at%20Robur>


OCaml TeXmacs plugin
════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-03/msg00009.html>


Nicolas Ratier announced
────────────────────────

  I made a basic OCaml plugin for TeXmacs (<http://www.texmacs.org>) I
  would like to keep it simple, but comments and improvements are
  welcome.
  <http://forum.texmacs.cn/t/ocaml-a-basic-ocaml-plugin-for-texmacs/813>


Release of ocaml-sf/learn-ocaml:0.14.0
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-ocaml-sf-learn-ocaml-0-14-0/9491/1>


Yurug announced
───────────────

  We are very pleased to announce the latest stable release of
  [Learn-OCaml], version `0.14.0'.

  Many thanks to all users and developers who reported bugs, contributed
  features, or patches! Special thanks to @erikmd who made many of the
  changes included in this release.

  A (mostly) comprehensive list of the features, fixes, and enhancements
  offered by this release is available in [the Release Notes ].

  A brief and incomplete summary of the changes:

  • A long-standing bug has been fixed. This bug was triggered when the
    user opened several sessions: the auto-sync mechanism could lead to
    overwriting the student's code with an older version.

  • The release assets now include a zip file containing the contents of
    the `www` directory. This eases the usage of the distributed
    binaries.

  If need be, feel free to open issues in the [Learn-OCaml bug tracker]
  or the [learn-ocaml.el bug tracker], or post in this thread to share
  thoughts or experience-feedback.

  Happy OCaml learning and teaching!


[Learn-OCaml] <https://github.com/ocaml-sf/learn-ocaml>

[the Release Notes ]
<https://github.com/ocaml-sf/learn-ocaml/releases/tag/v0.14.0>

[Learn-OCaml bug tracker]
<https://github.com/ocaml-sf/learn-ocaml/issues>

[learn-ocaml.el bug tracker]
<https://github.com/pfitaxel/learn-ocaml.el/issues>


Tutorial: Roguelike with effect handlers
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/tutorial-roguelike-with-effect-handlers/9422/18>


Continuing this thread, stw said
────────────────────────────────

  Sorry about the late reply, I was busy actually verifying that my
  concept works out. Thankfully it does :smile:

  The UI framework is inspired by [Concur] which means that every widget
  listens for some set of events and suspends computation until one of
  these events occurs. Once it does, it continues execution until it
  encounter the next await at which point it will suspend once
  more. Once a widget has fulfilled its purpose it terminates with some
  return value (e.g. text input is confirmed with enter -> return with a
  string).  Complex UIs are then built by composing simpler widgets. A
  more detailed explanation can be found in the link above.

  I've implemented this concept using an await function that takes a
  list of triggers and a handler for each possible event:
  ┌────
  │ effect Await : Event.t list -> Event.t
  │ let rec await triggers handler =
  │   handler (EffectHandlers.perform (Await triggers))
  │ 
  │ let rec check_box checked  =
  │   (* display check box *)
  │   ...;
  │   await [Mouse_press; Key_press] (function
  │   | Mouse_press ->
  │     print_endline "I've been (un-)checked!";
  │     check_box (not checked)
  │   | Key_press -> (* Terminate if any key is pressed *) checked)
  └────

  Every widget can then be implemented as a function which displays the
  widget and performs an `Await triggers' which is resumed by passing an
  event from `triggers', for example the check box above.

  The most complex widget I've implemented so far is a single line text
  input. It can be clicked or selected with tab.  Moving the mouse while
  holding the button down changes the selection. As an automaton:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/5/574e164b6189608283de32d9f375534ca80caffa.png>

  Obviously, this is not a directed acyclic graph and therefore not a
  perfect fit for the implicit state stored in the
  continuation. Specifically, `Pressed' has an edge to one of its
  multiple parents. We can extract the `Pressed' state into its own
  function and therefore avoid this issue by 'duplicating' this
  state. Now `Pressed' no longer has multiple parents:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/7/70a34d2f4bb81800a5e3b12b8e49147a0d80ece4.png>

  Some cycles remain and we can't remove them because they are essential
  to the functionality. Instead we throw an `exception Repeat' that
  returns us to a parent node (explicitly shown for Focused -> Pressed
  -> Released -> Focused).  To do that we modify `await':
  ┌────
  │ let rec await triggers handler =
  │   try handler (EffectHandlers.perform (Await triggers)) with
  │   | Repeat -> await triggers handler
  └────
  In the end this results in this main method for the text input, with
  only minor simplifications:
  ┌────
  │ method execute =
  │   (* Represent the Pressed state.
  │      We await the Mouse_release and handle Mouse_motion while we wait. *)
  │   let pressed (x,_) =
  │     selection <- Point x;
  │     await [`Mouse_release; `Mouse_motion] @@ function
  │     | `Mouse_release (_, LMB) ->
  │       ()
  │     | `Mouse_motion (x,_) ->
  │       self#select x;
  │       raise Repeat (* This restarts the await function *)
  │     | _ ->
  │       raise Repeat
  │   in
  │ 
  │   (* We start in the Unfocused state *)
  │   begin
  │     await [`Mouse_press; `Key_press] @@ function
  │     | `Mouse_press (pos, LMB) ->
  │        (* We have registered the press, but only when it is released
  │ 	  will we be focused. *)
  │        pressed pos
  │     | `Key_press Tab ->
  │       selection <- Area (0, List.length keys)
  │     | _ -> raise Repeat
  │   end;
  │ 
  │   (* We move into the Focused state *)
  │   begin
  │     await [`Codepoint; `Key_press; `Mouse_press] @@ function
  │     | `Key_press Tab | `Key_press Return ->
  │       () (* The only path without raising Repeat.
  │ 	    Therefore we only leave this await when a tab or return occurs *)
  │     | `Mouse_press (pos, LMB) ->
  │       pressed pos;
  │       raise Repeat
  │     | `Key_press c ->
  │       self#insert c;
  │       raise Repeat
  │     | _ -> raise Repeat
  │   end;
  │   (* We have reached the finished state. We can now return the entered text. *)
  │   self#text
  └────
  I think that this method captures the automaton above quite nicely and
  can be relatively easily understood (hopefully even when one is
  unfamiliar with the framework and accepts that some magic is happening
  in the background (: ).  Implementing automatons in terms of effect
  handlers seems to work quite well, at least for games and UIs. What
  these automatons have in common is that they can be thought of as
  flows, starting at some state and ending at one of multiple final
  states and only have few edges that don't fit this scheme, turning
  them into 'directed almost acyclic graphs'.

  There is obviously a lot more necessary for a UI framework
  (e.g. resizing the window/widgets, delegating the events to the
  correct widget, composing widgets, drawing on the screen etc.) and I
  plan to write about it at some point in the future. But for that I
  will first need to actually solve these problems as right now their
  implementation is quite barebones. The code can be found here for
  those interested (still very early in development!):
  <https://github.com/Willenbrink/bogue/>


[Concur]
<https://ajnsit.github.io/concur-documentation/ch02-01-anatomy-of-a-widget.html>


Awesome Multicore OCaml and Multicore Monorepo
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/awesome-multicore-ocaml-and-multicore-monorepo/9515/1>


Patrick Ferris announced
────────────────────────

  A short announcement of two repositories which some people may or may
  not have seen. Firstly, [Awesome Multicore OCaml], a place for
  gathering all of the rapidly changing experiments, ideas, libraries
  and resources for Multicore OCaml (including some of the discuss
  threads). If you are working on something or feel anything is missing
  please open a PR!

  Secondly, a [Multicore Monorepo] which aims to provide a very quick
  and easy way to try out effects and parallelism with quite a few
  libraries (such as Eio, Dream etc.). The breaking changes introduced
  by OCaml 5 can make it frustrating to get such a setup in place,
  although this is less and less true thanks to the [alpha
  repository]. The idea is that you should just be able to clone this
  repository, create a new `5.0.0+trunk' switch, install `dune' and
  start hacking. If that's not the case please do open an issue.


[Awesome Multicore OCaml]
<https://github.com/patricoferris/awesome-multicore-ocaml>

[Multicore Monorepo]
<https://github.com/patricoferris/ocaml-multicore-monorepo>

[alpha repository]
<https://github.com/kit-ty-kate/opam-alpha-repository>


ppx_viewpattern initial release
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ppx-viewpattern-initial-release/9516/1>


Simmo Saan announced
────────────────────

  I'm glad to announce the initial release of [ppx_viewpattern] –
  transformation for view patterns in OCaml.

  It _attempts to_ imitate [Haskell view patterns]. I wrote this ppx
  rewriter mostly out of curiosity, rather than need, but it turned out
  neat enough that others might find it interesting or even useful.


[ppx_viewpattern] <https://github.com/sim642/ppx_viewpattern>

[Haskell view patterns]
<https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/view_patterns.html>

Syntax
╌╌╌╌╌╌

  Use `[%view? pat when exp]' as a pattern to apply `exp' to whatever
  the pattern is matching and match the result of the `exp' application
  against `pat'.  This is analogous to the Haskell view pattern `exp ->
  pat'.

  The above extension node payload syntax is the best I could come up
  with to combine an expression and a pattern.  Honestly, I was even
  surprised that `when exp' is attached to a pattern in the AST (not a
  case), because normally it isn't part of the pattern itself.


Example
╌╌╌╌╌╌╌

  This allows one to write
  ┌────
  │ (* These cases are exactly like reduction rules! *)
  │ let rec reduce = function
  │   | Add (Int n1, Int n2) -> Some (Int (n1 + n2))
  │   | Add ([%view? Some p1' when reduce], p2) -> Some (Add (p1', p2))
  │   | Add (p1, [%view? Some p2' when reduce]) -> Some (Add (p1, p2'))
  │   (* ... *)
  │   | _ -> None
  └────
  instead of
  ┌────
  │ (* These nested cases are so annoying! *)
  │ let rec reduce = function
  │   | Add (Int n1, Int n2) -> Some (Int (n1 + n2))
  │   | Add (p1, p2) ->
  │     begin match reduce p1 with
  │       | Some p1' -> Some (Add (p1', p2))
  │       | None ->
  │ 	begin match reduce p2 with
  │ 	  | Some p2' -> Some (Add (p1, p2'))
  │ 	  | None -> None
  │ 	end
  │     end
  │   (* ... *)
  │   | _ -> None
  └────

  See [`examples/' on GitHub] for more.


[`examples/' on GitHub]
<https://github.com/sim642/ppx_viewpattern/tree/master/example>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-03-01 13:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-03-01 13:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 25341 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of February 22 to
March 01, 2022.

Table of Contents
─────────────────

data-encoding.0.5 release
Tutorial: Roguelike with effect handlers
For Diversity and the OCaml Community: Outreachy Summer 2022
Bogue, the OCaml GUI
Friday 03/04 Intern presentations – open attendance!
Affect: Composable concurrency primitives for OCaml 5.0
Segfault Systems Joins Tarides
OCaml User Survey 2022
Old CWN


data-encoding.0.5 release
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-data-encoding-0-5-release/9420/1>


Raphaël Proust announced
────────────────────────

  On behalf of [Nomadic Labs], I'm happy to announce the release of
  data-encoding version 0.5.

  This new version brings several bug fixes, some increased test
  coverage, minor improvements in the API, and a major new feature:


[Nomadic Labs] <https://www.nomadic-labs.com/>

Compact encodings: sub-byte tag sizes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This new version provides a new set of combinators for _compact_
  encodings. These compact encodings will handle all the verbose and
  error-prone bit-twidling process needed to combine multiple sub-byte
  discriminators into a single byte-size one.

  E.g., the encoding `let e1 = either (either bool unit) (option bool)'
  uses three bits in the shared tag and zero bytes after that; the
  encoding `let e2 = either int32 int64' uses one bit in the shared tag
  and either 4 or 8 bytes to represent the integer; the product encoding
  `let ee = tup2 e1 e2' uses four (3 + 1) bits in the shared tag and
  either 4 or 8 bytes to represent the integer of `e2'.


How to get
╌╌╌╌╌╌╌╌╌╌

  The code is available under MIT license on
  <https://gitlab.com/nomadic-labs/data-encoding>.

  It can be installed via `opam'.


Dario Teixeira asked and Raphaël Proust replied
───────────────────────────────────────────────

        Hi @raphael-proust! I have a question regarding the
        connection between `data-encoding' and
        `json-data-encoding', also developed at Nomadic Labs. The
        latter seems tied to JSON, whereas the former is more
        flexible, supporting also binary encodings. However, since
        `data-encoding' also supports JSON, doesn't it subsume
        `json-data-encoding' completely?

  The `data-encoding' library uses `json-data-encoding' for its JSON
  backend. It delegates conversion from OCaml values into and from JSON
  to the primitives provided in the interface of `json-data-encoding'.

  In a way, yes, as an end-user you don't need to use
  `json-data-encoding' directly because you can use the `Json' module of
  `data-encoding' instead. There are three possible reasons why you
  might add `json-data-encoding' as a (non-transitive) dependency to
  your project and use it directly in your code:

  • You want to keep the dependency set and the number of abstraction
    layers as small as possible. E.g., in order to reduce binary size.
  • You want some static guarantees that some encodings are only every
    used for JSON. E.g., in your logging system.
  • You need to define a JSON encoding which is rejected by
    `data-encoding' on grounds that it is invalid in binary. Note that
    • This is very specific to some combinators but basically some
      combinators will reject their inputs (raise `Invalid_argument')
      because using the serialiser would lead to undecodable data. Most
      typically, this happens if you try to concatenate two fields of
      unknown length. Decoding the result becomes a guessing game as to
      were one field stops and where the next begins. These could easily
      be represented as an array in JSON which includes all the
      delimiters you need to decode it.
    • There are other workarounds (e.g., prefixing the fields with a
      length field), but going for the JSON encoding directly is a valid
      approach if you only need JSON.


Raphaël Proust later announced
──────────────────────────────

  Version 0.5.1 of the data-encoding has just been released.

  This is a bugfix release making one of the library's internal checks
  more permissive. Without this fix (i.e., using version 0.5), some
  valid encodings are rejected (raising `Invalid_argument') by the
  library.

  You can update via opam: `opam install data-encoding.0.5.1'


Tutorial: Roguelike with effect handlers
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/tutorial-roguelike-with-effect-handlers/9422/1>


art-w announced
───────────────

  The recent conversations about [`eio' 0.1] and [agnostic blocking]
  have made me very curious about effect handlers. The multicore team
  has done an [awesome] job with their [tutorials], [examples] and
  [talks], but the laymen have been too quiet for such an exciting
  feature! Where are all the blog posts about how "you could have
  invented algebraic effects" and "one-shot continuations are like
  spaghetti"?

  In any case, I'm hoping to tease some of you into trying them out with
  [a simple tutorial about programming a roguelike with effect handlers]
  :)

  There's nothing new here besides the fun use-case! So if you already
  have an intuitive understanding of the syntax and motivations, you may
  be more interested by [a deeper look at the scope of effect handlers]
  – and a soft introduction to some less common features of the type
  system. /(this link was previously posted deep into the `eio' thread)/

  I would be grateful if you spot any mistake! I'm also curious of other
  fun applications for effect handlers… and if you feel like sharing
  your own surprises and discoveries, I believe it could really help
  others learn faster :)


[`eio' 0.1]
<https://discuss.ocaml.org/t/eio-0-1-effects-based-direct-style-io-for-ocaml-5/9298/97>

[agnostic blocking]
<https://discuss.ocaml.org/t/how-to-block-in-an-agnostic-way/9368/51>

[awesome] <https://github.com/patricoferris/awesome-multicore-ocaml>

[tutorials] <https://github.com/ocamllabs/ocaml-effects-tutorial>

[examples] <https://github.com/ocaml-multicore/effects-examples>

[talks]
<https://watch.ocaml.org/videos/watch/74ece0a8-380f-4e2a-bef5-c6bb9092be89>

[a simple tutorial about programming a roguelike with effect handlers]
<https://hackmd.io/@yF_ntUhmRvKUt15g7m1uGw/BJBZ7TMeq>

[a deeper look at the scope of effect handlers]
<https://hackmd.io/@yF_ntUhmRvKUt15g7m1uGw/Bk-5NXh15>


Kiran Gopinathan then said
──────────────────────────

  Great blog post! That seems like a very elegant implementation!

  Funny you should make a rougelike :smiley: , I guess effect handlers +
  games might be popular for games, because I also had a blog post about
  effect handlers and their applications, in particular for games,
  although in my case it was for animations:

  <https://gopiandcode.uk/logs/log-bye-bye-monads-algebraic-effects.html>


gasche also replied
───────────────────

  Note: the "upstream" status of effect handlers is a little
  uncertain/confusing right now. Your blog post (I didn't get a chance
  to read it yet, but it sounds very nice!) uses the experimental syntax
  of multicore-4.12+effects, but that syntax was intentionally /not/
  upstreamed, and it will /not/ be part of OCaml 5.0.

  I think there is a risk of confusion because the community is aware
  that Multicore OCaml has effect handlers, and also that Multicore
  OCaml has been merged upstream. So it can be tempting to believe that
  the upcoming OCaml release (or maybe one or two releases after that,
  we said the first Multicore release would be more like a preview) will
  support effect handlers as a language feature. It will not! Effects as
  a language feature were removed from Multicore OCaml before the
  upstream merge. And /no one knows/ if/when they will be supported
  upstream.

  So: I think that your blog posts on using effect handlers could have
  somewhere a short mention that the code is using an experimental
  extension of OCaml that is not supported by the upstream
  implementation.


  The reasoning for this choice is that we want to give a chance to a
  type system for effect handlers, but that still need quite a bit more
  time than the Multicore runtime itself. We don't want to encourage the
  ecosystem to rely on untyped effects, if it means a lot of pain
  upgrading to typed effects later (or risk having to support both).

  5.0 only contains basic support for effect handlers as a /runtime
  primitive/, but dos /not/ support handlers as a /language feature/. I
  think they should be considered experimental: you can rely on them for
  their intended purpose of exposing a flexible interface for concurrent
  fibers, but uses beyond that may break in the future.

  So, in a sense, we don't want people to use them. It's of course fine
  to use experimental features from experimental forks of the OCaml
  compiler (effect handlers, modular implicits or explicits, runtime
  type representations and what not), and the people working on these
  experimental features do benefit from other people trying them and
  giving them feedback. But we don't want people to depend on it /in
  production/, whatever that means. (For example, code using it is
  likely to get stuck on 4.12 forever and never see an upgrade to
  upcoming OCaml versions, although of course people could choose to
  port the experimental branch forward.)


For Diversity and the OCaml Community: Outreachy Summer 2022
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/for-diversity-and-the-ocaml-community-outreachy-summer-2022/9234/4>


Sonja Heinze announced
──────────────────────

  Just in case anyone is actually interested in this: the project
  submission deadline has been extended from March 4th to March 23rd. So
  the updated timeline now looks as follows:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/5/534ca9a08bce10f13530e6c98eae1797fdf13e52.png>

  where 2. and 3. probably need to be done a bit in parallel.


Bogue, the OCaml GUI
════════════════════

  Archive: <https://discuss.ocaml.org/t/ann-bogue-the-ocaml-gui/9099/23>


sanette announced
─────────────────

  Hi, some new developments. I have implemented a new `Sdl_area' widget
  where one can conveniently issue any SDL function (from the SDL
  Renderer API).

  Here is (below) the new 'labelled graph' example. In this example I am
  using regular "label" widgets for creating the nodes, and I am using
  an Sdl_area for drawing the lines.

  The nice things for labels to be regular widgets is that one can click
  on them. To demonstrate this, in this example they react to a click by
  jumping to another random location (with animation).

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/f/f9575838a7e5ea4c58485b955e96f7c9bbda384f_2_1266x1000.png>

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/d/d6958e266f27a557c5c8d8d37099d532eacf2c1c.gif>

  ┌────
  │ open Bogue
  │ module W = Widget
  │ module L = Layout
  │ 
  │ let n = 15 (* number of discs *)
  │ let radius = 20
  │ let width = 800
  │ let height = 600
  │ 
  │ let c = Draw.find_color "#e5b92c"
  │ let cb = Draw.find_color "#7b6b35"
  │ let disc_style = Style.(
  │     create ~border:(
  │       mk_border ~radius (mk_line ~color:Draw.(opaque c) ~width:1 ~style:Solid ()))
  │       ~background:(color_bg Draw.(opaque cb)) ())
  │ 
  │ let background = L.style_bg Style.(
  │     of_bg (gradient ~angle:45. Draw.[opaque grey; opaque black]))
  │ 
  │ let fg = Draw.(opaque white)
  │ 
  │ let create_disc i (x,y) =
  │   let w = 2*radius + 1 in
  │   let bg = Box.create ~style:disc_style ~width:w ~height:w () in
  │   W.label ~fg (string_of_int i)
  │   |> L.resident ~background:(L.box_bg bg) ~x:(x-radius) ~y:(y-radius) ~w ~h:w
  │ 
  │ let move_disc (x,y) d =
  │   let (x0, y0) = L.xpos d, L.ypos d in
  │   L.animate_x d (Avar.fromto x0 x);
  │   L.animate_y d (Avar.fromto y0 y)
  │ 
  │ let random_center _ =
  │   radius + Random.int (width - 2*radius),
  │   radius + Random.int (height - 2*radius)
  │ 
  │ let area =
  │   let sdlw = W.sdl_area ~w:width ~h:height () in
  │   let sdla = W.get_sdl_area sdlw in
  │   let centers = Array.init n random_center in
  │   let color = Draw.(opaque grey) in
  │   let draw_lines renderer = let open Draw in
  │     for i = 0 to n - 2 do
  │       let x0, y0 = to_pixels centers.(i) in
  │       let x1, y1 = to_pixels centers.(i+1) in
  │       line renderer ~color ~thick:6 ~x0 ~y0 ~x1 ~y1
  │     done in
  │   Sdl_area.add sdla draw_lines;
  │   let discs = Array.mapi create_disc centers |> Array.to_list in
  │   (* move the disc when click on it *)
  │   List.iteri (fun i d ->
  │       W.on_click ~click:(fun _ ->
  │ 	  centers.(i) <- random_center 0;
  │ 	  Sdl_area.update sdla;
  │ 	  let x,y = centers.(i) in
  │ 	  move_disc (x - radius, y - radius) d) (L.widget d))
  │     discs;
  │   L.superpose ~w:width ~h:height ~background (L.resident sdlw :: discs)
  │ 
  │ let board = Bogue.make [] [area]
  │ 
  │ let () = Bogue.run board
  └────


Friday 03/04 Intern presentations – open attendance!
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/friday-03-04-intern-presentations-open-attendance/9429/1>


Aya announced
─────────────

  This is Aya, one of the three [Outreachy] interns working on OCaml
  this winter :camel: After 3 very fast months, our internships are
  already coming to a close. We have had such a great time working on
  our projects and learning OCaml that we want to hold an event to mark
  the end of the internships, and we decided to open it up to the
  community :tada:

  As you might have seen in the [initial announcement], @pitag
  @shonfeder @gs0510 @tmattio and @pkel all volunteered to mentor us
  from December 2021 to now. Thank you all so so much for mentoring us
  and introducing us to OCaml :heart: :fire: It's been such an enjoyable
  experience!

  We are inviting anyone who is interested to attend a virtual session
  of 3 short presentations on *Friday, March 4th, 4-5pm CET* (we will
  post the link to join on Thursday). There will be time for Q&A after
  each presentation, and the whole session will be recorded and posted
  online shortly after as well.

  • @ayc9 will present on updating a standard PPX deriver (mentors:
    @pitag @shonfeder)
  • @SaySayo will present on syntax highlighting and other updates to
    the vscode extension (mentors: @tmattio @gs0510)
  • @JiaeK will present on building a basic monitoring dashboard for
    [ocaml.org] (mentors: @tmattio)

  We hope you can make it!

  -@ayc9 @SaySayo @JiaeK


[Outreachy] <https://outreachy.org/>

[initial announcement]
<https://discuss.ocaml.org/t/announcing-our-new-outreachy-interns/8932>

[ocaml.org] <http://ocaml.org/>


Affect: Composable concurrency primitives for OCaml 5.0
═══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/affect-composable-concurrency-primitives-for-ocaml-5-0/9430/1>


Daniel Bünzli announced
───────────────────────

  I looked a bit into the kind of fiber abstraction and concurrency
  structure I would like to use with the new tools OCaml 5.0 is going to
  offer.  You can find some results in affect's [`Fiber'] module.

  This fiber abstraction supports terminating by returning values or
  abnormally (by aborting or via a spurious exception). Termination of a
  fiber is aligned on function scopes: all the fibers spawn by a fiber
  function have to terminate in order for it to terminate.

  This means that if your fiber returns a value it waits for its spawns
  to terminate (in any way) before returning the value. And if your
  fiber returns abnormally (uncaught eception or explicit abort) it
  first aborts all its non-terminated spawns before returning abnormally
  – this provides affect's notion of cancellation.

  Explicit fiber aborts raise the `Abort' exception in fibers. Combined
  with a disciplined use of `Fun.protect' and an optional `finally'
  handler specified at fiber spawn, this lets them release the
  ressources they may hold when it's time to say goodbye.

  The module also provides a generic way of blocking and unblocking
  fibers that you can use to interface with your favourite event
  loop. It does so without requiring to fiddle with effects, you just
  need to make judicious use of [`Fiber.block'] and provide a suitable
  function to `Fiber.run''s built-in scheduler to let it know about
  fibers that can be unblocked.

  A grab bag of comments:

  1. The first goal of affect is to seek a concurrency and abort
     structure that are easy to understand, use and compose with event
     loops. Right now some efficiency and implementation aspects need to
     be improved. This will likely change the exposed set of primitive
     effects which doesn't feel exactly right yet (if you want to build
     your own scheduler).

  2. I use abort rather than cancel terminology. From my non-native
     english speaker perspective, cancelling is more about not doing
     something that was planned but didn't happen yet. Aborting is more
     about stopping something that is going on. It also melds better
     with the uncaught exception case.

  3. Say no to `unit' soups! Let fibers return values.

  4. At that point I don't feel the need to add a promise/future
     abstraction to the toolbox. The whole point of direct style is to
     get rid of this async madness.

  5. There's no synchronisation structure yet. Semaphores are always
     useful for throttling so I'll certainly add that at some point or a
     more fundamental primitive like an mvar.

  6. The [`Funix'] module has a few fiber friendly `Unix' module
     functions for playing with timers and the network, see [`ping.ml']
     for an example of use. In practice you want to be able to use
     something else than `select(2)' though. There are various ways one
     could go about this, see for example point 6. in these [design
     notes].

  7. The [`mouse.ml'] has a basic example on how to interface with the
     SDL event loop which provides another example on how one goes to
     interface `Fiber' with event loops.

  I'm not fully convinced by everything yet. It will certainly need one
  or two more design rounds. If you try it, feel free to comment or make
  suggestions on the issue tracker.

  Home page: <https://erratique.ch/software/affect>

  API docs: <https://erratique.ch/software/affect/doc/> (or `odig doc
  affect')

  Install:
  ┌────
  │ opam switch create 5.0.0+trunk
  │ opam pin add https://erratique.ch/repos/affect.git
  └────


[`Fiber'] <https://erratique.ch/software/affect/doc/Fiber/index.html>

[`Fiber.block']
<https://erratique.ch/software/affect/doc/Fiber/index.html#val-block>

[`Funix'] <https://erratique.ch/software/affect/doc/Funix/index.html>

[`ping.ml']
<https://github.com/dbuenzli/affect/blob/master/test/ping.ml>

[design notes]
<https://github.com/dbuenzli/affect/blob/master/DESIGN.md>

[`mouse.ml']
<https://github.com/dbuenzli/affect/blob/master/test/mouse.ml>


Segfault Systems Joins Tarides
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/segfault-systems-joins-tarides/9431/1>


Thomas Gazagnaire announced
───────────────────────────

  @kayceesrk and I are delighted to announce that Segfault Systems, a
  spinout from IIT-Madras, is joining Tarides.  Tarides has worked
  closely with Segfault Systems over the last couple of years, most
  notably on the award-winning Multicore OCaml project and the
  upstreaming plans for OCaml 5.0. This alliance furthers the goals of
  Tarides, bringing the compiler and benchmarking expertise of the
  Segfault team directly into the Tarides organisation, where it can be
  commercially funded and supported.

  All of Segfault Systems’ existing responsibilities and open-source
  commitments will migrate over to Tarides, where work will continue
  towards the three main objectives in 2022:

  • Releasing OCaml 5.0 with support for domains and effect handlers
  • Supporting the ecosystem to migrate the OCaml community over to
    OCaml 5.0
  • Improving developer productivity for OCaml 5.0 by releasing the best
    platform tools

  This alliance will complement the commercial offerings of Tarides –
  already strengthened by the integration of [OCaml Labs] – and
  contribute to Tarides’ mission: empowering developers, communities,
  and organisations to adopt OCaml as their primary programming
  experience by providing training, expertise, and development services
  around the OCaml language.

  Read the full announcement [here], including details of our goals and
  the focus for 2022. This alliance brings the headcount of Tarides up
  to 60+ people, all working towards making OCaml the best language for
  any and every project. Join our team and reach out for commercial
  services at [https://tarides.com/].


[OCaml Labs] <https://discuss.ocaml.org/t/ocaml-labs-joins-tarides/9229>

[here]
<https://tarides.com/blog/2022-03-01-segfault-systems-joins-tarides>

[https://tarides.com/] <https://tarides.com/>


OCaml User Survey 2022
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-user-survey-2022/9433/1>


Kim Nguyễn announced
────────────────────

  we are delighted to announce the [OCaml User Survey 2022]. With this
  survey, the OCSF is trying to get a better picture of the OCaml
  community and its needs. It would be very helpful if you could take a
  few minutes (10 to 15) to fill the survey and share it with other
  OCaml programmers.

  [https://forms.gle/oKy2Joz1cZhCPNtf6]

  The survey is run by the [OCaml Software Foundation]. It builds on
  [the previous iteration] issued in 2020. The results will be published
  here on discuss and on the [website of the OCSF]. We would like to
  particularly thank @cjr for his help as well as everyone who commented
  on the previous survey. We tried our best to take all remarks into
  account but surely missed something. Don't hesitate to give us your
  feedback (you can post here or send me a message/email).

  The survey will remain opened until March 11th 2022 (AOE).


[OCaml User Survey 2022] <https://forms.gle/oKy2Joz1cZhCPNtf6>

[https://forms.gle/oKy2Joz1cZhCPNtf6]
<https://forms.gle/oKy2Joz1cZhCPNtf6>

[OCaml Software Foundation] <https://ocaml-sf.org/>

[the previous iteration]
<https://discuss.ocaml.org/t/ann-ocaml-user-survey-2020/6624>

[website of the OCSF] <https://ocaml-sf.org/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-02-22 12:43 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-02-22 12:43 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of February 15 to 22,
2022.

Table of Contents
─────────────────

OCAML goes Quantum computing
Layout Parsing and Nicely Formatted Error Messages
ptime 1.0.0 and mtime 1.4.0
Timedesc 0.6.0
OCaml from the Very Beginning now free in PDF and HTML formats
Dune 3.0.0
Blog Post "2021 at OCamlPro"
Packstream 0.1
OCaml 4.14.0, first beta release
Old CWN


OCAML goes Quantum computing
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-goes-quantum-computing/9333/1>


Florian said
────────────

  It seems that silently OCAML is now entering the Quantum world.  It
  looks that the Interpreter for "Twist" [New programming language for
  Quantum computing] is made with OCAML: [GitHub for Twist]


[New programming language for Quantum computing]
<https://scitechdaily.com/twist-mits-new-programming-language-for-quantum-computing/>

[GitHub for Twist] <https://github.com/psg-mit/twist-popl22>


Anton Kochkov then added
────────────────────────

  Haskell has a nice package for quantum computing - Quipper. I
  recommend to take a look to it for inspiration as well:
  • <https://hackage.haskell.org/package/quipper-language>
  • <http://www.mathstat.dal.ca/~selinger/quipper/>
  • <https://arxiv.org/pdf/1304.3390.pdf>
  • <https://arxiv.org/pdf/2105.03522.pdf> (a new language that reuses
    linear types in the Haskell to represent quantum specifics during
    the Quipper type check)


Layout Parsing and Nicely Formatted Error Messages
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-layout-parsing-and-nicely-formatted-error-messages/9343/1>


Hbr announced
─────────────

  In a previous [post] I have described my way from LALR parsing to
  combinator parsing. Now I am more and more convinced that combinator
  parsing is really a good and flexible way to write parsers. The new
  release 0.5.0 of `Fmlib` focuses on layout parsing and nicely
  formatted error messages by using combinator parsing.

  The library can be installed via opam by `opam install fmlib'. There
  is a [github repository] hosting the source code. The [API] can be
  found online. See also a [tutorial] on combinator parsing.


[post]
<https://discuss.ocaml.org/t/my-way-from-lalr-parsing-to-combinator-parsing/7377>

[github repository] <https://github.com/hbr/fmlib>

[API] <https://hbr.github.io/fmlib/odoc/index.html>

[tutorial] <https://hbr.github.io/fmlib/odoc/fmlib_parse/parse.html>

Layout Parsing
╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Most programming languages express hierarchical structures by some
  kind of parentheses. Algol like languages use `begin' `end', C like
  languages use curly braces `{', `}' to enclose blocks of code. Since
  blocks can be nested inside blocks, the hierarchical or tree structure
  is well expressed by the syntax.

  For the human reader blocks are usually indented to make the
  hierarchical structure graphically visible. Programming languages like
  *Haskell* and *Python* ommit the parentheses and express the
  hierarchical structure by indentation. I.e. the indentation is part of
  the grammar. This is pleasing to the eye, because many parentheses can
  be ommitted.

  The hierarchical structure in the following schematical source file is
  immediately visible without the need of parentheses.

  ┌────
  │ xxxxxxxxxxx
  │     xxx
  │     xxx
  │         xxxxxxx
  │ xxxxxxxx
  │     xxx
  └────

  Lower level blocks are indented with respect to their parent block and
  siblings at the same level are vertically aligned.

  Because of this good readability configuration languages like yaml
  have become very popular.

  Unfortunately there are not many parsers available which support
  indentation sensitivity. The library [Fmlib] has support to parse
  languages whose grammar uses indentation to structure blocks
  hierarchically.

  There are only 3 combinators needed to introduce layout parsing in
  combinator parsing. Suppose that `p' is a combinator parsing a certain
  contruct. Then we have

  • `indent 4 p': Parse the construct described by `p' indented at least
    4 columns relative to its environment

  • `align p': Parse the construct desribed by `p' aligned vertically
    with its siblings

  • `detach p': Parse the construct described by `p' without any
    indentation or alignment restrictions

  In order to parse a list of ~p~s vertically aligned and indented
  relative to its environment by at least one column we just write

  ┌────
  │ one_or_more (align p) |> indent 1
  └────

  and parse a structure with the schematic layout

  ┌────
  │ xxxxxxxx
  │ 
  │     pppppppp
  │ 
  │     pppppp
  │ 
  │     pppp
  │ 
  │ xxxxx
  └────


[Fmlib]
<https://hbr.github.io/fmlib/odoc/fmlib_parse/Fmlib_parse/index.html>


User Frienly Error Messages
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  It is important to for a parser writer to make syntax error messages
  user friendly. [Fmlib] has some support to write friendly error
  messages. There is the operator `<?>' copied from the Haskell library
  `parsec' which helps to equip combinators with descriptive error
  message in case they fail to parse the construct successfully.

  At the end of a failed parsing, the syntax (or semantic) errors have
  to be presented to the user. Suppose there is a combinator parser for
  a yaml like structure. The library writes by default for you error
  messages in the form

  ┌────
  │ 1 |
  │ 2 | names:
  │ 3 |      - Alice
  │ 3 |      - Bob
  │ 4 |
  │ 5 |   category: encryption
  │       ^
  │ 
  │ I have encountered something unexpected. I was
  │ expecting one of
  │ 
  │     - at 3 columns after
  │ 
  │         - sequence element: "- <yaml value>"
  │ 
  │     - at 2 columns before
  │ 
  │         - key value pair: "<key>: <yaml value>"
  │ 
  │     - end of input
  └────

  The raw information (line and column numbers, individual expectations,
  failed indentation or alignment expectation) is available as well so
  that you can present the error messages to the user in any different
  form.

  There is also a component [Fmlib_pretty] in the library for pretty
  printing any ascii text.


[Fmlib]
<https://hbr.github.io/fmlib/odoc/fmlib_pretty/Fmlib_pretty/index.html>

[Fmlib_pretty]
<https://hbr.github.io/fmlib/odoc/fmlib_pretty/Fmlib_pretty/index.html>


ptime 1.0.0 and mtime 1.4.0
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ptime-1-0-0-and-mtime-1-4-0/9344/1>


Daniel Bünzli announced
───────────────────────

  It's my pleasure to announce new releases of ptime and mtime. Ptime
  and mtime provide types and clocks for POSIX and monotonic time.

  These releases change the JavaScript support strategy for clocks by
  implementing the primitives in pure JavaScript and linking them via
  `js_of_ocaml'.

  This means that both the `ptime.clock.jsoo' and `mtime.clock.jsoo'
  libraries no longer exist[^1]. Instead simply use the `ptime.clock.os'
  or `mtime.clock.os' libraries like you would do for your regular
  programs.

  By side effect, the packages also no longer depend on any of
  `js_of_ocaml''s packages.

  Thanks to Hugo Heuzard (@hhugo) for suggesting and implementing these
  changes. Thanks also to Jonah Beckford for his Windows build patches.

  Other changes are described in the release notes for [`ptime'] and
  [`mtime'].

  Home pages: [ptime], [mtime]

  Docs & manuals: [ptime], [mtime] or `odig doc ptime mtime'

  Install: `opam install ptime mtime'

  [^1]: I had intended to only deprecate these libraries by `warning' in
  the `META' files and requiring the replacement library but it seems
  the warning won't show up in many contexts including `dune' builds. So
  a breaking change it is.


[`ptime']
<https://github.com/dbuenzli/ptime/blob/master/CHANGES.md#v100-2022-02-16-la-forclaz>

[`mtime']
<https://github.com/dbuenzli/mtime/blob/master/CHANGES.md#v140-2022-02-17-la-forclaz-vs>

[ptime] <https://erratique.ch/software/ptime>

[mtime] <https://erratique.ch/software/mtime>

[ptime] <https://erratique.ch/software/ptime/doc>

[mtime] <https://erratique.ch/software/mtime/doc>


Timedesc 0.6.0
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-timedesc-0-6-0/9349/1>


Darren announced
────────────────

  I am pleased to announce the release of [Timedesc] 0.6.0.

  Timedesc is a very comprehensive date time handling library with good
  support of time zone.


[Timedesc] <https://github.com/daypack-dev/timere>

Features:
╌╌╌╌╌╌╌╌╌

  • Timestamp and date time handling with platform independent time zone
    support
    • Subset of the IANA time zone database is built into this library
  • Supports Gregorian calendar date, ISO week date, and ISO ordinal
    date
  • Supports nanosecond precision
  • ISO8601 parsing and RFC3339 printing


Changes
╌╌╌╌╌╌╌

  This release adds a fair number of quality of life improvements and
  additional features. Many thanks to @glennsl for the suggestions and
  feedback!

  The most important sections of the changelog are as follows:

  • Main breaking changes:
    • Changes in ISO week date functions (shorting label for arguments,
      quality of life changes)
    • Removed `_date' suffix in names of `Date.Ymd_date' and
      `Date.ISO_ord_date'
  • Added "partial date" modules with ISO8601 parsing and printing
    facilities
    • `ISO_week'
    • `Ym'
  • Added additional ISO8601 printing facilities for all three calendar
    systems
    • `Date.Ymd.pp/to_iso8601' (these are just aliases to the RFC3339
      printers)
    • `Date.ISO_week_date.pp/to_iso8601'
    • `Date.ISO_ord.pp/to_iso8601'
  • Added additional ISO8601 parsing facilities for all three calendar
    systems
    • `Date.Ymd.of_iso8601[_exn]'
    • `Date.ISO_week_date.of_iso8601[_exn]'
    • `Date.ISO_ord.of_iso8601[_exn]'
  • Added additional comparison functions to `Date'
    • `lt', `le', `gt', `ge', `compare'
  • Added arithemtic functions to `Date'
  • Added `pp/to_iso8601' functions as aliases to the rfc3339 functions
    to `Timedesc'
  • Patched ISO8601 parsers and RFC3339/ISO8601 printers to handle
    second level time zone offset
    • Rare occurrence in tzdb but picked up by some new tests


OCaml from the Very Beginning now free in PDF and HTML formats
══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-from-the-very-beginning-now-free-in-pdf-and-html-formats/9361/1>


John Whitington announced
─────────────────────────

  Thanks to a grant from the [OCaml Software Foundation], I am able to
  release my book [OCaml from the Very Beginning] at no cost in its
  existing PDF format, and in a new HTML format too.

  You can find it here:
  [https://johnwhitington.net/ocamlfromtheverybeginning/].

  The paperback and Kindle versions continue to be available from Amazon
  as before.

  The book has recently been updated to make it ready for OCaml 4.14
  which involved only minor changes to error handling and warnings. I
  have also opened the [source].


[OCaml Software Foundation] <https://ocaml-sf.org/>

[OCaml from the Very Beginning] <https://ocaml-book.com>

[https://johnwhitington.net/ocamlfromtheverybeginning/]
<https://johnwhitington.net/ocamlfromtheverybeginning/>

[source] <https://github.com/johnwhitington/mlbook>


Dune 3.0.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-3-0-0/9374/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune team, I’m delighted to announce the availability
  of dune 3.0.

  The team has been working on this release for over 6 months, and
  there’s a bunch of new work to report. I’ll only highlight the some of
  the interesting new developments:

  • The watch mode has been rewritten from scratch to be faster and more
    scalable. We also no longer rely on any 3rd party tools such as
    fswatch. If any of you still have a dune workspace dune is still
    struggling with, we cannot wait to hear from you.

  • The watch mode now also starts an RPC server in the background. This
    RPC protocol is going to be the basis for other tools to interact
    with dune. Watch out for announcement on the LSP side to see how
    we’ll be making use of it to improve the editing experience.

  • The dune cache has been rewritten as well. It is now simpler and
    more reliable. There are still some components missing, such as
    distribution of the artifacts on the network. Nevertheless, we
    welcome you all to experiment with this feature and give us
    feedback.

  • We’ve addressed one of our oldest feature requests: high level rules
    for ctypes projects. This feature is still experimental, so we need
    feedback from real world projects before declaring it as mature.

  Of course, there are many other fixes, enhancements, and only a few
  breaking changes in this release. We hope you have an easy time
  upgrading.

  Happy Hacking.

  /Editor’s note: for the full changelog, please follow the archive link
  above./


Blog Post "2021 at OCamlPro"
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/blog-post-2021-at-ocamlpro/9390/1>


Fabrice Le Fessant announced
────────────────────────────

  We just published a review of what OCamlPro did in 2021:

  <https://www.ocamlpro.com/blog/2022_01_31_2021_at_ocamlpro>

  A lot of OCaml, but also some Rust, Cobol, Solidity, and a lot of
  Formal Verification! OCamlPro is always looking for skilled OCaml
  developers to hire, so if you are interested, contact us at
  contact@ocamlpro.com


Packstream 0.1
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-packstream-0-1/9392/1>


Tomasz Barański announced
─────────────────────────

  I have a pleasure to announce the release of [Packstream] 0.1.

  Packstream is a library to parse/serialize [Packstream binary format].

  This is the initial release. It is functional but very very limited in
  scope. It allows parsing a binary stream into a Packstream datatype
  and serializing the datatype into a binary stream.


[Packstream] <https://github.com/tomob/packstream>

[Packstream binary format]
<https://7687.org/packstream/packstream-specification-1.html>


OCaml 4.14.0, first beta release
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-14-0-first-beta-release/9396/1>


octachron announced
───────────────────

  The release of OCaml 4.14.0 is close.

  The set of new features has been stabilized, and most opam packages
  already work with this release. After two alpha releases, we have
  created a first beta version to help you update your softwares and
  libraries ahead of the release.

  If you find any bugs, please report them at:

  <https://github.com/ocaml/ocaml/issues>

  The full release of OCaml 4.14.0 is currently expected for the middle
  of March.

  Compared to the last alpha, we have a last minute correction for one
  of the new function in the Seq module, some documentation
  improvements, few configuration and internal tweaks.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands

  ┌────
  │ opam update
  │ opam switch create 4.14.0~beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  With opam 2.1, the previous command line can be simplified to
  ┌────
  │ opam update
  │ opam switch create 4.14.0~beta1
  └────
  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:

  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.14.0~beta1+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or with opam 2.1:
  ┌────
  │ opam update
  │ opam switch create <switch_name> ocaml-variants.4.14.0~beta1+options <option_list>
  └────

  where `<option_list>' is a comma separated list of `ocaml-option-*'
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 4.14.0~beta1+flambda+nffa ocaml-variants.4.14.0~beta1+options ocaml-option-flambda
  │ ocaml-option-no-flat-float-array
  └────
  All available options can be listed with `opam search ocaml-option'.

  The source code for the beta is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.14.0-beta1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.14/ocaml-4.14.0~beta1.tar.gz>


Changes compared to the last alpha
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The full list of changes for OCaml 4.14 is available at
  <https://github.com/ocaml/ocaml/blob/4.14/Changes>


Standard library
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • *additional fixes* [10583], +[10998]: Add over 40 new functions in
     Seq. (François Pottier and Simon Cruanes, review by Nicolás Ojeda
     Bär, Daniel Bünzli, Naëla Courant, Craig Ferguson, Wiktor Kuchta,
     Xavier Leroy, Guillaume Munch-Maccagnoni, Raphaël Proust, Gabriel
     Scherer and Thierry Martinez)


[10583] <https://github.com/ocaml/ocaml/issues/10583>

[10998] <https://github.com/ocaml/ocaml/issues/10998>


Documentation
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [10397]: Document exceptions raised by Unix module functions on
    Windows (Martin Jambon, review by Daniel Bünzli, David Alsopp,
    Damien Doligez, Xavier Leroy, and Florian Angeletti)

  • [10794]: Clarify warning 57 (Ambiguous or-pattern variables under
    guard) (Wiktor Kuchta, review by Gabriel Scherer)


[10397] <https://github.com/ocaml/ocaml/issues/10397>

[10794] <https://github.com/ocaml/ocaml/issues/10794>


Build system
┄┄┄┄┄┄┄┄┄┄┄┄

  • [10828] Build native-code compilers on OpenBSD/aarch64 (Christopher
    Zimmermann)

  • [10835] Disable DT_TEXTREL warnings on x86 32 bit architecture by
    passing -Wl,-z,notext in mksharedlib and mkmaindll. Fixes relocation
    issues, reported in [9800], making local patches in Debian, Alpine,
    and FreeBSD superfluous. (Hannes Mehnert with Kate Deplaix and
    Stéphane Glondu, review by Xavier Leroy)


[10828] <https://github.com/ocaml/ocaml/issues/10828>

[10835] <https://github.com/ocaml/ocaml/issues/10835>

[9800] <https://github.com/ocaml/ocaml/issues/9800>


Code generation
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [10719]: Ensure that build_apply respects Lambda.max_arity (Stephen
    Dolan, review by Xavier Leroy)


[10719] <https://github.com/ocaml/ocaml/issues/10719>


Internal/compiler-libs
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • *additional fixes* [10718], +[11012]: Add "Shape" information to the
     cmt files. Shapes are an abstraction of modules that can be used by
     external tooling to perform definition-aware operations. (Ulysse
     Gérard, Thomas Refis and Leo White, review by Florian Angeletti)


[10718] <https://github.com/ocaml/ocaml/issues/10718>

[11012] <https://github.com/ocaml/ocaml/issues/11012>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-02-08 13:16 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-02-08 13:16 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 4624 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of February 01 to 08,
2022.

Table of Contents
─────────────────

Functori is hiring full-time engineers and Interns
Permanent position for Computer Scientist in cybersecurity verification at CEA List, France
pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
Old CWN


Functori is hiring full-time engineers and Interns
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/functori-is-hiring-full-time-engineers-interns/9266/1>


Mohamed Iguernlala announced
────────────────────────────

  Functori, a young and dynamic company based in Paris, is hiring
  talented engineers/PhDs to expand its team. Please find more details
  in the announcement (in French):
  <https://functori.com/annonce-recrutement.pdf>

  We are also looking for interns in the fields of programming
  languages, formal methods, and blockchains (details available on
  request).

  Feel free to share with anyone who may be interested.


Permanent position for Computer Scientist in cybersecurity verification at CEA List, France
═══════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-02/msg00004.html>


ANTIGNAC Thibaud announced
──────────────────────────

  We would like to share with you an exciting opportunity to join the
  Frama-C team at CEA List (a French public research institute). We are
  opening a permanent computer scientist position to work on formal
  verification of cybersecurity properties. More details about the
  position and the qualifications expected are available here:
  <https://frama-c.com/jobs/2022-02-01-permanent-computer-scientist-cyber-security-verification.html>

  Please do not hesitate to reach out or to share with potentially
  interested people!


pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-pyml-bindgen-a-cli-app-to-generate-python-bindings-directly-from-ocaml-value-specifications/8786/5>


Ryan Moore announced
────────────────────

New version
╌╌╌╌╌╌╌╌╌╌╌

  I wanted to announce a new version of `pyml_bindgen' has been merged
  into the opam repository, version 0.2.0.  Whenever it hits, feel free
  to try it out!

  The main addition is now you can embed Python files directly into the
  generated OCaml module and it will be evaluated at run time.  In this
  way, you don't need your users to mess with the `PYTHONPATH'
  environment variable or need them to install a particular Python
  module when using the generated OCaml code. (Another thanks to
  UnixJunkie and Thierry Martinez for their help with this!)

  There were also a few bugfixes and some nice new [examples] added to
  the GitHub repository.  One cool thing about the examples is that they
  show you how to set up your project to use Dune rules to automatically
  generate Python bindings whenever the value specification files
  change!


[examples]
<https://github.com/mooreryan/ocaml_python_bindgen/tree/main/examples>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-02-01 13:00 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-02-01 13:00 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 21540 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 25 to
February 01, 2022.

Table of Contents
─────────────────

ppx_seq v0.1.1
OCaml Labs Joins Tarides
For Diversity and the OCaml Community: Get Involved in Outreachy Summer 2022
Set up OCaml 2.0.0-beta13
First release of scfg
Brr 0.0.3, a toolkit for programming browsers
(anonymous?) polymorphic records
2 postdoc positions on Runtime Verification at CEA LIST, Université Paris-Saclay, France
Old CWN


ppx_seq v0.1.1
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-ppx-seq-v0-1-1/9227/1>


hyphenrf announced
──────────────────

  Hello everyone, my first contribution to opam-repository has just been
  merged and is waiting to hit the caches of [opam.ocaml.org].

  [ppx_seq] is a cute un-intrusive literal syntax for `Seq'. The
  rewriter is simple and has very small surface area: just `[%seq x; y;
  z; ...]' and `[%seq.empty]'.  It tries to be maximally compatible with
  all OCaml releases from 4.07 (when `Seq' was introduced) to 4.14 and
  beyond

  The reason I created this rewriter is to make it an easier choice to
  reach first for `Seq' as a general data structure (instead of
  e.g. list). That wasn't quite attractive before because of how minimal
  the `Seq' module was, it was mostly used as an intermediate step
  between two types of collections, but now with 4.14 about to be
  released, `Seq' is becoming a first-class data structure with a very
  versatile API.

  I hope my little rewriter helps make it even more attractive to
  use. Check it out and maybe leave me some feedback.  Thanks <3


[opam.ocaml.org] <https://opam.ocaml.org>

[ppx_seq] <https://github.com/hyphenrf/ppx_seq>


OCaml Labs Joins Tarides
════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-labs-joins-tarides/9229/1>


Thomas Gazagnaire announced
───────────────────────────

  Gemma Gordon (@gemmag) and I are delighted to announce that OCaml
  Labs, a spinout from the University of Cambridge, is joining
  Tarides. After successfully collaborating on many OCaml projects over
  the last four years, this alliance will formally combine the expertise
  of both groups. Joining forces will accelerate OCaml development and
  its broader adoption, and enable us to continue with our shared goal
  of bringing OCaml into mainstream use. Furthermore, it will bring the
  security, portability and performance of OCaml to a large spectrum of
  use-cases: from academic endeavours such as formal methods and
  existing threats within cyber security, to real-world applications for
  climate change, sustainable agriculture, and even space exploration!

  All of OCaml Labs’ existing responsibilities and open source
  commitments will migrate over to Tarides, and thanks to how closely
  the teams already work, business will continue without interruption to
  continuity or delivery. Gemma Gordon will step up as CEO of Tarides,
  and I will lead the technological vision and strategy as CTO.

  The OCaml 5.0 release will support multicore and effects handlers,
  influencing every aspect of the language and its ecosystem. The update
  will significantly improve both performance and user experience,
  whilst maintaining existing features that the community loves. Using
  the teams’ combined experience and zest for innovation, Tarides is
  looking to the future of the OCaml language and community with
  excitement. Since Tarides’ inception we have envisioned a future where
  all OCaml applications are easily deployable as specialised, secure
  and energy-efficient MirageOS unikernels. We believe that this
  alliance is a step further in that direction.

  _This alliance will complement the commercial offerings of Tarides and
  contribute to Tarides' mission: empowering developers, communities and
  organisations to adopt OCaml as their primary programming experience
  by providing training, expertise and development services around the
  OCaml language._

  Read the full announcement [here], including details of our goals and
  the focus for 2022.  This alliance brings the headcount of Tarides up
  to 60+ people, all working towards making OCaml the best language for
  any, and every project. Join our team and reach out for commercial
  services at: [https://tarides.com/]


[here] <https://tarides.com/blog>

[https://tarides.com/] <https://tarides.com/company>


For Diversity and the OCaml Community: Get Involved in Outreachy Summer 2022
════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/for-diversity-and-the-ocaml-community-get-involved-in-outreachy-summer-2022/9234/1>


Sonja Heinze announced
──────────────────────

  As @patricoferris [has mentioned] previously, the Outreachy call for
  open-source communities and project submissions has started. As a
  reminder, [Outreachy] is an initiative that provides a framework
  through which open-source communities can offer three month
  internships directed at people from any kind of under-represented
  background in open source. With that, Outreachy helps open-source
  communities grow on several levels: diversity, experience, size, and
  popularity.

  The OCaml community participated in Outreachy in summer 2019, summer
  2020, [summer 2021], and currently in [winter 2021/22]. All our
  interns have done and are doing really amazing jobs, and summer 2022
  is just around the corner! The following timeline illustrates the
  process:

  <https://i.imgur.com/DbzeiMO.png>

  So let's start getting involved!


[has mentioned]
<https://discuss.ocaml.org/t/become-an-outreachy-mentor-support-the-growth-and-diversity-of-the-ocaml-community/8213/15?u=pitag>

[Outreachy] <https://www.outreachy.org>

[summer 2021] <https://discuss.ocaml.org/t/outreachy-summer-2021/8438>

[winter 2021/22]
<https://discuss.ocaml.org/t/announcing-our-new-outreachy-interns/8932>

Ways to Get Involved
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Community members can take on different roles in the Outreachy effort,
  and all of them are very important! Maybe the most important (and most
  involved) role is being a mentor.


Mentoring
┄┄┄┄┄┄┄┄┄

  Mentors have two responsibilities: leading the project and guiding the
  interns/applicants.


Leading the Project
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈

  One responsability is leading the project. Concretely, that means
  outlining an internship project, submitting a project description to
  Outreachy, making sure that the context repo for that project gets
  ready for the application/"contribution" phase, and guiding the
  project throughout the internship, including reacting to changes.  All
  of that must match the Outreachy framework, which we [explained in
  detail] last round, based on the timeline structure shown above.


[explained in detail]
<https://discuss.ocaml.org/t/become-an-outreachy-mentor-support-the-growth-and-diversity-of-the-ocaml-community/8213#step-by-step-process-for-being-a-mentor-11>


Guiding the Intern and the Applicants
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈

  Their other responsibility is personal guidance. During the
  application/"contribution" period, mentors answer questions and review
  code for multiple applicants. During the internship, they also offer
  pair-programming sessions and facilitate more specific guidance, and
  general support for their interns.

  All of that is usually quite time-intensive, so it's important to have
  some support from other community members and strong support from a
  concrete co-mentor.


Co-mentoring
┄┄┄┄┄┄┄┄┄┄┄┄

  A co-mentor does the same job as described in the "Guiding the Intern
  and the Applicants" tasks above, so having a co-mentor is very
  important! Of course, if a co-mentor also wants to take part in the
  project's direction, that's great as well! This means that the line
  between co-mentoring and mentoring isn't always clear.


Volunteering (aka "Acting as a Joker :bat:")
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Mentors and co-mentors receive a lot of general questions related to
  OCaml and programming in addition to specific questions about the
  project. That's where Outreachy volunteers can be very helpful! They
  help all applicants and interns across projects with (usually)
  project-unspecific questions and give a very important technical base
  support.


Point Out Potential Project Ideas
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Apart from not having enough time, the main reason that stops folks
  from becoming a mentor is the lack of project ideas. So if you have
  potential project ideas, please point them out, even if you don't have
  time to mentor!  Generally, a self-contained, uncontroversial, and
  incremental project makes the most suitable project for Outreachy.
  It's also important for a project to be associated with a repo that
  can serve as a basis for easy contributions during the application
  phase. When in doubt, don't keep your ideas to yourself. Any idea can
  be helpful!


Prepare Your Repos
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  In general, if you maintain a repo, it's really nice to be welcoming
  to new contributors. Concretely, that means having clear contributing
  guidelines, good newcomer issues, and well-labeled issues. As a nice
  side-effect, this also makes your project a better target for future
  Outreachy projects.


Ready to Get Involved?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  If you've gotten interested in any of those roles or have any other
  comments, please just answer here in the thread.  It would be super
  nice to get a discussion going and start our Outreachy efforts early!


Sudha Parimala then said
────────────────────────

  I along with @shakthimaan @gs0510 are submitting a project:

  • Extend OCaml 5's parallel benchmark suite.

  The idea is to gather parallel benchmarks available elsewhere and make
  them available in our benchmark suite, to aid the development of the
  OCaml compiler and parallel programming libraries. Relevant repos:
  [sandmark] and [current-bench].


[sandmark] <https://github.com/ocaml-bench/sandmark>

[current-bench] <https://github.com/ocurrent/current-bench>


Set up OCaml 2.0.0-beta13
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta13/9248/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • Do not install opam-depext if it's not enabled.


Fixed
╌╌╌╌╌

  • Print a proper error if the version not found in the `.ocamlformat'
    file.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta13>


First release of scfg
═════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-scfg/9249/1>


zapashcanon announced
─────────────────────

  I'm pleased to announce the first release of [scfg] on opam.

  It provides a library and an executable to work with the [scfg
  configuration file format]. (disclaimer: scfg has been created by my
  good friend @emersion)

  Here's an example of an scfg file taken from the specification:

  ┌────
  │ train "Shinkansen" {
  │ 	model "E5" {
  │ 		max-speed 320km/h
  │ 		weight 453.5t
  │ 
  │ 		lines-served "Tōhoku" "Hokkaido"
  │ 	}
  │ 
  │ 	model "E7" {
  │ 		max-speed 275km/h
  │ 		weight 540t
  │ 
  │ 		lines-served "Hokuriku" "Jōetsu"
  │ 	}
  │ }
  └────

  Scfg is a file format designed to be simple and indeed the
  implementation was really straightforward. I'm planning to use it in
  small tools I wrote (mostly [sway] tools written in OCaml) but never
  released because I couldn't stand having to use TOML, YAML or JSON for
  them…

  The library provides an executable to validate and pretty-print an
  scfg file. It'll indent it properly, remove useless quoting and
  whitespaces:

  ┌────
  │ $ scfg spec.scfg
  │ train Shinkansen {
  │   model E5 {
  │     max-speed 320km/h
  │     weight 453.5t
  │     lines-served Tōhoku Hokkaido
  │   }
  │   model E7 {
  │     max-speed 275km/h
  │     weight 540t
  │     lines-served Hokuriku Jōetsu
  │   }
  │ }
  └────

  The library is made of four modules : `Types', `Parse', `Pp' and
  `Query'.

  The `Types' module simply defines the following types, which are all
  you need to deal with scfg:

  ┌────
  │ (** A directive has a name, a list of parameters and children (a list of directive). *)
  │ type directive =
  │   { name : string
  │   ; params : string list
  │   ; children : directive list
  │   }
  │ 
  │ (** A config is a list of directives. *)
  │ type config = directive list
  └────

  The others modules can be used as follow:

  ┌────
  │ let file = {|
  │   train A-Train {
  │     bla bla bla
  │   }
  │   train "John Col Train" {
  │     tut tut tut
  │   }
  │ |}
  │ 
  │ (* parsing the file *)
  │ let config =
  │   (* there's also a `Parse.from_file` function that should be more useful *)
  │   match Scfg.Parse.from_string file with
  │   | Error e ->
  │     Format.eprintf "error: %s@." e;
  │     exit 1
  │   | Ok config -> config
  │ 
  │ (* printing the file *)
  │ let () =
  │   Format.printf "```scfg@.%a@.```@." Scfg.Pp.config config
  │ 
  │ (* querying the file *)
  │ let () =
  │   (* gets the first directive with the name `train` *)
  │   match Scfg.Query.get_dir "train" config with
  │   | None -> Format.printf "No train found.@."
  │   | Some train -> (
  │     (* get the parameter at index 0 in the `train` directive *)
  │     match Scfg.Query.get_param 0 train with
  │     | Error _e -> Format.printf "Train has no name.@."
  │     | Ok name -> Format.printf "The first train is `%s`.@." name )
  └────

  For more have a look at the [project's README], the [documentation] or
  feel free to ask here ! :partying_face:


[scfg] <https://git.zapashcanon.fr/zapashcanon/scfg>

[scfg configuration file format] <https://git.sr.ht/~emersion/scfg>

[sway] <https://swaywm.org/>

[project's README]
<https://git.zapashcanon.fr/zapashcanon/scfg/src/branch/master#scfg>

[documentation] <https://doc.zapashcanon.fr/scfg/>


Brr 0.0.3, a toolkit for programming browsers
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-brr-0-0-3-a-toolkit-for-programming-browsers/9252/1>


Daniel Bünzli announced
───────────────────────

  It's my pleasure to announce the release `0.0.3' of [`Brr'], a toolkit
  for programming browsers in OCaml with the [`js_of_ocaml'] compiler.

  Once it has made it to the repo, install with `opam install brr' and
  consult the [API docs and manuals] (or via `odig doc brr').

  Among small additions and fixes, this release brings support for
  `js_of_ocaml' 4.0.0. Thanks to Hugo Heuzard (@hhugo) who has made the
  ground work in `js_of_ocaml' this means that:

  1. `Brr', `js_of_ocaml' and ([soon]) `gen_js_api' JavaScript bindings
     can now all be used in the same program without problems (issue
     [#2]).
  2. You no longer need to specify the `-no-check-prim' flag at
     bytecode link time. Linking against the `brr' library is
     sufficient, see the [build instructions].

  The [release notes] have all the details.


[`Brr'] <https://erratique.ch/software/brr>

[`js_of_ocaml'] <https://ocsigen.org/js_of_ocaml>

[API docs and manuals] <https://erratique.ch/software/brr/doc/>

[soon] <https://github.com/LexiFi/gen_js_api/pull/164>

[#2] <https://github.com/dbuenzli/brr/issues/2>

[build instructions]
<https://erratique.ch/software/brr/doc/web_page_howto.html>

[release notes]
<https://github.com/dbuenzli/brr/blob/master/CHANGES.md#v003-2022-01-30-la-forclaz-vs>


(anonymous?) polymorphic records
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/anonymous-polymorphic-records/9256/1>


nrolland asked
──────────────

  Is there a way to avoid to create records only to preserve
  polymorphism ?

  Say, for this, in haskell style
  ┌────
  │ h :: (forall r. (r -> a) -> (f r -> f b)) -> f a -> f b
  │ h malg = malg id
  └────


octachron replied
─────────────────

  You can use objects, they can have polymorphic methods:

  ┌────
  │ let f (id:<f:'a. 'a -> 'a>) = id#f 0, id#f "zero"
  └────


Maëlan also replied
───────────────────

  The following doesn’t help reducing the syntactic noise, but note that
  when using a record for non-prenex polymorphism like this, your record
  has only one field and is immutable, so (with a recent enough OCaml)
  you can unbox it and get rid of the runtime overhead:

  ┌────
  │ type ('a, 'b) fwrap = { f : 'r. ('r -> 'a) -> 'r list -> 'b list } [@@unboxed]
  │ 
  │ let apply_id : type a b. (a, b) fwrap -> a list -> b list =
  │   fun w xs -> w.f Fun.id xs
  │ (* is compiled the same as just: *)
  │ let apply_id_magic : type a b. (a, b) fwrap -> a list -> b list =
  │   fun w xs -> (Obj.magic w) Fun.id xs
  │ 
  │ let mwrap : type a. (a, a) fwrap = { f = List.map }
  │ (* is compiled to nothing at all (alias of List.map). *)
  └────


2 postdoc positions on Runtime Verification at CEA LIST, Université Paris-Saclay, France
════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-02/msg00001.html>


Julien Signoles announced
─────────────────────────

  The Software Safety and Security Lab at CEA LIST, Université
  Paris-Saclay, France has 2 open postdoc positions in the area of
  runtime verification for code safety and security:

  • Designing Compilation Techniques for Improving Efficiency of E-ACSL,
    a Runtime Assertion Checker for C Programs

    <http://julien-signoles.fr/positions/postdoc-eacsl.pdf>

  • Control Flow Integrity for Remote Attestation

    <http://julien-signoles.fr/positions/postdoc-cfi.pdf>

  The candidates will:
  • solve challenging research problems;
  • implement their results in Frama-C, an industrial-strength
    open-source framework for analyses of C code;
  • evaluate their solutions on concrete benchmarks or/and use cases;
  • publish their results in international conferences and journals.

  Strong knowledge in at least one of the following areas is welcome:
  • programming
    • OCaml and C
    • formal semantics
  • formal verification
    • runtime verification, static analysis, formal specification
      languages, …
  • compilation
    • code generation, program transformation, type system, …

  Interested applicants should send a CV and a motivation letter to
  Julien Signoles (julien dot signoles at cea dot fr).


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-01-25 12:44 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-01-25 12:44 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of January 18 to 25,
2022.

Table of Contents
─────────────────

wu-manber-fuzzy-search 0.1.0 (new library)
findlib-1.9.2
Signals and Threads on Memory Management
OCaml 4.14.0, first alpha release
A brief survey for Learn-OCaml Community
Blog post: Js_of_ocaml, a bundle size study
Interesting OCaml Articles
Old CWN


wu-manber-fuzzy-search 0.1.0 (new library)
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-wu-manber-fuzzy-search-0-1-0-new-library/9173/1>


Ifaz Kabir announced
────────────────────

  I'm happy to introduce wu-manber-fuzzy-seach, my library for doing
  fuzzy searches using the Wu and Manber fuzzy search algorithm.

  The novel part of this library particularly, when compared to
  `agrep/ocamlagrep', is that I additionally provide a right-leaning
  variant of the algorithm. The variant reports better matches and error
  counts when looking at the first match. Here's an example of the
  differences.

  ┌────
  │ # open Wu_Manber;;
  │ # StringSearch.(search ~k:2 ~pattern:"brown" ~text:"quick brown fox" |> report);;
  │ - : string = "Pattern matched with 2 errors at character 9 of text"
  │ # StringSearch.(search_right_leaning ~k:2 ~pattern:"brown" ~text:"quick brown fox" |> report);;
  │ - : string = "Pattern matched with 0 errors at character 11 of text"
  └────

  It's a pure OCaml implementation, using `Optint.Int63.t' as
  bit-vectors. I don't current support all the extensions that
  `agrep/ocamlagrep' supports, and will definitely not match the
  performance: OCaml+C vs pure OCaml.

  The documentation for the library can be found [here].

  It's not on `opam' yet, but there is a [PR].

  Expect more bitvector, Levenshtein distance, and fuzzy search
  shenanigans in the near future!


[here] <https://ifazk.github.io/wu-manber-fuzzy-search/>

[PR] <https://github.com/ocaml/opam-repository/pull/20479>


findlib-1.9.2
═════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2022-01/msg00040.html>


Gerd Stolpmann announced
────────────────────────

  findlib-1.9.2 is out. The only change is a fix for a build problem
  regarding the OCaml-5 trunk.

  For manual, download, manuals, etc. see here:

  <http://projects.camlcity.org/projects/findlib.html>

  An updated OPAM package will follow soon.


Signals and Threads on Memory Management
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/signals-and-threads-on-memory-management/9190/1>


gasche said
───────────

  I just had an excellent time listening to the last Signals and Threads
  podcast episode on [Memory Management], with Stephen Dolan (@stedolan)
  as the guest and Yaron Minsky (@Yaron_Minsky) as the host discussing:
  • memory management in programming languages in general
  • memory management in OCaml
  • ongoing research by Stephen and Leo White (@lpw25) on
    memory-management and data-representation features for OCaml
    (unboxed types, local values on the stack).

  The link <https://signalsandthreads.com/memory-management/> contains
  both the audio and a full text transcript.

  I would warmly recommend giving it a try if you are interested in
  programming language implementation. There is new stuff to learn for
  everyone, and I also liked the presentation of the parts I was already
  familiar with.


[Memory Management] <https://signalsandthreads.com/memory-management/>


Yaron Minsky replied
────────────────────

  Thanks for the nice words. Interviewing Dolan was fun and I learned a
  lot.

  Local types are still very new: we're hoping to start rolling it out
  in a limited way internally in the next few weeks, and I expect we'll
  learn a lot from that. We plan on discussing it more publicly as well,
  but that's a bit farther out. In the meantime, the source is all
  available [on Github] if anyone wants to poke around.

  The approach to stack allocation is different and simpler than the one
  in Rust, as Dolan explained in the episode.  Instead of having
  implicit, polymorphic lifetime variables, function arguments can be
  marked as local, which prevents the function in question from stashing
  a reference to those types. This avoids the need to deal with
  higher-rank polymorphism, which Rust's lifetime approach requires, and
  as a result makes inference work nicely.

  Another neat trick is that you can create functions that can allocate
  on the parent stack frame (by dint of not having their own stack
  frame). This lets you build smart constructors for stack-allocated
  values.

  Local types are apparently an example of modal types, though I don't
  really know enough type theory to have a deep sense of what that
  means. But it's a powerful thing, and local types appear to be useful
  for more than just stack allocation, as we're just starting to
  discover.


[on Github] <https://github.com/ocaml-flambda/ocaml-jst>


Yaron Minsky then added
───────────────────────

  And, I suppose as I should always mention: we're looking for people to
  come and work with Dolan and Leo and the rest of the team on this kind
  of stuff.

  More here:

  <https://blog.janestreet.com/applied-PL-research/>


OCaml 4.14.0, first alpha release
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-14-0-first-alpha-release/9191/1>


octachron announced
───────────────────

  The set of new features for the future version 4.14.0 of OCaml has
  been (finally) stabilized, three months after the release of OCaml
  4.13.1. I am thus happy to announce the first alpha release for OCaml
  4.14.0 .

  This alpha version is here to help fellow hackers join us early in our
  bug hunting and opam ecosystem fixing fun (see below for the
  installation instructions). You can see the progress on this front at
  <https://github.com/ocaml/opam-repository/issues/20501> .

  If you find any bugs, please report them here:

  <https://github.com/ocaml/ocaml/issues>

  Most major OCaml developer tools are already supported with this alpha
  (from odoc to merlin), thus I expect us to switch to beta releases in
  the beginning of February. The full release is expected to happen in
  late February.

  This early release will give us time to focus on the release of OCaml
  5.0.

  If you are interested by the list of new features and the ongoing list
  of bug fixes, the updated change log for OCaml 4.14.0 is available at:

  <https://github.com/ocaml/ocaml/blob/4.14/Changes>

  Happy hacking, Florian Angeletti for the OCaml team.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.14.0~alpha1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  With opam 2.1, the previous command line can be simplified to
  ┌────
  │ opam update
  │ opam switch create 4.14.0~alpha1
  └────
  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.14.0~alpha1+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or with opam 2.1:
  ┌────
  │ opam update
  │ opam switch create <switch_name> ocaml-variants.4.14.0~alpha1+options <option_list>
  └────

  where `<option_list>' is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 4.14.0~alpha1+flambda+nffa ocaml-variants.4.14.0~alpha1+options ocaml-option-flambda
  │ ocaml-option-no-flat-float-array
  └────
  All available options can be listed with `opam search ocaml-option'.

  If you want to test this version, it is advised to install the alpha
  opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This alpha repository contains various fixes in the process of being
  upstreamed.

  The source code for the alpha is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.14.0-alpha1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.14/ocaml-4.14.0~alpha1.tar.gz>


A brief survey for Learn-OCaml Community
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-brief-survey-for-learn-ocaml-community/9193/1>


Erik Martin-Dorel announced
───────────────────────────

  [This post is just a follow-up of an earlier message on [caml-list],
  intended to reach more learn-ocaml instructors, so you can ignore this
  one if you already replied!]

  The OCaml Software Foundation is developing the teaching platform
  Learn-OCaml that provides auto-graded exercises for OCaml, and was
  initially authored by OCamlPro for the OCaml MOOC:
  <https://ocaml-sf.org/learn-ocaml>.

  The platform is free software and easy to deploy; this is great, but
  as a result we keep learning of users/deployments that we had no idea
  of. We would be interested in having a better view of our user-base.

  If you use Learn-OCaml as a teacher, could you fill *[this Evento
  survey]* to let us know?  (the survey will be closed on 2022-02-07)

  → It contains these questions:
  • Where are you using Learn-OCaml? (in which university (a specific
    course?), which company, online community or…?)
  • Would you like to see your university/company added in
    [github.com/ocaml-sf/learn-ocaml-places]?
  • How many students/learners use your deployment in a year?

  And just to recall, a few links:

  • For an example of Learn-OCaml instance, see
    <https://discuss.ocaml.org/t/interesting-ocaml-exercises-from-francois-pottier-available-online/7050>
  • Last October we had a 0.13.0 release with several new features:
    <https://discuss.ocaml.org/t/ann-release-of-ocaml-sf-learn-ocaml-0-13-0/8577>
  • For any question related to Learn-OCaml, feel free to create a
    discussion topic on <https://discuss.ocaml.org>, category
    *`Community'*, tag *`learn-ocaml'* (/similarly to this discussion
    topic!/ :slight_smile:)
  • And if need be, opening an issue in
    <https://github.com/ocaml-sf/learn-ocaml/issues> if of course warmly
    welcome as well.


[caml-list]
<https://sympa.inria.fr/sympa/arc/caml-list/2021-12/msg00007.html>

[this Evento survey]
<https://evento.renater.fr/survey/learn-ocaml-community-survey-vsn3yc7j>

[github.com/ocaml-sf/learn-ocaml-places]
<https://github.com/ocaml-sf/learn-ocaml-places#readme>


Blog post: Js_of_ocaml, a bundle size study
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/blog-post-js-of-ocaml-a-bundle-size-study/9211/1>


Javier Chávarri announced
─────────────────────────

  Hi all, I hope your Monday is going great. :slight_smile:

  I wanted to analyze bundle size performance in Js_of_ocaml, so I
  rewrote an existing ReScript web app to compare both outputs.

  Here is the blog post with all the data, conclusions, and takeaways:

  <https://www.javierchavarri.com/js_of_ocaml-bundle-size-study/>

  It has been a very interesting experiment, that helped me learn more
  about Js_of_ocaml and the way it generates JavaScript code, and also
  improve some small things along the way in the libraries I was using
  for the project.

  The conclusions, while maybe already known by others, are also quite
  exciting to me, as the experiment confirms my suspicion that
  Js_of_ocaml bundle size scales just fine as applications get more
  complex, so it is suitable for a quite significant number of real
  world scenarios.

  I hope you find it interesting and exciting as well. Please share any
  feedback you might have! Or any questions if anything is unclear.


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/94>


Yotam Barnoy said
─────────────────

  <https://blog.darklang.com/first-thoughts-on-rust-vs-ocaml/#tooling-musing>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-01-11  8:20 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-01-11  8:20 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 13456 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 04 to 11,
2022.

Table of Contents
─────────────────

New release of PPrint (20220103)
Bogue, the OCaml GUI
Cohttp 5.0.0 and 2.5.6
Multicore OCaml: December 2021 and the Big PR
Set up OCaml 2.0.0-beta12
Old CWN


New release of PPrint (20220103)
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-pprint-20220103/9097/1>


François Pottier announced
──────────────────────────

  I am pleased to announce a new release of PPrint, the pretty-printing
  library, with [improved documentation].

  The documentation can also be viewed offline:

  ┌────
  │ opam update
  │ opam install pprint.20220103
  │ opam install odig
  │ odig odoc                 # this may take some time
  │ odig doc pprint           # this opens the doc in your browser
  └────

  Happy pretty-printing!


[improved documentation]
<http://cambium.inria.fr/~fpottier/pprint/doc/pprint/>


Bogue, the OCaml GUI
════════════════════

  Archive: <https://discuss.ocaml.org/t/ann-bogue-the-ocaml-gui/9099/1>


sanette announced
─────────────────

  I'm happy to announce a brand new version of [Bogue], a GUI (Graphical
  User Interface) library entirely written in `ocaml', using SDL2 for
  hardware accelerated graphics.

  The doc can be found [here], it will be enriched over time.

  Install with `opam install bogue'

  In addition to the library, this installs an executable `boguex' to
  showcase about 50 useful constructions, see `boguex -h' for the list.

  Some screenshots of a demo compiled with the latest version:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/6/619a6b3c5d7a9860e4c24df7d8b931815e9b95a1.png>

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/3/3e5e04d1db0022d4070b7fd3dab45f4399828e90.png>

  Note that many widgets are not shown in this demo: tables, menus,
  drop-down select lists, knob buttons,… I will add more images to the
  doc when I have some time!


[Bogue] <https://github.com/sanette/bogue>

[here] <http://sanette.github.io/bogue/Principles.html>


Cohttp 5.0.0 and 2.5.6
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-cohttp-5-0-0-and-2-5-6/9109/1>


Marcello Seri announced
───────────────────────

  We are glad to announce the release of version [5.0.0] and [2.5.6] of
  cohttp and its dependent packages.

  The latter is a bug fix release that in particular backports the
  compatibility with the upcoming release 0.15 of core and async.

  The first introduces the breaking changes [announced in the previous
  release]. I append the changelog below, which explains in details the
  changes and emphasizes the breaking changes:


[5.0.0]
<https://github.com/ocaml/opam-repository/pull/20246#issue-1080986510>

[2.5.6]
<https://github.com/ocaml/opam-repository/pull/20245#issue-1080822215>

[announced in the previous release]
<https://discuss.ocaml.org/t/ann-release-of-cohttp-4-0-0/7537>

Cohttp.Header: new implementation (lyrm #747)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • New implementation of Header modules using an associative list
    instead of a map, with one major semantic change (function `get',
    see below), and some new functions (`clean_dup', `get_multi_concat')
  • More Alcotest tests as well as fuzzing tests for this particular
    module.


Purpose
┄┄┄┄┄┄┄

  The new header implementation uses an associative list instead of a
  map to represent headers and is focused on predictability and
  intuitivity: except for some specific and documented functions, the
  headers are always kept in transmission order, which makes debugging
  easier and is also important for [RFC7230§3.2.2] that states that
  multiple values of a header must be kept in order.

  Also, to get an intuitive function behaviour, no extra work to enforce
  RFCs is done by the basic functions. For example, RFC7230§3.2.2
  requires that a sender does not send multiple values for a non
  list-value header. This particular rule could require the `Header.add'
  function to remove previous values of non-list-value headers, which
  means some changes of the headers would be out of control of the
  user. With the current implementation, an user has to actively call
  dedicated functions to enforce such RFCs (here `Header.clean_dup').


[RFC7230§3.2.2] <https://tools.ietf.org/html/rfc7230#section-3.2.2>


Semantic changes
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Two functions have a semantic change : `get' and `update'.


get
┈┈┈

    `get' was previously doing more than just returns the value
  associated to a key; it was also checking if the searched header could
  have multiple values: if not, the last value associated to the header
  was returned; otherwise, all the associated values were concatenated
  and returned. This semantics does not match the global idea behind the
  new header implementation, and would also be very inefficient.

  ⁃ The new `get' function only returns the last value associated to the
    searched header.
  ⁃ `get_multi_concat' function has been added to get a result similar
    to the previous `get' function.


update
┈┈┈┈┈┈

  `update' is a pretty new function (#703) and changes are minor and
  related to `get' semantic changes.

  ⁃ `update h k f' is now modifying only the last occurrences of the
    header `k' instead of all its occurrences.
  ⁃ a new function `update_all' function has been added and work on all
    the occurrences of the updated header.


New functions :
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  ⁃ `clean_dup' enables the user to clean headers that follows the
    [RFC7230§3.2.2] (no duplicate, except `set-cookie')
  ⁃ `get_multi_concat' has been added to get a result similar to the
    previous `get' function.


[RFC7230§3.2.2] <https://tools.ietf.org/html/rfc7230#section-3.2.2>


Cohttp.Header: performance improvement (mseri, anuragsoni #778)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

    *Breaking* the headers are no-longer lowercased when parsed, the
  headers key comparison is case insensitive instead.


cohttp-lwt-unix: Adopt ocaml-conduit 5.0.0 (smorimoto #787)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  *Breaking* `Conduit_lwt_unix.connect''s `ctx' param type chaged from
   `ctx' to `ctx Lazy.t'


other changes
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • cohttp-mirage: fix deprecated fmt usage (tmcgilchrist #783)
  • lwt_jsoo: Use logs for the warnings and document it (mseri #776)
  • lwt: Use logs to warn users about leaked bodies and document it
    (mseri #771)
  • lwt, lwt_unix: Improve use of logs and the documentation, fix bug in
    the Debug.enable_debug function (mseri #772)
  • lwt_jsoo: Fix exception on connection errors in chrome (mefyl #761)
  • lwt_jsoo: Fix `Lwt.wakeup_exn' `Invalid_arg' exception when a js
    stack overflow happens in the XHR completion handler (mefyl #762).
  • lwt_jsoo: Add test suite (mefyl #764).

  We wish to thank to all the users and the contributors for their help
  leading to this release.


Multicore OCaml: December 2021 and the Big PR
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-december-2021-and-the-big-pr/9115/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the December 2021 [Multicore OCaml] monthly report!  The
  [previous updates] along with this update have been compiled by
  myself, @ctk21, @kayceesrk and @shakthimaan.

  Well, it's finally here! @kayceesrk opened the [Multicore OCaml
  PR#10831] to the main OCaml development repository that represents the
  "minimum viable" implementation of multicore OCaml that we decided on
  in [November's core team review].  The branch pushes the limits of
  GitHub's rendering capability, with around 4000 commits.

  Once the PR was opened just before Christmas, the remaining effort has
  been for a number of developers to pore over [the diff] and look for
  any unexpected changes that crept in during multicore development. A
  large number of code changes, improvements and fixes have been merged
  into the ocaml-multicore trees since the PR was opened to facilitate
  this upstreaming process. We're expecting to have the PR merged during
  January, and then will continue onto the "post-MVP" tasks described
  last month, but working directly from ocaml/ocaml from now on.  We
  therefore remain on track to release OCaml 5.00 in 2022.

  In the multicore ecosystem, progress also continued:
  • `Eio' continues to improve as the recommended effects-based
    direct-style IO library to use with Multicore OCaml.
  • A newer `domainslib.0.4.0' has been released that includes bug fixes
    and API changes.
  • The continuous benchmarking pipeline with further integration
    enhancements between Sandmark and current-bench is making progress.

  We would like to acknowledge the following external contributors as
  well::

  • Danny Willems (@dannywillems) for an OCaml implementation of the
    Pippenger benchmark and reporting an undefined behaviour.
  • Matt Pallissard (@mattpallissard) reported an installation issue
    with `Eio' with vendored uring.
  • Edwin Torok (@edwintorok) for contributing a PR to `domainslib' to
    allow use of a per-channel key.

  As always, the Multicore OCaml updates are listed first, which contain
  the upstream efforts, improvements, fixes, test suite, and
  documentation changes. This is followed by the ecosystem updates to
  `Eio', `Tezos', and `Domainslib'.  The Sandmark, sandmark-nightly and
  current-bench tasks are finally listed for your reference.

  /editor’s note: please follow the archive link above for the full
  changelog./


[Multicore OCaml] <https://github.com/ocaml-multicore/ocaml-multicore>

[previous updates] <https://discuss.ocaml.org/tag/multicore-monthly>

[Multicore OCaml PR#10831] <https://github.com/ocaml/ocaml/pull/10831>

[November's core team review]
<https://discuss.ocaml.org/t/multicore-ocaml-november-2021-with-results-of-code-review/8934#core-team-code-review-1>

[the diff] <http://github.com/ocaml/ocaml/pull/10831.diff>


Stéphane Lavergne asked and Robin Björklin replied
──────────────────────────────────────────────────

        To clarify for relative newbies like myself: this would be
        a new way to do concurrent I/O, like Async and Lwt, but
        unlike those, it wouldn't require the use of a promise
        monad? In other words, does this mean that we'll have the
        choice between Async, Lwt and Eio in the near future for
        our concurrent I/O needs?

  That's correct as far as I can tell. This presentation provides an
  introduction to the current state of eio:
  <https://watch.ocaml.org/videos/watch/74ece0a8-380f-4e2a-bef5-c6bb9092be89>


Set up OCaml 2.0.0-beta12
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta12/9123/1>


Sora Morimoto announced
───────────────────────

Fixed
╌╌╌╌╌

  • Fallback to the version in which the assets exist if no assets exist
    in the latest opam release.
  • Instruct Cygwin setup to use "sys" symlinks during setup (partial
    workaround for bug with native symlinks in Cygwin setup - some
    depexts may still be affected)

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta12>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2022-01-04  7:56 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2022-01-04  7:56 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 22488 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of December 28, 2021
to January 04, 2022.

Table of Contents
─────────────────

A hack for toplevel breakpoints using effect handlers
Multi-shot continuations gone forever?
New release of Menhir (20211230)
Improved documentation for Fix
pp-binary-ints 0.1.1
Old CWN


A hack for toplevel breakpoints using effect handlers
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-hack-for-toplevel-breakpoints-using-effect-handlers/9065/1>


wiktor announced
────────────────

  I started playing with effect handlers and wondered if they could be
  used to implement toplevel breakpoints. It's a big hack and probably
  unsound at the moment, but it works and here's an example interaction:

  ┌────
  │ let arr =
  │   let fact n =
  │     let arr = Array.make (n+1) 1 in
  │     let rec loop i =
  │       if i <= n then begin
  │ 	Break.break ["i", i; "arr", arr];
  │ 	arr.(i) <- arr.(i-1) * i;
  │ 	loop (i+1)
  │       end
  │     in
  │     (loop 1; arr)
  │   in
  │     fact 5;;
  │ # (* We hit a breakpoint and obtain the continuation k *)
  │   k ();;
  │ - : bool = true
  │ # (* the bools are leaking from the execute_phrase function
  │    * inside the toplevel *)
  │   k ();;
  │ - : bool = true
  │ # i;;
  │ - : int = 3
  │ # arr;;
  │ - : int array = [|1; 1; 2; 1; 1; 1|]
  │ # (* let's disturb the computation of factorials *)
  │   arr.(i-1) <- 42;;
  │ - : unit = ()
  │ # k ();;
  │ - : bool = true
  │ # (* btw: here the user is like a scheduler for yield-based async *)
  │   k ();;
  │ - : bool = true
  │ # k ();;
  │ val arr : int array = [|1; 1; 42; 126; 504; 2520|]
  │ - : bool = true
  └────

  Currently I don't try to clean up bindings or values, which is a
  source of unsoundness. After the last `k ()' we got two results: First
  the computation of `let arr ...' finished, and then the computation of
  `k ()' finished. But `k' is a part of the execution of `let arr ...',
  so these two executions "intersect" without one being contained in the
  other. This makes the question of what should the current variable
  bindings be complicated. Setting the bindings at end of execution is
  futile, when a continuation may in such a way leak bindings from
  breakpoint time.

  Possibly a stack discipline for the execution of phrases is required
  to make the environments behave properly: at the end of executing a
  phrase we cancel (with another effect, maybe) other executions which
  "depend" on the current execution (evaluate the `k' obtained from a
  breakpoint in the current execution). This should eliminate these
  "intersections" and we could throw out the bindings added by the
  cancelled executions.

  I haven't tried anything with polymorphism yet, but type variables
  should probably be changed into abstract types inside the binders.

  Here's the code:
  <https://github.com/ocaml-multicore/ocaml/compare/multicore-pr...wiktorkuchta:toplevel-break>


wiktor later said
─────────────────

  Well, this might have been unnecessary, as most of it can be done
  properly in userspace (with more syntactic overhead).

  ┌────
  │ open EffectHandlers
  │ open Deep
  │ 
  │ type ('a, 'b) res =
  │   | Bp of 'a * ((unit, ('a, 'b) res) continuation)
  │   | Fin of 'b
  │ 
  │ module type P1 = sig  val i : int  val arr : int array end
  │ type payload = P1 of (module P1)
  │ type _ eff += Break : payload -> unit eff
  │ 
  │ let arr () =
  │   let fact n =
  │     let arr = Array.make (n+1) 1 in
  │     let rec loop i =
  │       if i <= n then begin
  │ 	perform (Break (P1 (module struct let i = i let arr = arr end)));
  │ 	arr.(i) <- arr.(i-1) * i;
  │ 	loop (i+1)
  │       end
  │     in
  │     (loop 1; arr)
  │   in
  │     fact 5;;
  │ 
  │ let with_break th =
  │   try_with (fun () -> Fin (th ())) ()
  │   { effc = fun (type a) (e : a eff) ->
  │       match e with
  │       | Break p -> Some (fun (k : (a,_) continuation) -> Bp (p, k))
  │       | _ -> None }
  │ 
  │ let cont = function
  │   | Bp (_, k) -> continue k ()
  │   | Fin _ -> failwith "computation finished, cannot continue"
  │ 
  │ let get = function
  │   | Bp (r, _) -> r
  │   | Fin _ -> failwith "computation finished, no breakpoint payload"
  │ 
  │ let get1 r = match get r with P1 m -> m
  └────

  ┌────
  │ # let r = with_break arr;;
  │ val r : (payload, int array) res = Bp (P1 <module>, <abstr>)
  │ # open (val get1 r);;
  │ val i : int = 1
  │ val arr : int array = [|1; 1; 1; 1; 1; 1|]
  └────

  The main pain point is having to define the payload types. In basic
  cases the payload type could be just a simple polymorphic variant. It
  would be nice if it could be completely inferred, but it's unlikely as
  `Break` has to have a statically known argument.

  With a bit of help from tooling (ppxes for code generation and
  shorthands in the toplevel), this could be better than printf
  debugging.


Guillaume Munch-Maccagnoni then said
────────────────────────────────────

  This is an interesting experiment.
  • This reminds me of the idea of high-level stack inspection for
    debugging and security (articulated for instance in Clements' PhD
    thesis _[Portable and high-level access to the stack with
    Continuation Marks]_; here's [another more recent paper] from the
    Racket people that might be relevant). One can ask whether a PPX can
    provide high-level stack inspection or if one needs support from the
    compiler for that. It's nice to experiment.
  • A few years ago someone asked whether there could be a use to
    untyped algebraic effects in OCaml (in the sense that they do not
    appear in the effect annotation in function types). I proposed
    debugging as an example. Someone suggested that it is not too hard
    to adapt the interface types of all functions in the call chain to
    add the appropriate effect annotation (and remove it afterwards),
    but I was not convinced.


[Portable and high-level access to the stack with Continuation Marks]
<https://www2.ccs.neu.edu/racket/pubs/dissertation-clements.pdf>

[another more recent paper]
<https://dl.acm.org/doi/10.1145/3385412.3385981>


Multi-shot continuations gone forever?
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multi-shot-continuations-gone-forever/9072/1>


cyberpink asked
───────────────

  What happens with multi-shot continuations now that
  Obj.clone_continuation was removed?
  ([https://github.com/ocaml-multicore/ocaml-multicore/pull/651])

  Anything that requires a "fork" operation, like say, a probabilistic
  programming EDSL, needs this. None of the old examples I've looked at
  like [Delimcc on top of effects] have been updated to use a new
  method, and I haven't been able to find any hints of one.

  Are multi-shot continuations just not possible now? Are there plans to
  add something equivalent back in later?


[https://github.com/ocaml-multicore/ocaml-multicore/pull/651]
<https://github.com/ocaml-multicore/ocaml-multicore/pull/651>

[Delimcc on top of effects]
<https://github.com/ocaml-multicore/effects-examples/blob/master/delimcc.ml>


Nicolás Ojeda Bär replied
─────────────────────────

  Yes, multi-shot continuations are gone and is unlikely that they will
  find their way back any time soon. One (good) reason is explained in
  <https://dl.acm.org/doi/10.1145/3434314> :

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/8/8d26520ef0f790fd3dc4407458d925c1a28fdbca.png>

  and

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/b/b28fa14f967364743277c0132a804c430d2d66d1.png>


Guillaume Munch-Maccagnoni then said
────────────────────────────────────

  I think the question still stands. You cut the sentence “_Extending
  our system with multi-shot continuations is future work (§8)_”. Also
  the paper is about a particular model based on separation logic rather
  than OCaml itself (for instance the authors also mention that their
  continuations are affine instead of linear unlike in OCaml multicore).

  Nevertheless, the multicore designers were aware that duplicating
  continuations makes it complicated to reason about resources. The
  topic of mixing continuations and linearity has been better studied
  from the angle of algebraic models of computation and proof
  theory. Essentially, with an effect system you could ensure that
  certain kinds of effects do not happen in the delimited part of the
  program (including allocating a resource), which controls copiability
  of the stack from the point of view of reasoning about the
  program. This is inspired by some logics that mix classical and
  intuitionistic or linear logic. From this angle the ability to copy a
  continuation would be restricted to a sub-part of the language which
  is pure to some degree. This should also be a suitable starting point
  if one wanted to develop a program logic to formalise the reasoning
  about such programs.

  However according to [#651] there were more technical reasons to drop
  `clone_continuation', such as breaking compiler optimizations. I am
  curious as well to know whether there are plans to reintroduce
  `clone_continuation' at some point, but obviously this would require
  some effort.


[#651] <https://github.com/ocaml-multicore/ocaml-multicore/pull/651>


KC Sivaramakrishnan said
────────────────────────

  @nojb and @gadmm have already answered why we've dropped support for
  `clone_continuation' now. We will need to track the copiability of the
  continuation in the continuation type and compiler optimisations also
  need to be made aware of the possibility of copying. Given the
  pervasive nature of its effects, there are no immediate plans to bring
  the feature back. We will have to come back to this after we have
  typed effects.

        Anything that requires a “fork” operation, like say, a
        probabilistic programming EDSL

  One can get pretty far with PPL with just one-shot continuations. My
  student and I did some experiments building a DSL for a PPL to learn
  about the space: <https://github.com/Arnhav-Datar/EffPPL>. Having
  spoken to PPL experts there are indeed some usecases where multi-shot
  continuations are useful, but from what I understand, the one-shotness
  isn't a blocker for PPL.

  I would be interested in collecting usecases where multi-shot
  continuations are absolutely necessary.


gasche then said
────────────────

  Interesting!

  My (probably naive) mental model of HANSEI-style libraries, using
  multishot continuations, is that they are extensions/generalization of
  a non-probabilistic "logic/non-deterministic monad" that searches for
  the set of solutions to a problem. Multishot continuations are
  naturally used in non-deterministic computations at backtracking
  points, to explore different search directions and collect the
  result. It is possible to avoid multishot continuations by replaying
  the whole search from the start each time (reference: [Capturing the
  future by replaying the past]), but this involves duplicated
  computations so it is less efficient (reference: [Asymptotic speedup
  with first-class control]).

  Can you give some intuition of how other approaches to probalistic
  inference work, that do not require multishot continuations? Are they
  also duplicating computations, or are they using a magic trick to
  avoid this issue with a different inference algorithm?

  I tried to find an answer to this question by reading the [internship
  report], but I couldn't locate an answer. (The report mentions HANSEI
  in the related work, but it does not discuss this question.) The
  report explains that the inference algorithm, called HMC (Hamiltonian
  Monte Carlo), uses automatic differenciation; so it uses a sort of
  symbolic manipulation / analysis of the probabilistic program to
  sample. But does this avoid repeated computations?  It may be the case
  instead that the differential is as large or larger than the program
  itself, and that the search algorithm using this differential in
  effect perform a program-sized computation at each search step,
  duplicating computations.


[Capturing the future by replaying the past]
<https://arxiv.org/pdf/1710.10385>

[Asymptotic speedup with first-class control]
<https://arxiv.org/abs/2007.00605>

[internship report]
<https://github.com/Arnhav-Datar/EffPPL/blob/main/EffPPL_Report.pdf>


Sadiq said
──────────

  Not a PPL but I've been hacking on a little effects-based model
  checker for concurrent data structures that implements dynamic partial
  order reduction (<https://github.com/sadiqj/dscheck/> - a
  WIP!). Multi-shot continuations would have been very useful.

  I ended up implementing something that involves maintaining a schedule
  and repeatedly replaying the computation. It looks very similar to
  what [Capturing the future..] proposes.


[Capturing the future..] <https://arxiv.org/pdf/1710.10385>


New release of Menhir (20211230)
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-menhir-20211230/9077/1>


François Pottier announced
──────────────────────────

  Dear OCaml & Menhir users,

  I am pleased to announce a new release of Menhir, with a major
  improvement.

  The code back-end has been rewritten from the ground up by Émile
  Trotignon and by myself, and now produces efficient and well-typed
  OCaml code. The infamous Obj.magic is not used any more.

  Furthermore, the new code back-end produces code that is more
  aggressively optimized, leading to a significant reduction in memory
  allocation and a typical performance improvement of up to 20% compared
  to the previous code back-end.

  ┌────
  │ opam update
  │ opam install menhir.20211230
  └────

  Happy well-typed parsing in 2022!


2021/12/30
╌╌╌╌╌╌╌╌╌╌

  • The code back-end has been rewritten from the ground up by Émile
    Trotignon and François Pottier, and now produces efficient and
    *well-typed* OCaml code. The infamous `Obj.magic' is not used any
    more.

    The table back-end and the Coq back-end are unaffected by this
    change.

    The main side effects of this change are as follows:

    • The code back-end now needs type information. This means that
      /either/ Menhir's type inference mechanism must be enabled (the
      	 easiest way of enabling it is to use Menhir via `dune'
      	 and to check that the `dune-project' file says `(using
      	 menhir 2.0)' or later)
      /or/ the type of every nonterminal symbol must be explicitly given
           via a `%type' declaration.

    • The code back-end no longer allows the type of any symbol to be an
      open polymorphic variant type, such as `[> `A ]'. As a workaround,
      we suggest using a closed polymorphic variant instead.

    • The code back-end now adheres to the /simplified/ error-handling
      strategy, as opposed to the /legacy/ strategy.

      For grammars that do /not/ use the `error' token, this makes no
      difference.

      For grammars that use the `error' token in the limited way
      permitted by the simplified strategy, this makes no difference
      either. The simplified strategy makes the following requirement:
      the `error' token should always appear at the end of a production,
      whose semantic action should abort the parser by raising an
      exception.

      Grammars that make more complex use of the `error' token, and
      therefore need the `legacy' strategy, cannot be compiled by the
      new code back-end.  As a workaround, it is possible to switch to
      the table back-end (using `--table --strategy legacy') or to the
      ancient code back-end (using `--code-ancient'). *In the long run,
      we recommend abandoning the use of the `error' token*. Support for
      the `error' token may be removed entirely at some point in the
      future.

    The original code back-end, which has been around since the early
    days of Menhir (2005), temporarily remains available (using
    `--code-ancient'). It will be removed at some point in the future.

    The new code back-end offers several levels of optimization, which
    remain undocumented and are subject to change in the future. At
    present, the main levels are roughly as follows:

    • `-O 0 --represent-everything' uses a uniform representation of the
      stack and produces straightforward code.
    • `-O 0' uses a non-uniform representation of the stack; some stack
      cells have fewer fields; some stack cells disappear altogether.
    • `-O 1' reduces memory traffic by moving `PUSH' operations so that
      they meet `POP' operations and cancel out.
    • `-O 2' optimizes the reduction of unit productions (that is,
      productions whose right-hand side has length 1) by performing a
      limited amount of code specialization.

    The default level of optimization is the maximum level, `-O 2'.

  • The new command line switch `--exn-carries-state' causes the
    exception `Error' to carry an integer parameter: `exception Error of
    int'. When the parser detects a syntax error, the number of the
    current state is reported in this way. This allows the caller to
    select a suitable syntax error message, along the lines described in
    [Section 11] of the manual. This command line switch is currently
    supported by the code back-end only.

  • The `$syntaxerror' keyword is no longer supported.

  • Document the trick of wrapping module aliases in `open struct
    ... end', like this: `%{ open struct module alias M =
    MyLongModuleName end %}'.  This allows you to use the short name `M'
    in your grammar, but forces OCaml to infer types that refer to the
    long name `MyLongModuleName'.  (Suggested by Frédéric Bour.)


[Section 11]
<http://cambium.inria.fr/~fpottier/menhir/manual.html#sec68>


Improved documentation for Fix
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-improved-documentation-for-fix/9079/1>


François Pottier announced
──────────────────────────

  My last contribution for 2021 is an improved documentation for Fix, a
  library that helps with various algorithmic constructions that involve
  memoization, recursion, and numbering.

  The documentation can be [viewed online].

  It can also be viewed locally (on your own machine) as follows:

  ┌────
  │ opam update
  │ opam install fix.20211231
  │ opam install odig
  │ odig odoc                 # this may take some time
  │ odig doc fix              # this opens the doc in your browser
  └────

  Happy fix'in' in 2022!


[viewed online] <http://cambium.inria.fr/~fpottier/fix/doc/fix/>


pp-binary-ints 0.1.1
════════════════════

  Archive: <https://discuss.ocaml.org/t/ann-pp-binary-ints-0-1-1/9080/1>


Ifaz Kabir announced
────────────────────

  Tired of printing octals and hexadecimals and then mentally converting
  them to bits. Ever wanted to just see the bits in an int? Now you can!

  Just run `opam install pp-binary-ints' and off you go:
  ┌────
  │ # Pp_binary_ints.Int.to_string 0b10101001;;
  │ - : string = "10101001"
  └────

  You can find the documentation for the project and more examples of
  how to use it [here].

  The library is very customizable.

  • You can choose to print with `0b' prefixes and `_' separators.
  • You can choose to print zeros just like the non-zeros, with prefixes
    and separators.
  • If you use zero padding, you can control how many leading zeros show
    up with the `~min_width' argument.
  • It correctly handles the edge cases when adding `_' separators: you
    won’t get leading underscores.
  • It includes pretty printers that work with `Format' and `Fmt' , not
    just `to_string' functions.
  • Supports `int', `int32', `int64', and `nativeint'.
  • Don't like the default prefixes and suffixes? Customize the prefixes
    and suffixes with the provided functor.


[here]
<https://ifazk.github.io/pp-binary-ints/pp-binary-ints/index.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-12-28  8:59 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-12-28  8:59 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of December 21 to 28,
2021.

Happy Winter Solstice!

Table of Contents
─────────────────

New release of Feat
Debugger support for OCaml
Old CWN


New release of Feat
═══════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-12/msg00010.html>


François Pottier announced
──────────────────────────

  I am happy to announce a new release of Feat, a library that offers
  support for counting, enumerating, and sampling objects of a certain
  kind, such as (say) the inhabitants of an algebraic data type.

  This new release integrates a contribution by Jonah Beckford. The
  library is now split in three packages: `feat-core' is parameterized
  over an implementation of big integers; `feat' instantiates
  `feat-core' with big integers provided by `zarith'; `feat-num'
  instantiates it with big integers provided by `num'.

  ┌────
  │ opam update
  │ opam install feat
  │ # or: opam install feat-num
  └────

  More details can be found here:

  <https://gitlab.inria.fr/fpottier/feat/>


Debugger support for OCaml
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/debugger-support-for-ocaml/9057/1>


Christian Lindig asked
──────────────────────

  What is the current state of debugger support for OCaml? I am aware of
  ocamldebug but every time I'm trying to use it I feel thrown back to
  2000 where it essentially existed in the same form (and still has no
  command line editing built in). Despite the powerful concept of time
  traveling, it does not seem very useful today. For example, it can't
  be attached to a running program and it does not work with native
  code. What is the state of GDB support? What debugger would one use on
  macOS?


linoscope replied
─────────────────

  Have you taken a look at ocamlearlybird ([github], [announcement])? I
  have never used it myself, but based on [the demo] it seems pretty
  nice.


[github] <https://github.com/hackwaly/ocamlearlybird>

[announcement]
<https://discuss.ocaml.org/t/ann-ocamlearlybird-1-0-0-beta1/7180>

[the demo] <https://imgur.com/U3GDHXM>


Sid Kshatriya also replied
──────────────────────────

  I agree that debugging in OCaml seems to be stuck in time.

  This is extremely unfortunate because it is able to do time traveling
  (as you mention) which is something that many other languages still
  cannot boast.

  • `ocamldebug' does not work properly when there is more than 1 OS
    thread
  • As types are erased during compile time in OCaml, it can be
    difficult to debug polymorphic functions. Rust and C/C++
    monomorphise all code so there is never any confusion about the type
    of anything in the debugger. Golang and Java have type information
    available during runtime so again, debugging is easy. In this
    respect OCaml is similar to Haskell while using the byte-code
    debugger.
  • The future of ocamldebug is unknown on multicore

  As far as GDB support is concerned, there was a project to improve GDB
  support (so you could print out variables like in ocamldebug IIUC) but
  it never got merged into trunk.

  However, if you are interested in low level debugging in gdb, here is
  a [recent] answer related to this.

  My guess is that `ocamldebug' will continue to work for the single
  domain, single thread case in OCaml 5.00 but ocamldebug is currently
  broken in multicore there (AFAIK).


[recent]
<https://discuss.ocaml.org/t/multicore-ocaml-september-2021-effect-handlers-will-be-in-ocaml-5-0/8554/9>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-12-21  9:11 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-12-21  9:11 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of December 14 to 21,
2021.

Table of Contents
─────────────────

Are you teaching using the Learn-OCaml platform?
A SOCKS implementation for OCaml
Old CWN


Are you teaching using the Learn-OCaml platform?
════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-12/msg00007.html>


Erik Martin-Dorel announced
───────────────────────────

  The OCaml Software Foundation is developing the teaching platform
  Learn-OCaml that provides auto-graded exercises for OCaml, and was
  initially authored by OCamlPro for the OCaml MOOC:
  <https://ocaml-sf.org/learn-ocaml/>

  The platform is free software and easy to deploy; this is great, but
  as a result we keep learning of users/deployments that we had no idea
  of. We would be interested in having a better view of our
  user-base. If you use Learn-OCaml as a teacher, could you answer this
  email (To: e.mdorel@gmail.com) and let us know?

  Ideally we would like to know:

  • Where are you using Learn-OCaml?  → in which university (in a
    specific course?), or in which company, online community or … ?
  • How many students/learners use your deployment in a year?

  Also FYI:

  • For an example of Learn-OCaml instance, see
    <https://discuss.ocaml.org/t/interesting-ocaml-exercises-from-francois-pottier-available-online/7050>
  • Last October we had a 0.13.0 release, full of new features:
    <https://discuss.ocaml.org/t/ann-release-of-ocaml-sf-learn-ocaml-0-13-0/8577>
  • For any question related to Learn-OCaml, feel free to create a
    discussion topic on <https://discuss.ocaml.org/> , category
    Community, tag /learn-ocaml/.
  • And if need be, opening an issue in
    <https://github.com/ocaml-sf/learn-ocaml/issues> if of course warmly
    welcome as well.


A SOCKS implementation for OCaml
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-socks-implementation-for-ocaml/9041/1>


Renato Alencar announced
────────────────────────

  I have been working on a SOCKS implementation for OCaml and specially
  for MirageOS. It's not really complete or stable yet (not even
  published), it only has a couple of proof of concepts on the examples
  directory and it doesn't integrate with the well known libraries of
  the ecosystem.

  I would like to ask for feedback, and some thoughts about how could we
  have that in Conduit and Cohttp for example, so It'd be just plugged
  in into those libraries without having to directly depending on it. I
  plan to implement that for those libraries and have it submitted
  upstream, but not without some clear thoughts about how to make a
  clear interface for that.

  Besides being sloppy, I have a few issues described on GitHub, and it
  should be addressed on the next few days. Anyone is welcome to discuss
  those issues as some of them are still foggy for me, and having some
  other views on that would be great.

  <https://github.com/renatoalencar/ocaml-socks-client>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-12-14 11:02 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-12-14 11:02 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of December 07 to 14,
2021.

Table of Contents
─────────────────

kqueue-ml 0.2.0 and poll 0.1.0
SWIPl-OCaml v0.5 - Never write your own unification algorithms again!
opam 2.1.2
Set up OCaml 2.0.0-beta10
A hassle-free setup to release binaries for different platforms: the opam release process experiment
Set up OCaml 2.0.0-beta11
What's the best way to save an huge amount of data in a file
p5scm 0.1.0
nanoid 1.0.0
Other OCaml News
Old CWN


kqueue-ml 0.2.0 and poll 0.1.0
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-kqueue-ml-0-2-0-and-poll-0-1-0/8958/1>


Anurag Soni announced
─────────────────────

  I'd like to announce new releases for [kqueue-ml] (version 0.2.0) and
  an initial release of [poll] (version 0.1.0).

  *Kqueue-ml*: Thin bindings to the kqueue event notification
   system. Changes since the last release:

  • Remove dependency on ctypes
  • Limit support to 64 bit systems
  • Adds constant values to be used as filter flags in the public API

  Installation: [opam install kqueue]

  Caveat: This is again mostly tested on macOS, but I plan to work on
  testing and fixing bugs for getting the library to work well on the
  various BSD systems, so please open issues if you use it on a BSD
  system and notice problems (Thanks!).

  *Poll*: Portable OCaml interface to macOS/Linux/Windows native IO
   event notification mechanisms

  Installation: [opam install poll]

  This is the first release of poll, which builds on top of `kqueue-ml'
  and adds bindings to the system IO event notifications on linux and
  windows to provide a portable polling interface. It uses kqueue on
  macOS, epoll on linux, and uses [wepoll] on windows so it can leverage
  IOCP on windows instead of select. All io events will be level
  triggered, i.e. there will be a notification as long as the file
  descriptor being watched is ready to read/write.

  If you experience any problems, please open an issue on the Github
  Issue tracker :slightly_smiling_face:


[kqueue-ml] <https://github.com/anuragsoni/kqueue-ml/>

[poll] <https://github.com/anuragsoni/poll>

[opam install kqueue] <https://opam.ocaml.org/packages/kqueue/>

[opam install poll] <https://opam.ocaml.org/packages/poll/poll.0.1.0/>

[wepoll] <https://github.com/piscisaureus/wepoll>


SWIPl-OCaml v0.5 - Never write your own unification algorithms again!
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-swipl-ocaml-v0-5-never-write-your-own-unification-algorithms-again/8968/1>


Kiran Gopinathan announced
──────────────────────────

  Hey all! I am just posting to announce a new package I've been working
  on: OCaml bindings to SWI-Prolog (ver 8.5 or higher)!

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/b/b5a466fc6bc98f83b6935205ea9b4ff1d16a324d.png>

  It's currently in the process of being submitted to OPAM, but it's my
  first time writing a package with bindings to C (using ctypes), so
  some further changes might be needed? maybe?, but you can find the
  source code repository here: [repo]/[github mirror].

  As a sneak peek of what the API looks like, here's a hello world:
  ┌────
  │ (* initialise SWIProlog *)
  │ let () = Swipl.initialise ()
  │ (* setup the prolog database with some facts *)
  │ let () = Swipl.load_source "hello :- writeln('hello world')."
  │ (* construct a Swipl term in OCaml *)
  │ let hello = Swipl.Syntax.(!"hello")
  │ (* send the term to the Prolog engine *)
  │ let () = Swipl.with_ctx @@ fun ctx -> Swipl.call ctx hello
  └────

  I've taken care to provide some detailed documentation + quick start
  guide using odoc (see
  <https://gopiandcode.github.io/SWIPL-OCaml/swipl/index.html>) - the
  quick start guide shows a step by step walkthrough on using the
  library to write a type inference algorithm for lambda calculus using
  OCaml+Prolog (no need to write your own UF).

  Anyway, hope this might be useful for others - I have spent way too
  long racking my brains on writing dumb custom unification algorithms,
  but now, no more!


[repo] <https://gitlab.com/gopiandcode/swipl-ocaml>

[github mirror] <https://github.com/Gopiandcode/SWIPL-OCaml>


Kiran Gopinathan later added
────────────────────────────

  Here's another example that might be interesting for those who have
  experience with SWI-Prolog.

  You can even get native interaction with CHR:
  <https://en.wikipedia.org/wiki/Constraint_Handling_Rules> is a very
  elegant framework which comes bundled with SWI Prolog that allows
  users to write complex domain specific constraint solving engines in a
  concise declaritive way.

  Here's a CHR system that models the interaction between `salt' and
  `water' (basic I know, but look up CHR to see some more powerful
  examples):
  ┌────
  │ let () = Swipl.load_source "
  │ :- use_module(library(chr)).
  │ 
  │ :- chr_constraint salt/0, water/0, salt_water/0.
  │ 
  │ salt, water <=> salt_water.
  │ 
  │ reducesTo_(Goal, C) :-
  │ 	call(Goal),
  │ 	call(user:'$enumerate_constraints'(C)).
  │ reducesTo(Goal, Constraints) :-
  │ 	findall(Constraint, reducesTo_(Goal, Constraint), Constraints).
  │ "
  └────

  Which we can then embed into OCaml using the following code:
  ┌────
  │ let solve_constraints ls =
  │   (* Create a new term variable context *)
  │   Swipl.with_ctx (fun ctx ->
  │     (* create a term for the result *)
  │     let result = Swipl.fresh ctx in
  │     (* encode the constraint store *)
  │     let goal = encode ls in
  │     (* send the query to the Prolog engine *)
  │     Swipl.call ctx (reducesTo goal result);
  │     (* extract the result *)
  │     decode ctx result
  │   )
  │ (* val solve_constraints: t list -> t list *)
  └────
  (Again, some steps have been omitted for brevity, and you should check
  out the quick start guide for a step by step walkthrough).


opam 2.1.2
══════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-1-2/8973/1>


Kate announced
──────────────

  We are pleased to announce the minor release of [opam 2.1.2].

  This opam release consists of [backported] fixes, including:

  • Fallback on `dnf' if `yum' does not exist on RHEL-based systems
    ([#4825])

  • Use `--no-depexts' in CLI 2.0 mode. This further improves the use of
    opam 2.1 as a drop-in replacement for opam 2.0 in CI, for example
    with setup-ocaml in GitHub Actions. ([#4908])

  To upgrade simply run:
  ┌────
  │ bash -c "sh <(curl -fsSL https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh) --version 2.1.2"
  └────


[opam 2.1.2] <https://github.com/ocaml/opam/releases/tag/2.1.2>

[backported] <https://github.com/ocaml/opam/issues/4920>

[#4825] <https://github.com/ocaml/opam/pull/4825>

[#4908] <https://github.com/ocaml/opam/pull/4908>


Set up OCaml 2.0.0-beta10
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta10/8974/1>


Sora Morimoto announced
───────────────────────

Added
╌╌╌╌╌

  • Added "extends" experimentally.


Changed
╌╌╌╌╌╌╌

  • Remove some hacks as `--no-depexts' is now used in CLI 2.0 mode from
    opam 2.1.2.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta10>


A hassle-free setup to release binaries for different platforms: the opam release process experiment
════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-hassle-free-setup-to-release-binaries-for-different-platforms-the-opam-release-process-experiment/8975/1>


Kate announced
──────────────

  On top of the [opam 2.1.2 announcement], I’d like share an experiment
  with the opam release script used for this release.

  As you might know, for each releases of opam we provide pre-compiled
  binaries for ease of use.  We’ve had a release script which up to this
  point required a specific setup to get it running correctly. For
  instance we had to setup a local OpenBSD machine (possibliy
  virtualised), a macOS/x86_64 machine and a macOS/arm64. This setup is
  rather tedious to reproduce.

  To improve this situation I’ve experimented over the past week with
  [QEMU] and [Rosetta 2] to make it a "one click script":

  <https://github.com/ocaml/opam/pull/4947>

  This change makes so that the script now only requires a
  macOS/arm64. From there you can:
  • compile locally for macOS/arm64 binaries
  • compile locally for macOS/x86_64 binaries (using Rosetta 2)
  • compile for BSDs (using QEMU)
  • compile for Linux (using Docker)

  With this, the [binaries] for this release have been compiled with
  this more reproducible setup, and now include FreeBSD/x86_64 binaries
  as well :sparkles:

  If someone wants to have a similar setup to distribute binaries here
  is the git repository (using Git LFS to store the large files). Feel
  free to use and experiment with it:

  <https://gitlab.com/kit-ty-kate/qemu-base-images>

  For now it only has OpenBSD/x86_64 and FreeBSD/x86_64 images but it
  could theoretically have more. Although I’m not accepting PRs for now
  (for obvious security reasons), I’m open to suggestions to add more
  platforms. See the [README] for high level details about the setup.


[opam 2.1.2 announcement]
<https://discuss.ocaml.org/t/ann-opam-2-1-2/8973>

[QEMU] <https://en.wikipedia.org/wiki/QEMU>

[Rosetta 2] <https://en.wikipedia.org/wiki/Rosetta_(software)#Rosetta_2>

[binaries] <https://github.com/ocaml/opam/releases/tag/2.1.2>

[README]
<https://gitlab.com/kit-ty-kate/qemu-base-images/-/blob/master/README.md>


Set up OCaml 2.0.0-beta11
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta11/9002/1>


Sora Morimoto announced
───────────────────────

Fixed
╌╌╌╌╌

  • Add support for more styles for the ocamlformat configuration in
    lint-fmt action.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta11>


What's the best way to save an huge amount of data in a file
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/whats-the-best-way-to-save-an-huge-amount-of-data-in-a-file/9003/5>


Deep in this thread, Simon Cruanes announced
────────────────────────────────────────────

  What a coincidence, I wrote an [Avro library] very recently. The paint
  is still fresh. However, it might be worth giving it a try as it's
  exactly the targeted use case: many rows of relatively simple data,
  encoded as binary; it also supports gzip compression (per "block" of N
  many rows, with N configurable). And there's no need to worry about
  endianess.

  It typically uses code generation from a schema (a json file).

  There's libraries for Avro in java (with all the Spark ecosystem) and
  also python (see "fastavro").


[Avro library] <https://github.com/c-cube/ocaml-avro>


p5scm 0.1.0
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-p5scm-0-1-0/9014/1>


Jason Nielsen announced
───────────────────────

  I’ve released [p5scm] which is now up on `opam'.  It is a scheme-like
  implementation on top of `camlp5''s [pa_schemer.ml] extension.  I know
  that `camlp5' isn't the cool kid on the block these days but it is a
  powerful tool and pretty cool in my estimation ;-).


[p5scm] <https://github.com/drjdn/p5scm>

[pa_schemer.ml]
<https://github.com/camlp5/camlp5/blob/master/etc/pa_schemer.ml>


nanoid 1.0.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-nanoid-1-0-0/9017/1>


mefyl announced
───────────────

  I'm pleased to announce the release of [nanoid 1.0.0]. NanoID are
  [popular unique ids] amongst the javascript ecosystem. This library
  brings an equivalent native implementation and a virtual library to
  transparently branch between the native implementation and the
  original javascript one. The intent is to enable pieces of code
  generating such ids to be moved transparently between frontend and
  backend of a web stack.

  This is an humble first contribution to gain some experience and will
  hopefully be followed by more of our internal developments.


[nanoid 1.0.0] <https://github.com/routineco/ocaml-nanoid>

[popular unique ids] <https://github.com/ai/nanoid>


Other OCaml News
════════════════

>From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Monorobot: a Slack bot for monorepos]
  • [opam 2.1.2 release]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Monorobot: a Slack bot for monorepos]
<https://tech.ahrefs.com/monorobot-a-slack-bot-for-monorepos-374260e2ca43?source=rss----303662d88bae--ocaml>

[opam 2.1.2 release] <http://opam.ocaml.org/blog/blog/opam-2-1-2/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-11-30 10:51 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-11-30 10:51 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 21112 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of November 23 to 30,
2021.

Table of Contents
─────────────────

opam 2.1.1, opam 2.0.10, and opam-depext 1.2
OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
New release of Fix
New release of Menhir (20211125)
Lwt 5.5.0, Lwt_domain 0.1.0, Lwt_react.1.1.5
OCaml's CI is gradually moving to GitHub Actions
How to combine 3 monads: Async/Lwt, Error and State?
Old CWN


opam 2.1.1, opam 2.0.10, and opam-depext 1.2
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-opam-2-1-1-opam-2-0-10-opam-depext-1-2/8872/1>


R. Boujbel announced
────────────────────

  We are pleased to announce several minor releases: [opam 2.0.10],
  [opam 2.1.1], and [opam-depext 1.2].

  The opam releases consist of backported fixes, while `opam-depext' has
  been adapted to be compatible with opam 2.1, to allow for workflows
  which need to maintain compatibility with opam 2.0. With opam 2.1.1,
  if you export `OPAMCLI=2.0' into your environment then workflows
  expecting opam 2.0 should now behave even more equivalently.

  You'll find more information in the [blog post ].


[opam 2.0.10] <https://github.com/ocaml/opam/releases/tag/2.0.10>

[opam 2.1.1] <https://github.com/ocaml/opam/releases/tag/2.1.1>

[opam-depext 1.2]
<https://github.com/ocaml-opam/opam-depext/releases/tag/1.2>

[blog post ] <https://opam.ocaml.org/blog/opam-2-0-10-2-1-1-depext/>


OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
══════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-otoml-0-9-0-a-compliant-and-flexible-toml-parsing-manipulation-and-pretty-printing-library/8152/10>


Daniil Baturin announced
────────────────────────

  A new 0.9.3 relase is available. Still not 1.0.0 just in case. The
  change I'm most glad I managed to make is that the lexer is now
  re-entrant and doesn't use any mutable state. Where can I apply for
  the "Designed for multicore OCaml" certification sticker? ;)


Breaking change in the functor interface
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I found an oversight that took a breaking change to fix. It didn't
  break any package that was already in the OPAM repository, so I'm glad
  I noticed it before it caused anyone trouble.

  My idea to make the functor take separate integer and float modules
  turned out to be misguided: it wouldn't compose with `Otoml.get_float
  ~strict:false' and similar functions that apply type conversions.

  Logically, `Otoml.get_float ~strict:false (Otoml.integer 5)' should
  produce `Otoml.TomlFloat 5.0'. However, it means that `get_float'
  needs to know how to convert integers to float. If integer and float
  types are in separate modules, that isn't possible.

  So I combined both integers and floats in a single `TomlNumber'. That
  way people who want to bring their own bignum libraries will have to
  write more code, but numbers will behave as they are expected to in a
  dynamically typed format.

  ┌────
  │ module BigNumber = struct
  │   type int = Z.t
  │   type float = Decimal.t
  │ 
  │   let int_of_string = Z.of_string
  │   let int_to_string = Z.to_string
  │   let int_of_boolean b = if b then Z.one else Z.zero
  │   let int_to_boolean n = (n <> Z.zero)
  │ 
  │   (* Can't just reuse Decimal.to/of_string because their optional arguments
  │      would cause a signature mismatch. *)
  │   let float_of_string s = Decimal.of_string s
  │ 
  │   (* Decimal.to_string uses "NaN" spelling
  │      while TOML requires all special float values to be lowercase. *)
  │   let float_to_string x = Decimal.to_string x |> String.lowercase_ascii
  │   let float_of_boolean b = if b then Decimal.one else Decimal.zero
  │   let float_to_boolean x = (x <> Decimal.zero)
  │ 
  │   let float_of_int = Decimal.of_bigint
  │   let int_of_float = Decimal.to_bigint
  │ end
  │ 
  │ module Otoml = Otoml.Base.Make (BigNumber) (Otoml.Base.StringDate)
  └────

  The next release will likely be 1.0.0 for real.


New release of Fix
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-new-release-of-fix/8895/1>


François Pottier announced
──────────────────────────

  I am pleased to announce a new release of Fix, with several new
  modules contribued by Frédéric Bour (thanks!).

  In short, Fix is a toolkit that helps perform memoization and fixed
  point computations (including data flow analyses). More generally, it
  offers a number of basic algorithmic building blocks that can be
  useful in many circumstances.

  ┌────
  │ opam update
  │ opam install fix.20211125
  └────

  Documentation can be found here:

  • <https://gitlab.inria.fr/fpottier/fix/-/blob/master/README.md>
  • <http://cambium.inria.fr/~fpottier/fix/doc/fix/Fix/index.html>

  Enjoy,

  François Pottier
  francois.pottier@inria.fr
  <http://cambium.inria.fr/~fpottier/>


2021/11/25
╌╌╌╌╌╌╌╌╌╌

  • The new module `CompactQueue' offers a minimalist mutable FIFO
    queue. It is comparable with OCaml's `Queue' module. In comparison
    with `Queue', it uses a more compact internal representation:
    elements are stored contiguously in a circular array. This has a
    positive impact on performance: both time and memory consumption are
    reduced. This data structure is optimized for maximum
    throughput. (Contributed by Frédéric Bour, reviewed by François
    Pottier.)

  • The new functor `DataFlow.ForCustomMaps' offers a forward data flow
    analysis that is tuned for greater performance. (Contributed by
    Frédéric Bour, reviewed by François Pottier.)

  • The new module `Indexing' offers a safe API for manipulating indices
    into fixed-size arrays. This API involves some dynamic checks as
    well as static type checks, thereby (hopefully) greatly reducing the
    risk of confusion in code that uses many arrays and many indices
    into these arrays. (Contributed by Frédéric Bour, reviewed by
    François Pottier.)

  • In `DataFlow', allow the function `foreach_root' (which is part of
    the signature `DATA_FLOW_GRAPH') to call `contribute x _' several
    times at a single root `x'.


New release of Menhir (20211125)
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-menhir-20211125/8896/1>


François Pottier announced
──────────────────────────

  I am pleased to announce a new release of Menhir, with an exciting
  contribution by Frédéric Bour: a groundbreaking performance
  improvement in `menhir --list-errors'. This is made possible by an
  entirely new reachability algorithm, which has been designed and
  implemented by Frédéric, and which is described in our paper "Faster
  Reachability Analysis for LR(1) Parsers". This is the link to the
  paper:

  <http://cambium.inria.fr/~fpottier/publis/bour-pottier-reachability.pdf>

  To install the new release, just type

  ┌────
  │ opam update
  │ opam install menhir.20211125
  └────

  Enjoy!

  François Pottier
  Francois.Pottier@inria.fr
  <http://cambium.inria.fr/~fpottier/>

  • The command `menhir --list-errors' has been sped up by a factor of
    up to x100, and requires up to x1000 less memory, thanks to a new
    LR(1) reachability algorithm, which has been designed and
    implemented by Frédéric Bour.

  • Better document the restricted way in which the `error' token must
    be used when using `--strategy simplified'. Menhir now checks that
    this token is used only at the end of a production, and warns if
    this is not the case. (Better yet, our suggestion is to not use the
    `error' token at all!)

  • The `$syntaxerror' keyword is now forbidden when using `--strategy
    simplified'. This keyword will be entirely removed in the next
    release. Incidentally, we have just found out that it behaves
    differently under the code back-end and under the table back-end.

  • Disable OCaml warning 39 (unused rec flag) in the OCaml code
    produced by Menhir's code back-end. This does not affect the table
    back-end.  (Reported by Armaël Guéneau.)

  • Fix a bug in `--random-*' which could cause Menhir to diverge if the
    grammar uses the `error' token.

  • Warn if a terminal symbol is named `Error'. This creates a name
    clash in the public interface of the generated parser.

  • Menhir now requires OCaml 4.03.0 (instead of 4.02.3) and Dune 2.8.0
    (instead of 2.0.0).


Lwt 5.5.0, Lwt_domain 0.1.0, Lwt_react.1.1.5
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-lwt-5-5-0-lwt-domain-0-1-0-lwt-react-1-1-5/8897/1>


Raphaël Proust announced
────────────────────────

  It is my pleasure to announce the release of Lwt version 5.5.0,
  Lwt_domain version 0.1.0, Lwt_react version 1.1.5, Lwt_ppx version
  2.0.3 and Lwt_ppx_let version 5.5.0.

  <https://github.com/ocsigen/lwt/releases/tag/5.5.0>

  All those packages can be installed via opam as usual.


:rotating_light:  Deprecation
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  One notable change is the deprecation of `Lwt_main.yield' and
  `Lwt_unix.yield'. It is recommended to use `Lwt.pause' instead.


:rocket:  Lwt_domain: an interface to multicore parallelism
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Another notable change is the addition of the Lwt_domain package. This
  package includes a single module `Lwt_domain' with functions to
  execute some computations in parallel, using the features of Multicore
  OCaml. The package requires an OCaml compiler with domains support to
  install.

  Code for this package is the work of @sudha with reviews and packaging
  from Lwt contributors.


Other changes
╌╌╌╌╌╌╌╌╌╌╌╌╌

  The full list of changes is available in the [CHANGES file].


[CHANGES file] <https://github.com/ocsigen/lwt/blob/5.5.0/CHANGES>


OCaml's CI is gradually moving to GitHub Actions
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamls-ci-is-gradually-moving-to-github-actions/8902/1>


Sora Morimoto announced
───────────────────────

  The OCaml team started switching to GitHub Actions last year for some
  of the official OCaml repositories. Also, we have released some CI
  related stuff, such as setup-ocaml, to the community. Some OCaml
  hackers also know that CI in the OCaml community is gradually
  switching to GitHub Actions nowadays.

  However, what gradually became a problem when we started switching was
  that the number of concurrent jobs that could run in a free account on
  GitHub was not enough for our activeness.

  One of the major pain points for compiler contributors is that the
  wait time for CI to complete, which is unrelated to the actual build,
  is too long. However, this has been a pain point in all services, even
  before GitHub Actions.

  The GitHub team did their best to help us make it better. As a result,
  they offered to upgrade the OCaml organization's plan to the team plan
  for free, which means that we can now benefit from a range of
  features, including access to 3x more concurrent runners than before.

  • About team plan:
    <https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration>
  • Concurrency/plan:
    <https://docs.github.com/en/get-started/learning-about-github/githubs-products#github-team>

  We would like to thank GitHub for supporting our team and Ahmed Bilal,
  who supported this effort.


How to combine 3 monads: Async/Lwt, Error and State?
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/how-to-combine-3-monads-async-lwt-error-and-state/8906/9>


Deep in this thread, Ivan Gotovchits said
─────────────────────────────────────────

  The monads library provides the transformers for some well-known
  monads. All these monads have a more or less standard implementation,
  offering the same performance as any other monadic library can
  offer. Like there is no better way of implementing the state monad
  other than a function. We have experimented a lot with different
  performance optimizations, such as boxing and unboxing it and inlining
  various operators, and keep experimenting to get the maximum from the
  current compiler. In BAP, we heavily use the monads library, first of
  all for our [knowledge representation and reasoning engine], which is
  the foundation for all BAP analyses. We also use it for [emulating
  binary programs].  The rich interface is here to make our life easier
  and more comfortable when we use monads. It definitely comes for free¹
  as the number of functions doesn't affect the performance of the
  underlying monad.

  But… there is always a but :) Stacking monads using a transformer does
  have a price. Even with the flambda compiler. The latter is doing an
  excellent job of unstacking them and eliminating the overhead of
  having a chain of monads. But our latest experiments show that a
  custom-made monad (still with the monads library) performs better
  under either branch of the compiler. We [have rewritten our main
  monads] that were relying on transformers and got from 20% to 50%
  performance improvement. But that is not to say that the monads
  library itself is slow or that we're not using it, it is to say that
  there are other options to transformers that might work in some cases.
  See the linked PR if you want to learn the trick.

  ¹⁾ Provided that we ignore the size of the executable, e.g., linking
  the core_kernel library results in a quite large binary, which may
  increase the startup time. Insignificantly, but in some use cases, it
  might be a significant factor.


[knowledge representation and reasoning engine]
<https://binaryanalysisplatform.github.io/bap/api/master/bap-knowledge/Bap_knowledge/Knowledge/index.html>

[emulating binary programs]
<https://binaryanalysisplatform.github.io/bap/api/master/bap-primus/Bap_primus/Std/index.html>

[have rewritten our main monads]
<https://github.com/BinaryAnalysisPlatform/bap/pull/1361>


Ivan Gotovchits then said
─────────────────────────

  As it was already suggested, you can use [monad transformers], to
  compose several monads into a single monad. As a show-case, we will
  use the [monads] library (disclaimer, I am an author of this library),
  which you can install with

  ┌────
  │ opam install monads
  └────

  It offers most of the well-known monads in a form of a monad
  transformer, which in terms of OCaml, is a functor that takes a monad
  and returns a new monad that enriches it with some new behavior. For
  example, to make a non-deterministic error monad, we can do
  `Monad.List.Make(Monad.Result.Error)' and get a monadic structure
  (i.e., a module that implements the [Monad.S] interface) that is both
  a list monad and an error monad.  The small caveat is that the
  operations of the wrapped monad, the error monad in our case, are not
  available directly, so we have to _lift_ them, e.g.,
  ┌────
  │ let fail p = lift @@ Monad.Result.Error.fail p
  └────
  So that in the end, the full implementation of the transformed monad
  still requires some boilerplate code,

  ┌────
  │ module ListE = struct
  │   type 'a t = 'a list Monad.Result.Error.t
  │   include Monad.List.Make(Monad.Result.Error)
  │   let fail p = lift@@Monad.Result.Error.fail p
  │   (* and so on for each operation that is specific to the wrapped monad *)
  │ end
  └────

  Now, let's try wrapping the Lwt monad into the state. We don't want to
  add the Error monad because Lwt is already the error monad and adding
  an extra layer of errors monad is not what we want. First of all, we
  need to adapt the `Lwt' monad to the `Monad.S' interface, e.g.,
  ┌────
  │ module LwtM = struct
  │   type 'a t = 'a Lwt.t
  │   include Monad.Make(struct
  │       type 'a t = 'a Lwt.t
  │       let return = Lwt.return
  │       let bind = Lwt.bind
  │       let map x ~f = Lwt.map f x
  │       let map = `Custom map
  │     end)
  │ end
  └────

  If we want to keep the state type monomorphic, then we will need a
  module for it. Suppose your state is represented as,
  ┌────
  │ module State = struct
  │   type t = string Map.M(String).t
  │ end
  └────

  Now, we can use it to build our `State(Lwt)' Russian doll,
  ┌────
  │ module IO = struct
  │   include Monad.State.T1(State)(LwtM)
  │   include Monad.State.Make(State)(LwtM)
  │ 
  │   (* let's lift [read] as an example *)
  │   let read fd buf ofs len =
  │     lift (Lwt_unix.read fd buf ofs len)
  │ end
  └────

  The `Monad.State.T1' functor is used to create the types for the
  generated monad. You can write them manually, of course, like as we
  did in the List(Error) example, but the type generating modules are
  here for the convenience¹

  Now, let's get back to the problem of the lifting. It looks tedious to
  impossible to lift every operation from Lwt.  Commonly, we try to put
  the smaller monad inside, to minimize the work, but it doesn't work
  with Lwt as the latter is not a transformer. So what is the solution?
  For me, the solution is to not lift the operations at all, but
  instead, define your IO abstraction and hide that it is using Lwt
  underneath the hood. This will make the code that uses this new
  abstraction more generic and less error-prone so that it can focus on
  the business logic and the implementation details could be hidden
  inside the monad implementation. This is what the monads are for,
  anyway.

  ¹⁾ We omit the types from the output of the `Make' functor since for a
  long time OCaml didn't allow the repetition of types in a structure so
  having the types in it will prevent us from composing various flavors
  of monads using `include'. It is also a long-time convention widely
  used in many OCaml libraries, including Core and Async. A convention
  that we probably don't need anymore.


[monad transformers] <https://en.wikipedia.org/wiki/Monad_transformer>

[monads]
<https://binaryanalysisplatform.github.io/bap/api/master/monads/Monads/Std/index.html>

[Monad.S]
<https://binaryanalysisplatform.github.io/bap/api/master/monads/Monads/Std/Monad/index.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-11-16  8:41 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-11-16  8:41 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 20114 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of November 09 to 16,
2021.

Table of Contents
─────────────────

Early preview of the Algorithmic with OCaml Book
pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
ocaml-wayland (pure OCaml wayland protocol library)
Set up OCaml 2.0.0-beta6
Set up OCaml 2.0.0-beta7
Set up OCaml 2.0.0-beta8
phylogenetics, a library for molecular evolution
release of svmwrap: a wrapper around libsvm-tools
GeoPub - A XMPP web client
Old CWN


Early preview of the Algorithmic with OCaml Book
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/early-preview-of-the-algorithmic-with-ocaml-book/8785/1>


Damien Guichard announced
─────────────────────────

  Please report bugs, bad English & nonsenses.  But do not report
  omissions (it is work-in-progress plus it's not an ocaml bible).

  <https://www.cjoint.com/c/KKjulI1Dx03>

  Why the book is not bottom up, instead some concepts are used without
  explained ?

  • Because some notions (what is the `unit' type ? what is a queue ?)
    are considered easy-enough to go without saying.

  What will be in the missing chapter 6 ?

  • Type polymorphism, universal quantification, `Stdlib.compare', weak
    polymorphism, constrained polymorphism, phantom types, type
    variance.

  What will be in the chapters 12 and more ?
  • High performance lexing
  • Recursive-descent parsing
  • The art of searching
  • Detailed construction of the ERic 0.3 application

  Will the source files go to a repository ?

  • No. The source files are already included in the zip archive.


pyml_bindgen: a CLI app to generate Python bindings directly from OCaml value specifications
════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-pyml-bindgen-a-cli-app-to-generate-python-bindings-directly-from-ocaml-value-specifications/8786/1>


Ryan Moore announced
────────────────────

  I wanted to announce the first release of [pyml_bindgen], a CLI app
  for generating Python bindings using [pyml] directly from OCaml value
  specifications.

  Manually writing bindings to Python libraries can get tedious pretty
  quickly.  `pyml_bindgen' aims to help you avoid a lot of the
  repetitive work when binding Python libraries by letting you focus on
  the OCaml side of things and (mostly) not worrying about the
  implementation of the pyml bindings.


[pyml_bindgen] <https://github.com/mooreryan/ocaml_python_bindgen>

[pyml] <https://github.com/thierry-martinez/pyml/>

Quick start
╌╌╌╌╌╌╌╌╌╌╌

  First, install `pyml_bindgen'.  It is available on [Opam].

  ┌────
  │ $ opam install pyml_bindgen
  └────

  Say you have a Python class you want to bind and use in OCaml.
  (Filename: `adder.py')

  ┌────
  │ class Adder:
  │     @staticmethod
  │     def add(x, y):
  │ 	return x + y
  └────

  To do so, you write OCaml value specifications for the class and
  methods you want to bind.  (Filename: `val_specs.txt')

  ┌────
  │ val add : x:int -> y:int -> unit -> int
  └────

  Then, you run `pyml_bindgen'.

  ┌────
  │ $ pyml_bindgen val_specs.txt adder Adder --caml-module Adder > lib.ml
  └────

  Now you can use your generated functions in your OCaml code.
  (Filename: `run.ml')

  ┌────
  │ open Lib
  │ 
  │ let () = Py.initialize ()
  │ 
  │ let result = Adder.add ~x:1 ~y:2 ()
  │ 
  │ let () = assert (result = 3)
  └────

  Finally, set up a dune file and run it.

  ┌────
  │ (executable
  │  (name run)
  │  (libraries pyml))
  └────

  ┌────
  │ $ dune exec ./run.exe
  └────


[Opam] <https://opam.ocaml.org/packages/pyml_bindgen/>


Documentation
╌╌╌╌╌╌╌╌╌╌╌╌╌

  For more information on installing and using `pyml_bindgen', check out
  the [docs].  There you will find lots of tips and examples to help you
  get started!


[docs] <https://mooreryan.github.io/ocaml_python_bindgen/>


ocaml-wayland (pure OCaml wayland protocol library)
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-wayland-pure-ocaml-wayland-protocol-library/7616/2>


Thomas Leonard announced
────────────────────────

  ocaml-wayland has been very stable over the last few months and so
  I've now released [version 1.0]. The main changes are improved error
  handling and diagnostics.

  I've been using this to write an Xwayland adaptor, which acts as an
  X11 window manager to Xwayland, converting between the two
  protocols. This allows running X11 apps in VMs and having them appear
  alongside other application windows on the host. It can also be used
  to fix other problems, such as support for HiDPI screens and Sway's
  buggy clipboard support:

  <https://roscidus.com/blog/blog/2021/10/30/xwayland/>


[version 1.0]
<https://github.com/talex5/ocaml-wayland/releases/tag/v1.0>


Set up OCaml 2.0.0-beta6
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta6/8795/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • Unlock opam 2.1 on the Ubuntu and macOS runners.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta6>


Set up OCaml 2.0.0-beta7
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta7/8796/1>


Sora Morimoto announced
───────────────────────

Fixed
╌╌╌╌╌

  • Return an empty array to avoid depext failure when depext flags are
    not passed.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta7>


Set up OCaml 2.0.0-beta8
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta8/8821/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • Use 2.1 mode instead of 2.0 mode on the Ubuntu and macOS runners.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta8>


phylogenetics, a library for molecular evolution
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-phylogenetics-a-library-for-molecular-evolution/8812/1>


Philippe announced
──────────────────

  I'm happy to announce the availability on opam of [phylogenetics], a
  bioinformatics library dedicated to [molecular evolution] and
  phylogeny. It provides a few algorithms and data structures that can
  be useful to study how biological sequences like proteins or genes
  have evolved, or to simulate datasets under various evolutionary
  models.

  Comments/questions welcomed on the repo's issue tracker!


[phylogenetics] <https://github.com/biocaml/phylogenetics>

[molecular evolution]
<https://en.wikipedia.org/wiki/Molecular_evolution>


release of svmwrap: a wrapper around libsvm-tools
═════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-svmwrap-a-wrapper-around-libsvm-tools/8818/1>


UnixJunkie announced
────────────────────

  I am pleased to announce the availability in opam of the svmwrap
  package.  A wrapper around libsvm's svm-train and svm-predict
  executables.  Currently, only regression modeling is supported, using
  the linear, RBF, sigmoid or polynomial kernel.

  <https://github.com/UnixJunkie/svmwrap>

  The quite scary usage looks like this:
  ┌────
  │ usage: svmwrap
  │   -i <filename>: training set or DB to screen
  │   --feats <int>: number of features
  │   [-o <filename>]: predictions output file
  │   [-np <int>]: ncores
  │   [--kernel <string>] choose kernel type {Lin|RBF|Sig|Pol}
  │   [-c <float>]: fix C
  │   [-e <float>]: epsilon in the loss function of epsilon-SVR;
  │   (0 <= epsilon <= max_i(|y_i|))
  │   [-g <float>]: fix gamma (for RBF and Sig kernels)
  │   [-r <float>]: fix r for the Sig kernel
  │   [--iwn]: turn ON instance-wise-normalization
  │   [--scale]: turn ON [0:1] scaling (NOT PRODUCTION READY)
  │   [--no-plot]: no gnuplot
  │   [{-n|--NxCV} <int>]: folds of cross validation
  │   [-q]: quiet
  │   [-v|--verbose]: equivalent to not specifying -q
  │   [--seed <int>]: fix random seed
  │   [-p <float>]: training set portion (in [0.0:1.0])
  │   [--pairs]: read from .AP files (atom pairs; will offset feat. indexes by 1)
  │   [--train <train.liblin>]: training set (overrides -p)
  │   [--valid <valid.liblin>]: validation set (overrides -p)
  │   [--test <test.liblin>]: test set (overrides -p)
  │   [{-l|--load} <filename>]: prod. mode; use trained models
  │   [{-s|--save} <filename>]: train. mode; save trained models
  │   [-f]: force overwriting existing model file
  │   [--scan-c]: scan for best C
  │   [--scan-e <int>]: epsilon scan #steps for SVR
  │   [--scan-g]: scan for best gamma
  │   [--regr]: regression (SVR); also, implied by -e and --scan-e
  │   [--e-range <float>:<int>:<float>]: specific range for e
  │   (semantic=start:nsteps:stop)
  │   [--c-range <float,float,...>] explicit scan range for C
  │   (example='0.01,0.02,0.03')
  │   [--g-range <float,float,...>] explicit range for gamma
  │   (example='0.01,0.02,0.03')
  │   [--r-range <float,float,...>] explicit range for r
  │   (example='0.01,0.02,0.03')
  └────

  For people who know my linwrap opam package (a wrapper around
  liblinear tools), this is quite similar.
  <https://github.com/UnixJunkie/linwrap>


GeoPub - A XMPP web client
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-geopub-a-xmpp-web-client/8819/1>


pukkamustard announced
──────────────────────

  I'd like to announce an initial, proof-of-concept release of GeoPub -
  an XMPP web client. Unlike many XMPP clients the focus is not on
  instant messaging but on creating, displaying and managing things such
  as events, maps, information on local organizations and other local
  knowledge (see [the openEngiadina] project for the context).

  This initial release is not really anything useful but a
  proof-of-concept how such an application can be developed using XMPP
  and OCaml. There are many rough edges and broken hacks that need
  fixing. I'd be very grateful for your feedback, thoughts and ideas.

  The source code of the app is on [codeberg] and a pre-built hosted
  version is available [here].

  The application consists of some parts and ideas that I'd like to
  illustrate separately:


[the openEngiadina] <https://openengiadina.net>

[codeberg] <https://codeberg.org/openEngiadina/geopub>

[here] <https://geopub.openengiadina.net/>

ocaml-xmpp
╌╌╌╌╌╌╌╌╌╌

  [ocaml-xmpp] is a XMPP client library for OCaml (documentation
  available [online].


[ocaml-xmpp] <https://codeberg.org/openEngiadina/ocaml-xmpp>

[online] <https://inqlab.net/projects/ocaml-xmpp/>

Reactive
┄┄┄┄┄┄┄┄

  ocaml-xmpp is reactive in the sense that the XMPP connection is
  abstracted as a React event of Stanzas (small pieces of information
  that flow over XMPP):

  ┌────
  │ val stanzas : t -> Stanza.t React.event
  └────

  This React event can be filtered for messages in a specific
  conversation, for example.


Transports
┄┄┄┄┄┄┄┄┄┄

  XMPP works with different transport mechanisms and ocaml-xmpp supports
  this. Currently ocaml-xmpp can be used from Unix with a TCP/SSL
  connection to a XMPP server and from web browsers with a WebSocket
  connection. This is implemented by abstracting the XMPP transport:

  ┌────
  │ module type TRANSPORT = sig
  │   (** {2 Connection} *)
  │ 
  │   type options
  │   (** Additional options that may be passed to the transport *)
  │ 
  │   type t
  │   (** Type of an instantiated connection to an XMPP server *)
  │ 
  │   val connect : host:string -> options -> t Lwt.t
  │ 
  │   val close : t -> unit Lwt.t
  │ 
  │   val closed : t -> unit Lwt.t
  │ 
  │   (** {2 XML Stream} *)
  │ 
  │   type stream
  │ 
  │   val open_stream : t -> to':string -> stream Lwt.t
  │ 
  │   val stream_id : stream -> string Lwt.t
  │ 
  │   val send_xml : stream -> Xmlc.t -> unit Lwt.t
  │ 
  │   val signals : stream -> Xmlc.signal Lwt_stream.t
  │ 
  │   val stop_stream : stream -> unit Lwt.t
  │ end
  └────

  A transport establishes the underlying connection to a server and can
  create XML streams (in XMPP a connection is by multiple XML streams
  sequentially). For technical reasons XML parsing is also handled by
  the transport and a stream of XML signals (element start, data,
  element end) is returned. This is due to the fact that XML parsing in
  XMPP needs to be done slightly differently when using TCP (a single
  XML document over the entire stream) or WebSockets (every WebSocket
  frame is a parse-able XML document).

  The Unix/TCP/SSL transport uses Markup.ml and whereas the WebSocket
  transport uses Xmlm (and Brrr).


Parser combinators for XML
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  For parsing streams of XML signals to OCaml types ocaml-xmpp contains
  a parser combinator helper library: [Xmlc]. This allows parser for XML
  such as this:

  ┌────
  │ <bind xmlns='urn:ietf:params:xml:ns:xmpp-bind'><jid>w4iu4ckn3kjbqvcd@demo.openengiadina.net/z8Pkzfa8</jid></bind>
  └────

  to be parses like this:

  ┌────
  │ Xmlc.Parser.(
  │   element (Ns.bind "bind") (fun _ ->
  │     element (Ns.bind "jid") (fun _ ->
  │       text >>| String.concat "" >>= fun jid_s ->
  │       match Jid.of_string jid_s with
  │       | Some jid -> return jid
  │       | None -> fail_with "invalid JID")))
  └────


[Xmlc] <https://inqlab.net/projects/ocaml-xmpp/xmlc/Xmlc/index.html>


XMPP extensions
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Inspiration for the scope of the core library is taken from the
  [Strophe] XMPP libraries - everything that does not have directly to
  do with XMPP transport, authentication or stream management is kept
  outside of the core library.

  There are already some "extension" libraries outside of the core for
  useful XMPP features (e.g. [Roster management], [PubSub] and
  [pinging]).

  One thing that I do want to add to the core library is stream
  management according to [XEP-0198]. I expect this addition to change
  the core library API - the API is not stable yet!

  Much inspiration was taken from [Jackline] - an OCaml XMPP client -
  and in particular [this post] on Jackline. Many thanks to @hannes.


[Strophe] <http://strophe.im/>

[Roster management]
<https://inqlab.net/projects/ocaml-xmpp/xmpp/Xmpp_roster/index.html>

[PubSub]
<https://inqlab.net/projects/ocaml-xmpp/xmpp/Xmpp_pubsub/index.html>

[pinging]
<https://inqlab.net/projects/ocaml-xmpp/xmpp/Xmpp_ping/index.html>

[XEP-0198] <https://xmpp.org/extensions/xep-0198.html>

[Jackline] <https://github.com/hannesm/jackline>

[this post] <https://hannes.nqsb.io/Posts/Jackline>


reactor
╌╌╌╌╌╌╌

  GeoPub uses Brr. I had some trouble figuring out a suitable
  "architecture" for managing complex logic and ended up hacking an
  [Elm] inspired helper library: [reactor.mli]. State updates for the
  entire application are then handled in a single [update function].

  I'm not yet very happy with this machinery and I'm pretty sure I'm
  using react in wrong and dangerous ways. I'd be very grateful for
  ideas on how to improve this. THis might be related to this
  discussion:
  <https://discuss.ocaml.org/t/structuring-frp-specifically-note-applications/8645/17>.

  The reason for using React over Note is because ocaml-xmpp uses a lot
  of Lwt and `Lwt_react' provides nice bindings for working with both. I
  guess something similar could be created for Note (e.g. `Lwt_note')
  and I'm open to using Note (also in ocaml-xmpp).


[Elm] <https://elm-lang.org/>

[reactor.mli]
<https://codeberg.org/openEngiadina/geopub/src/branch/main/src/reactor/reactor.mli>

[update function]
<https://codeberg.org/openEngiadina/geopub/src/branch/main/src/geopub/main.ml#L28>


Leaflet
╌╌╌╌╌╌╌

  GeoPub displays a map using the [Leaflet.js] JavaScript
  library. GeoPub contains OCaml bindings to Leaflet using Brr:
  [leaflet.mli]. Writing this was very straightforward and pleasant (I
  like Brr!).

  One issue I have is that the Leaflet map needs to be manipulated very
  imperatively, whereas the rest of the application is much more
  functional. This causes some mismatches. I guess one needs to find a
  way of hiding the impressiveness of Leaflet (e.g. like
  [react-leaflet]).


[Leaflet.js] <https://leafletjs.com/>

[leaflet.mli]
<https://codeberg.org/openEngiadina/geopub/src/branch/main/src/leaflet/leaflet.mli>

[react-leaflet] <https://github.com/PaulLeCam/react-leaflet>


Guix for build and development environments
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I use [Guix] for providing a build and development environment. With
  guix installed one can run `guix shell' in the GeoPub repository to
  get a reproducible build environment. All dependencies are fetched and
  made available by Guix in this environment (e.g. `ocaml-xmpp' or the
  OCaml compiler).

  I will publish `ocaml-xmpp' on OPAM once the API is more stable and an
  initial release can be made.


[Guix] <https://guix.gnu.org/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-11-09 10:08 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-11-09 10:08 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of November 02 to 09,
2021.

Table of Contents
─────────────────

OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
Build System Engineer at Jane Street
Real-world use example of ts2ocaml
First release of `ts2ocaml' - generates OCaml bindings from .d.ts files!
OUPS meetups are back!
Old CWN


OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
══════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-otoml-0-9-0-a-compliant-and-flexible-toml-parsing-manipulation-and-pretty-printing-library/8152/9>


Daniil Baturin announced
────────────────────────

  OTOML 0.9.2 is now available from the OPAM repository.


Breaking changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  It makes a breaking change to the `get_array' accessor: it now has
  type `Otoml.get_array' now has type `?strict:bool -> (t -> 'a) -> t ->
  'a list' , that is, it requires an accessor function that will be
  applied to every item of the array.

  For example, you can use `Otoml.find t (Otoml.get_array
  Otoml.get_string) ["foo"]' to retrieve an array of strings from a TOML
  document's key `foo' .

  The motivation for the change is that it allows retrieving arrays of
  unwrapped OCaml values in one step. The old behaviour can still be
  emulated using an identify function for the accessor, for example the
  built-in `Otoml.get_value : 'a -> 'a' .


New features
╌╌╌╌╌╌╌╌╌╌╌╌

  New `Otoml.path_exists t ["some"; "table"; "key"]' allows checking if
  a key path exists in a TOML document.

  `Otoml.Printer.to_string/to_channel' functions now provide
  `~force_table_array' option. When set to true, it forces every array
  that contains nothing but tables to be rendered using the `[[...]]~'
  table array syntax.


Bug fixes
╌╌╌╌╌╌╌╌╌

  Unicode escape sequences are now printed correctly.

  If a table has subtables and non-table items, the non-table items are
  forcibly moved before the first subtable for printing. This way the
  output parses correctly, otherwise the non-table items would be
  mistakenly treated as subtable members. This way hand-constructed TOML
  tables are always formatted correctly even if the user inserts
  non-table items after a subtable.


Testing
╌╌╌╌╌╌╌

  I added a minimal test suite for the read-write interface. If anyone
  wants to contribute to it, that will be much appreciated. Ideally, all
  lookup functions and all accessors/constructors should be tested to
  work as expected.

  Both parser and formatter are now tested with the
  [github.com/BurntSushi/toml-test] and are fully compliant (one
  formatter test is skipped because the test itself is malformed).


[github.com/BurntSushi/toml-test]
<https://github.com/BurntSushi/toml-test>


Future plan
╌╌╌╌╌╌╌╌╌╌╌

  My idea was to call it 1.0.0 when it passes both parsing and formatter
  tests. That goal is reached now, but I'd like to see if anyone has any
  more ideas for the API that cannot be implemented without breaking
  changes. If not, I'll call it 1.0.0 in the next release.


Build System Engineer at Jane Street
════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-build-system-engineer-at-jane-street/8737/1>


Andrey Mokhov announced
───────────────────────

  Jane Street is looking for new build system engineers! I've worked in
  this team for two years and I love the job.  Here is why:

  • You frequently change focus from low-level work, like debugging a
    weird file-system issue, to high-level work, like designing a cloud
    build cache.

  • Your colleagues are amazing. If you're like me, you'll feel like an
    imposter in most conversations but it's OK since everyone is kind
    and helpful, so you'll learn something new every day.

  • Most of your work is open-source and benefits the wider OCaml
    community.

  For balance, let me also say a few words about challenges.

  • Build systems accumulate years of knowledge of many people on how to
    get things done. When this knowledge goes out of date, you are often
    the only person to fix it. For this reason, build systems work can
    be daunting.

  • It's far from our core business, so you don't get to work on any of
    our cool trading systems. Your role is to empower others.

  • Our team is small, so we may have to turn down some good
    candidates. However, please don't get discouraged by this! If in
    doubt, send me a message and we'll chat.

  • There is no remote work for now.

  To apply, follow [this link] and mention the build systems role in
  your application.

  Our plans for 2022 include: implementing cloud builds in Dune, better
  integration with other tools like IDEs and the OCaml compiler, and
  making Dune even faster than it is today. To learn more about our
  work, listen to [this podcast].

  And feel free to message me or @jeremiedimino if you have any
  questions!


[this link]
<https://janestreet.com/join-jane-street/position/4274814002/>

[this podcast] <https://signalsandthreads.com/build-systems/>


Real-world use example of ts2ocaml
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/real-world-use-example-of-ts2ocaml/8745/1>


Sora Morimoto announced
───────────────────────

  Some OCaml/JavaScript enthusiasts may know that we spent almost two
  years working on a tool automatically generating OCaml bindings from
  TypeScript's type definition files. To prepare for its release, we
  just published a repository to show an example use of it.

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/3/3473fc11da0c56335e8de2b91bd7d9172444913a_2_1380x374.png>

  <https://github.com/ocsigen/ts2ocaml-example>

  This example generates and actually uses a binding to a small
  JavaScript library called [pretty-bytes], and it doesn't only generate
  the binding, but also converts JSDoc comments to odoc ones.

  We believe we can release ts2ocaml as early as this month, please look
  forward to the new announcement!


[pretty-bytes] <https://github.com/sindresorhus/pretty-bytes>


First release of `ts2ocaml' - generates OCaml bindings from .d.ts files!
════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-ts2ocaml-generates-ocaml-bindings-from-d-ts-files/8772/1>


Cannorin announced
──────────────────

  We're pleased to announce that ts2ocaml is now public!

  <https://github.com/ocsigen/ts2ocaml>

  This is a tool which parses TypeScript definition files (`.d.ts') of a
  JS package and then generates an OCaml binding for the package.

  ts2ocaml currently supports js_of_ocaml as a target via
  [LexiFi/gen_js_api], and ReScript is also going to be supported too!

  You can install ts2ocaml from NPM: `npm install -g @ocsigen/ts2ocaml'.
  Please take a look at the documentation on our GitHub repository
  before using it.

  Also, we appreciate any feedback or bug reports, especially since this
  is the first release of ts2ocaml!

  This tool is heavily inspired by ts2fable, which generates Fable (F#
  AltJS) bindings from `.d.ts' files. This tool is also written in
  Fable. Thank you very much for the great language and an awesome
  ecosystem, Fable team!


[LexiFi/gen_js_api] <https://github.com/LexiFi/gen_js_api>


OUPS meetups are back!
══════════════════════

  Archive: <https://discuss.ocaml.org/t/oups-meetups-are-back/8776/1>


zapashcanon announced
─────────────────────

  We (@Vertmo, @lsylvestre, Colin González and myself) are happy to
  announce that the [OUPS (OCaml Users in PariS) meetups] are back.

  If you're not familiar with OUPS, the idea is to have people using
  OCaml (developers, applications' users, researchers, …) to meet in
  Paris where a talk is given, followed by some discussions while eating
  pizza and drinking beer.

  We're planning to have the first meetup happening this year in
  December.

  Thus we're looking for speakers willing to give a talk for the first
  meetups or the following ones.

  The talks usually happen at [IRILL]'s offices, [4 Place Jussieu, 75005
  Paris]. We'll prefer talks in french and with someone able to be
  physically present, but we're open about english and remote talks.

  If you want to give a talk in December or in the future, you can let
  us know here or [on zulip] where we plan to have our main discussions.
  We also have [a group on Framagit] where we'll store some stuff. If
  you don't like Zulip, I'm also on IRC (#oups in [libera.chat]) and
  [matrix] but not everyone is.

  The four of us are doing a PhD in the following places: [ENS] ([Parkas
  team]), [Université de Paris] ([Irif]) + [Nomadic Labs], [Université
  Paris-Saclay] ([LMF]) + [OCamlPro], [Sorbonne Université] ([APR team -
  LIP6]) ; so we have a good coverage of the OCaml users in Paris but we
  don't know everyone. Even if you don't want to give a talk, if you
  know someone that may be interested, please talk to him about OUPS !
  :)

  Also, if there's a subject you'd like to hear about at OUPS, you can
  tell us and we'll try to find a speaker to give a talk about it.

  We'll come back to you very quickly about the December meetup.


[OUPS (OCaml Users in PariS) meetups]
<https://www.meetup.com/fr-FR/ocaml-paris/>

[IRILL] <https://www.irill.org/>

[4 Place Jussieu, 75005 Paris]
<https://www.openstreetmap.org/#map=19/48.84650/2.35457>

[on zulip] <https://oups.zulipchat.com>

[a group on Framagit] <https://framagit.org/oups>

[libera.chat] <https://libera.chat/>

[matrix] <https://matrix.to/#/#oups:matrix.org>

[ENS] <https://www.ens.psl.eu/>

[Parkas team] <https://parkas.di.ens.fr/>

[Université de Paris] <https://u-paris.fr/>

[Irif] <https://www.irif.fr/>

[Nomadic Labs] <https://www.nomadic-labs.com/>

[Université Paris-Saclay] <https://www.universite-paris-saclay.fr/>

[LMF] <https://lmf.cnrs.fr/>

[OCamlPro] <https://www.ocamlpro.com/>

[Sorbonne Université] <https://www.sorbonne-universite.fr/>

[APR team - LIP6] <https://www.lip6.fr/recherche/team.php?acronyme=APR>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-11-02  8:50 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-11-02  8:50 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of October 26 to
November 02, 2021.

Table of Contents
─────────────────

Lists.ocaml.org: service temporarily sunsetted
Talk at Func Prog Sweden
First OPAM releases of Scad_ml and [@@deriving scad]
Other OCaml News
Old CWN


Lists.ocaml.org: service temporarily sunsetted
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/lists-ocaml-org-service-temporarily-sunsetted/8692/1>


Anil Madhavapeddy announced
───────────────────────────

  *This note does not concern the main OCaml email list, which continues
  to be available through <https://sympa.inria.fr/sympa/arc/caml-list/>*

  The lists.ocaml.org e-mail service has been going through a rough time
  in the past few years, with vast swathes of spam regularly hitting our
  ingress email server and require manual unblocking every time.  It was
  set up [back in 2012] as an augmentation of the main OCaml mailing
  list and really helped with some big projects in the early days (the
  design of and migration to ppx from camlp4, for example).  However, in
  the intervening years e-mail has reduced in importance as a primary
  community communication mechanism (as evidenced, for example, in this
  forum).

  With the latest spam surge, I've moved the service into read-only mode
  with all the mailboxes and archives still available on the website,
  but with mail delivery and list creation/admin disabled. All existing
  links should continue to work to historical links online without
  change.  The only mailing list on there that was still active to my
  knowledge is the opam-commits cron list, which will be replaced by an
  ocurrent-based deployer for that website shortly.

  I hope to bring e-mail back to ocaml.org sometime in 2022, as it's an
  important communications medium that is highly accessible. One
  challenge is spam, and another is the inflexibility of GNU Mailman and
  its upgrade mechanism (essentially a manual process from 2 to
  3). Therefore, if there is anyone in the community interested in
  building a simple e-mail list manager in OCaml, that would be of
  interest :slight_smile:


[back in 2012]
<https://sympa.inria.fr/sympa/arc/caml-list/2012-12/msg00015.html>


Talk at Func Prog Sweden
════════════════════════

  Archive: <https://discuss.ocaml.org/t/talk-at-func-prog-sweden/8703/1>


Leonardo Laguna Ruiz announced
──────────────────────────────

  Here's a link for the talk I gave at the Func Prog Sweden meetup. In
  that talk I show the process we follow some years ago in order to move
  all our code base to OCaml and why it was an excellent decision.

  <https://youtu.be/FGXiAARXE2M>

  [Wolfram System Modeler] is a simulation environment that can be used
  to model multi-domain systems. For example systems composed of
  electrical, thermal, hydraulic, mechanical, etc, components.

  One of the main parts of System Modeler is the model compiler (Kernel)
  which takes models written in the Modelica language and compiles them
  into efficient simulation executables. This compiler was ported to
  OCaml by using custom tool that performed the code to code translation
  of our old code base.

  Slides
  <https://a2076202-c90b-450e-901b-cb56c346913c.usrfiles.com/ugd/a20762_adfa899586c7413a8c17f7b708dbc177.pdf>


[Wolfram System Modeler] <https://www.wolfram.com/system-modeler/>


First OPAM releases of Scad_ml and [@@deriving scad]
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-opam-releases-of-scad-ml-and-deriving-scad/8718/1>


geoffder announced
──────────────────

  I'd like to announce the first release onto opam of [Scad_ml] and
  [ppx_deriving_scad]. The former being a DSL front-end to the
  [OpenSCAD] solid modelling language, and the latter providing
  transformation function generation for custom types (a pattern that I
  have found useful during my time using `Scad_ml'.

  When I decided I wanted to pick up OpenScad, I was pleasantly
  surprised to discover that the `Scad_ml' library already existed on
  GitHub, credits to <https://github.com/namachan10777>. Over time I
  filled out the rest of the OpenSCAD language coverage, as well as some
  additional helpful math, and reorganized things to try and keep it
  from getting too messy as more and more was tacked on. Finally, after
  some help in the ocaml discord (from NULL and octachron), we also now
  can track whether shapes are 2D or 3D with minimal changes to the user
  interface, preventing misapplications of operations that would
  otherwise only appear in the OpenSCAD console.

  The `[@@deriving scad]' ppx is my solution to make a habit I developed
  to get around the otherwise fully declarative nature of working in
  OpenSCAD more ergonomic. Shapes in OpenSCAD cannot be queried in any
  way, so upon creation, the locations of it's vertices or it's origin
  are not available. Of course, since you created it, you know exactly
  it's dimensions, and where you have moved it, but what if you want to
  use the location of one of it's vertices, wherever that ends up after
  a series of transformations? What I did for some time before learning
  how to write a ppx, was put the coordinates I cared about into a
  record with the shape, and mapped over the type (by hand (and regex))
  with the relevant functions (typically transform and rotate). Turns
  out writing a ppx with `Ppxlib' and `metaquot' isn't so bad, and I
  really wish I did it sooner!

  Anyway, to the few of you out there that might use OpenSCAD, I hope
  that these tools might come in handy!


[Scad_ml] <https://github.com/namachan10777/scad-ml>

[ppx_deriving_scad] <https://github.com/geoffder/ppx_deriving_scad>

[OpenSCAD] <https://openscad.org/>


Other OCaml News
════════════════

>From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Hiring a Developer Educator]
  • [Verification for Dummies: SMT and Induction]
  • [SCoP Passed Phase 1 of the DAPSI Initiative!]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Hiring a Developer Educator]
<https://blog.janestreet.com/hiring-a-developer-educator/>

[Verification for Dummies: SMT and Induction]
<https://www.ocamlpro.com/2021/10/14/verification-for-dummies-smt-and-induction/>

[SCoP Passed Phase 1 of the DAPSI Initiative!]
<https://tarides.com/blog/2021-10-14-scop-selected-for-dapsi-phase2>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-10-19  8:23 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-10-19  8:23 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 6261 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of October 12 to 19,
2021.

Table of Contents
─────────────────

Verification for Dummies: SMT and Induction
OCaml Café: Wed, Oct 13 @ 1pm (U.S. Central)
Windows-friendly OCaml 4.12 distribution 2nd preview release (0.2.0)
Release of ocaml-sf/learn-ocaml:0.13.0
Old CWN


Verification for Dummies: SMT and Induction
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/verification-for-dummies-smt-and-induction/8631/1>


OCamlPro announced
──────────────────

  We are pleased to share with you [Verification for Dummies: SMT and
  Induction], a complete and detailed series of blogposts written by
  Adrien Champion about Induction as a formal verification technique.

  The subject is treated with many concrete and executable examples. All
  examples can be (and should be) launched locally by readers thanks to
  small and easy to find tools. Modification and experimentation are
  strongly encouraged!

  Take a look at all the notions covered:

  • introduction to formal logics and formal frameworks;
  • SMT-solving: modern, low-level verification building blocks;
  • declarative transition systems;
  • transition system unrolling;
  • BMC and induction proofs over transition systems;
  • candidate strengthening.

  We hope you enjoy reading and we look forward to your feedback!


[Verification for Dummies: SMT and Induction]
<https://www.ocamlpro.com/2021/10/14/verification-for-dummies-smt-and-induction/>


OCaml Café: Wed, Oct 13 @ 1pm (U.S. Central)
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-cafe-wed-oct-13-1pm-u-s-central/8610/14>


Claude Jager-Rubinson announced
───────────────────────────────

  The video of @dra27's talk on OPAM is now available:
  <https://youtu.be/RHSdlH4el0g>. Thanks so much for the great talk,
  David!  And thanks to everybody who attended!  (The video starts a
  couple of minutes into the talk because yours truly forgot to start
  recording.  D'oh!)

  We already have some ideas for the next meeting but if there's a topic
  that you'd like to hear about or are interested on presenting on,
  please message me.


Windows-friendly OCaml 4.12 distribution 2nd preview release (0.2.0)
════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-windows-friendly-ocaml-4-12-distribution-2nd-preview-release-0-2-0/8488/3>


jbeckford announced
───────────────────

  0.2.5 is available. This release brings significant user friendly
  improvements.

  There is a new binary called `with-dkml.exe'. Just plop `with-dkml' in
  front of a Windows command that requires access to Unix scripts
  (ie. `with-dkml opam install') and it should just work.

  There is now a section called **Beyond Basics** in [the Diskuv OCaml
  user documentation] that walks through:
  • the first and second tutorials of [Getting Started - Learn OCaml]
  • the bare Opam essentials you need as a beginner (how to find and
    select an Opam switch, and how to find and install packages using
    `with-dkml opam install'), all without leaving the Command Prompt
  • installing Visual Studio Code with the OCaml plugin

  Huge thanks to @Butanium who lent me much of his time to validate
  usability from the perspective of a newcomer. More feedback is always
  welcome.

  Links:
  • [Installation instructions for the latest version]
  • [Release notes for all versions]

  PS. You won't need `with-dkml' most of the time. The Beyond Basics
  documentation shows how to run Dune and the OCaml native compiler
  directly from the Visual Studio Command Prompt.


[the Diskuv OCaml user documentation]
<https://diskuv.gitlab.io/diskuv-ocaml/index.html>

[Getting Started - Learn OCaml] <https://ocaml.org/learn/tutorials/>

[Installation instructions for the latest version]
<https://diskuv.gitlab.io/diskuv-ocaml/index.html#two-step-installation-instructions>

[Release notes for all versions]
<https://gitlab.com/diskuv/diskuv-ocaml/-/releases>


Release of ocaml-sf/learn-ocaml:0.13.0
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-ocaml-sf-learn-ocaml-0-13-0/8577/6>


Erik Martin-Dorel announced
───────────────────────────

  Just FYI, a bugfix release learn-ocaml `0.13.1' has just been tagged
  and:

  • [released in GitHub] ← see the Release Notes and binaries-assets
  • [pushed to Docker Hub] ← `ocamlsf/learn-ocaml' being the official
    distribution of Learn-OCaml
  • [submitted to OPAM default repository]


[released in GitHub]
<https://github.com/ocaml-sf/learn-ocaml/releases/tag/v0.13.1>

[pushed to Docker Hub]
<https://hub.docker.com/r/ocamlsf/learn-ocaml/tags>

[submitted to OPAM default repository]
<https://github.com/ocaml/opam-repository/pull/19787>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-09-28  6:37 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-09-28  6:37 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 6911 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of September 21 to
28, 2021.

Table of Contents
─────────────────

Brr 0.0.2, a toolkit for programming browsers
Become an Outreachy Mentor: support the growth and diversity of the OCaml community
OCaml 4.13.0 (and 4.12.1)
Other OCaml News
Old CWN


Brr 0.0.2, a toolkit for programming browsers
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-brr-0-0-2-a-toolkit-for-programming-browsers/8521/1>


Daniel Bünzli announced
───────────────────────

  It's my pleasure to announce the release `0.0.2' of [`Brr'], a toolkit
  for programming browsers in OCaml with the [`js_of_ocaml'] compiler.

  Once it has made it to the repo, install with `opam install brr' and
  consult the [API docs and manuals] (or via `odig doc brr').

  This release fixes binding bugs, adds a few new bindings and tweaks
  some existing signatures. Thanks to all of those who provided bug
  reports, suggestions and code.

  The [release notes] have all the details.


[`Brr'] <https://erratique.ch/software/brr>

[`js_of_ocaml'] <https://ocsigen.org/js_of_ocaml>

[API docs and manuals] <https://erratique.ch/software/brr/doc/>

[release notes]
<https://github.com/dbuenzli/brr/blob/master/CHANGES.md#v002-2020-09-23-zagreb>


Become an Outreachy Mentor: support the growth and diversity of the OCaml community
═══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/become-an-outreachy-mentor-support-the-growth-and-diversity-of-the-ocaml-community/8213/13>


Thibaut Mattio announced
────────────────────────

  I've submitted two projects for the winter session:

  • Integrate a package health check in ocaml.org

  To essentially integrate a version of check.ocamllabs.io that can be
  used by opam-repository maintainers and opam users into the next
  version of ocaml.org (<https://v3.ocaml.org>).

  • Support `.eml' files in OCaml's VSCode extension

  To add support for Dream's [`.eml' files] syntax in the extension, and
  eventually have error reporting for these files from OCaml LSP Server.

  I'm more than interested in having co-mentors for these two projects,
  so if you wanted to mentor Outreachy interns but didn't have any
  project ideas, don't hesitate to reach out :slight_smile:

  Another way to help that does not involve mentoring is to find good
  first issues that will help onboard and select candidates for the
  projects. Any help on this effort to identify, create and document
  good first issues for the different projects is more than welcome!


[`.eml' files]
<https://github.com/aantron/dream/tree/master/example/7-template>


OCaml 4.13.0 (and 4.12.1)
═════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-13-0-and-4-12-1/8529/1>


octachron announced
───────────────────

  The OCaml team ha the pleasure of celebrating the 175th anniversary of
  the discovery of Neptune by announcing the joint releases of OCaml
  version 4.13.0 and 4.12.1 .

  Some of the highlights in the 4.13.0 release are:

  • Safe points: a multicore prerequisite that ensures that
    ocamlopt-generated code can always be interrupted.
  • The best-fit GC allocation policy is now the default policy (and
    many other GC improvements).
  • Named existential type variables in pattern matching: `Showable
    (type a) (x, show : a * (a -> string))'.

  • Improved error messages for functor application and functor types.
  • Let-punning for monadic let: `let* x = x in' can be shortened to
    `let* x in'.
  • Module type substitutions: `SIG with module type T = F(X).S'.

  • Many other quality of life improvements
  • Many bug fixes

  The 4.12.1 release is a collection of safe bug fixes, cherry-picked
  from the 4.13.0 development cycle. If you were using OCaml 4.12.0 and
  cannot yet upgrade to 4.13.0, this release is for you.

  The full list of changes can be found in the changelogs
  below. (*Editor note*: as it’s quite long, it is not included
  here. Please follow the link to the original article to read it.)

  Those releases are available as OPAM switches, and as a source
  download here:

  • <https://github.com/ocaml/ocaml/archive/4.13.0.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.13/>

  and there:

  • <https://github.com/ocaml/ocaml/archive/4.12.1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.12/>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Announcing Tezos’ 8th protocol upgrade proposal: Hangzhou]
  • [Measuring OCaml compilation speed after a refactoring]
  • [Writing Lifters Using Primus Lisp]
  • [Tarides Returns to FIC 2021]
  • [Generating static and portable executables with OCaml]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Announcing Tezos’ 8th protocol upgrade proposal: Hangzhou]
<https://marigold.dev/blog/announcing-hangzhou/>

[Measuring OCaml compilation speed after a refactoring]
<http://gallium.inria.fr/blog/measuring-compilation-time/>

[Writing Lifters Using Primus Lisp]
<http://binaryanalysisplatform.github.io/2021/09/15/writing-lifters-using-primus-lisp/>

[Tarides Returns to FIC 2021]
<https://tarides.com/blog/2021-09-06-tarides-returns-to-fic-2021>

[Generating static and portable executables with OCaml]
<https://www.ocamlpro.com/2021/09/02/generating-static-and-portable-executables-with-ocaml/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-09-21  9:09 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-09-21  9:09 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 14820 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of September 14 to
21, 2021.

Table of Contents
─────────────────

opam-grep: search through the sources of all the packages in opam-repository
Hardcaml MIPS CPU Learning Project and Blog
Puzzling through some GADT errors
Parany for multicore OCaml
OCaml 4.13.0, second release candidate
Unicode 14.0.0 update for Uucd, Uucp, Uunf and Uuseg
Set up OCaml 2.0.0-beta4
Become an Outreachy Mentor: support the growth and diversity of the OCaml community
The OCaml 4.13 preview for Merlin is now available
Old CWN


opam-grep: search through the sources of all the packages in opam-repository
════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-opam-grep-search-through-the-sources-of-all-the-packages-in-opam-repository/8434/3>


Kate announced
──────────────

  I've just released opam-grep.0.2.0 with quite a bit of change compared
  to the previous version. Here is the highlight:
  • Complete rewrite from shell script to OCaml, making it more portable
  • Use the faster `ripgrep' and `ugrep' over `grep' when available
    (suggestion by @Engil)
  • Use the `progress' library to show progress instead of a
    non-portable/DIY spinner

  See the [changelog] for the full list of relevant changes.

  *Big thanks to @CraigFe for the `progress' library (such a treat!) and
  to @dbuenzli for `bos' and `cmdliner' in particular, making it easy to
  do such rewrite* :relaxed:


[changelog]
<https://github.com/kit-ty-kate/opam-grep/blob/master/CHANGES.md>


Hardcaml MIPS CPU Learning Project and Blog
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/hardcaml-mips-cpu-learning-project-and-blog/8088/10>


Alexander (Sasha) Skvortsov announced
─────────────────────────────────────

  Hi everyone! We are excited to announce that we have completed this
  project and blog. Progress has been slow these past few months due to
  work, internships, and college, but we’ve now released [v1.0.0 on
  GitHub]. We also published posts on:

  • [Design patterns, conventions, and testing]
  • [How the Always DSL can be used to write safe “pseudo-imperative”
    code in Hardcaml]
  • [Hardcaml’s testing and interactive simulation tools]
  • [A recap of some interesting hardware/CPU features in our design]

  Finally, we published a [conclusion blog post], which wraps up some
  strengths/weaknesses of Hardcaml, as well as some takeaways on OCaml
  and blogging more generally.

  Thank you to @andyman and @fyquah95 for building Hardcaml, and for
  helping us out on GitHub issues! We really appreciate your time and
  suggestions.

  Overall, we’ve come to the conclusion that Hardcaml is a much better
  tool for hardware design than Verilog. This has been a great
  experience, and we walk away with a better understanding of hardware,
  functional programming, and technical writing.


[v1.0.0 on GitHub]
<https://github.com/askvortsov1/hardcaml-mips/releases/tag/v1.0.0>

[Design patterns, conventions, and testing]
<https://ceramichacker.com/blog/14-8x-design-patterns-conventions-and-testing>

[How the Always DSL can be used to write safe “pseudo-imperative” code
in Hardcaml]
<https://ceramichacker.com/blog/15-9x-always-dsl-and-the-control-unit>

[Hardcaml’s testing and interactive simulation tools]
<https://ceramichacker.com/blog/16-10x-testing-and-debugging-hardcaml>

[A recap of some interesting hardware/CPU features in our design]
<https://ceramichacker.com/blog/18-11x-cpu-functionality-wrap-up>

[conclusion blog post]
<https://ceramichacker.com/blog/20-1212-project-conclusion>


Puzzling through some GADT errors
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/puzzling-through-some-gadt-errors/8478/8>


Deep in this thread, gasche said
────────────────────────────────

  Not exactly what you are asking for, but @Octachron wrote an excellent
  [chapter on GADTs] in the OCaml manual, which could be recommended to
  people starting GADT programming. It explains why recursive functions
  on GADT need "explicit polymorphic annotations" in less
  "implementation driven" terms.

  (The chapter also demonstrates the new naming scheme for existential
  type variables introduced by GADT constructors, which can help a lot
  working through type errors, but are still a bit heavy and deserve a
  gentle introduction.)


[chapter on GADTs] <https://ocaml.org/releases/4.12/manual/gadts.html>


octachron then added
────────────────────

  I have only written the nomenclature part and a bit of the explanation
  for recursive functions in this chapter, @garrigue is the author of
  most of this chapter.


Parany for multicore OCaml
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/parany-for-multicore-ocaml/8495/1>


UnixJunkie announced
────────────────────

  There is now an implementation using multicore-OCaml in the 'domains'
  branch.

  <https://github.com/UnixJunkie/parany/tree/domains>

  People are very welcome to give it a try and share the speedup they
  observe, especially compared to fork-based parallelism.

  Thanks to @nilsbecker for having motivated me.


UnixJunkie later added
──────────────────────

  If you don't use the domains branch, then parany is using fork-based
  parallelism.  If you want to use the domains branch, you need to
  install multicore-ocaml first:
  ┌────
  │ opam switch create 4.12.0+domains
  │ eval `opam config env`
  └────


OCaml 4.13.0, second release candidate
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-13-0-second-release-candidate/8496/1>


octachron announced
───────────────────

  The release of OCaml 4.13.0 is expected for next week.

  Since we had a native code generation bug fix and two minor
  configuration tweaks since the first release candidate, we are
  publishing a second release candidate.  If you find any bugs, please
  report them here:

  <https://github.com/ocaml/ocaml/issues>

  Happy hacking, Florian Angeletti for the OCaml team.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.13.0~rc2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:

  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.13.0~rc2+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────

  where <option_list> is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 4.13.0~rc2+flambda+nffa
  │ --packages=ocaml-variants.4.13.0~rc2+options,ocaml-option-flambda,ocaml-option-no-flat-float-array
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with "opam search ocaml-option".

  The source code for the release candidate is also available at these
  addresses:

  • <https://github.com/ocaml/ocaml/archive/4.13.0-rc2.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.13/ocaml-4.13.0~rc2.tar.gz>


Changes since the first release candidate
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#10626], [#10628]: Wrong reloading of the x86-64 instruction for
    integer multiplication by a constant, causing the assembler to
    reject the ocamlopt-generated code. (Xavier Leroy, report by Dave
    Aitken, review by Vincent Laviron)

  • [#10176], [#10632(new in rc2)]: By default, call the assembler
    through the C compiler driver (Sébastien Hinderer, review by Gabriel
    Scherer, David Allsopp and Xavier Leroy)

  • [#10451], [#10635(new in rc2)]: Replace the use of iconv with a C
    utility to convert $(LIBDIR) to a C string constant on Windows when
    building the runtime. Hardens the generation of the constant on Unix
    for paths with backslashes, double-quotes and newlines. (David
    Allsopp, review by Florian Angeletti and Sébastien Hinderer)


[#10626] <https://github.com/ocaml/ocaml/issues/10626>

[#10628] <https://github.com/ocaml/ocaml/issues/10628>

[#10176] <https://github.com/ocaml/ocaml/issues/10176>

[#10632(new in rc2)] <https://github.com/ocaml/ocaml/issues/10632>

[#10451] <https://github.com/ocaml/ocaml/issues/10451>

[#10635(new in rc2)] <https://github.com/ocaml/ocaml/issues/10635>


Unicode 14.0.0 update for Uucd, Uucp, Uunf and Uuseg
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-unicode-14-0-0-update-for-uucd-uucp-uunf-and-uuseg/8497/1>


Daniel Bünzli announced
───────────────────────

  Unicode 14.0.0 was released on the 14th of september.

  It adds 838 new characters to the standard including, for our friends
  from Central Asia, support for [Old Uyghur].  For information about
  all the other additions, see [the announcement page].

  Accordingly the libraries mentioned at the end of this message had to
  be updated, consult the individual release notes for details. Both
  Uucd and Uucp are incompatible releases sinces new script and block
  enumerants had to be added.

  Best,

  Daniel

  P.S. Though I'm not very fond of the concept, I recently enabled
  sponsors on my github account as an experiment. So I'd like to thanks
  my [github sponsors], @davesnx became the first one monday.


[Old Uyghur]
<https://unicode.org/charts/PDF/Unicode-14.0/U140-10F70.pdf>

[the announcement page]
<http://blog.unicode.org/2021/09/announcing-unicode-standard-version-140.html>

[github sponsors] <https://github.com/sponsors/dbuenzli/>


Set up OCaml 2.0.0-beta4
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta4/8501/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • Set `OPAMSOLVERTIMEOUT' to `1000' to avoid a timeout even if the
    opam solver is slow.
  • Increase cache hit ratio by loosening restore keys of opam cache.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta4>


Become an Outreachy Mentor: support the growth and diversity of the OCaml community
═══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/become-an-outreachy-mentor-support-the-growth-and-diversity-of-the-ocaml-community/8213/8>


Sonja Heinze announced
──────────────────────

  Hey all, I've just submitted an Outreachy project for the winter
  round. The project is to write the basic ppx_deriving plugins in
  ppxlib; that is, the ones that don't already have a version based on
  ppxlib. I think both, having them available to use, and having their
  code available as simple examples of how to use Ppxlib.Deriving would
  be very nice! And improving ppxlib's documentation and finding simple
  issues on already existing PPXs to prepare for Outreachy, will be
  beneficial as well.

  Of course, it's not clear if someone with the right interest comes
  along for this project, but if we don't find an intern for it this
  round, I can just re-submit the same project next round.


Sonja Heinze
────────────

  Btw, the deadline to submit projects was extended and is now Sept
  23rd. So the timeline in our post above is slightly outdated.


The OCaml 4.13 preview for Merlin is now available
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-the-ocaml-4-13-preview-for-merlin-is-now-available/8436/6>


Continuing this thread, Kate announced
──────────────────────────────────────

  The OCaml 4.13 preview for ocaml-lsp-server is now available as well.

  To install it along with the OCaml 4.13 rc, please refer to the first
  post.

  If you encounter any problems while using ocaml-lsp-server, please
  feel free to report it directly in
  <https://github.com/ocaml/ocaml-lsp/pull/506>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-09-07 13:23 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-09-07 13:23 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 18117 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of August 31 to
September 07, 2021.

Table of Contents
─────────────────

Just reinvented OOP
v3.OCaml.org: A roadmap for OCaml's online presence
Become an Outreachy Mentor: support the growth and diversity of the OCaml community
Generating static and portable executables with OCaml
OCaml quant-developer at Bloomberg. London or New York
HTTP client library
Other OCaml News
Old CWN


Just reinvented OOP
═══════════════════

  Archive: <https://discuss.ocaml.org/t/just-reinvented-oop/8399/1>


Yawar Amin said
───────────────

  ┌────
  │ let ( .![] ) obj f = f obj
  │ 
  │ type person = { id : int; name : string }
  │ 
  │ let id { id; _ } = id
  │ 
  │ let bob = { id = 1; name = "Bob" }
  │ let next_id = bob.![id].![succ]
  └────

  ==> 2


Kiran Gopinathan replied
────────────────────────

  Haha, what a coincidence, just did the same very recently while
  translating a rust library to OCaml:
  <https://github.com/Gopiandcode/ego/blob/5daf312f8a444f9abcde5996c671b9282727a972/lib/generic.ml#L211>
  ┌────
  │ let eclasses = eg.@[eclasses] in
  │ let cost_map = Id.Map.create 10 in
  │ let node_total_cost node =
  │   let has_cost id = Id.Map.mem cost_map (eg.@[find] id) in
  │   if List.for_all has_cost (L.children node)
  │   then let cost_f id = fst @@ Id.Map.find cost_map (eg.@[find] id) in Some (E.cost cost_f
  │ node)
  │   else None in
  │   (* ... *)
  └────
  with `.@[]' defined as:
  ┌────
  │ let (.@[]) self fn = fn self [@@inline always]
  └────

  for bonus(?) points, you can name the first parameter self:
  ┌────
  │ let add_enode self (node: Id.t L.shape) =
  │   let node = self.@[canonicalise] node in
  │   (* ... *)
  └────
  I don't normally write code like this in OCaml, but in this case, it
  made porting from rust easier, because the code mostly looked the
  same.


hyphenrf also replied
─────────────────────

  You can use the multiple-indexing syntax to implement slicing (well,
  technically subs) sugar:
  ┌────
  │ let (.:[;..]) s = function
  │   | [|start; finish|] -> String.sub s start (finish - start)
  │   | _ -> raise (Invalid_argument "slice takes exactly two indexes")
  └────
  ┌────
  │ # "hello world".:[1;5];;
  │ - : string = "ello"
  └────
  The new indexing syntax is quite versatile :>


Kiran Gopinathan added
──────────────────────

  Oh wow, this is perfect! brb, off to reimplement the python slicing
  semantics in OCaml:
  ┌────
  │ let (.@[;..]) ls = function[@warning "-8"]
  │   | [| start; -1 |] ->
  │     List.to_iter ls
  │     |> Iter.zip_i
  │     |> Iter.drop_while (Pair.fst_map ((>) start))
  │     |> Iter.map snd
  │   | [| start; finish |] ->
  │     List.to_iter ls
  │     |> Iter.zip_i
  │     |> Iter.drop_while (Pair.fst_map ((>) start))
  │     |> Iter.take_while (Pair.fst_map ((>) finish))
  │     |> Iter.map snd
  │   | [| start; finish; step |] ->
  │     List.to_iter ls
  │     |> Iter.zip_i
  │     |> Iter.drop_while (Pair.fst_map ((>) start))
  │     |> Iter.take_while (Pair.fst_map ((>) finish))
  │     |> Iter.filter (Pair.fst_map (fun ind -> (ind - start) mod step = 0))
  │     |> Iter.map snd
  └────


v3.OCaml.org: A roadmap for OCaml's online presence
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/v3-ocaml-org-a-roadmap-for-ocamls-online-presence/8368/19>


Continuing this thread, Anil Madhavapeddy replied to many comments
──────────────────────────────────────────────────────────────────

  Many thanks for all the constructive comments and suggestions so far,
  and also for those who have gotten in touch to contribute. Please do
  keep them coming (either on this thread or on the various issue
  trackers that @jonludlam and @patricoferris have pointed to).  I'll
  answer some earlier questions here:

        Having said that, the colors on the [packages landing page
        ] feel very aggressive to me. Might be my setup here, but
        I would like to have a slightly less harsh contrast.

        Also, there is a bit of an overlap in content with
        [https://ocamlverse.github.io/ ] for some things (eg best
        practices, community) but the (to me) most valuable
        feature is missing: The ecosystems overview, where I can
        find packages sorted thematically. Could such a section
        also have a place in the packages subpage somewhere?
        Alternatively, maybe opam can allow to “tag” packages in
        the future so one could see all packages for graphics,
        databases etc.

  The styling of the /packages sub-URL does indeed differ from the main
  design, but this is simply due to a temporary technical detail. The
  majority of the site uses React/NextJS to generate the frontend, and
  this uses the now-trendy medium-contrast colours and also features
  like fast-page-switching that NextJS offers.  However, the
  documentation portion generated around 2.7 million individual pages
  when run across the full opam repository, and so we restored to
  dynamic generation of the content for that. What's going to happen
  next is a rationalisation of the code across the ReScript and OCaml
  frontends so that there will be no observable difference in the colour
  schemes across the full site.

  Regarding creating a categorised list of recommendations, that is
  absolutely in scope for the v3 iteration of the site. However, this
  metadata should ideally live in the opam-repository (for example,
  using `tags' as you suggest, which opam already supports). If anyone
  would like to have a go at this, I'd encourage PRs to the
  opam-repository to add the relevant tag metadata for a
  codex. Meanwhile, @lambda_foo @tmattio and @patricoferris are working
  on the core OCaml Platform workflow information for the guides section
  of the website which will cover opam, merlin, lsp-server, dune and so
  on.

        Do we have access to all of the previous years’ workshops
        to add to [watch.ocaml.org]?  I can see pieces of 2015,
        2017, 2020 and this year. @avsm

        Is it possible to add the ML Workshop as well?

  Absolutely. The watch.ocaml.org has held up nicely after the OCaml
  Workshop, so I think it's in good shape to populate with more
  videos. This needs a volunteer to help us upload the past [nine years]
  of videos from YouTube to watch.ocaml.org. If anyone wants to have a
  go, please message me and I'll create you an account.

        It’s a bit unclear what you meant in this paragraph. Does
        that mean that you plan to kill the ocaml planet ? I would
        find it a little bit sad.

        One of the reason why you may feel it doesn’t work well
        may be that it has been constantly broken in the current
        version of the site…

  I'm not sure why you think the current ocaml.org new feed has been
  broken – it's been working fairly reliably for the past decade. The
  only real problem came up a few times when a feed's domain expired and
  got taken over by domain squatters, at which point we got spam into
  the main page of ocaml.org.

  What I meant with that part of the announcement is that the
  syndication feed should not be mistaken with original news on the
  website. Right now it's difficult to distinguish official
  announcements (such as compiler or opam releases) as they are a little
  scattered (e.g. on opam.ocaml.org). The plan is to combine the
  [platform-blog] with the new website directly. I've also been
  considering just having a special tag on this forum so that nice
  announcement posts could also be syndicated to the website easily (for
  example, @gasche's compiler newsletters).

  My general desire is to _grow_ the planet feed and syndication system,
  but to clearly demarcate them as not being published by ocaml.org and
  to manage them via more modern decentralised techniques that feature
  spam, moderation and archival. PeerTube is a good example of this for
  videos that is working well, and I'd welcome suggestions for Atom/RSS
  (there must be something in this space, ideally ActivityPub-based).

  Depending on how the experiments go, it's very likely that we'll have
  a Matrix homeserver for ocaml.org where CI bots can report status
  information (see this [prototype PR]) for ocaml-ci that will also
  apply to opam-repository. The goal here is to for ocaml.org to publish
  its data using an open protocol, which can then be syndicated into
  whatever technologies are in vogue (e.g. Discord, Slack, Teams, …).

  So if you spot some decentralised syndication system that you think
  might be interesting for OCaml, please do let me know.  Even better,
  if you'd like to develop one to tailor it to our needs, let me know
  even sooner ;-)


[packages landing page ] <https://v3.ocaml.org/packages>

[https://ocamlverse.github.io/ ] <https://ocamlverse.github.io/>

[watch.ocaml.org] <http://watch.ocaml.org>

[nine years] <https://ocaml.org/meetings/ocaml/2012/>

[platform-blog] <https://github.com/ocaml/platform-blog>

[prototype PR] <https://github.com/ocurrent/ocaml-ci/pull/362>


Become an Outreachy Mentor: support the growth and diversity of the OCaml community
═══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/become-an-outreachy-mentor-support-the-growth-and-diversity-of-the-ocaml-community/8213/3>


Anil Madhavapeddy announced
───────────────────────────

  There's been a very disappointing response to this call for mentors to
  increase the diversity of our community. Precisely *noone* has been in
  touch for the winter call, leaving the burden of mentorship on the
  same people that did all the work this summer.

  Before making [new calls for programs like GSoC], let's get Outreachy
  onto more sustainable ground please. We are purely limited by
  mentorship time at present. This can be as simple as organising new
  first issues for projects in the ecosystem, and all the way to pair
  programming with a mentee. You can chose how to be involved.


[new calls for programs like GSoC]
<https://discuss.ocaml.org/t/v3-ocaml-org-a-roadmap-for-ocamls-online-presence/8368/16?u=avsm>


Generating static and portable executables with OCaml
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/generating-static-and-portable-executables-with-ocaml/8405/1>


OCamlPro announced
──────────────────

  It has been a few times now that we have been tasked to generate
  portable binaries for different projects. Over time, we have gathered
  quite some know-how and, seeing the question frequently arise in the
  community, we decided to share this experience.

  You can find the article written by Louis Gesbert on[ the OCamlPro
  blog]


        Distributing OCaml software on opam is great (if I dare
        say so myself), but sometimes you need to provide your
        tools to an audience outside of the OCaml community, or
        just without recompilations or in a simpler way.

        However, just distributing the locally generated binaries
        requires that the users have all the required shared
        libraries installed, and a compatible libc. It's not
        something you can assume in general, and even if you don't
        need any C shared library or are confident enough it will
        be installed everywhere, the libc issue will arise for
        anyone using a distribution based on a different kind, or
        a little older than the one you used to build.

        There is no built-in support for generating static
        executables in the OCaml compiler, and it may seem a bit
        tricky, but it's not in fact too complex to do by hand,
        something you may be ready to do for a release that will
        be published. So here are a few tricks, recipes and advice
        that should enable you to generate truly portable
        executables with no external dependency whatsoever. Both
        Linux and macOS will be treated, but the examples will be
        based on Linux unless otherwise specified.

  Don't hesitate to share your thoughts with us, have a good reading!


[ the OCamlPro blog]
<https://www.ocamlpro.com/2021/09/02/generating-static-and-portable-executables-with-ocaml/>


OCaml quant-developer at Bloomberg. London or New York
══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-quant-developer-at-bloomberg-london-or-new-york/8409/1>


Philip Craig announced
──────────────────────

  Extend a financial contracts DSL that is implemented in OCaml.

  It's London or New York based. It's not a remote position.

  Please see details and/or apply at
  (<https://careers.bloomberg.com/job/detail/93825>)


HTTP client library
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-http-client-library/8428/1>


Hannes Mehnert announced
────────────────────────

  we just released to the opam-repository the [`http-lwt-client']
  package, which consists of both a library doing HTTP requests and a
  binary (`hurl') that does HTTP requests.

  The code is based on [HTTP/AF] and [H2], and uses [tls] for HTTPS
  connections. Both HTTP/1(.1) and HTTP/2 protocols are supported. The
  motivation behind this package is to have a http client that has a
  reasonably small dependency cone, is purely implemented in OCaml, and
  uses the asynchronous task library lwt.

  This package uses [happy-eyeballs] to connect to a remote host via
  IPv4 and IPv6, as proposed by IETF [RFC 8305]: on any computer with
  either IPv4 or IPv6 connectivity, a remote IPv6 or IPv4 server will be
  connected. Preference is given to IPv6.

  If a https url is provided, the server certificate is verified using
  the [ca-certs] package.

  If you experience any issues or have further needs for this package,
  please report an issue on the GitHub issue tracker.

  The installation is just an `opam install http-lwt-client' away :)


[`http-lwt-client'] <https://github.com/roburio/http-lwt-client>

[HTTP/AF] <https://github.com/inhabitedtype/httpaf>

[H2] <https://github.com/anmonteiro/ocaml-h2>

[tls] <https://github.com/mirleft/ocaml-tls>

[happy-eyeballs] <https://github.com/roburio/happy-eyeballs>

[RFC 8305] <https://tools.ietf.org/html/rfc8305>

[ca-certs] <https://github.com/mirage/ca-certs>


Hannes Mehnert later added
──────────────────────────

  now [0.0.2] is released that unifies the response type and API
  (previously it was a variant and clients had to write code for both
  HTTP1 and HTTP2). Now, a single record and Status/Headers/Version
  module aliases are provided (very close to HTTP/AF). Enjoy.


[0.0.2] <https://github.com/ocaml/opam-repository/pull/19410>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Goodbye Core_kernel]
  • [Tarides Engineers to Present at ICFP 2021]
  • [Benchmarking OCaml projects with current-bench]
  • [What the interns have wrought, 2021 edition]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Goodbye Core_kernel] <https://blog.janestreet.com/goodbye-Core_kernel/>

[Tarides Engineers to Present at ICFP 2021]
<https://tarides.com/blog/2021-08-26-tarides-engineers-to-present-at-icfp-2021>

[Benchmarking OCaml projects with current-bench]
<https://tarides.com/blog/2021-08-26-benchmarking-ocaml-projects-with-current-bench>

[What the interns have wrought, 2021 edition]
<https://blog.janestreet.com/what-the-interns-have-wrought-2021/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-08-24 13:44 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-08-24 13:44 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 13392 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of August 17 to 24,
2021.

Table of Contents
─────────────────

routes v1.0.0 released
Feather 0.3.0
Release of GopCaml-mode (0.0.3) and GopCaml-mode-Merlin (0.0.4) - Wizardry release
Share my experience about running OCaml on WebAssembly
Old CWN


routes v1.0.0 released
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-routes-v1-0-0-released/8319/1>


Anurag Soni announced
─────────────────────

  I'd like to announce release of version 1.0.0 of [routes]. The PR to
  opam repository has been merged, and the new release should be
  available via opam once the package cache refreshes.

  *Routes* provides a DSL for bi-directional URI dispatch. It allows
  writing route definitions that can be used for both matching, and
  printing URI paths.

  Changes since the last opam release:

  • Support for merging two routers by adding a union operation ([#115],
    [@Chattered])
  • Support for wildcard parameters ([#118], [#129], [@Lupus]) ->
    Compile time checks ensure that wildcard parameters can only be
    defined at the end of a route
  • Support `map' operation for path parameter definitions, and support
    defining path prefixes that can be pre-prended to other routes
    ([#121], [@Chattered])
  • Addition of a `ksprintf' style function for routes. ([#123],
    [@Chattered])

  Examples of how to use the library are available in the [tests] and in
  a [small demo]

  Documentation can be found [here]

  *Edit*

  1.0.0 is available via opam now -
  <http://opam.ocaml.org/packages/routes/routes.1.0.0/>


[routes] <https://github.com/anuragsoni/routes/>

[#115] <https://github.com/anuragsoni/routes/pull/115>

[@Chattered] <https://github.com/Chattered>

[#118] <https://github.com/anuragsoni/routes/pull/118>

[#129] <https://github.com/anuragsoni/routes/pull/129>

[@Lupus] <https://github.com/Lupus>

[#121] <https://github.com/anuragsoni/routes/pull/121>

[#123] <https://github.com/anuragsoni/routes/pull/123>

[tests]
<https://github.com/anuragsoni/routes/blob/b9bb8a0f50b7bd9fbd0c79113142ea82830ce2bb/test/routing_test.ml>

[small demo]
<https://github.com/anuragsoni/routes/blob/b9bb8a0f50b7bd9fbd0c79113142ea82830ce2bb/example/no_http.ml>

[here] <https://anuragsoni.github.io/routes/>


Feather 0.3.0
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-feather-0-3-0/8322/1>


Charles announced
─────────────────

  I'm happy to announce Feather 0.3.0! Feather is a minimal library for
  bash-like scripting and process execution.  ([github/tutorial],
  [documentation]) This release adds two major features:


[github/tutorial] <https://github.com/charlesetc/feather>

[documentation]
<https://www.charlesetc.com/feather/feather/Feather/index.html>

1. A new interface for collecting the exit status, stdout, and stderr of a Feather command.
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  For example, you can easily print a process's stderr if it exits
  non-zero:

  ┌────
  │ open Feather;;
  │ let stderr, status =
  │   process "ls" [ "/tmp/does-not-exist" ] |> collect stderr_and_status
  │ in
  │ if status <> 0 then failwith ("ls failed with stderr:\n" ^ stderr)
  └────
  where the types are

  ┌────
  │ val process : string -> string list -> cmd
  │ 
  │ type 'a what_to_collect
  │ val stderr_and_status : (string * int) what_to_collect
  │ 
  │ val collect :
  │   ?cwd:string ->
  │   ?env:(string * string) ->
  │   'a what_to_collect ->
  │   cmd ->
  │   'a
  └────

  as you can imagine, we expose several of these
  `what_to_collect''s. Here's the full set:

  ┌────
  │ val stdout : string what_to_collect
  │ val stderr : string what_to_collect
  │ val status : int what_to_collect
  │ 
  │ val stdout_and_stderr : (string * string) what_to_collect
  │ val stdout_and_status : (string * int) what_to_collect
  │ val stderr_and_status : (string * int) what_to_collect
  │ 
  │ type everything = { stdout : string; stderr : string; status : int }
  │ val everything : everything what_to_collect
  └────
  We considered different design approaches here. I think what we landed
  on keeps the call site readable and the types of the interface simple.

  It should be noted: the simplest way to run a command without
  collecting anything is to use [Feather.run].


[Feather.run]
<https://www.charlesetc.com/feather/feather/Feather/index.html#val-run>


2. The ability to wait on background processes and collect their output.
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Starting with Feather 0.1.0, you were able to start processes in the
  background, but the only way to wait for them to complete was to use
  Feather's [async wrapper].  For those wanting an async-less,
  direct-style interface, we now expose new methods to do this properly:

  ┌────
  │ type 'a background_process
  │ 
  │ val run_in_background :
  │   ?⁠cwd:string ->
  │   ?⁠env:(string * string) Base.list ->
  │   cmd ->
  │   unit background_process
  │ 
  │ val collect_in_background :
  │   ?cwd:string ->
  │   ?env:(string * string) list ->
  │   'a what_to_collect ->
  │   cmd ->
  │   'a background_process
  │ 
  │ val wait : 'a background_process -> 'a
  │ val wait_all : unit -> unit
  └────
  where an example use might be

  ┌────
  │ let server_process =
  │    process "my-server.exe" [] |> collect_in_background stdout_and_status
  │ in
  │ ... do other things ...
  │ match Feather.wait server_process with
  │ | (stdout, 0) -> ...
  │ | (_, 1) -> ...
  └────

  Thanks again to @Firobe and @tmarti2 for their contributions to this
  release! I think we've made a lot of progress here and I'm excited to
  see where things go :slight_smile:


[async wrapper]
<https://www.charlesetc.com/feather/feather_async/Feather_async/index.html>


Release of GopCaml-mode (0.0.3) and GopCaml-mode-Merlin (0.0.4) - Wizardry release
══════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-gopcaml-mode-0-0-3-and-gopcaml-mode-merlin-0-0-4-wizardry-release/8333/1>


Kiran Gopinathan announced
──────────────────────────

  I'm pleased to announce the latest version of *GopCaml-mode* (0.0.3),
  and the new release of *GopCaml-mode-Merlin* (0.0.4).

  GopCaml-mode-Merlin is a brand *new!* variant of GopCaml-mode that
  uses the Merlin parser rather than the OCaml compiler-libs one, and
  thus has some level of robustness to invalid syntax:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/a09586b9db3bf19667b6969c701a40f0791a2a9d.gif>

  If that's piqued your interest, I'd recommend checking out the release
  posts for the previous versions for more details on what GopCaml can
  do, and how to get it: [0.0.2 release], [0.0.1 release]

  The Merlin parser seems to assign text-regions for syntactic
  constructs slightly more liberally than the standard OCaml parser, so
  the overlays can feel a bit weird if you're used to the normal GopCaml
  overlays, but the benefit is that all your favorite structural
  movement/transformation operations work even when you're dealing with
  ill-formed programs, allowing for a more fluid editing experience:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/9/9f2976b47018e2d892b9cea09da913d07f8c1f00.gif>


[0.0.2 release]
<https://discuss.ocaml.org/t/ann-release-of-gopcaml-mode-0-0-2-unicode-compatibility-update/7425>

[0.0.1 release]
<https://discuss.ocaml.org/t/introducing-gopcaml-mode-structural-ocaml-editing/5310>

Detailed Changelog
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • *new!* [for GopCaml-mode-Merlin] *Robustness to ill-formated syntax*
    • Vendored a copy of Merlin to reuse its parser and thereby gain
      it's robustness to invalid syntax.
  • *new!* *Added support for customisable verbosity*
    • Customise the Emacs variable `gopcaml-messaging-level` to change
      the level of messages that are output by GopCaml. Set it to
      `'none` to disable messages entirely.
  • *new!* *Fixed bug when starting zipper mode at the start of a file.*
    • Zipper mode selects the immediately prior byte position to avoid
      inconsistencies when the cursor is just on the edge of an
      expression, but when the cursor is at position 1, this causes an
      error as 0 is not a valid point.
  • *new!* *Special casing of shebangs*
    • Added support for handling shebangs at the start of a buffer.
    • Implemented as part of a larger library for preprocessing
      buffertext before running the parser on it - could be extended to
      support additional preprocessing in the future.
    • Another possible direction for extension is to use an Emacs
      callback to modify the text, although this may not be ideal, as
      the parsing has to be as fast as possible.


Get Gopcaml-mode
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Its as easy as 1, 2, 3!

  1. Install from opam (either `gopcaml-mode` xor
     `gopcaml-mode-merlin`):

     ┌────
     │ opam install gopcaml-mode
     └────
     or
     ┌────
     │ opam install gopcaml-mode-merlin
     └────

  2. Compile your emacs with support for dynamic modules
  3. Load gopcaml-mode in your init.el:
     ┌────
     │ (let ((opam-share (ignore-errors (car (process-lines "opam" "var" "share")))))
     │     (when (and opam-share (file-directory-p opam-share))
     │       ;; Register Gopcaml mode
     │       (add-to-list 'load-path (expand-file-name "emacs/site-lisp" opam-share))
     │ 	(autoload 'gopcaml-mode "gopcaml-mode" nil t nil)
     │ 	(autoload 'tuareg-mode "tuareg" nil t nil)
     │ 	(autoload 'merlin-mode "merlin" "Merlin mode" t)
     │       ;; Automatically start it in OCaml buffers
     │       (setq auto-mode-alist
     │       (append '(("\\.ml[ily]?$" . gopcaml-mode)
     │ 	  ("\\.topml$" . gopcaml-mode))
     │ 	auto-mode-alist))
     │       ))
     └────

  See the [release post ] for version 0.0.1 for detailed instructions on
  how you can install it.


[release post ]
<https://discuss.ocaml.org/t/introducing-gopcaml-mode-structural-ocaml-editing/5310>


Contribute
╌╌╌╌╌╌╌╌╌╌

  • Github: [GitHub - Gopiandcode/gopcaml-mode: [MIRROR] Ultimate Ocaml
    Editing Mode]
  • Gitlab: [Kiran Gopinathan / gopcaml-mode · GitLab ]


[GitHub - Gopiandcode/gopcaml-mode: [MIRROR] Ultimate Ocaml Editing
Mode] <https://github.com/Gopiandcode/gopcaml-mode>

[Kiran Gopinathan / gopcaml-mode · GitLab ]
<https://gitlab.com/gopiandcode/gopcaml-mode>


Share my experience about running OCaml on WebAssembly
══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/share-my-experience-about-running-ocaml-on-webassembly/8343/1>


Vincent Chan announced
──────────────────────

  In the last two weeks, I was working on migrating OCaml to
  WebAssembly. I wrote an article to share my experience.

  [Run OCaml in the browser by WebAssembly | by Vincent Chan | Aug, 2021
  | Medium]


[Run OCaml in the browser by WebAssembly | by Vincent Chan | Aug, 2021 |
Medium]
<https://okcdz.medium.com/run-ocaml-in-the-browser-by-webassembly-31ce464594c6>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-08-17  6:24 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-08-17  6:24 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of August 10 to 17,
2021.

Table of Contents
─────────────────

http-multipart-formdata v3.0.1 released
Call for participation: ML Family Workshop 2021
Coq-of-ocaml to translate OCaml to Coq
Old CWN


http-multipart-formdata v3.0.1 released
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-http-multipart-formdata-v3-0-1-released/8261/2>


Continuing the thread from last week, Hannes Mehnert asked
──────────────────────────────────────────────────────────

  Thanks for your work on that. I'm curious about the different
  "multipart" libraries now available for OCaml – anyone has a brief
  comparison of them?

  • [http-multipart-formdata] as announced above
  • [multipart_form] by @dinosaure
  • [multipart-form-data] by cryptosense

  Are there functional differences? Correctness? Performance? Or just a
  matter of style and co-development?


[http-multipart-formdata]
<https://github.com/lemaetech/http-multipart-formdata>

[multipart_form] <https://github.com/dinosaure/multipart_form/>

[multipart-form-data]
<https://github.com/cryptosense/multipart-form-data>


Bikal Lem replied
─────────────────

  One obvious difference among the three is `http-multipart-formdata'
  doesn't depend on any IO/Promise libraries, such as lwt or async. so
  you may find it easier to integrate in your project.

  `mulitpart-form-data' exposes a callback based streaming api, whereas
  http-multipart-formdata exposes a non-callback, non-blocking based API
  streaming api.

  The API surface of `http-multipart-formdata' is kept as low as
  possible, primarily 3 API calls - `boundary, reader' and `read' call.

  The dependency list of `http-multipart-formdata' is the thinnest. This
  may or may not be an issue depending on your aesthetics. However,
  relatively/comparatively the less your dependencies, the easier it is
  to integrate the lib with other OCaml libs and environments such as
  various OSes.


Bikal Lem added
───────────────

  I should also add `http-multipart-formdata' has been implemented with
  zero-copy streaming and minimal allocation in mind.


Call for participation: ML Family Workshop 2021
═══════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-08/msg00005.html>


Jonathan Protzenko announced
────────────────────────────

  We are happy to announce that the ML Family Workshop is back for its
  2021 edition, which we will be held online on Thursday August 26th, in
  conjunction with ICFP 2021. We invite you to subscribe to, and attend
  the workshop, in addition to the main ICFP conference.

  We are thrilled to announce that Don Syme will give this year's
  keynote: "Narratives and Lessons from The Early History of F#". Please
  join us!

  The program features 14 exciting submissions, including 4 short talks.
  The workshop will be held online in the 6pm-3am time band (Seoul
  Time).  Talks will be pre-recorded and uploaded online for those who
  cannot attend.

  • Program:
    <https://icfp21.sigplan.org/home/mlfamilyworkshop-2021#program>
  • Keynote:
    <https://icfp21.sigplan.org/details/mlfamilyworkshop-2021-papers/15/Keynote-Narratives-and-Lessons-from-The-Early-History-of-F>-
  • ICFP home: <http://icfp21.sigplan.org/home>


Program committee
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Danel Ahman (University of Ljubljana)
  • Robert Atkey (University of Strathclyde)
  • Frédéric Bour (Tarides)
  • Ezgi Çiçek (Facebook London)
  • Youyou Cong (Tokyo Institute of Technology)
  • Richard A. Eisenberg (Tweag I/O)
  • Martin Elsman (University of Copenhagen, Denmark)
  • Ohad Kammar (University of Edinburgh)
  • Naoki Kobayashi (University of Tokyo, Japan)
  • Benoît Montagu (Inria)
  • Jonathan Protzenko (Microsoft Research) (Chair)
  • Kristina Sojakova (INRIA Paris)
  • Don Syme (Microsoft)
  • Matías Toro (University of Chile)
  • Katsuhiro Ueno (Tohoku University)


Coq-of-ocaml to translate OCaml to Coq
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/coq-of-ocaml-to-translate-ocaml-to-coq/8288/1>


Guillaume Claret announced
──────────────────────────

  I am pleased to present the [coq-of-ocaml] project, to translate a
  subset of OCaml to the [Coq] proof assistant. The aim is to do formal
  verification on OCaml programs. The idea is to generate a Coq
  translation as close as possible to the original code in terms of
  intent but using the Coq syntax. As a short example, if we take the
  following OCaml code and run `coq-of-ocaml':
  ┌────
  │ type 'a tree =
  │ | Leaf of 'a
  │ | Node of 'a tree * 'a tree
  │ 
  │ let rec sum tree =
  │   match tree with
  │   | Leaf n -> n
  │   | Node (tree1, tree2) -> sum tree1 + sum tree2
  └────
  we get the following Coq file:
  ┌────
  │ Require Import CoqOfOCaml.CoqOfOCaml.
  │ Require Import CoqOfOCaml.Settings.
  │ 
  │ Inductive tree (a : Set) : Set :=
  │ | Leaf : a -> tree a
  │ | Node : tree a -> tree a -> tree a.
  │ 
  │ Arguments Leaf {_}.
  │ Arguments Node {_}.
  │ 
  │ Fixpoint sum (tree : tree int) : int :=
  │   match tree with
  │   | Leaf n => n
  │   | Node tree1 tree2 => Z.add (sum tree1) (sum tree2)
  │   end.
  └────

  We support the following OCaml features:
  • the core of OCaml (functions, let bindings, pattern-matching,…)
  • type definitions (records, inductive types, synonyms, mutual types)
  • monadic programs
  • modules as namespaces
  • modules as polymorphic records (signatures, functors, first-class
    modules)
  • multiple-file projects (thanks to Merlin)
  • both `.ml' and `.mli' files
  • existential types (we use impredicative sets option in Coq)

  We also have some support for the GADTs, the polymorphic variants, and
  the extensible types.  We are in particular working on having an
  axiom-free translation of the GADTs to Coq. We do not support:
  • side-effects outside of a monad (references, exceptions, …);
  • object-oriented programming;
  • various combinations of OCaml features for which `coq-of-ocaml'
    should generate a warning.

  Our main example and use case is the [coq-tezos-of-ocaml]
  project. This contains a translation of most of the [economic
  protocol] of the [Tezos] blockchain (around 30.000 lines of OCaml
  translated to 40.000 lines of Coq). For example, we verify the
  comparison functions defined in
  [src/proto_alpha/lib_protocol/script_comparable.ml] with
  [src/Proto_alpha/Proofs/Script_comparable.v].

  We are looking for the application to other projects too.

  We think the best way to use `coq-of-ocaml' is to continue developing
  in OCaml and run `coq-of-ocaml' to keep a synchronized translation in
  Coq. Having a working Coq translation (as compiling in Coq) forces us
  to avoid some OCaml constructs. We believe these constructs would
  probably be hard to verify anyway. Then, on the Coq side, we can
  verify some important or easy to catch properties. If there is a
  regression in the OCaml code, re-running `coq-of-ocaml' should make
  the proofs break.


[coq-of-ocaml] <https://clarus.github.io/coq-of-ocaml/>

[Coq] <https://coq.inria.fr/>

[coq-tezos-of-ocaml]
<https://nomadic-labs.gitlab.io/coq-tezos-of-ocaml/>

[economic protocol]
<https://gitlab.com/tezos/tezos/-/tree/master/src/proto_alpha/lib_protocol>

[Tezos] <https://tezos.com/>

[src/proto_alpha/lib_protocol/script_comparable.ml]
<https://gitlab.com/tezos/tezos/-/blob/master/src/proto_alpha/lib_protocol/script_comparable.ml>

[src/Proto_alpha/Proofs/Script_comparable.v]
<https://nomadic-labs.gitlab.io/coq-tezos-of-ocaml/docs/proofs/script_comparable>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-08-10 16:47 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-08-10 16:47 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 10581 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of August 03 to 10,
2021.

Table of Contents
─────────────────

Lwt 5.4.2
OCaml Workshop 2021: Call for Volunteers
opam 2.1.0!
containers 3.5
Short contract job for OCaml/C++ programmer
http-multipart-formdata v3.0.1 released
wtr (Well Typed Router) v2.0.0 released
New playlist just dropped
Other OCaml News
Old CWN


Lwt 5.4.2
═════════

  Archive: <https://discuss.ocaml.org/t/ann-lwt-5-4-2/8248/1>


Raphaël Proust announced
────────────────────────

  We are glad to announce the release of version 5.4.2 of Lwt: a
  bugfix-only release.

  <https://github.com/ocsigen/lwt/releases/tag/5.4.2>

  You can update to this version in `opam' :

  ┌────
  │ opam update
  │ opam upgrade lwt
  └────

  Thanks to the contributors for finding and fixing the bugs, leading to
  this release. Check out the release notes (link above) for a full
  list.


OCaml Workshop 2021: Call for Volunteers
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-workshop-2021-call-for-volunteers/8253/1>


Frédéric Bour announced
───────────────────────

  The OCaml Workshop will be held virtually, just like last year. We are
  looking for volunteers to fill the role of session host.


[Session Hosts]
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  On August 27, the session hosts will assist session chairs in
  streaming the pre-recorded videos as well as helping and moderating
  the Q&A sessions. They will also be responsible for security and be
  ready to react to potential threats and wrongdoers.

  This year there will be only one broadcast for each session, but the
  workshop day will be quite long. There will be six sessions, lasting
  one hour and a half, as well as a one hour keynote.


[Session Hosts]
<https://icfp20.sigplan.org/home/ocaml-2020#session-hosts>

[Duties]
┄┄┄┄┄┄┄┄

  • Moderating the text chats
  • Controlling microphones in the video-conferencing
  • Watching for the time
  • Performing sound checks
  • Welcoming and otherwise guiding participants


[Duties] <https://icfp20.sigplan.org/home/ocaml-2020#duties>


opam 2.1.0!
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-1-0/8255/1>


R. Boujbel announced
────────────────────

  We are happy to announce two opam releases: the freshly new [2.1.0] &
  the LTS support [2.0.9].


[2.1.0] <https://github.com/ocaml/opam/releases/tag/2.1.0>

[2.0.9] <https://github.com/ocaml/opam/releases/tag/2.0.9>

What's new in opam 2.1.0?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Integration of system dependencies (formerly the `opam-depext`
    plugin), increasing their reliability as it integrates the solving
    step
  • Creation of lock files for reproducible installations (formerly the
    `opam-lock` plugin)
  • Switch invariants, replacing the _"base packages"_ in opam 2.0 and
    allowing for easier compiler upgrades
  • Improved options configuration (see the new `option` and expanded
    `var` sub-commands)
  • CLI versioning, allowing cleaner deprecations for opam now and also
    improvements to semantics in future without breaking
    backwards-compatibility
  • opam root readability by newer and older versions, even if the
    format changed
  • Performance improvements to opam-update, conflict messages, and many
    other areas

  You'll find these features presentation in the [blog post] ; and for a
  full complete you can take a look [pre-releases changelogs].


[blog post] <https://opam.ocaml.org/blog/opam-2-1-0>

[pre-releases changelogs] <https://github.com/ocaml/opam/releases>


What's in 2.0.9
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This 2.0.9 version contains back-ported fixes, you can find more
  information in this [blog post], especially for fish users & sandbox
  updates.

  *Tremendous thanks to all involved people, all those who've tested,
   re-tested, tested again, given feedback, commented on issues, tested,
   tested, tested again…!*

  /The opam team/ 🐪


[blog post] <https://opam.ocaml.org/blog/opam-2-0-9>


containers 3.5
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-containers-3-5/8257/1>


Simon Cruanes announced
───────────────────────

  I'm glad to announce that version 3.5 of [containers] has just been
  released. There's a bugfix for bitvectors, and a tasteful assortment
  of new functions (see changelog). I want to thank all the
  contributors, among whom first time contributor @favonia.

  The release and changelog can be found [here]


[containers] <https://github.com/c-cube/ocaml-containers>

[here] <https://github.com/c-cube/ocaml-containers/releases/tag/v3.5>


Short contract job for OCaml/C++ programmer
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/short-contract-job-for-ocaml-c-programmer/8260/1>


Ashish Agarwal announced
────────────────────────

  We have a small project (possibly only days of work) for an
  experienced OCaml and C++ programmer. If you are available for a short
  engagement as a contractor, please DM me. Thank you.


http-multipart-formdata v3.0.1 released
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-http-multipart-formdata-v3-0-1-released/8261/1>


Bikal Lem announced
───────────────────

  I am pleased to announce v3.0.1 of `http-multipart-formdata'. This
  release follows a major overhaul of the parser as well as the design
  of the library. Here is the summary of changes:

  1. Flatten module `Part_header' to `part_header'
  2. Implement reader/pull based parser to retrieve multipart parts,
     i.e. implement a `streaming' design. This is very useful if the
     HTTP file upload is large.
  3. Implement push-based incremental input model, i.e. the library is
     now a non-blocking multipart parser
  4. Remove dependency on IO based libs such as `lwt, async' since it is
     no longer needed due to point 3 above.

  Github repo: [http-multipart-formdata]

  API doc : [API manual]


[http-multipart-formdata]
<https://github.com/lemaetech/http-multipart-formdata>

[API manual]
<https://lemaetech.co.uk/http-multipart-formdata/http-multipart-formdata/Http_multipart_formdata/index.html>


wtr (Well Typed Router) v2.0.0 released
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-wtr-well-typed-router-v2-0-0-released/8262/1>


Bikal Lem announced
───────────────────

  I am pleased to announce v2.0.0 release of `wtr (Well Typed
  Router)'. `wtr' is a trie-based router for OCaml HTTP web
  applications.

  v2.0.0 release adds support for specifying and matching HTTP methods
  in a router. So now we can do the following;
  ┌────
  │ Wtr.(
  │     create
  │       [ {%wtr| get,post,head,delete  ; /home/about/  |} about_page
  │       ; {%wtr| head                  ; /home/:int/   |} prod_page
  │       ]
  └────
  Note: we can specify single or multiple HTTP methods supported by a
  route.

  The release also features a pretty-printer - `Wtr.pp' - for a `Wtr.t'
  type. This has proven to be very useful when diagnosing/understanding
  routing issues. Sample output below,
  ┌────
  │ POST
  │   /home
  │     /about
  │       /
  │     /:float
  │       /
  │ HEAD
  │   /home
  │     /about
  │       /
  │     /:int
  │       /
  └────

  The manual has also been improved in this release.

  • [wtr API]
  • [CoHTTP demo]
  • [CLI demo]
  • [Changes v2.0.0]


[wtr API] <https://lemaetech.co.uk/wtr/wtr/Wtr/index.html>

[CoHTTP demo]
<https://github.com/lemaetech/wtr/blob/main/examples/cohttp.ml>

[CLI demo] <https://github.com/lemaetech/wtr/blob/main/examples/demo.ml>

[Changes v2.0.0]
<https://github.com/lemaetech/wtr/blob/main/CHANGES.md#v200-2021-08-02>


New playlist just dropped
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/new-playlist-just-dropped/8272/1>


Rahul announced
───────────────

  Haven't watched them all yet, but these look like they'd be a great
  resource for anyone wanting to learn OCaml:
  <https://www.youtube.com/watch?v=MUcka_SvhLw&list=PLre5AT9JnKShBOPeuiD9b-I4XROIJhkIU>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [opam 2.1.0 is released!]
  • [opam 2.0.9 release]


[OCaml Planet] <http://ocaml.org/community/planet/>

[opam 2.1.0 is released!]
<https://www.ocamlpro.com/2021/08/05/opam-2-1-0-is-released/>

[opam 2.0.9 release]
<https://www.ocamlpro.com/2021/08/05/opam-2-0-9-release/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-07-27  8:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-07-27  8:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 19204 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of July 20 to 27,
2021.

Table of Contents
─────────────────

pyre-ast: full-fidelity Python parser in OCaml
OCaml+Opam Images for Docker for Windows
Borns a stream talking about OCaml/Reason & ReScript language
An Update on the State of the PPX Ecosystem and `ppxlib''s Transition
How to send email from Dream
Old CWN


pyre-ast: full-fidelity Python parser in OCaml
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-pyre-ast-full-fidelity-python-parser-in-ocaml/8177/1>


Jia Chen announced
──────────────────

  I am happy to announce the initial opam release of [`pyre-ast'], a
  Python parsing library.

  The library features its full-fidelity to the official Python
  spec. Apart from a few technical edge cases, as long as a given file
  can be parsed/rejected by the CPython interpreter, `pyre-ast' will be
  able to parse/reject it as well. Furthermore, abstract syntax trees
  obtained from `pyre-ast' is guaranteed to 100% match the results
  obtained by Python's own `ast.parse' API, down to every AST node and
  every line/column number.

  Another notable feature of this library is that it represents the
  Python syntax using the *tagless-final style*. This style typically
  offers more flexibility and extensibility for the downstream consumers
  of the syntax, and allow them to build up their analysis without
  explicitly constructing a syntax tree. That said, for developers who
  are less familiar with the tagless-final approach, we also offer
  alternative interfaces that operates on traditional syntax tree
  represented as algebraic data types.

  Documentation of the library can be found [here].

  The reason why we can can claim full-conformance with CPython is
  really simple: the library is, under the hood, merely an OCaml wrapper
  around the parsing logic in CPython source code.  The project was
  initially motivated to replace the custom `menhir'-based parser
  currently used in the Pyre type checker (hence the name), but I
  figured that it would be useful to release this as a standalone `opam'
  package to the community so other static Python analyzers or other
  DSLs with Python-based syntax can leverage it as well.

  The library has yet to be put into production for Pyre (I'm working on
  it though) so please do expect bugs/jankiness at times. Feedback and
  bug reports are very welcomed.

  Happy parsing!


[`pyre-ast'] <https://github.com/grievejia/pyre-ast>

[here] <https://grievejia.github.io/pyre-ast/doc/pyre-ast/>


OCaml+Opam Images for Docker for Windows
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-opam-images-for-docker-for-windows/8179/1>


Antonin Décimo announced
────────────────────────

  I'm glad to announce the availability of OCaml and opam [native
  Windows Container][windows-containers] images for Docker for
  Windows. This is the result of my hard work at Tarides, with precious
  help from @dra27, @talex5, @avsm, and the rest of the team.

  They can be found under the [ocaml/opam][hub] repository in the Docker
  Hub. Try them with [Docker for Windows][docker-for-windows]! Be sure
  to [switch Docker to Native Windows Containers][enable-native].

  ┌────
  │ docker run -it ocaml/opam:windows-mingw
  │ docker run -it ocaml/opam:windows-msvc
  └────

  We provide images for the mingw-w64 (from OCaml 4.02 to 4.12) and the
  MSVC (from OCaml 4.06 to 4.12) ports. They are based on each release
  of Windows 10 amd64 currently supported by [Microsoft on the Docker
  Hub][mcr]. The images use opam 2.0, and we plan to update to opam 2.1
  when it's released. The images also ship a [Cygwin][cygwin]
  installation, [Git for Windows][git-for-windows], and the [winget
  package manager][winget].

  We use @fdopen's [OCaml for Windows][ocaml-for-windows] distribution
  and opam-repository fork. As it is getting deprecated at the end of
  August 2021, we'll transition to opam 2.1 and the standard
  opam-repository when that happens.

  In order to get the correct environment for any `RUN' command
  involving OCaml or opam, prefix the command with

  • `ocaml-env exec --64 --' if based on mingw-w64; or
  • `ocaml-env exec --64 --ms=vs2019 --' if based on MSVC.

  The images are built at <https://base-images.ocamllabs.io/>, using an
  [OCurrent][ocurrent] pipeline that [builds Docker
  images][docker-base-images]. You can rebuild them yourself using the
  [OCluster][ocluster] set of tools that I have ported to Windows.

  We provide a comprehensive set of tags (replace _port_ with either
  _mingw_ or _msvc_):
  • `windows-port': the latest version of OCaml for each Windows
    version;
  • `windows-port-winver': the latest version of OCaml for Windows 10
    _winver_;
  • `windows-port-ocaml-mlver': OCaml version _mlver_ for each Windows
    version;
  • `windows-port-winver-ocaml-mlver': OCaml version _mlver_ for Window
    10 _winver_.

  When the Windows version is not specified in the tag, the image is a
  multiarch image that will work on every supported version of Windows
  10. Docker automatically selects the appropriate one based on the host
  version.

  We will be using these images in the upcoming `ocaml-ci' and
  `opam-repo-ci' for Windows.

  Further work on these include the transition to opam 2.1, and we'll
  provide the Cygwin port of OCaml when it's fixed upstream and
  available in the Cygwin package repository.

  Happy hacking!


Borns a stream talking about OCaml/Reason & ReScript language
═════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-borns-a-stream-talking-about-ocaml-reason-rescript-language/8185/1>


David Sancho announced
──────────────────────

  I'm very excited to announce starting a new show in Twitch to bring
  OCaml, Reason and ReScript community best brains to casually
  talk. It's called emelleTV

  It's made by [@fakenickels] and myself [@davesnx], and we will try to
  do our best!

  Our first guest is [@___zth___]

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/e/e9f08607687aeb843968a430e4e9082541cf87c2_2_1380x690.jpeg>

  We go live on [http://twitch.tv/emelletv] next Wednesday.  Subscribe
  to not miss it!

  Thanks for reading, hope to see you there!


[@fakenickels] <https://twitter.com/fakenickels>

[@davesnx] <https://twitter.com/davesnx>

[@___zth___] <https://twitter.com/___zth___>

[http://twitch.tv/emelletv] <http://twitch.tv/emelletv>


An Update on the State of the PPX Ecosystem and `ppxlib''s Transition
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/an-update-on-the-state-of-the-ppx-ecosystem-and-ppxlib-s-transition/8200/1>


Sonja Heinze announced
──────────────────────

  I hope you're all having a nice summer (or a nice whichever season
  you're in, of course)!  We've set up a new [wiki page on the ppxlib
  repository] containing a status overview of the current `ppxlib'
  transition, which aims at keeping the PPX ecosystem always
  up-to-date. We'll keep that wiki page up-to-date, as well.

  @jeremiedimino and @NathanReb have already explained our three-part
  plan for this transition in different posts here on discuss. Nothing
  has changed in that plan, but it has been a while since we [last
  posted about the overall transition] and even longer since we [last
  posted about the `Astlib' transition in detail]. So if you want, you
  can refresh your memory about that transition and get updated about
  its current state (in more detail than the new wiki page) by reading
  this post.


[wiki page on the ppxlib repository]
<https://github.com/ocaml-ppx/ppxlib/wiki/The-State-of-the-PPX-Transition>

[last posted about the overall transition]
<https://discuss.ocaml.org/t/ppxlib-0-22-an-update-on-the-state-of-ppx/7296>

[last posted about the `Astlib' transition in detail]
<https://discuss.ocaml.org/t/ppx-omp-2-0-0-and-next-steps/6231>

Which Issues `ppxlib' was Facing
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  With `ocaml-migrate-parsetree' (`OMP'), the PPX ecosystem became
  cross-compiler-compatible.  With `ppxlib', the latest compiler
  features were supported more easily and broadly within the PPX
  ecosystem, while `ppxlib' also brought along other improvements such
  as the one in performance and the clear composition semantics when
  using several PPXs. With that, both `OMP' and `ppxlib' have taken away
  several maintenance burdens from the PPX maintainers and have created
  a more homogeneous and up-to-date PPX ecosystem. However, we were
  facing the following issues:
  1. To keep the PPX ecosystem cross-compiler compatible
     1. `ppxlib' was handling parts of the unstable `compiler-libs' API
        to abstracting them away;
     2. the `OMP~/~ppxlib' maintainers needed to keep the AST migration
        information up-to-date by coordination with the compiler devs.
  2. To guarantee new feature support, `ppxlib' needed to bump the
     `ppxlib' AST to the newest version.
  3. Bumping the AST implies a breaking change. That was an issue for a
     homogeneous and up-to-date PPX ecosystem.
  4. Not all PPXs migrated from `OMP' to `ppxlib'. That was also an
     issue for a homogeneous and up-to-date PPX ecosystem.

  Some time ago, there was the very ambitious plan of tackling Issues 1,
  2, and 3 all at once by writing a stable AST abstraction and
  upstreaming it to the compiler. That plan has been put on ice for
  now. Instead we're currently on track with a more down-to-earth plan,
  outlined below.


Tackling the Issues in Three Parts
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The plan we're currently following contains three simultaneous
  parts. It approaches three of the four issues I've pointed out
  above. However, it leaves the need to bump the AST (Issue 2)
  untouched.


Part One: `Astlib' as an Interface between `ppxlib' and the Compiler
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  The first part works towards continuous cross-compiler compatibility
  (Issue 1 above) while making the situation of still having PPXs based
  on `OMP' (Issue 4 above) even more of a problem. It consists of
  implementing an interface module called `Astlib' between `ppxlib' and
  the compiler, then upstreaming it to the compiler. As long as `Astlib'
  is stable and up-to-date, the rest of `ppxlib' won't be affected by
  any compiler changes—neither by new AST versions nor by compiler
  library changes.

  The first step of this part of the plan was moving the `OMP' driver
  and other `OMP' features from `OMP' to `ppxlib'. That was done in
  August 2020, and it introduced `OMP2'. Since the PPX driver has to be
  unique, this was the start of having the PPX ecosystem split into the
  two incompatible worlds of `OMP1' PPXs on one hand and `ppxlib' PPXs
  on the other hand.

  By now, we have written [`Astlib' as an internal `ppxlib' library] and
  have reduced `ppxlib''s compiler library usage as much as possible to
  keep `Astlib' minimal. As you can see, it contains a minimal compiler
  library sub-API in addition to the former `OMP' modules of our
  supported ASTs and the migration information between them. We will
  upstream `Astlib' to the compiler asking for it to be kept stable and
  up-to-date, while also keeping our local copy for old compiler
  support.


[`Astlib' as an internal `ppxlib' library]
<https://github.com/ocaml-ppx/ppxlib/tree/master/astlib>


Part Two: Sending Patch PRs when Bumping the AST
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  So, thanks to Part One of the plan, `ppxlib' will always be compatible
  with the development compiler _OCaml trunk_ and the newest compiler
  version. However, to also support the newest compiler features, we
  need to bump the internal `ppxlib' AST to the newest version. That
  modifies some of the AST nodes and so it breaks any PPX that rewrites
  one of those nodes (Issue 3 above). Usually just a handful of PPXs are
  affected, but we still want them to be up-to-date.

  Our current plan doesn't provide a solution for that problem, but it
  does make handling the problem more efficient and, once again, it
  takes away the burden from the PPX maintainers.  Since the AST bump to
  `4.10', whenever we bump the AST, we send patch PRs to the PPXs we
  break. Not much has changed since February, when @NathanReb last
  [explained our workflow of sending patch PRs] in detail.  To some it
  up: we create a workspace with all `ppxlib' reverse dependencies on
  opam fulfilling a certain standard, which we call the
  _ppx-universe_. We then fix the PPXs that break all at once and open
  the PRs.

  Lately, the _ppx-universe_ has also proven very useful to make
  well-founded decisions regarding our API by having an easy look at our
  reverse dependencies. You can find a [_ppx-universe_ snapshot],
  currently from March, on our repo.

  In our experience, once the _ppx-universe_ is created and "builds up
  to the expected breakages," writing a couple of patches takes very
  little time, so we plan to make the tooling that creates and interacts
  with the workspace more sophisticated.


[explained our workflow of sending patch PRs]
<https://discuss.ocaml.org/t/ppxlib-0-22-an-update-on-the-state-of-ppx/7296>

[_ppx-universe_ snapshot] <https://github.com/ocaml-ppx/ppx_universe>


Part Three: Porting PPXs to Put an End to the "Split-World Situation"
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  As explained above, Part One split the PPXs into the two incompatible
  worlds of `OMP1' PPXs on one hand and `ppxlib' PPXs on the other
  hand. That made the fact that some PPXs were still based on `OMP'
  (Issue 4 above) even more of a problem. For some PPX maintainers, the
  reason to avoid porting their PPXs to `ppxlib' was that `ppxlib'
  depended on `base' and `stdio', so we decided to tackle this situation
  by three means:

  • Dropping the `base' and the `stdio' dependencies, which was done in
    August last year. Now, all dependencies are the very basic `ocaml',
    `dune', `ocaml-compiler-libs', `stdlib-shims', `sexplib0' and
    `ppx_derivers'.
  • Porting and reviewing some of the most important PPXs ourselves. So
    far we've ported `js_of_ocaml', `bisect_ppx', and `tyxml' with the
    help of the respective maintainers, and we've also reviewed several
    ports.
  • Spreading the word about the need to port PPXs and asking for help.

  About a year ago, we made a non-exhaustive [list of PPXs that needed
  to be ported].  Since then, this community has proven to be awesome
  and there has been an amazing porting effort by a lot of people. So by
  now, all packages on that list have been ported with the exception of
  one(*). So hopefully the "split world" situation can soon be
  considered past.  :tada:

  By the way, thanks to all involved in porting PPXs to `ppxlib'! It has
  been a great joint effort so far. :heart: And if anyone still has or
  comes across a project somewhere that needs porting and wants to port
  it, that's awesome!

  You can find the full list of opam packages that are still stuck in
  the `OMP1' world by [filtering for them in opam's health check
  pipeline].  However, notice that that's a generated list, so it also
  contains libraries that intrinsically form part of the `OMP1'
  ecosystem (such as `ppx_tools_versioned'), PPXs that have already been
  ported but haven't relesed their port on opam yet (such as
  `graphql_ppx'), deprecated PPXs that aren't marked as deprecated yet
  (such as `mirage-dns'), and several PPXs that only transitively depend
  on `OMP1'.

  (*) `ppx_import' has a PR for a port to `ppxlib', but it's not quite
  ready to be merged just yet.


[list of PPXs that needed to be ported]
<https://github.com/ocaml-ppx/ppxlib/issues?q=is%3Aissue+label%3Aport-to-ppxlib+>

[filtering for them in opam's health check pipeline]
<http://check.ocamllabs.io:8080/?comp=4.12&available=4.12&show-latest-only=true&sort-by-revdeps=true&maintainers=&logsearch=ocaml-migrate-parsetree%5C.1%5C.8%5C.0&logsearch_comp=4.12>


How to send email from Dream
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/how-to-send-email-from-dream/8201/1>


Joe Thomas announced
────────────────────

  I’ve written a short [blog post ] about what I learned building simple
  email features for a web server written in the Dream framework. The
  accompanying source code is available here:

  <https://github.com/jsthomas/dream-email-example>

  I’m interested in adding more examples and tutorials to the OCaml
  ecosystem and would be happy to get your feedback, positive or
  negative, on this write-up (here or via email/github/discord).


[blog post ] <https://jsthomas.github.io/ocaml-email.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-07-20 12:58 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-07-20 12:58 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 24945 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of July 13 to 20,
2021.

Table of Contents
─────────────────

Writing a REST API with Dream
OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
soupault: a static website generator based on HTML rewriting
OCaml 4.13.0, second alpha release
OCamlFormat 0.19.0
OCaml Café: Wed, Aug 4 @ 7pm (U.S. Central)
Old CWN


Writing a REST API with Dream
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/writing-a-rest-api-with-dream/8150/1>


Joe Thomas announced
────────────────────

  I've written a short [blog post] about the positive experience I had
  using Dream to build a REST API. The accompanying source code is
  available here:

  <https://github.com/jsthomas/sensors>

  I'm interested in adding more examples and tutorials to the OCaml
  ecosystem and would be happy to get your feedback on this writeup
  (here or via email/github).


[blog post] <https://jsthomas.github.io/ocaml-dream-api.html>


OTOML 0.9.0 — a compliant and flexible TOML parsing, manipulation, and pretty-printing library
══════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-otoml-0-9-0-a-compliant-and-flexible-toml-parsing-manipulation-and-pretty-printing-library/8152/1>


Daniil Baturin announced
────────────────────────

  I don't really like to base a release announcement on bashing another
  project, but this whole project is motivated by my dissatisfaction
  with [To.ml]—the only TOML library for OCaml, so here we go. OTOML is
  a TOML library that you (hopefully) can use without writing long rants
  afterwards. ;)

  In short:

  • [TOML 1.0-compliant] (To.ml is not).
  • Good error reporting.
  • Makes it easy to look up nested values.
  • Bignum and calendar libraries are pluggable via functors.
  • Flexible pretty-printer with indentation.

  OPAM: <https://opam.ocaml.org/packages/otoml/> GitHub:
  <https://github.com/dmbaturin/otoml>

  Now let's get to details.

  TOML is supposed to be human-friendly so that people can use it as a
  configuration file format. For that, both developer and end-user
  experience must be great. To.ml provides neither. I've been using
  To.ml in my projects for a long time, and


[To.ml] <https://opam.ocaml.org/packages/toml/>

[TOML 1.0-compliant] <https://toml.io/en/v1.0.0>

Standard compliance
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  TOML is neither minimal nor obvious really, it's much larger than the
  commonly used subset and the spec is not consistent and not easy to
  read, but To.ml fails at rather well-known things, like dotted keys,
  arrays of tables and heterogeneous arrays.

  OTOML passes all tests in the [test suite], except the tests related
  to bignum support. Those tests fail because the default implementation
  maps integers and floats to the native 31/63-bit OCaml types. More on
  that later.


[test suite] <https://github.com/BurntSushi/toml-test>


Error reporting
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Let's look at error reporting. To.ml's response to any parse error is
  a generic error with just line and column numbers.

  ┌────
  │ utop # Toml.Parser.from_string "foo = [" ;;
  │ - : Toml.Parser.result =
  │ `Error
  │   ("Error in <string> at line 1 at column 7 (position 7)",
  │    {Toml.Parser.source = "<string>"; line = 1; column = 7; position = 7})
  └────

  Menhir offers excellent tools for error reporting, so I took time to
  make descriptive messages for many error conditions (there _are_
  generic "syntax error" messages still, but that's better than nothing
  at all).

  ┌────
  │ utop # Otoml.Parser.from_string_result "foo = [" ;;
  │ - : (Otoml.t, string) result =
  │ Error
  │  "Syntax error on line 1, character 8: Malformed array (missing closing square bracket?)\n"
  │ 
  │ utop # Otoml.Parser.from_string_result "foo = {bar " ;;
  │ - : (Otoml.t, string) result =
  │ Error
  │  "Syntax error on line 1, character 12: Key is followed by end of file or a malformed TOML construct.\n"
  └────


Looking up nested values
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Nested sections are common in configs and should be easy to work
  with. This is how you do it in OTOML:

  ┌────
  │ utop # let t = Otoml.Parser.from_string "[this.is.a.deeply.nested.table]
  │ answer=42";;
  │ val t : Otoml.t =
  │   Otoml.TomlTable
  │    [("this",
  │      Otoml.TomlTable...
  │ 
  │ utop # Otoml.find t Otoml.get_integer ["this"; "is"; "a"; "deeply"; "nested"; "table"; "answer"] ;;
  │ - : int = 42
  └────

  For comparison, this is how it was done in To.ml:

  ┌────
  │ utop # let toml_data = Toml.Parser.(from_string "
  │ [this.is.a.deeply.nested.table]
  │ answer=42" |> unsafe);;
  │ val toml_data : Types.table = <abstr>
  │ 
  │ utop # Toml.Lenses.(get toml_data (
  │   key "this" |-- table
  │   |-- key "is" |-- table
  │   |-- key "a" |-- table
  │   |-- key "deeply" |-- table
  │   |-- key "nested" |-- table
  │   |-- key "table" |-- table
  │   |-- key "answer"|-- int ));;
  │ - : int option = Some 42
  └────


Extra dependencies
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The TOML spec includes first-class RFC3339 dates, for better or
  worse. The irony is that most uses of TOML (and, indeed, most
  configuration files in the world) don't need that, so it's arguably a
  feature bloat—but if we set out to support TOML as it's defined, that
  question is academic.

  The practical implication is that if the standard library of a
  language doesn't include a datetime type, a TOML library has to decide
  how to represent those values. To.ml makes ISO8601 a hard dependency,
  so if you don't use dates, you end up with a useless dependency. And
  if you prefer another library (or need functionality no present in
  ISO8601), you end up with two libraries: one you chose to use, and one
  more forced on you.

  Same goes for the arbitrary precision arithmetic. Most configs won't
  need it, but the standard demands it, so something needs to be done.

  Luckily, in the OCaml land we have functors, so it's easy to make all
  these dependencies pluggable. So I made it a functor that takes three
  modules.

  ┌────
  │ module Make (I : TomlInteger) (F : TomlFloat) (D : TomlDate) :
  │   TomlImplementation with type toml_integer = I.t and type toml_float = F.t and type toml_date = D.t
  └────

  This is how to use Zarith for big integers and keep the rest
  unchanged:

  ┌────
  │ (* No signature ascription:
  │    `module BigInteger : Otoml.Base.TomlInteger` would make the type t abstract,
  │    which is inconvenient.
  │  *)
  │ module BigInteger = struct
  │   type t = Z.t
  │   let of_string = Z.of_string
  │   let to_string = Z.to_string
  │   let of_boolean b = if b then Z.one else Z.zero
  │   let to_boolean n = (n <> Z.zero)
  │ end
  │ 
  │ module MyToml = Otoml.Base.Make (BigInteger) (Otoml.Base.OCamlFloat) (Otoml.Base.StringDate)
  └────


Printing
╌╌╌╌╌╌╌╌

  To.ml's printer can print TOML at you, that's for certain. No
  indentation, nothing to help you navigate nested values.

  ┌────
  │ utop # let toml_data = Toml.Parser.(from_string "[foo.bar]\nbaz=false\n [foo.quux]\n xyzzy = [1,2]" |> unsafe) |>
  │ Toml.Printer.string_of_table |> print_endline;;
  │ [foo.bar]
  │ baz = false
  │ [foo.quux]
  │ xyzzy = [1, 2]
  └────

  We can do better:

  ┌────
  │ utop # let t = Otoml.Parser.from_string "[foo.bar]\nbaz=false\n [foo.quux]\n xyzzy = [1,2]" |>
  │ Otoml.Printer.to_channel ~indent_width:4 ~collapse_tables:false stdout;;
  │ 
  │ [foo]
  │ 
  │ [foo.bar]
  │     baz = false
  │ 
  │ [foo.quux]
  │     xyzzy = [1, 2]
  │ val t : unit = ()
  │ 
  │ utop # let t = Otoml.Parser.from_string "[foo.bar]\nbaz=false\n [foo.quux]\n xyzzy = [1,2]" |>
  │ Otoml.Printer.to_channel ~indent_width:4 ~collapse_tables:false ~indent_subtables:true stdout;;
  │ 
  │ [foo]
  │ 
  │     [foo.bar]
  │ 	baz = false
  │ 
  │     [foo.quux]
  │ 	xyzzy = [1, 2]
  │ val t : unit = ()
  └────


Maintenance practices
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Last but not least, good maintenance practices are also important, not
  just good code. To.ml is at 7.0.0 now. It has a [CHANGES.md] file, but
  I'm still to see the maintainers document what the breaking change is,
  who's affected, and what they should do to make their code compatible.

  For example, in 6.0.0 the breaking change was a rename from
  `TomlLenses' to `Toml.Lenses'. In an earlier release, I remember the
  opposite rename. Given the standard compatibility problems going
  unfixed for years, that's like rearranging furniture when the roof is
  leaking.

  I promise not to do that.


[CHANGES.md]
<https://github.com/ocaml-toml/To.ml/blob/master/CHANGES.md>


Conclusion
╌╌╌╌╌╌╌╌╌╌

  I hope this library will help make TOML a viable configuration file
  format for OCaml programs.

  It's just the first version of course, so there's still room for
  improvement. For example, the lexer is especially ugly: due to TOML
  being highly context-sensitive, it involves massive amounts of lexer
  hacks for context tracking.  Maybe ocamllex is a wrong tool for the
  job abd it should be replaced with something else (since I'm using
  Menhir's incremental API anyway, it's not tied to any lexer API).

  The printer is also less tested than the parser, so there may be
  unhandled edge cases. It also has some cosmetic issues like newlines
  between parent and child tables.

  Any feedback and patches are welcome!


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/15>


Daniil Baturin announced
────────────────────────

  [soupault 3.0.0] is now available.

  It now uses the new [OTOML] library for loading the configs, which has
  some positive side effects, e.g. keys in the output of `soupault
  --show-effective-config' (that shows your config plus default values
  you didn't set explicitly) now come in the same order as in your
  config file.

  It also provides TOML and YAML parsing functions to Lua plugins and
  has colored log headers (can be disabled with NO_COLOR environment
  variables).


[soupault 3.0.0] <https://soupault.app/blog/soupault-3.0.0-release/>

[OTOML] <https://opam.ocaml.org/packages/otoml/>


OCaml 4.13.0, second alpha release
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-13-0-second-alpha-release/8164/1>


octachron announced
───────────────────

  The release of OCaml 4.13.0 is approaching. We have released a second
  alpha version to help fellow hackers join us early in our bug hunting
  and opam ecosystem fixing fun (see below for the installation
  instructions). You can see the progress on this front at
  <https://github.com/ocaml/opam-repository/issues/18791> .

  Beyond the usual bug fixes (see the full list below), this second
  alpha integrates a new feature for native code: poll points. Those
  poll points currently fixes some issues with signals in non-allocating
  loops in native code. More importantly, they are prerequisite for the
  multicore runtime.

  Another change is the removal of the removal of interbranch
  propagation of type information.  The feature, already postponed from
  4.12, has been removed to focus for now on better error message in the
  `-principal' mode.

  If you find any bugs, please report them here:

  <https://github.com/ocaml/ocaml/issues>

  The first beta release may follow soon since the opam ecosystem is in
  quite good shape; and we are on track for a full release in September.

  Happy hacking, Florian Angeletti for the OCaml team.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.13.0~alpha2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────

  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:

  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.13.0~alpha2+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where <option_list> is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and no-flat-float-array switch:
  ┌────
  │ opam switch create 4.13.0~alpha2+flambda+nffa
  │ --packages=ocaml-variants.4.13.0~alpha2+options,ocaml-option-flambda,ocaml-option-no-flat-float-array
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with "opam search ocaml-option".

  If you want to test this version, it is advised to install the alpha
  opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This alpha repository contains various fixes in the process of being
  upstreamed.

  The source code for the alpha is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.13.0-alpha2.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.13/ocaml-4.13.0~alpha2.tar.gz>


Changes since the first alpha release
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

New feature
┄┄┄┄┄┄┄┄┄┄┄

  • [10039]: Safepoints Add poll points to native generated code. These
    are effectively zero-sized allocations and fix some signal and
    remembered set issues. Also multicore prerequisite.  (Sadiq Jaffer,
    Stephen Dolan, Damien Doligez, Xavier Leroy, Anmol Sahoo, Mark
    Shinwell, review by Damien Doligez, Xavier Leroy, and Mark Shinwell)


[10039] <https://github.com/ocaml/ocaml/issues/10039>


New bug fixes
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [10449]: Fix major GC work accounting (the GC was running too
    fast). (Damien Doligez, report by Stephen Dolan, review by Nicolás
    Ojeda Bär and Sadiq Jaffer)

  • [10454]: Check row_more in nondep_type_rec.  (Leo White, review by
    Thomas Refis)

  • [10468]: Correctly pretty print local type substitution, e.g. type t
    := …, with -dsource (Matt Else, review by Florian Angeletti)

  • [10461], [10498]: `caml_send*' helper functions take derived
    pointers as arguments.  Those must be declared with type Addr
    instead of Val. Moreover, poll point insertion must be disabled for
    `caml_send*', otherwise the derived pointer is live across a poll
    point. (Vincent Laviron and Xavier Leroy, review by Xavier Leroy and
    Sadiq Jaffer)

  • [10478]: Fix segfault under Windows due to a mistaken initialization
    of thread ID when a thread starts. (David Allsopp, Nicolás Ojeda
    Bär, review by Xavier Leroy)

  • [9525], [10402]: ocamldoc only create paragraphq at the toplevel of
    documentation comments (Florian Angeletti, report by Hendrik Tews,
    review by Gabriel Scherer)

  • [10206]: Split labels and polymorphic variants tutorials Splits the
    labels and polymorphic variants tutorial into two. Moves the GADTs
    tutorial from the Language Extensions chapter to the tutorials.
    (John Whitington, review by Florian Angeletti and Xavier Leroy)


[10449] <https://github.com/ocaml/ocaml/issues/10449>

[10454] <https://github.com/ocaml/ocaml/issues/10454>

[10468] <https://github.com/ocaml/ocaml/issues/10468>

[10461] <https://github.com/ocaml/ocaml/issues/10461>

[10498] <https://github.com/ocaml/ocaml/issues/10498>

[10478] <https://github.com/ocaml/ocaml/issues/10478>

[9525] <https://github.com/ocaml/ocaml/issues/9525>

[10402] <https://github.com/ocaml/ocaml/issues/10402>

[10206] <https://github.com/ocaml/ocaml/issues/10206>


Removed feature
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [ *breaking change* ] [9811]: remove propagation from previous
    branches Type information inferred from previous branches was
    propagated in non-principal mode. Revert this for better
    compatibility with -principal mode. For the time being, infringing
    code should result in a principality warning. (Jacques Garrigue,
    review by Thomas Refis and Gabriel Scherer)

  The up-to-date list of changes for OCaml 4.13 is available at
  <https://github.com/ocaml/ocaml/blob/4.13/Changes> .


[9811] <https://github.com/ocaml/ocaml/issues/9811>


OCamlFormat 0.19.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocamlformat-0-19-0/8167/1>


Guillaume Petiot announced
──────────────────────────

  We are happy to announce the release of [OCamlFormat 0.19.0].

  OCamlformat is an auto-formatter for OCaml code, writing the parse
  tree and comments in a consistent style, so that you do not have to
  worry about formatting it by hand, and to speed up code review by
  focusing on the important parts.

  OCamlFormat is beta software. We expect the program to change
  considerably before we reach version 1.0.0. In particular, upgrading
  the `ocamlformat` package will cause your program to get
  reformatted. Sometimes it is relatively pain-free, but sometimes it
  will make a diff in almost every file. We are working towards having a
  tool that pleases most usecases in the OCaml community, please bear
  with us!

  To make sure your project uses the last version of ocamlformat, please
  set

  ┌────
  │ version=0.19.0
  └────

  in your `.ocamlformat' file.

  Main changes in `ocamlformat.0.19.0' are:
  • OCaml 4.13 features are supported
  • `ppxlib' dependency has been dropped
  • A new `line-endings={lf,crlf}' option has been added for windows
    compatibility

  Here is the [full list of changes].

  We encourage you to try ocamlformat, that can be installed from opam
  directly ( `opam install ocamlformat' ), but please remember that it
  is still beta software. We have a [FAQ for new users ] that should
  help you decide if ocamlformat is the right choice for you.


[OCamlFormat 0.19.0] <https://github.com/ocaml-ppx/ocamlformat>

[full list of changes]
<https://github.com/ocaml-ppx/ocamlformat/releases/tag/0.19.0>

[FAQ for new users ]
<https://github.com/ocaml-ppx/ocamlformat#faq-for-new-users>


Nicolás Ojeda Bär then added
────────────────────────────

        A new `line-endings={lf,crlf}' option has been added for
        windows compatibility

  Just to expand a bit on this feature: previously, `ocamlformat' would
  use the system EOL convention (ie LF on Unix-like OSs and CRLF on
  Windows). This meant that if you applied `ocamlformat' on systems with
  different EOL conventions, you would get a diff on every line on every
  file purely due to the changed newlines. Furthermore, this meant
  `ocamlformat' was hard to use if your project used LF on Windows (a
  common usage).

  With the new option, `ocamlformat' enforces a given EOL
  convention. The system EOL convention is no longer used for any
  purpose and the EOL convention used is the one specified in
  `ocamlformat''s config (LF by default).


OCaml Café: Wed, Aug 4 @ 7pm (U.S. Central)
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-cafe-wed-aug-4-7pm-u-s-central/8169/1>


Michael Bacarella announced
───────────────────────────

  Please join us at the next OCaml Cafe, a friendly, low stakes
  opportunity to ask questions about the OCaml language and ecosystem,
  work through programming problems that you’re stuck on, and get
  feedback on your code. Especially geared toward new and intermediate
  users, experienced OCaml developers will be available to answer your
  questions.  Bring your code and we’ll be happy to review it, assist
  with debugging, and provide recommendations for improvement.

  This month, OCaml Café will consist of two parts. First, Rudi Grinberg
  of [OCaml Labs] will present an informal introduction to [Dune], the
  OCaml build system. Learn about Dune from one the people developing
  it. Following Rudi’s presentation, we will open the discussion to all
  things OCaml-related.

  Full [Zoom meeting details here].
  • Add to your [Google Calendar]
  • Add to your [iCal]


[OCaml Labs] <https://ocamllabs.io/>

[Dune] <https://dune.build/>

[Zoom meeting details here]
<https://hfpug.org/event/ocaml-cafe-introduction-to-dune-and-open-forum/>

[Google Calendar]
<https://www.google.com/calendar/event?action=TEMPLATE&text=OCaml+Caf%C3%A9%3A+Introduction+to+Dune+and+Open+Forum&dates=20210804T190000/20210804T210000&details=OCaml+Caf%C3%A9+offers+a+friendly%2C+low+stakes+opportunity+to+ask+questions+about+the+OCaml+language+and+ecosystem%2C+work+through+programming+problems+that+you%E2%80%99re+stuck+on%2C+and+get+feedback+on+your+code.+Especially+geared+toward+new+and+intermediate+users%2C+experienced+OCaml+developers+will+be+available+to+answer+your+questions.%C2%A0+Bring+your+code+and+we%26%238217%3Bll+be+happy+to+review+it%2C+assist+with+debugging%2C+and+provide+recommendations+for+improvement.+%0AThis+month%2C+OCaml+Caf%C3%A9+will+consist+of+two+parts.%C2%A0+First%2C+Rudi+Grinberg+of+OCaml+Labs+will+present+an+informal+introduction+to+Dune%2C+the+OCaml+build+system.%C2%A0+Learn+about+Dune+from+one+the+people+developing+it.%C2%A0+Following+Rudi%26%238217%3Bs+presentation%2C+we+will+open+the+discussion+to+all+things+OCaml-related.+%0AWhether+you%E2%80%99re+still+trying+to+make+sense+of+currying+or+can+spot+non-tail-recursive+code+from+across+the+room%2C+we+hope+that+you%E2%80%99ll+join+us+with+your+questions+about+OCaml%2C+or+just+to+hang+out+with+the+OCaml+community.+%0A%0AClaude+Ru+%28View+Full+Event+Description+Here%3A+https%3A%2F%2Fhfpug.org%2Fevent%2Focaml-cafe-introduction-to-dune-and-open-forum%2F%29&location=Zoom&trp=false&sprop=website:https://hfpug.org&ctz=America%2FChicago>

[iCal]
<https://hfpug.org/event/ocaml-cafe-introduction-to-dune-and-open-forum/?ical=1>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-07-06 12:33 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-07-06 12:33 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of June 29 to July
06, 2021.

Table of Contents
─────────────────

LibreRef - LablGtk-based Digital Reference Tool Application
u2f - universal second factor
Reproducible OPAM packages / MirageOS
Dune 2.9.0
Hardcaml MIPS CPU Learning Project and Blog
dune-release 1.5.0
anders 0.7.1
Old CWN


LibreRef - LablGtk-based Digital Reference Tool Application
═══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-libreref-lablgtk-based-digital-reference-tool-application/8077/1>


Kiran Gopinathan announced
──────────────────────────

  I'm not sure if this is that close to the typical uses of OCaml, but
  posting this here just in case anyone was interested in another
  end-user facing application using LablGtk.

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/b/b72b4bd7838e41dbaed2254350799c5e75245a3d_2_250x250.png>

        LibreRef is a free as in freedom digital referencing tool
        for artists.

  It's written in OCaml using LablGtk and Cairo to implement the GUI.

  You can find the source code at: [gitlab] ([github mirror])

  A picture is worth a thousand words, so before I continue, here are a
  few examples of it in action:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/1/126997c61b83b700feac41e380b42c560bdf2340.gif>

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/4/49b11ef943e491ba220332d257bc6a15b506ed6b.gif>

  Overall, getting LablGtk to work was fairly straightforward, although
  the documentation was a bit lacking (although the same might be said
  of Gtk itself).

  I was able to piece together the correct uses of most of the API calls
  by relying on either the examples from the repository or by
  translating snippets of code from online back into LablGtk.

  As for deploying it as an application, I found the AppImage &
  LinuxDeploy toolchain to work well with the resulting binary
  (admittedly I've only tested it with two devices so far), and it meant
  that I could publish the program without having to ask people to setup
  the full OCaml & Opam toolchain, which would probably be a large ask.

  As for the implementation, I think it was fairly elegant (if I say so
  myself :slight_smile:), although I may have gone overboard with
  functors (see this higher-order functor in the GUI interface:
  <https://gitlab.com/gopiandcode/libre-ref/-/blob/master/gui.mli#L175>)
  and some aspects of the separation of concerns weren't so well
  established.


[gitlab] <https://gitlab.com/gopiandcode/libre-ref>

[github mirror] <https://github.com/Gopiandcode/LibreRef>


u2f - universal second factor
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-u2f-universal-second-factor/8078/1>


Hannes Mehnert announced
────────────────────────

  it is our pleasure to announce the just released opam package u2f,
  which is a server side implementation of the FIDO standard for
  two-factor authentication using a special device (yubikey etc.). The
  device does challenge-response authentication with the server using
  public key cryptography.

  The implementation is stateless and does not use a specific IO
  library, but only achieves the logic for constructing a registration
  request, verifying a response thereof, and authorization requests with
  responses thereof. Please have a look at
  <https://github.com/roburio/u2f> if you're interested. It is licensed
  under the permissive 2-clause BSD license.

  We use this library in an example server (in the `bin' directory) that
  uses dream. The live server is online at <https://u2f-demo.robur.coop>
  – please let us know if you run into any trouble, or open an issue on
  the GitHub repository.

  One question though: we're unable to generate the documentation from
  the mli – already asked on discord with no result. Anyone with a
  better understanding of odoc etc. can take a look why `dune build
  @doc' outputs a nearly empty file? Thanks a lot :)

  The development was sponsored by skolem.tech.


Reproducible OPAM packages / MirageOS
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/reproducible-opam-packages-mirageos/8079/1>


Hannes Mehnert announced
────────────────────────

  we are pleased to announce reproducible binary images for MirageOS
  unikernels (see the blog post at
  <https://hannes.robur.coop/Posts/Deploy>). The binaries are located at
  <https://builds.robur.coop> (all components are open source and linked
  from the page).

  Additionally, the required tools to achieve reproducible builds are
  released as binary packages for various operating systems as well on
  the same site. They are used by the infrastructure to run daily builds
  (always with the HEAD of opam-repository to not loose any updates /
  new releases). The custom overlay
  <https://git.robur.io/robur/unikernel-repo> is used that adds some
  development packages.

  Happy to hear your thoughts and feedback here. (Earlier post
  <https://discuss.ocaml.org/t/reproducible-builds-with-ocaml-opam-and-mirageos/4877>)

  This work was funded by the [NGI Pointer] project "Funding The Next
  Generation Ecosystem of Internet Architects".


[NGI Pointer] <https://pointer.ngi.eu>


Dune 2.9.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-9-0/8087/1>


Emilio Jesús Gallego Arias announced
────────────────────────────────────

  Dear all, on behalf of the Dune team I'm pleased to announce the
  release of Dune 2.9.0. This is the last release on the Dune 2.x series
  and could be considered a maintenance release as it mostly consists on
  bug fixes and miscellaneous tweaks and features for sites,
  instrumentation, and mdx support.

  Please find the full list of changes below:
  • Add `(enabled_if ...)' to `(mdx ...)'
    (<https://github.com/ocaml/dune/pull/4434>, @emillon)

  • Add support for instrumentation dependencies
    (<https://github.com/ocaml/dune/pull/4210>, fixes
    <https://github.com/ocaml/dune/issues/3983>, @nojb)

  • Add the possibility to use `locks' with the cram tests stanza
    (<https://github.com/ocaml/dune/pull/4480>, @voodoos)

  • Allow to set up merlin in a variant of the default context
    (<https://github.com/ocaml/dune/pull/4145>, @TheLortex, @voodoos)

  • Add `(package ...)' to `(mdx ...)'
    (<https://github.com/ocaml/dune/pull/4691>, fixes
    <https://github.com/ocaml/dune/issues/3756>, @emillon)

  • Handle renaming of `coq.kernel' library to `coq-core.kernel' in Coq
    8.14 (<https://github.com/ocaml/dune/pull/4713>, @proux01)

  • Fix generation of merlin configuration when using `(include_subdirs
    unqualified)' on Windows (<https://github.com/ocaml/dune/pull/4745>,
    @nojb)

  • Fix bug for the install of Coq native files when using
    `(include_subdirs qualified)'
    (<https://github.com/ocaml/dune/pull/4753>, @ejgallego)

  • Allow users to specify install target directories for `doc' and
    `etc' sections. We add new options `--docdir' and `--etcdir' to both
    Dune's configure and `dune install'
    command. (<https://github.com/ocaml/dune/pull/4744>, fixes
    <https://github.com/ocaml/dune/issues/4723>, @ejgallego, thanks to
    @JasonGross for reporting this issue)

  • Fix issue where Dune would ignore `(env ... (coq (flags ...)))'
    declarations appearing in `dune' files
    (<https://github.com/ocaml/dune/pull/4749>, fixes
    <https://github.com/ocaml/dune/issues/4566>, @ejgallego @rgrinberg)

  • Disable some warnings on Coq 8.14 and `(lang coq (>= 0.3))' due to
    the rework of the Coq "native" compilation system
    (<https://github.com/ocaml/dune/pull/4760>, @ejgallego)

  • Fix a bug where instrumentation flags would be added even if the
    instrumentatation was disabled (@nojb,
    <https://github.com/ocaml/dune/pull/4770>)

  • Fix <https://github.com/ocaml/dune/issues/4682>: option `-p' takes
    now precedence on environement variable `DUNE_PROFILE'
    (<https://github.com/ocaml/dune/pull/4730>,
    <https://github.com/ocaml/dune/pull/4774>, @bobot, reported by
    @dra27 <https://github.com/ocaml/dune/issues/4632>)

  • Fix installation with opam of package with dune sites. The
    `.install' file is now produced by a local `dune install' during the
    build phase (<https://github.com/ocaml/dune/pull/4730>,
    <https://github.com/ocaml/dune/pull/4645>, @bobot, reported by
    @kit-ty-kate <https://github.com/ocaml/dune/issues/4198>)

  • Fix multiple issues in the sites feature
    (<https://github.com/ocaml/dune/pull/4730>,
    <https://github.com/ocaml/dune/pull/4645> @bobot, reported by
    @Lelio-Brun <https://github.com/ocaml/dune/issues/4219>, by @Kakadu
    <https://github.com/ocaml/dune/issues/4325>, by @toots
    <https://github.com/ocaml/dune/issues/4415>)


Hardcaml MIPS CPU Learning Project and Blog
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/hardcaml-mips-cpu-learning-project-and-blog/8088/1>


"Alexander (Sasha) Skvortsov announced
──────────────────────────────────────

  Tl;dr: I’m [writing a blog] about making a MIPS CPU in Hardcaml.

  Hi! My name is Sasha, and I’m a student at Penn State majoring in CS
  and Math. Last semester, I took a computer engineering class where we
  built a pipelined MIPS CPU in Verilog as a semester-long project. I
  enjoyed the class, but a lot of frustration came from Verilog itself.

  A few months ago, I came across the [Signals and Threads Programmable
  Hardware episode]. I really liked the idea of [Hardcaml]: a library to
  write and test hardware designs in OCaml. Representing circuits as
  functions felt like a good abstraction, and I’ve been wanting to learn
  OCaml for a while.

  So this summer, a friend and I are rewriting the Verilog MIPS CPU we
  made last semester into Hardcaml.  We’re still working on the project,
  but have made some good progress and wanted to share it in case anyone
  finds it interesting / useful. If anyone wants to take a look, it’s
  [up on GitHub].

  We’ve written some blog posts about our project:

  1. [Some more background on what we’re doing and why]
  2. [An ELI5 overview of how hardware, and pipelined CPUs in
     particular, work]
  3. [Another high-level overview of Verilog, hardware design, FPGAs,
     and why I think OCaml might be a great fit for hardware design]
  4. [How to set up a Hardcaml project, including testing and Verilog
     generation]
  5. [How to split Hardcaml circuits into multiple modules]

  There’s also a few more that we’ve written code for, but are still
  drafting blog posts about:

  • How to work with memory in Hardcaml
  • How to design stateful, sequential circuits in Hardcaml
  • A safer design pattern for Hardcaml circuits

  I’m new to both OCaml and blogging, and this has definitely been a fun
  experience so far! Would love to hear any feedback / comments.


[writing a blog] <https://ceramichacker.com/>

[Signals and Threads Programmable Hardware episode]
<https://signalsandthreads.com/programmable-hardware/>

[Hardcaml] <https://github.com/janestreet/hardcaml>

[up on GitHub] <https://github.com/askvortsov1/hardcaml-mips>

[Some more background on what we’re doing and why]
<https://ceramichacker.com/blog/1-1x-hardcaml-mips-intro-what-and-why>

[An ELI5 overview of how hardware, and pipelined CPUs in particular,
work]
<https://ceramichacker.com/blog/2-2x-a-bit-on-computers-hardware-and-cpus>

[Another high-level overview of Verilog, hardware design, FPGAs, and why
I think OCaml might be a great fit for hardware design]
<https://ceramichacker.com/blog/4-3x-verilog-fpgas-and-why-ocaml>

[How to set up a Hardcaml project, including testing and Verilog
generation]
<https://ceramichacker.com/blog/5-4x-ocaml-setup-hardcaml-basics-and-project-plan>

[How to split Hardcaml circuits into multiple modules]
<https://ceramichacker.com/blog/11-5x-multi-module-circuits-in-hardcaml>


dune-release 1.5.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-release-1-5-0/8095/1>


Nathan Rebours announced
────────────────────────

  On behalf of the dune-release team I'm pleased to announce that we're
  releasing dune-release.1.5.0.

  It has been quite a while since the last release so there are numerous
  changes and improvements in this one, along with a lot of bug fixes.

  The two main new features in 1.5.0 are:
  • A draft release mode that creates a draft Github release and a draft
    PR to opam-repository. It comes with an `undraft' command that will
    undraft both and update the opam file's `url.src' field
    accordingly. We believe this feature will prove helpful to
    maintainers of tools such as `dune' which releases are often watched
    by distribution maintainers. Draft releases allow you to wait until
    you have opam-repository's CI approval to actually create a GH
    release that will notify anyone watching the repository. This
    feature is still a bit experimental, we have ideas on how to improve
    it but we wanted to get a first version out to collect feedback on
    how it is used and what you folks expect from it.
  • A `check' command that you can run ahead of a release to know if
    dune-release has all the information it needs in the repository,
    along with running the lint, build and test checks it normally runs
    after building the tarball. We're aware that it can be frustrating
    to see dune-release fail right in the middle of the release
    process. We're trying to improve this situation and this is a first
    step in that direction.

  You can see the full changelog [here]

  You'll note we also deprecated a few features such as delegates (as we
  announced in [this post]), opam 1.x and the `--user' option and
  corresponding config file field.  This release is likely to be the
  last 1.x release of `dune-release' except for important bug fixes as
  we'll start working on 2.0 soon.

  Our main goals for 2.0 are to make the experience for github users as
  seemless as possible. We want the tool to do the right thing for those
  users without them having to configure anything. Delegates got in the
  way there and that's why we're removing them.  We do care about our
  non github users and we've worked on making it as configurable as
  possible so that you can integrate it in your release workflow. The
  situation should already have improved quite a bit with this release
  as we fixed several bugs for non github hosted repositories. We want
  to make sure that these users will be happy with dune-release 2.0 as
  well.  Hopefully in the future dune-release will support other release
  workflows such as handling gitlab hosted repositories but we want to
  make sure our main user base is happy with the tool before adding
  this.

  We'll communicate a bit more on our plans for 2.0 in the next few
  months. Our hope is that it will hit opam before the end of this year.

  We hope that you'll like this new version and wish you all successful
  and happy releases!


[here] <https://github.com/ocamllabs/dune-release/releases/tag/1.5.0>

[this post]
<https://discuss.ocaml.org/t/replacing-dune-release-delegates/4767>


anders 0.7.1
════════════

  Archive: <https://discuss.ocaml.org/t/ann-anders-0-7-1/8098/1>


Namdak Tonpa announced
──────────────────────

  The HTS language proposed by Voevodsky exposes two different presheaf
  models of type theory: the inner one is homotopy type system presheaf
  that models HoTT and the outer one is traditional Martin-Löf type
  system presheaf that models set theory with UIP. The motivation behind
  this doubling is to have an ability to express semisemplicial
  types. Theoretical work on merging meta-theoretical and homotopical
  languages was continued in [2LTT] [Anenkov, Capriotti, Kraus,
  Sattler].

  While we are on our road to HTS with Lean-like tactic language,
  currently we are at the stage of regular cubical (HoTT) type checker
  with CHM-style primitives, or more general CCHM type checker. You may
  try it at Github: [groupoid/anders].

  ┌────
  │ $ opam install anders
  │ $ anders
  │ Anders theorem prover [PTS][MLTT][CCHM-4][HTS].
  │ 
  │    invoke = anders | anders list
  │      list = [] | command list
  │   command = check filename     | lex filename
  │           | parse filename     | help
  │           | cubicaltt filename | girard
  │           | trace
  └────

  Anders is idiomatic and educational. We carefully draw the favourite
  Lean-compatible syntax to fit 130 LOC in Menhir, the MLTT core (based
  on Mini-TT) is 500 LOC and pretypes presheaf is another 500 LOC.


[2LTT] <https://arxiv.org/pdf/1705.03307.pdf>

[groupoid/anders] <https://github.com/groupoid/anders>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-06-29 12:24 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-06-29 12:24 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of June 22 to 29,
2021.

Table of Contents
─────────────────

wasicaml - a code emitter for OCaml targeting WebAssembly
opam 2.1.0~rc2
Set up OCaml 2.0.0-beta2
Any OCaml bindings to Apache Arrow?
Compiler engineer for OCaml and WebAssembly, Germany
v3.0.0 release of reparse, reparse-lwt, reparse-lwt-unix
Progress 0.2.0
http-multipart-formdata v2.0.0
Old CWN


wasicaml - a code emitter for OCaml targeting WebAssembly
═════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-06/msg00017.html>


Gerd Stolpmann announced
────────────────────────

  I'd like to announce a new project to develop a code generator that
  emits WebAssembly:

  <https://github.com/remixlabs/wasicaml>

  With the support of RemixLabs I could already create a very first
  version that takes the OCaml bytecode as input and translates it to
  WebAssembly.  While this approach probably doesn't lead to the fastest
  code, it is easy to accomplish, and it demonstrates the challenge (and
  already shows how to solve many of the part problems along the road).

  To be precisely, the target of the translator is wasm32-unknown-wasi,
  i.e.  the WASI ABI. This ABI is still in early development, but
  provides already the syscalls (or better, host calls) to access files,
  to get the current time, and to read the environment. This is almost
  enough to run a compiler - I only had to add system() so that ocamlc
  can start external preprocessors.  Also, due to the fact that the
  current wasm implementations still lack exception handling, I had to
  assume the presence of a host emulation of exceptions (which is easy
  to provide if the host environment is Javascript, but not necessarily
  for other environments).

  The translator takes the OCaml bytecode as input, i.e. you first
  create an excecutable

  ┌────
  │ $ ocamlc -o myexec ...
  └────

  and then make wasm out of it:

  ┌────
  │ $ wasicaml -o myexec.wasm myexec
  └────

  If you omit the .wasm suffix, wasicaml will put a preamble in front of
  the wasm code that starts the execution:

  ┌────
  │ $ wasicaml -o myexec_wasm myexec
  │ $ ./myexec_wasm
  └────

  Because of this trick, many problems of cross-compiling can be
  avoided.

  You may ask what the benefits of yet another "Web" language are. We
  already have two emitters targeting Javascript - isn't that enough?
  Well, two answers here.

  First, WASI is a proper LLVM target. Because of this, you can link
  code from other languages with your executable (e.g. C or Rust). So
  you are not limited to OCaml but can use any language that also
  targets the WASI ABI. E.g. you can do

  ┌────
  │ $ wasicaml -o myexec.wasm myexec -ccopt -lfoo
  └────

  to also link in libfoo.a (which must also be compiled to wasm). So it
  is multi-lingual from the beginning.

  Second, WebAssembly can be used outside the web, too. WASI targets
  more the command-line, and server plugins, and generally any
  OS-independent environments. For example, imagine you have an Electron
  app with a great UI, but for some special functionality you need to
  include some OCaml code, too. You don't want to give up the
  OS-independence, and WASI gives you now a natural option to add the
  OCaml code. And you still have access to the filesystem without
  hassle. - Another example is edge computing, i.e. when the cloud is
  extended by computers outside the data center, and the code should be
  in a form so that it can be run on as many platforms as possible. -
  All in all, WASI plays well when you need to combine OS-independence
  with a classic way of organizing the code as command or as server
  function, and you also need predictable performance.

  The challenge of translating OCaml to wasm is mainly the garbage
  collector.  Wasm doesn't permit many of the tricks ocamlopt is using
  to know in which memory (or register) locations OCaml values are
  stored. In wasm, there are no registers but the closest vehicle are
  local variables. Now, it is not possible to scan these variables from
  the GC function, making it practically impossible to put OCaml values
  there while a function is called that might trigger a GC. There is
  also no really cheap way of obtaining a stack descriptor.

  Wasicaml inherits the stack from the bytecode interpreter and uses it
  as its own shadow stack for OCaml values. As wasicaml bases on the
  bytecode representation of the code, the bytecode instructions already
  ensure that values always live in this stack when the GC might
  run. Wasicaml additionally tries to identify values that don't need
  this special treatment (like ints and bools) and that are preferably
  stored in local variables, giving the wasm executor freedom to put
  these into registers or other high-speed locations. (Unfortunately,
  most of the type information is already erased in the bytecode, and
  this is definitely one of the deficiencies of the bytecode approach.)

  In order to maximize the performance, it is probably best to avoid the
  stack whenever possible. The current approach of transforming the
  bytecode hasn't brought to an end yet with respect to such
  optimizations. For example, there could be more analyses that figure
  out when GC runs are actually possible and when it is safe to use
  local variables.

  Another problem of the bytecode basis is that all function calls are
  indirect, preventing the wasm executor from inlining functions.

  As a project, I'd like to see wasicaml progressing in two directions.
  First, make the current approach as good as possible - although basing
  it on the bytecode representation has its downsides, it is easy to
  understand and it is possible to figure out what the necessary
  ingredients for fast code are. Second, get an idea where a possible
  real wasm backend would fit into the OCaml compiler (maybe it is c–
  but maybe this doesn't give us much and you start better with lambda).

  Anyway, welcome to the new world of WebAssembly!

  Gerd

  PS. If you are interested in WebAssembly and like to work with me on
  another Wasm port for some time, there is a position:
  <https://www.mixtional.de/recruiting/2021-01/index.html>

  PPS. Wasicaml is a project of Figly, Inc., commonly known as
  RemixLabs, developing a reactive low-code and code collaboration
  platform.  <https://remixlabs.com/>


opam 2.1.0~rc2
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-1-0-rc2/8042/1>


David Allsopp announced
───────────────────────

  The opam team has great pleasure in announcing opam 2.1.0~rc2!

  The focus since beta4 has been preparing for a world with more than
  one released version of opam (i.e.  2.0.x and 2.1.x). The release
  candidate extends CLI versioning further and, under the hood, includes
  a big change to the opam root format which allows new versions of opam
  to indicate that the root may still be read by older versions of the
  opam libraries. A plugin compiled against the 2.0.9 opam libraries
  will therefore be able to read information about an opam 2.1 root
  (plugins and tools compiled against 2.0.8 are unable to load opam
  2.1.0 roots).

  Please do take this release candidate for a spin! It is available in
  the Docker images at ocaml/opam on [Docker Hub] as the opam-2.1
  command (or you can `sudo ln -f /usr/bin/opam-2.1 /usr/bin/opam' in
  your `Dockerfile' to switch to it permanently). The release candidate
  can also be tested via our installation script (see the [wiki] for
  more information).

  Thank you to anyone who noticed the unannounced first release
  candidate and tried it out. Between tagging and what would have been
  announcing it, we discovered an issue with upgrading local switches
  from earlier alpha/beta releases, and so fixed that for this second
  release candidate.

  Assuming no showstoppers, we plan to release opam 2.1.0 next week. The
  improvements made in 2.1.0 will allow for a much faster release cycle,
  and we look forward to posting about the 2.2.0 plans soon!


[Docker Hub] <https://hub.docker.com/r/ocaml/opam/tags>

[wiki]
<https://github.com/ocaml/opam/wiki/How-to-test-an-opam-feature#from-a-tagged-release-including-pre-releases>


Set up OCaml 2.0.0-beta2
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta2/8046/1>


Sora Morimoto announced
───────────────────────

  This release includes changes to address a corner case primarily
  related to multicore OCaml.

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-beta2>


Any OCaml bindings to Apache Arrow?
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/any-ocaml-bindings-to-apache-arrow/8047/2>


UnixJunkie asked and Laurent Mazare announced
─────────────────────────────────────────────

        Looks interesting:

        <https://arrow.apache.org/>

        <https://arrow.apache.org/overview/>

  I've put together some simple [ocaml-arrow] library. It works
  reasonably well and is quite battle tested but definitely needs a bit
  of cleanup as the bits under src/ are deprecated in favor of the ones
  under c_api/. There is also a ppx to automatically convert ocaml
  records to/from arrow. Some examples using this can be seen in the
  [tests directory].

  If there is some interest, I can certainly push up on cleaning this
  and make an actual opam package.


[ocaml-arrow] <https://github.com/LaurentMazare/ocaml-arrow>

[tests directory]
<https://github.com/LaurentMazare/ocaml-arrow/blob/master/c_api/tests/ppx.ml>


Compiler engineer for OCaml and WebAssembly, Germany
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/compiler-engineer-for-ocaml-and-webassembly-germany/8053/1>


Gerd Stolpmann announced
────────────────────────

  We are developing a compiler for a no-code platform that translates
  our DSL to bytecode and/or WebAssembly. The language is largely of
  functional type but is also able to manage state with a spreadsheet
  model, allowing reactive programming without having to resort to
  libraries. The language is statically typed using a Hindley-Milner
  type checker. The compiler is primarily written in OCaml. Other
  languages of our platform are Go, C, Elm, and Javascript.

  We are looking for a compiler engineer with skills in code generation
  for WebAssembly:

  • Translation of an intermediate representation to WebAssembly
  • Writing runtimes and SDKs targeting WebAssembly
  • Code optimization

  See the full ad here:
  <https://www.mixtional.de/recruiting/2021-01/index.html>


v3.0.0 release of reparse, reparse-lwt, reparse-lwt-unix
════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-v3-0-0-release-of-reparse-reparse-lwt-reparse-lwt-unix/8058/1>


Bikal Lem announced
───────────────────

  I am happy to announce v3.0.0 of `reparse' - an OCaml library for
  constructing various types of parsers in OCaml.

  The release follows a complete overhaul of the internal working of the
  library to achieve the following goals:

  1. Allow construction of efficient, zero-copy parsers. See [String
     parser for example]. The library provides a [Make functor]
     parametrised over a `Promise' and a `Input' type allowing you
     control over both parser memory allocation and copying.

  2. Support usage of async libraries - lwt and async. Following the
     first point the library can now be used together with `lwt' and/or
     `async'. A lwt parse - for example - can now be used seamlessly
     with your other lwt code. The integration is seamless.

  3. Provide `Make_buffered' functor to produce parsers where the input
     type natively doesn't allow random read, for example sockets, lwt
     streams and channels. There is now two new supporting packages
     `reparse-lwt' which provides parsing from `char Lwt_stream.t'
     input type and `reparse-lwt-unix' which provides parsing from
     `Lwt_unix.file_descr' and ~Lwt_unix.input_channel' respectively.

  4. Provide `Make_unbuffered' functor to produce parsers where the
     input type natively supports random read, for example strings,
     bigstrings, bytes.

  5. Introduce function `unsafe_any_char' to allow efficient
     (zero-copy?) parsing.

  6. Prune dependencies by removing `base'.

  P.S. The documentation is bit behind in this release so please bear
  with me while work through the issues in the coming days.

  [Reparse repo]


[String parser for example]
<https://github.com/lemaetech/reparse/blob/master/lib/reparse.mli#L1237>

[Make functor]
<https://github.com/lemaetech/reparse/blob/master/lib/reparse.mli#L1230>

[Reparse repo]
<https://github.com/lemaetech/reparse/blob/master/lib/reparse.ml>


Progress 0.2.0
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-progress-0-2-0/8063/1>


Craig Ferguson announced
────────────────────────

  I'm pleased to announce the 0.2.0 release of [`Progress'], now
  available via Opam.

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/7/727d878b6d17f3c48e6946f4df424bcc59938da3.png>

  `Progress' is an OCaml library for defining and using progress
  bars. It has the following features:

  • allows user-defined progress bar layouts;
  • supports rendering multiple progress bars simultaneously;
  • dynamically responds to changes in terminal size;
  • supports interleaving logging with progress bar rendering.

  This second release contains a much-improved DSL for specifying
  progress bars, alongside improvements and extensions to the rendering
  logic. The bars in the screenshot above are defined as follows:

  ┌────
  │ let bar ~color ~total =
  │   let open Progress.Line in
  │   list
  │     [ spinner ~color:(Progress.Color.ansi ~green) ()
  │     ; brackets (elapsed ())
  │     ; bar ~color total
  │     ; bytes
  │     ; parens (const "eta: " ++ eta total)
  │     ]
  └────

  It also comes with more complete [documentation] and many more
  [examples], including:

  • a Cargo-like progress bar w/ logging of intermediate results:

    <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/4/4b148999f7b6029ac0155b049b6a7cf1fa8b40f1_2_1380x500.png>

  • a Yarn-like stack of spinners:

    <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/6/67ccf011a403a4c082829f69d5a609b4c0c23f6e.png>

  • a showcase of various progress bar styles:

    <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/d/d4df4a2df07fd161982243251fbee56d52a4afbf_2_1034x538.png>


  The changelog is [here] and the API documentation is [here]. The
  library is not yet feature-complete, but should still be reasonably
  useful :-) Happy hacking!


[`Progress'] <https://github.com/craigfe/progress>

[documentation]
<https://craigfe.github.io/progress/progress/Progress/index.html>

[examples] <https://github.com/CraigFe/progress/tree/main/examples>

[here]
<https://github.com/CraigFe/progress/blob/0.2.0/CHANGES.md#020-2021-06-26>

[here] <https://craigfe.github.io/progress/progress/Progress/index.html>


http-multipart-formdata v2.0.0
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-http-multipart-formdata-v2-0-0/8064/1>


Bikal Lem announced
───────────────────

  I am pleased to announce v2.0.0 release of
  `http-multpart-formdata'. This release departs from previous in-memory
  representation of http multipart forms to a streaming, memory
  efficient representation. The new streaming mechanism should help when
  processing larg file uploads in your OCaml web applications.

  1. [httpaf sample web app]
  2. [http-multipart-formdata repo]


[httpaf sample web app]
<https://github.com/lemaetech/http-multipart-formdata/blob/master/examples/multipart_httpaf.ml>

[http-multipart-formdata repo]
<https://github.com/lemaetech/http-multipart-formdata>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-06-22  9:04 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-06-22  9:04 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of June 15 to 22,
2021.

Table of Contents
─────────────────

First releases of dirsp-exchange: auditable variant of Signal Protocol and ProScript-to-OCaml translator
Job offer: 3 year research engineer in static analysis of OCaml programs at Inria Rennes
IRC channels available on libera.chat
Set up OCaml 2.0.0-beta
First release of Jsonxt - a set of JSON parsers and writers
mula 0.1.0, ML's radishal Universal Levenshtein Automata library
New release of mlcuddidl, the OCaml interface to the CUDD BDD library
first release of orf: OCaml Random Forests
Old CWN


First releases of dirsp-exchange: auditable variant of Signal Protocol and ProScript-to-OCaml translator
════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-releases-of-dirsp-exchange-auditable-variant-of-signal-protocol-and-proscript-to-ocaml-translator/8008/1>


jbeckford announced
───────────────────

  I'm pleased to announce the first release of [dirsp-exchange],
  available today from the Opam repositories.

  The intent of the *[dirsp]* libraries is to provide software engineers
  with auditable source code that has some level of safety assurance
  (typically proofs) from security researchers.

  The first libraries are:

  • dirsp-exchange-kbb2017 0.1.0 - The KBB2017 protocol for securing a
    two-party conversation. Similar to Signal Protocol v3 and Olm
    Cryptographic Ratchet.
  • dirsp-ps2ocaml 0.1.0 - A ProScript to OCaml translator. ProScript is
    an executable subset of JavaScript that can be formally verified.

  and a couple more supporting libraries.

  `dirsp-exchange-kbb2017' has a build process that generates its own
  OCaml code using `dirsp-ps2ocaml' on formally verified ProScript
  source code.

  The canonical example for `dirsp-exchange-kbb2017' is:

  ┌────
  │ module P       = Dirsp_proscript_mirage.Make()
  │ module ED25519 = P.Crypto.ED25519
  │ module K       = Dirsp_exchange_kbb2017.Make(P)
  │ module U       = K.UTIL
  │ 
  │ (* Alice sends a message to Bob *)
  │ let aliceSessionWithBob = T.newSession (* ... supply some keys you create with ED25519 and U ... *) ;;
  │ let aliceToBobSendOutput = T.send
  │   aliceIdentityKey
  │   aliceSessionWithBob
  │   (P.of_string "Hi Bob!")
  │ 
  │ (* Now you can send the output "aliceToBobSendOutput" from Alice to Bob.
  │    Let's switch to Bob's computer. He gets notified of a new message using a notification library of
  │ your choosing, and then does ...  *)
  │ 
  │ let bobSessionWithAlice = T.newSession (* ... supply some keys ... *);;
  │ let bobFromAliceReceiveOutput = T.recv
  │   bobIdentityKey
  │   bobSignedPreKey
  │   bobSessionWithAlice
  │   theEncryptedMessageBobReceivedFromAlice
  │ assert (bobFromAliceReceiveOutput.output.valid)
  │ Format.printf "Bob just received a new message: %s\n"
  │   (bobFromAliceReceiveOutput.plaintext |> P.to_bytes |> Bytes.to_string)
  └────

  These are early releases, especially `dirsp-ps2ocaml'.

  Online docs are at <https://diskuv.github.io/dirsp-exchange>

  Feedback, contributions and downloads are very welcome!


[dirsp-exchange] <https://github.com/diskuv/dirsp-exchange#readme>


Job offer: 3 year research engineer in static analysis of OCaml programs at Inria Rennes
════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-offer-3-year-research-engineer-in-static-analysis-of-ocaml-programs-at-inria-rennes/8012/1>


Benoit Montagu announced
────────────────────────

  as part of a project between Inria and Nomadic Labs, we are offering a
  3 year research engineer position, to work on static analysis for
  OCaml programs.  The position will start in October in the Celtique
  Inria research team, in the vibrant city of Rennes, France.  If you
  are a talented OCaml programmer, if you are interested in static
  analysis, or if you simply want to know more about this project,
  please contact me!

  The detailed job description is here:
  <https://jobs.inria.fr/public/classic/fr/offres/2021-03821>

  Please feel free to transfer this announce to people that you think
  could be interested.


IRC channels available on libera.chat
═════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-06/msg00014.html>


Deep in this thread, Romain Calascibetta announced
──────────────────────────────────────────────────

  Just to let you know that I spent a time to re-implement the IRC
  protocol in OCaml and to deploy a simple MirageOS as a logger to save
  discussions into a Git repository. The bot is currently deployed, the
  explanation is available here:
  <https://github.com/dinosaure/cri/tree/master/unikernel> And used for
  #mirage@irc.libera.chat

  It's a nice example about MirageOS/unikernel and I may deploy one to
  save #ocaml@irc.libera.chat as whitequark already does with her bot.


Set up OCaml 2.0.0-beta
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-beta/8016/1>


Sora Morimoto announced
───────────────────────

  Hopefully, this will be the last release before stable 2.0.0. This
  release allows you to add multiple custom repositories, which enables
  testing with multicore and beta repository.

  ┌────
  │ - name: Use Multicore OCaml
  │   uses: ocaml/setup-ocaml@v2
  │   with:
  │     ocaml-compiler: ocaml-variants.4.12.0+domains+effects
  │     opam-repositories: |
  │       multicore: https://github.com/ocaml-multicore/multicore-opam.git
  │       default: https://github.com/ocaml/opam-repository.git
  └────


First release of Jsonxt - a set of JSON parsers and writers
═══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-jsonxt-a-set-of-json-parsers-and-writers/8018/1>


Stephen Bleazard announced
──────────────────────────

  Jsonxt provides a number of JSON parsers and writers for RFC 8259
  compliant JSON as well as non-standard extensions supported by Yojson.
  Features include
  • RFC 8259 compliant when in strict and basic mode
  • Performance focused especially for files and strings
  • Support for standard and extended JSON tree types:
    • Strict follows a strict interpretation of RFC 8259 with all
      numbers represented as floats.
    • Basic extends the strict type to include convenience types while
      maintaining RFC compliance.  This is compatible with Yojson's
      Basic type
    • Extended adds additional non-standard types including tuples and
      variants and is not RFC compliant. This is compatible with
      Yojson's Safe type
  • A number of different parsers including
    • A standard JSON tree parser for various sources including string,
      file and channel
    • A Stream parser that returns a stream of raw JSON tokens.
    • A monad based parser compatible with async
  • Writers including
    • File and string writers
    • A monad based writer that is compatible with async
    • A stream writer that converts a stream of JSON tokens
  • Support for streaming JSON via the [Stream] module
  • Standard interfaces including Yojson compatibility
  • Support for `ppx_deriving_yojson' and `ppx_yojson_conv' via Yojson
    compatibility

  The package is available via opam, with documentation on [github.io].
  The source can be found at [github/jsonxt]


[Stream] <https://ocaml.org/api/Stream.html>

[github.io]
<https://stevebleazard.github.io/ocaml-jsonxt/jsonxt/index.html>

[github/jsonxt] <https://github.com/stevebleazard/ocaml-jsonxt>


mula 0.1.0, ML's radishal Universal Levenshtein Automata library
════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-mula-0-1-0-mls-radishal-universal-levenshtein-automata-library/8021/1>


Ifaz Kabir announced
────────────────────

  I'm happy to announce the release of my library `mula'. The package
  uses Universal Levenshtein Automata (ULA) to not only check if a word
  is within a certain edit distance of another, but to also output what
  the edit distance is! It uses the automata themselves to calculate
  edit distances. A fun use case for this is that we can feed a set of
  words to the automaton and immediately rank the words by their edit
  distance.

  `Mula' supports both the standard Levenshtein edit distance as well as
  the Demarau-Levenshtein distance which counts transpositions of two
  adjacent characters as a single edit. I also support getting live
  error counts, so you can feed part of a string into an automaton, and
  get the minimum number of errors that have occurred so far.

  I currently have matching working using non-deterministic ULA, but I
  have partially started the work toward the deterministic versions. It
  should be possible to pre-compute the DFAs for up to edit distance 3
  and pack it with the library, never needing to be recomputed because
  the Universal Automata are independent of the input strings. But the
  non-deterministic automata support very large edit distances:
  (Sys.int_size - 1)/2, so they have value on their own.

  This library came about from a desire to add a "did you mean" feature
  to a toy compiler, but not wanting to write the kind of dynamic
  programming code that you can find in the OCaml compiler [1] or
  merlin/spelll [2,3].

  You can find the library [here] and the documentation [here].  It's
  not on `opam' yet, but I have submitted a [pull request].

  Happy OCamling!

  References:
  1. Edit distance in the OCaml
     compiler. <https://github.com/ocaml/ocaml/blob/e5e9c5fed56efdd67601e4dbbaebeb134aee361c/utils/misc.ml#L516>.
  2. Edit distance in
     merlin. <https://github.com/ocaml/merlin/blob/444f6e000f6b7dc58dac44d6ac096fc0e09894cc/src/utils/misc.ml#L527>
  3. Edit distance in
     spelll. <https://github.com/c-cube/spelll/blob/3da1182256ff2507a0be812f945a7fe1a19adf9b/src/Spelll.ml#L26>


[here] <https://github.com/ifazk/mula/>

[here] <https://ifazk.github.io/mula/mula/index.html>

[pull request] <https://github.com/ocaml/opam-repository/pull/18895>


Ifaz Kabir then added
─────────────────────

Some details:
╌╌╌╌╌╌╌╌╌╌╌╌╌

  I followed the paper by Touzet [1] as much as possible. If you take a
  look at the code, you'll see a a lot of +1's for 1-indexing. This was
  to keep the implementation as close to the paper as possible! (If you
  do want to check the implementation against the paper, note that the
  paper has a typo in Definition 2). For the Demarau-Levenshtein
  automaton, I adapted Figure 9 from Mitankin's thesis [2]. I'm
  convinced that my adaptation works, but my adaptation of Touzet's
  subsumption relation for Demarau-Levenshtein might be slightly
  sub-optimal. If you have question about the adaptation, feel free to
  ask!

  `mula' does not completely replace c-cube's `spelll' package. In
  particular I don't support any indexs, etc. But there are some
  interesting differences in the automata they use. (`w' stands for the
  base word here)
  1. The `spelll' package creates the Levenshtein Automaton for a single
     string/word (LA_w), `mula' uses Universal Levenshtein Automata
     (ULA).
  2. `Spelll' computes a DFA from a non-deterministic automaton that
     uses eplison transitions. ULA do not have epsilon transitions, but
     for transitions it looks ahead into the base word `w'. Additionally
     the NFA's states/transitions are computable on the fly, so there is
     no need to store the NFA in memory.
  3. `Spelll''s automata transitions using characters. `mula' computes a
     bitvector from an input character to transition from states to
     states. (Computing the bitvector is where the look ahead comes in).
  4. `Spelll''s automata return `true~/~false', and uses a separate
     function to calculate edit distances. `Mula' uses the automaton
     itself to calculate edit distances, the outputs have type `int
     option'. (LA_w can be modified to support this though!)

  References:
  1. On the Levenshtein Automaton and the Size of the Neighborhood of a
     Word. Hélène Touzet
     <https://hal.archives-ouvertes.fr/hal-01360482/file/LATA2016.pdf>
  2. Universal Levenstein Automata: Building and Properties. Petar
     Nikolaev
     Mitankin. <https://store.fmi.uni-sofia.bg/fmi/logic/theses/mitankin-en.pdf>


New release of mlcuddidl, the OCaml interface to the CUDD BDD library
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-mlcuddidl-the-ocaml-interface-to-the-cudd-bdd-library/8028/1>


nberth announced
────────────────

  I'm pleased to write this first release announcement for the
  [mlcuddidl] package.

  These bindings to the CUDD BDD library were initially written by
  Bertrand Jeannet and have been around as an OPAM package for quite
  some time now.  The source code is now hosted on [framagit].

  This release of version 3.0.7 mostly ports the package to OCaml
  versions ≥ 4.10.


[mlcuddidl] <https://opam.ocaml.org/packages/mlcuddidl>

[framagit] <https://framagit.org/nberth/mlcuddidl>


first release of orf: OCaml Random Forests
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-orf-ocaml-random-forests/8034/1>


UnixJunkie announced
────────────────────

  I finished implementing a classifier and regressor using Random
  Forests (seminal paper:
  <https://link.springer.com/article/10.1023/A:1010933404324>):

  <https://github.com/UnixJunkie/orf>

  Some caveats:
  • this is somewhat slow; especially the classifier (and I don’t know
    so much how to accelerate it; probably two orders of magnitude
    slower than sklearn).
  • this is not super generic (int IntMap sparse features only; i.e. a
    sparse vector of integers represents a sample).

  The package is now available in opam (opam install orf).

  Two interfaces are exposed:

  RFC (for classification)
  <https://github.com/UnixJunkie/orf/blob/master/src/RFC.mli>

  RFR (for regression)
  <https://github.com/UnixJunkie/orf/blob/master/src/RFR.mli>

  The test file shows some usage examples:
  <https://github.com/UnixJunkie/orf/blob/master/src/test.ml>

  If you want to help, I tried to flag a few things for the near future:
  <https://github.com/UnixJunkie/orf/issues>

  If you use it and if it is useful to you, I would be happy to know.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-06-01  9:23 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-06-01  9:23 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of May 25 to June 01,
2021.

Table of Contents
─────────────────

Dream — a simple, yet feature-complete Web framework
Ocaml developer at Routine, Paris, Remote OK
Feather 0.2.0
BAP 2.3.0 Release
Building Ahrefs codebase with Melange
Lwt 5.4.1
Other OCaml News
Old CWN


Dream — a simple, yet feature-complete Web framework
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/dream-a-simple-yet-feature-complete-web-framework/7909/1>


Anton Bachin announced
──────────────────────

  I am pleased to announce [*Dream*], a very easy-to-use Web framework
  with high performance, secure defaults, and thorough documentation!

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/3/3384d2a4557f6ab17b585711a47e4f6c90a77652.png>

  It is available now from opam, with `opam install dream'.

  Dream offers:

  • [WebSockets] and [GraphQL].
  • A [template syntax], which you can see in the image above.
  • Trivial [HTTPS and HTTP/2 support], allowing simple deployments
    without a proxy.
  • [Sessions] with pluggable [back ends].
  • Easy [secure cookies] and [CSRF-safe forms].

  …and more, yet Dream sticks to a simple programming model:

  • Web apps are just [bare functions] from requests to responses.
  • [Middlewares] are just higher-order wrapper functions.
  • [Routes] tell the [router] which of these functions to call.

  Indeed, for those who like algebra, there is a certain [structure] to
  Dream. However, that's not the point of this post!

  Dream is meant to be very easy to understand. It sticks to base types,
  introducing only a few types of its own, and uses existing languages,
  such as HTML for templates, and URLs for routes. Dream itself is one
  module in one opam package, which lives in a monorepo. The [docs] are
  on one page.

  Dream is loosely coupled. Even though Dream offers many defaults, it
  is unopinionated, and you can quickly configure or replace
  anything. For example, it is easy to [use TyXML] for templates, and
  Dream happily supports such usage with examples.

  Security-sensitive features, such as cookies, are arranged so that
  simple and obvious usage is automatically secure.  Wherever security
  still depends on the Dream app, the docs [highlight] it. Dream has
  selected a modern [cipher] as a default, supports [key rotation], and
  offers suggestions for other purposes, such as password hashing. It
  implements and abstracts away all of the [OWASP] security guidelines
  that are relevant to its level.

  Dream is designed for full internationalization. It has a centralized
  [error handler] that intercepts even lower-level HTTP errors, so that
  you can decorate them with your app's own error template, and leak no
  hardcoded strings. Dream's URL encoders [favor] internationalized
  (UTF-8) URIs, and the router accepts them.

  Finally, Dream is designed for a wide range of applications, including
  with or without a proxy, standalone or embedded in larger binaries,
  and with external static assets or [assets compiled in].


[*Dream*] <https://github.com/aantron/dream>

[WebSockets]
<https://github.com/aantron/dream/tree/master/example/k-websocket#files>

[GraphQL]
<https://github.com/aantron/dream/tree/master/example/w-graphql-subscription#files>

[template syntax]
<https://github.com/aantron/dream/tree/master/example/7-template#files>

[HTTPS and HTTP/2 support]
<https://github.com/aantron/dream/tree/master/example/l-https#files>

[Sessions]
<https://github.com/aantron/dream/tree/master/example/b-session#files>

[back ends] <https://aantron.github.io/dream/#back-ends>

[secure cookies] <https://aantron.github.io/dream/#cookies>

[CSRF-safe forms] <https://aantron.github.io/dream/#forms>

[bare functions] <https://aantron.github.io/dream/#type-handler>

[Middlewares] <https://aantron.github.io/dream/#type-middleware>

[Routes] <https://aantron.github.io/dream/#type-route>

[router] <https://aantron.github.io/dream/#val-router>

[structure] <https://aantron.github.io/dream/#algebra>

[docs] <https://aantron.github.io/dream/>

[use TyXML]
<https://github.com/aantron/dream/tree/master/example/w-tyxml#files>

[highlight]
<https://github.com/aantron/dream/tree/master/example/7-template#security>

[cipher] <https://aantron.github.io/dream/#cryptography>

[key rotation] <https://aantron.github.io/dream/#servers>

[OWASP] <https://cheatsheetseries.owasp.org/>

[error handler]
<https://github.com/aantron/dream/tree/master/example/9-error#files>

[favor] <https://aantron.github.io/dream/#val-to_percent_encoded>

[assets compiled in]
<https://github.com/aantron/dream/tree/master/example/w-one-binary#files>

Documentation
╌╌╌╌╌╌╌╌╌╌╌╌╌

  Dream is very extensively documented. See…

  • [*Examples*], the first several of which make up a tutorial. Each
    example is a complete project.
  • The online [*playground*], which features many of the examples, and
    is itself a [Dream app]!
  • The [*API docs*].

  In particular, see

  • Deployment examples for [Heroku], Digital Ocean [with Docker], and
    Digital Ocean [with systemd], all of which include GitHub Actions
    scripts and instructions.
  • Full-stack examples with [js_of_ocaml], [ReScript], and [Melange].
  • Examples in [Reason syntax].
  • Development [watching] and [live reloading].


[*Examples*]
<https://github.com/aantron/dream/tree/master/example#readme>

[*playground*] <http://dream.as/ocaml>

[Dream app]
<https://github.com/aantron/dream/tree/master/example/z-playground>

[*API docs*] <https://aantron.github.io/dream/>

[Heroku]
<https://github.com/aantron/dream/tree/master/example/z-heroku#files>

[with Docker]
<https://github.com/aantron/dream/tree/master/example/z-docker-esy#files>

[with systemd]
<https://github.com/aantron/dream/tree/master/example/z-systemd#files>

[js_of_ocaml]
<https://github.com/aantron/dream/tree/master/example/w-fullstack-jsoo#files>

[ReScript]
<https://github.com/aantron/dream/tree/master/example/w-fullstack-rescript#files>

[Melange]
<https://github.com/aantron/dream/tree/master/example/r-fullstack-melange#files>

[Reason syntax]
<https://github.com/aantron/dream/tree/master/example#reason>

[watching]
<https://github.com/aantron/dream/tree/master/example/w-fswatch#files>

[live reloading]
<https://github.com/aantron/dream/tree/master/example/w-live-reload#files>


Contributing
╌╌╌╌╌╌╌╌╌╌╌╌

  Dream has already received several very helpful [contributions], and
  more are very welcome! See [`CONTRIBUTING.md']. I must also
  acknowledge all the people working on Dream's [dependecies] and [prior
  art]. In particular, Dream relies heavily on the HTTP and WebSocket
  [servers] primarily by Spiros Eliopoulos (@seliopou) and Antonio Nuno
  Monteiro (@anmonteiro).

  Apart from accepting code, docs, and examples, Dream will happily link
  to:

  • Blogs and articles, as different people learn best from different
    presentations.
  • "Downstream" libraries to use with Dream.

  For example, Thibaut Mattio (@tmattio) is working on
  [dream-livereload], a live-reloading middleware for Dream, similar to
  the [example], which he also contributed! Once dream-livereload is
  slightly more mature, Dream will link to it from its README.

  There is also [dream-serve], a live-reloading static site server based
  on Dream and libuv, which was used to develop the docs.


[contributions] <https://github.com/aantron/dream/graphs/contributors>

[`CONTRIBUTING.md']
<https://github.com/aantron/dream/blob/master/docs/CONTRIBUTING.md>

[dependecies]
<https://github.com/aantron/dream/blob/b79b06dd6add32beba6eee6864ce99413634b7b3/dream.opam#L49-L111>

[prior art] <https://github.com/aantron/dream#acknowledgements>

[servers]
<https://github.com/aantron/dream/tree/b79b06dd6add32beba6eee6864ce99413634b7b3/src/vendor>

[dream-livereload] <https://github.com/tmattio/dream-livereload>

[example]
<https://github.com/aantron/dream/tree/master/example/w-live-reload#files>

[dream-serve] <https://github.com/aantron/dream-serve>


Roadmap
╌╌╌╌╌╌╌

  Dream is currently in an alpha state. It is thought (by me) to be
  internally quite stable. However, there will probably be various API
  tweaks before release 1.0.0.

  My current, rough plan is to release several alphas of Dream over six
  months or so. The releases will address:

  1. Flow control for very large responses, and getting the "advanced"
     part of the I/O API to be as close to zero-copy and non-allocating
     as possible (or reasonable).
  2. Remaining (optional) [security enhancements], such as a [default
     content security policy].
  3. Remaining [session improvements], such as re-keying.
  4. Friction in handling of JSON, database access, etc. This is not
     properly part of or due to Dream, but it should be addressed for a
     better Web development experience.
  5. Multicore and effects support.

  That's all. Let's bring OCaml to the Web! Happy Web programming!


  <https://github.com/aantron/dream>


[security enhancements]
<https://github.com/aantron/dream/issues?q=is%3Aissue+is%3Aopen+label%3Asecurity>

[default content security policy]
<https://github.com/aantron/dream/issues/48>

[session improvements] <https://github.com/aantron/dream/issues/13>


Anton Bachin then added
───────────────────────

  For readers who saw the repo during the earlier ["leak,"] the main
  updates are:

  • A large number of new examples, including [deployment].
  • The [playground], which runs the examples, and itself served as a
    test.
  • An esy-based [quick start] script.

  There have also been very many smaller changes to the code, API, and
  the rest of the docs, but the above changes are the biggest "chunks."
  The rest is too much to detail :)


["leak,"] <https://discuss.ocaml.org/t/7605>

[deployment]
<https://github.com/aantron/dream/tree/master/example#deploying>

[playground] <http://dream.as>

[quick start] <https://github.com/aantron/dream#quick-start>


Ivan Gotovchits asked and Anton Bachin replied
──────────────────────────────────────────────

        I was always wondering how does the source code that uses
        [templates] work with OCaml tooling, in particular with
        merlin, ocp-indent, ocaml-format, tuareg and other editor
        modes?

  It doesn't work well in practice with anything other than syntax
  highlighting. Note that you control the syntax mode with the
  extension. If your template is mostly HTML, you can name it
  `foo.eml.html'.

  The intent is that the templates should contain mostly HTML in a large
  project, and most of them would be in their own `template/'
  subdirectory. OCaml tooling wouldn't be needed for these mostly-HTML
  files. For a still-small, but real example of this, see the
  Playground's [`client.eml.html'].

  The one-file `.ml' projects with templates, where tooling is a
  problem, are mostly good for the very first steps of getting started,
  and examples.

  There is also an issue about this in the repo, [#55 " how to apply
  ocamlformat"].

  Note that, as in the announcement text, you can use Dream with other
  templaters, including [TyXML], which has an [HTML PPX]. In addition,
  if you are using Reason, you can use [TyXML JSX]. Either of these
  options interacts well with tooling, as far as I know.

  I didn't make TyXML the default because it considerably increases the
  Dream learning curve for getting basic tasks done. However, Dream
  still supports the choice of using TyXML with examples and links.


[templates] <https://aantron.github.io/dream/#templates>

[`client.eml.html']
<https://github.com/aantron/dream/blob/fa20aebf36307a07b59c9ea018c25e508415d91a/example/z-playground/client/client.eml.html>

[#55 " how to apply ocamlformat"]
<https://github.com/aantron/dream/issues/55>

[TyXML]
<https://github.com/aantron/dream/tree/master/example/w-tyxml#files>

[HTML PPX]
<https://github.com/aantron/dream/tree/master/example/w-tyxml#html-syntax>

[TyXML JSX]
<https://github.com/aantron/dream/tree/master/example/r-tyxml#files>


Ocaml developer at Routine, Paris, Remote OK
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-ocaml-developer-at-routine-paris-remote-ok/7911/1>


mefyl announced
───────────────

  Routine (<https://routine.co>) is looking for an OCaml developer.

  Routine is a personal productivity assistant. The technological
  revolves heavily around OCaml which represents 90% of the codebase,
  the remaining 10% being the UI in Typescript and Vue.js. We target
  both the browser and desktop through electron, using Js_of_ocaml.

  While the product is "just" a web app, our technological and academic
  background leads us to use designs that, I think, can pique the
  interest of seasoned Ocaml developer. Amongst other things :

  • Type-driven programming based on ppx derivers that produces
    typescript declaration for frontend bindings, JSON schema to expose
    and consume external REST APIs (Google, Notion, …), automatic SQL
    bindings, etc.
  • Angstrom based parsing for the interactive console with highlighting
    and completion.
  • Incremental based state updates to refresh minimal subsets of the
    app.
  • Highly concurrent implementation through Lwt, exception-free design.

  We use state of the art CI/CD and development processes. We plan on
  distributing open sources packages of these utilities (type-driven
  system, Google API bindings, Notion API bindings, …). Future exciting
  subjects could be extending Angstrom with manual rollback to implement
  generic completions or binding Vue in OCaml directly using melange or
  rescript to achieve rock solid typing down to the very frontend code
  (highly prospective teases, don't quote me on this yet :).

  The company is very much a startup, having just completed YC batch W21
  and closed its first round of investment.  Salary is up to market
  standard depending on the profile, plus usual options package, to be
  discussed.

  While we expect great OCaml and general computer science proficiency,
  we're open to most levels of experience.  Thoroughness and a love for
  well rounded, robust and beautiful software design is a must have -
  but that comes bundled with OCaml love, right ?

  Do not hesitate to reach out for any question here, at
  quentin.hocquet@routine.co or refer this to someone who may be
  interested.

  Thanks for your time and happy camel riding !


Feather 0.2.0
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-feather-0-2-0/7916/1>


Charles announced
─────────────────

  I'm happy to announce feather version 0.2.0! Feather is a minimal
  library for bash-like scripting and process execution.  ([github],
  [opam])

  This release fixes some bugs and adds three new functions

  • `val and_ : cmd -> cmd -> cmd' — chain two commands, short
    circuiting if the first fails, akin to bash's `&&' operator.
  • `val or_ : cmd -> cmd -> cmd' — chain two commands, short circuiting
    if the first succeeds, akin to bash's `||' operator.
  • `val sequence : cmd -> cmd -> cmd' — chain two commands regardless
    of exit status.

  We include two new operators `&&.' and `||.' which correspond to
  `and_' and `or_' respectively. They'll be found in the `Feather.Infix'
  module, which has been renamed from `Feather.File_redirection_infix'.

  Many thanks to new contributors @Firobe @juxd and @tmarti2 for making
  this release possible!


[github] <https://github.com/charlesetc/feather>

[opam] <https://opam.ocaml.org/packages/feather/>


BAP 2.3.0 Release
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-bap-2-3-0-release/7926/1>


Ivan Gotovchits announced
─────────────────────────

  We're proud to release the next stable version of Carnegie Mellon
  University Binary Analysis Platform ([BAP]). The full list of changes
  can be found on the [release page] but the most interesting new
  features are highlighted below.


[BAP] <https://github.com/BinaryAnalysisPlatform/bap>

[release page]
<https://github.com/BinaryAnalysisPlatform/bap/releases/tag/v2.3.0>

The Primus Lisp Frontend
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Now BAP is able to understand not only binary programs but sources
  written in Primus Lisp. In case if you don't know, [Primus Lisp] is
  our DSL for writing analysis and library stubs (e.g., to specify
  semantics of missing library functions). Now, it is possible to reify
  Primus Lisp programs into static representation. For example, we can
  translate the following Lisp program

  ┌────
  │ ;; file demo.lisp
  │ 
  │ (defun example1 (x)
  │   (set R0 1)
  │   (set R1 2)
  │   (set R3 (+ R1 R2 (* R1 R2 3)))
  │   (memory-write R4 (+ R3 R1))
  │   (if (> R0 (* R0 R0))
  │       (exec-addr 0xDEADBEEF)
  │     (set R0 (* R0 R2 R3))))
  └────

  into the BIL (BAP Instruction Language) AST and then pretty print it,
  ┌────
  │ $ bap show --primus-lisp-load=demo --target=armv7+le -obap:bil example1
  │ example1:
  │ "{
  │    R0 := 1
  │    R1 := 2
  │    R3 := R1 + R2 + R1 * R2 * 3
  │    mem := mem with [R4] <- low:8[R3 + R1]
  │    #1 := R0 * R0 < R0
  │    if (#1) {
  │      jmp 0xDEADBEEF
  │    }
  │    else {
  │      R0 := R0 * R2 * R3
  │    }
  │  }"
  └────

  This new feature not only allows us to reify our Lisp stubs into
  static form but also enables the main killer feature. It is now
  possible to specify the semantics of machine instructions in Primus
  Lisp. This feature enables rapid development and experimentation with
  CPU semantics. And this brings us to the next new feature.


[Primus Lisp]
<https://binaryanalysisplatform.github.io/bap/api/master/bap-primus/Bap_primus/Std/Primus/Lisp/index.html>


New Target: RISC-V
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The first application of the Primus Lisp Frontend was writing the
  RISC-V semantics. It took me only one day to write the semantic of the
  [minimal subset] of RISC-V instruction. Well, partially it is because
  RISCV-V is truly RISC, like the `add' instruction just adds,

  ┌────
  │ (defun ADDI (dst rm rn)
  │   (set$ dst (+ rm rn)))
  └────


[minimal subset]
<https://github.com/BinaryAnalysisPlatform/bap/pull/1287>


New Target: ARMv8 (Aarch64)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The next target that we tried was Aarch64, the 64-bit ARM
  architecture. It was a little bit [harder] but still definitely more
  readable than the official ARM semantics.


[harder]
<https://github.com/BinaryAnalysisPlatform/bap/blob/master/plugins/arm/semantics/aarch64.lisp>


Adds namespaces (packages) to Primus Lisp
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Since now we have much more code in Primus Lisp we found ourselves
  struggling with name clashes. The Primus Lisp program model is a set
  of mututally recursive overloaded definitions, so naming things is
  crucial for us. Therefore we implemented namespaces (which are,
  following Common Lisp trandition, named packages). We ended up in a
  very Common Lisp look and fill but without inheriting CL problems,
  like the dependency on the order of inclusion and package
  redefinitions, and so on. Given our model, and that Primus Lisp
  features type inference and Haskell-style type classes for
  overloading, it wasn't that easy to implement :)


Adds the `bap dependencies' command
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The [command] outputs program dependencies such as libraries and
  symbols. The information is collected recursively with various output
  options, including dependency graph, YAML, JSON, and SEXP.

  Much like `nm~+~ldd' on steroids and cross-platform (works on
  PE/ELF/COFF, and on binaries that are not native to the host). So it
  could be quite useful even if you're not doing program analysis, but
  just want to solve a nasty missing library feature or figure our what
  programs use what libraries, e.g.,
  ┌────
  │ $ bap dependencies `which ping` --recursive --ldconfig -ograph | graph-easy --as boxart
  │                      ┌────────────────┐
  │                      │ libresolv.so.2 │ ──────────────────────────────────┐
  │                      └────────────────┘                                   │
  │                        ▲                                                  │
  │                        │                                                  │
  │                        │                                                  │
  │ ┌──────────────┐     ┌──────────────────────────┐     ┌────────────────┐  │
  │ │ libidn.so.11 │ ◀── │           ping           │ ──▶ │ libnettle.so.6 │  │
  │ └──────────────┘     └──────────────────────────┘     └────────────────┘  │
  │   │                    │                 │              │                 │
  │   │                    │                 │              │                 │
  │   │                    ▼                 │              │                 │
  │   │                  ┌────────────────┐  │              │                 │
  │   │                  │  libcap.so.2   │  │              │                 │
  │   │                  └────────────────┘  │              │                 │
  │   │                    │                 │              │                 │
  │   │                    │                 │              │                 │
  │   │                    ▼                 ▼              │                 │
  │   │                  ┌──────────────────────────┐       │                 │
  │   └────────────────▶ │        libc.so.6         │ ◀─────┘                 │
  │                      └──────────────────────────┘                         │
  │                        │                      ▲                           │
  │                        │                      └───────────────────────────┘
  │                        ▼
  │                      ┌────────────────┐
  │                      │ ld-linux.so.2  │
  │                      └────────────────┘
  └────


[command] <https://github.com/BinaryAnalysisPlatform/bap/pull/1294>


What's Next?
╌╌╌╌╌╌╌╌╌╌╌╌

  We are working on decompilation and integrating with Ghidra, so in
  2.4.0 you should expect that bap will output C code for binaries. But
  it is not all, we're even working into turning BAP into a program
  analysis framework that enables analysis of source code programs. And
  even crazier, we're working on adding compilation capabilities to BAP,
  i.e., an ability to compile/recompile the input sources. So soon BAP
  will outlive its name, or we will need to find a new interpretation
  for the BAP acronym, something like the Best Analysis Platform ;)

  We also plan to make BAP more available for non-seasoned OCaml users
  and want to push bap into mainstream Linux distributions and overall
  lower the entrance barrier.  Of course, with the end goal to lure
  users into installing opam))


Questions and Suggestions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Please, do not hesitate to ask questions and provide your suggestions
  and, ideally, join our [community]. Even if you don't plan to work on
  binary analysis, BAP offers lots of opportunities for writing your toy
  programs for learning the language, or maybe even student projects.


[community] <https://gitter.im/BinaryAnalysisPlatform/bap>


Building Ahrefs codebase with Melange
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/building-ahrefs-codebase-with-melange/7941/1>


Javier Chávarri announced
─────────────────────────

  At Ahrefs, we make extensive use of OCaml and ReScript —previously
  [known as BuckleScript]. So we have been following the latest
  developments in the ReScript ecosystem with great interest.

  A few months ago, [António Monteiro] released [Melange], a fork of
  ReScript with an emphasis of keeping compatibility with OCaml
  ecosystem. One of the key features of Melange is that it uses OCaml
  4.12, with all the upsides that that entails (ppxlib, let syntax,
  better errors, …). Besides that, Melange has been modeled recently [as
  just a `compiler-libs' library], so it can be integrated with other
  OCaml code in a single opam switch.

  We decided to give Melange a try recently at Ahrefs, and shared the
  results of this experiment in a blog post:

  <https://tech.ahrefs.com/building-ahrefs-codebase-with-melange-9f881f6d022b>

  We are currently looking into how a deeper integration with Dune would
  look like. If your team or company has tried Melange, or is interested
  on doing so, we would be very interested to hear your use cases and
  share experiences.


[known as BuckleScript]
<https://rescript-lang.org/blog/bucklescript-is-rebranding>

[António Monteiro] <https://discuss.ocaml.org/u/anmonteiro/summary>

[Melange] <https://github.com/melange-re/melange>

[as just a `compiler-libs' library]
<https://github.com/melange-re/melange/pull/107>


Lwt 5.4.1
═════════

  Archive: <https://discuss.ocaml.org/t/ann-lwt-5-4-1/7943/1>


Raphaël Proust announced
────────────────────────

  We are glad to announce the release of version 5.4.1 of Lwt: a
  bugfix-only release.

  <https://github.com/ocsigen/lwt/releases/tag/5.4.1>

  You can update to this version in `opam':

  ┌────
  │ opam update
  │ opam upgrade lwt
  └────

  Thanks to the contributors for finding and fixing the bugs, leading to
  this release. Check out the release notes (link above) for a full
  list.


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Beta release of Frama-C 23.0~rc1 (Vanadium)]
  • [Building Ahrefs codebase with Melange]
  • [Computing an integer using a Grothendieck topos]
  • [ ReScript 9.1]
  • [Tutorial: Format Module of OCaml]
  • [Tarides project SCoP is selected as one of the brightest Data
    Portability projects in Europe!]
  • [Alt-Ergo Users’ Club Annual Meeting (2021)]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Beta release of Frama-C 23.0~rc1 (Vanadium)]
<https://frama-c.com/fc-versions/vanadium.html>

[Building Ahrefs codebase with Melange]
<https://tech.ahrefs.com/building-ahrefs-codebase-with-melange-9f881f6d022b>

[Computing an integer using a Grothendieck topos]
<http://math.andrej.com/2021/05/18/computing-an-integer-using-a-sheaf-topos/>

[ ReScript 9.1] <https://rescript-lang.org/blog/release-9-1>

[Tutorial: Format Module of OCaml]
<https://www.ocamlpro.com/2021/05/06/tutorial-format-module-of-ocaml/>

[Tarides project SCoP is selected as one of the brightest Data
Portability projects in Europe!]
<https://tarides.com/blog/2021-04-30-scop-selected-for-dapsi-initiative>

[Alt-Ergo Users’ Club Annual Meeting (2021)]
<https://www.ocamlpro.com/2021/04/29/alt-ergo-users-club-annual-meeting-2021/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-05-25  7:30 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-05-25  7:30 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of May 18 to 25,
2021.

Table of Contents
─────────────────

Applied PL research at Jane Street
IRC channels available on libera.chat
B Trees in Ocaml via Fmlib 0.3.0
GitHub Actions for OCaml: now stable and on the ocaml org
Set up OCaml 2.0.0-alpha
FrontC 4.1.0 (Vingt ans après)
Old CWN


Applied PL research at Jane Street
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-applied-pl-research-at-jane-street/7877/1>


Yaron Minsky announced
──────────────────────

  This isn't exactly news, but we're (still) actively looking to hire
  people to do applied PL research, with a particular focus on
  type-level work. Follow this link if you want to see how to apply.

  <https://blog.janestreet.com/applied-PL-research/>

  Please share it around with anyone who you think might be on the
  market!

  *About the job*

  Part of our ambition is to grow OCaml into a language that does an
  ever better job of being convenient and expressive by default, while
  allowing for the kind of precise control you need when building high
  performance systems, where it's needed.

  That's led us to do research on stack-allocation, unboxed types,
  algebraic effects, type-level resource tracking, and more. We think
  it's an exciting direction for the language, and there's a lot of
  challenging and novel work to be done, and the main thing that could
  speed us up is having more of the right people to work on it!

  Jane Street is an excellent laboratory for this kind of work: big
  enough to have serious and demanding use-cases, but small and nimble
  enough to be able to try out new language features, and then back out
  of them or change them in incompatible ways if need be.

  And all the work we do on the compiler is in the open, with the goal
  of getting the final results into a state where they can be
  upstreamed.

  Also, it's a great team! Full of serious experts who have collectively
  contributed a lot to OCaml and PL research over the years, and also a
  really nice set of people to work with. And I think the team has a
  good balance of the practical and theoretical: working hard to do the
  right thing, but also finding practical ideas that can make forward
  progress in the near term.

  *Who are we looking for*

  We're looking for people with a good balance of theoretical and
  engineering backgrounds, since the work is demanding on both fronts.

  We're happy to hire people at a range of experience levels: people who
  have just finished a post-doc or PhD, up to experienced academics and
  people in industry.

  The team has a presence in New York and London, and we're hiring in
  both offices. No remote work, I'm afraid.


IRC channels available on libera.chat
═════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-05/msg00022.html>


Adrien Nader announced
──────────────────────

  Due to the recent troubles on freenode[1][2], I've connected to
  irc.libera.chat early in order to create and register the same
  channels that I know and take care ofa on freenode (i.e. #ocaml and
  #ocaml-fr).

  I am not stating libera.chat is better than freenode.net although the
  amount of staffers moving makes me think freenode.net will not be
  running fine for a much longer time.

  At the moment I believe it is better to keep both channels running and
  to encourage people to connect on libera.chat too. In the future, I
  might force migration by progressively silencing the channel that
  should be abandoned.

  If you maintain a relay bot, can you please add it on libera.chat too?

  As far as I know, there is no Matrix bridge available currently. It
  seems the discussion/process for bridge additions occurs at [3].

  A good news is that I've gotten the full rights on the channel,
  something which was requiring paperwork on freenode (which I had
  already mentioned but never got around to doing and for which I never
  even remotely got time for).

  [1] <https://lwn.net/Articles/856543/> (this still constantly changes)
  [2]
  <https://en.wikipedia.org/wiki/Freenode#2021_ownership_change_and_conflict>
  [3] <https://github.com/matrix-org/matrix-appservice-irc/issues/208>


B Trees in Ocaml via Fmlib 0.3.0
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/b-trees-in-ocaml-via-fmlib-0-3-0/7880/1>


Hbr announced
─────────────

  I am pleased to announce the release (0.3.0) of fmlib, a functional
  library with managed effects.

  The main new feature of release 0.3.0 are B trees. B trees can be used
  to implement finite sets and finite maps. Fmlib's B trees have
  functionality similar to the modules `Set' and `Map' of the standard
  library.

  The modules `Set' and `Map' of the standard library are based on AVL
  trees. B trees offer the same functionality but have on modern
  processors a better cache performance and have better data locality.

  The current B tree implementation in `Fmlib' implements B trees by
  using arrays which are guaranteed to fit into a cache line. The design
  of B trees is described [here]. The API can be found [here].

  The library `Fmlib' has four main components:

  • [Standard Datatypes]: This component offers some modules from
    `Stdlib' with additional functionality. E.g. `Fmlib_std.Array'
    offers functions to insert elements into arrays, remove elements
    from an array and binary search in a sorted array. It has the
    modules `Result' and `Option' which can be used to avoid exceptions
    and use exceptions in a more structured way. The modules `Result'
    and `Option' in `Fmlib' offer a complete monadic interface and offer
    the `let*' operator to write well readable monadic code.

  • [Pretty Printing]: Print tree like structures in a nice way and use
    the library completely functional. The library does not assume a
    specific IO method. The pretty printer generates a lazy stream of
    characteres which can be written by all io functions.

  • [Combinator Parsing]: Easily parse textual input by the use of
    combinators. The library supports indentation sensitivity and can
    therefore be used to parse yaml files, haskell, python,
    etc. Furthermore no input method is assumed. The generated parsers
    are sink of tokens (or characters). You can choose any input method
    and push the tokens/characters into the parsers. The generated
    parsers are fully incremental. Parser can be stored at any position
    of the input stream and in case of interactive editing, parsing can
    be resumed from any point of the stream.

  • [Interface to Javascript]: This components contains primitives to
    interface to javascript via `js_of_ocaml'.

  `Fmlib' can be installed via opam:

  ┌────
  │ opam update
  │ opam install fmlib
  │ opam install fmlib_std
  │ opam install fmlib_pretty
  │ opam install fmlib_parse
  │ opam install fmlib_js
  └────

  The source code of the library is located at [github]


[here] <https://fmlib_ocaml.readthedocs.io>

[here] <https://hbr.github.io/fmlib/odoc/fmlib_std>

[Standard Datatypes] <https://hbr.github.io/fmlib/odoc/fmlib_std>

[Pretty Printing] <https://hbr.github.io/fmlib/odoc/fmlib_pretty>

[Combinator Parsing] <https://hbr.github.io/fmlib/odoc/fmlib_parse>

[Interface to Javascript] <https://hbr.github.io/fmlib/odoc/fmlib_js>

[github] <https://github.com/hbr/fmlib>


GitHub Actions for OCaml: now stable and on the ocaml org
═════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/github-actions-for-ocaml-now-stable-and-on-the-ocaml-org/7889/1>


Anil Madhavapeddy announced
───────────────────────────

  I [announced a beta] of OCaml/opam support for GitHub Actions back in
  Nov 2019, and the functionality has turned out to be popular. A number
  of projects in our community have been using the Action, and it can be
  found in the [GitHub Marketplace].

  It has been sufficiently popular that it's definitely time to get it
  off my personal GitHub account, and so I have transferred it to its
  new home at <https://github.com/ocaml/setup-ocaml>.  I am also very
  pleased to announce that @smorimoto and @dra27 are also now
  maintainers – they have both made significant improvements to it, and
  @smorimoto in particular has been working with the GitHub ecosystem to
  further improve the efficiency of the Action (such as by adding
  reliable caching).  Thank you to them both and [all the other
  contributors] for your help improving the CI experience around OCaml.

  If anyone else wishes to contribute to improving the action, please do
  get involved on [the issue tracker].  And of course, if you are still
  referencing `avsm/setup-ocaml' in your own workflow definition, this
  is a good time to change it to `ocaml/setup-ocaml'.

  This is probably a good time to note that the other [ci-scripts]
  repository on the ocaml/ GitHub organisation is in sore need of either
  new maintainers (for the Travis CI), or being retired due to lack of
  support (primarily due to the shift to GitHub Actions). I'm immensely
  grateful to Travis CI for the decade of mostly free builds they have
  provided our community to date.


[announced a beta]
<https://discuss.ocaml.org/t/github-actions-for-ocaml-opam-now-available/4745>

[GitHub Marketplace]
<https://github.com/marketplace/actions/set-up-ocaml>

[all the other contributors]
<https://github.com/ocaml/setup-ocaml/graphs/contributors>

[the issue tracker] <https://github.com/ocaml/setup-ocaml/issues>

[ci-scripts] <https://github.com/ocaml/ocaml-ci-scripts>


Set up OCaml 2.0.0-alpha
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-set-up-ocaml-2-0-0-alpha/7895/1>


Sora Morimoto announced
───────────────────────

  This is the announcement of the first alpha release of setup-ocaml
  v2. This includes quite a few changes, including reliable cache, as
  described in a recent [post].

  There are so many changes, so I would like to list only the notable
  changes. (The full changelog can be found at the bottom of the post.)


[post]
<https://discuss.ocaml.org/t/github-actions-for-ocaml-now-stable-and-on-the-ocaml-org/7889>

The "ocaml-version" input is now named "ocaml-compiler"
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This was changed because calling it "OCaml Version" is not appropriate
  enough, e.g. to use the new variant naming convention introduced from
  4.12.


32 bits compiler support
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌


Semver-style version matching support
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  With the naughty exception of `4.02.2' , point releases are meant to
  be strictly compatible, so once OCaml dev team release a new point
  release, upgrading should be a no-brainer. With that in mind, it's
  obviously not smart to rewrite every workflow every time a new point
  release is released, so you can now specify versions in the style like
  `4.12.x'.


Reliable cache feature
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The action supports not only the compiler cache, but also the [dune
  cache]. However, note that it is not available on the macOS runners
  until opam 2.0.9 is released. The dune cache is actually quite
  powerful for large projects, if you're interested in it, check out the
  comparison section of [ocaml/setup-ocaml#66]. The reliable cache
  feature uses the [@actions/cache] package internally, and I worked
  with the GitHub team to make it fast enough for setup-ocaml to be up
  to 4x faster. For the Ubuntu runners, you can set up your environment
  with cache in about 30~40 seconds at the fastest.


[dune cache] <https://github.com/ocaml/dune/blob/2.8.5/doc/caching.rst>

[ocaml/setup-ocaml#66] <https://github.com/ocaml/setup-ocaml/pull/66>

[@actions/cache]
<https://github.com/actions/toolkit/tree/main/packages/cache>


Automatic pinning and depext handling of local packages
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  For example, if you have a very large number of local packages, like
  the [Irmin] project, it can be quite a pain for a human to have to
  write a script to pin them all in your workflow. The action pins and
  depext the local packages if they exist in the repository by
  default. You can also use the glob pattern to select which local
  packages to handle, as described [here].

  <https://github.com/ocaml/setup-ocaml/releases/tag/v2.0.0-alpha>


[Irmin] <https://github.com/mirage/irmin>

[here]
<https://github.com/ocaml/setup-ocaml/blob/master/examples.md#using-glob-patterns-to-filter-local-packages>


FrontC 4.1.0 (Vingt ans après)
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-frontc-4-1-0-vingt-ans-apres/7906/1>


Ivan Gotovchits announced
─────────────────────────

  More than twenty years after its original release [FrontC] is still
  alive and getting new updates. Mostly it started with my frustration
  with its Makefiles that ended up in switching to menhir and dune and
  adding cram tests that finally enabled us to safely touch the grammar
  definitions and introduce a few c99 … c11 language features as well as
  more GNU extensions. Our end goal is to get a robust and easy-to-use C
  parser that is capable of taking a C program on a modern Linux
  distribution and get it parsed into a C abstract tree. It is not that
  trivial as it may sound as modern C library headers (especially GNU
  libc) use non-standard or standard but very modern C features, and
  most of the OCaml parsers that I have seen are still unable to parse
  them, including parsers from FramaC, C11parser, and even compcert
  parser (mostly they do not handle complex floating-point types and
  various extension types and some GCC attributes).

  Therefore, FrontC is still useful, especially if all that you want is
  to start doing program analysis with minimal initial effort, just do
  (but wait until it is [merged])

  ┌────
  │ opam install FrontC
  └────

  and start hacking!

  With that said, FrontC is mostly maintained at leisure time by
  volunteers, so the pull requests are very welcome.


[FrontC] <https://github.com/BinaryAnalysisPlatform/FrontC>

[merged] <https://github.com/ocaml/opam-repository/pull/18736>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-05-11 14:47 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-05-11 14:47 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 27361 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of May 04 to 11,
2021.

Table of Contents
─────────────────

Software engineer position at LexiFi (Paris)
Open source editor for iOS, iPadOS and macOS
Backend developer position at Issuu (Copenhagen)
25 years of OCaml
OCaml compiler development newsletter, issue 1: before May 2021
After so many years, I discover 'Str.bounded_full_split regexp str n'
Parser for the Scala programming language?
Old CWN


Software engineer position at LexiFi (Paris)
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-software-engineer-position-at-lexifi-paris/7782/1>


Alain Frisch announced
──────────────────────

  [LexiFi] is hiring! We are looking for a fully-time software engineer
  to join our core development team. The vast majority of our stack is
  implemented in OCaml, and we have plenty of exciting projects on a
  wide range of topics.

  More info on <https://www.lexifi.com/careers/software_engineer/>


[LexiFi] <https://www.lexifi.com>


Open source editor for iOS, iPadOS and macOS
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/open-source-editor-for-ios-ipados-and-macos/7624/15>


Continuing this thread, Nathan Fallet announced
───────────────────────────────────────────────

  Just updated the editor, I redesigned the macOS version, and it just
  looks better and more native

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/6/6b03c462755fb37a2d5018013c3d1c8bd45f53bf_2_1380x766.jpeg>

  What are your first impressions on it?


Backend developer position at Issuu (Copenhagen)
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-backend-developer-position-at-issuu-copenhagen/7793/1>


Dario Teixeira announced
────────────────────────

  We are looking for a Backend Developer with experience in machine
  learning – and preferably also OCaml! – to join our Research &
  Development team. You will help build machine learning research
  prototypes and be responsible for integrating them into new and
  existing products.

  At Issuu, we use OCaml extensively in our production systems. If you
  love OCaml and functional programming in general, Issuu is a great
  place to put your passion into real-world products!

  Please find more information about this position at the following
  link:
  <https://jobs.lever.co/issuu/f502cb20-b216-4c67-8357-d748e1b35178>


Anentropic asked and Dario Teixeira replied
───────────────────────────────────────────

        I would love to hear more about your OCaml backend stack

  Well, we love to talk about our OCaml stack! :slightly_smiling_face:

  We rely on the Jane Street ecosystem a lot, using Core as a Stdlib
  replacement and Async for monadic concurrency.

  AMQP forms the backbone of our messaging system, and therefore we use
  [amqp-client] extensively.

  We use both MySQL and Postgresql databases in production. For the
  former we use [ppx_mysql], and for the latter, [PGOCaml]. (Thanks to
  Docker, we can give PGOCaml compile-time access to the DB without
  having to depend on the actual production DB.)

  We currently use Protobuf for serialisation, but spend a great amount
  of time complaining about it. We rely on [ocaml-protoc-plugin] to
  generate the OCaml code from Protobuf definitions.

  Anyway, that's just the basics of our stack. Do let me know if there's
  something else you'd like to know in more detail!


[amqp-client] <https://github.com/andersfugmann/amqp-client>

[ppx_mysql] <https://github.com/issuu/ppx_mysql>

[PGOCaml] <https://github.com/darioteixeira/pgocaml>

[ocaml-protoc-plugin] <https://github.com/issuu/ocaml-protoc-plugin>


roddy asked and Dario Teixeira replied
──────────────────────────────────────

        Do you use Protobuf for interop with non-OCaml systems? If
        not, I'm curious about whether you've considered
        [bin_prot] as an alternative; it seems like an obvious
        choice if you're using Core/Async.

  Yes, we use Protobuf mainly because we have a heterogeneous stack,
  where besides OCaml we also have services running Python, Kotlin, or
  Elixir.


[bin_prot]
<https://github.com/janestreet/bin_prot/blob/master/README.md>


Tim McGilchrist asked and Dario Teixeira
────────────────────────────────────────

        I'm curious about how you structure the business code (for
        want of a better word), in between the technical layers of
        talking to AMQP or an SQL store. Are there larger scale
        patterns like CQRS or DDD that you use to organise code?

  How do you package up code for deployment? Docker / AWS something.
  We're slowly migrating to a micro-service architecture (the pros and
  cons of which are outside the scope of this thread; that's a can of
  worms I'd rather not open…) whose cast of characters includes
  "entities" (responsible for storing/retrieving data from DBs), generic
  backend services that encapsulate business logic, frontend services,
  and backend-for-frontend services.

  We're using Docker for deployment on AWS (mostly), and slowly
  migrating from Docker Swarm to Kubernetes.


25 years of OCaml
═════════════════

  Archive: <https://discuss.ocaml.org/t/25-years-of-ocaml/7813/1>


Xavier Leroy announced
──────────────────────

  25 years ago, on May 9th 1996, release 1.00 of the Objective Caml
  language and system was announced:
  <https://sympa.inria.fr/sympa/arc/caml-list/1996-05/msg00003.html>

  It was already the consolidation of many years of work, integrating
  Jérôme Vouillon and Didier Rémy's work on objects and classes within
  Caml Special Light, itself a combination of my work on modules and
  native-code compilation with earlier code taken from Caml Light,
  especially Damien Doligez's GC.

  Little did I know that O(bjective) Caml would still be there 25 years
  later!

  A lot happened during this time, including several major evolutions of
  the language, and, much more importantly, the emergence of a community
  of users and an ecosystem of tools and libraries.  But maybe this was
  just the beginning for something even bigger?  We'll see…

  Happy birthday, OCaml!


David Allsopp replied
─────────────────────

  Most pleasingly, with a [very small number of patches], the Windows
  port still works in Visual Studio 2019:

  ┌────
  │ C:\Birthday>ocaml.exe
  │ 	Objective Caml version 1.00
  │ 
  │ #print_endline "Happy 25th Birthday, OCaml!";;
  │ Happy 25th Birthday, OCaml!
  │ - : unit = ()
  │ ##quit;;
  │ 
  │ C:\Birthday>type hooray.ml
  │ let rec hip_hip n =
  │   if n > 0 then
  │     let () = print_endline "hip hip! hooray!" in
  │     hip_hip (pred n)
  │ 
  │ let () = hip_hip 25
  │ C:\Birthday>ocamlopt -o hooray.exe hooray.ml
  │ 
  │ C:\Birthday>hooray
  │ hip hip! hooray!
  │ ...
  └────


[very small number of patches]
<https://github.com/dra27/ocaml/commits/25-years-of-ocaml>


On the OCaml Maling List, Roberto Di Cosmo also replied
───────────────────────────────────────────────────────

  Long live OCaml!

  Thanks Xavier, and to all the brilliant minds that contributed to the
  evolution and adoption of this beautiful language, and system, in this
  past quarter of a century.

  If I may add a personal note, one truly remarkable fact is that some
  rather complex code written in 1998 using OCaml 1.07 [1] could be
  compiled and run last year using OCaml 4.x *without modifications*:
  the only visible changes were the new warnings spotting potential
  issues in the code, thanks to the many improvements to the compiler
  over time.

  For the curious, all the details are here:
  <https://www.dicosmo.org/Articles/2020-ReScienceC.pdf>

  Cheers

  Roberto

  [1] that was the first version including support for marshalling
  closures, added in a fantastic one week-spring in Pisa exactly for
  this code :-)


OCaml compiler development newsletter, issue 1: before May 2021
═══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-compiler-development-newsletter-issue-1-before-may-2021/7831/1>


gasche announced
────────────────

  I'm happy to introduce the first issue of the "OCaml compiler
  development newsletter". I asked frequent contributors to the OCaml
  compiler codebase to write a small burb on what they have been doing
  recently, in the interest of sharing more information on what people
  are interested in, looking at and working on.

  This is by no means exhaustive: many people didn't end up having the
  time to write something, and it's fine. But hopefully this can give a
  small window on development activity related to the OCaml compiler,
  structured differently from the endless stream of [Pull Requests] on
  the compiler codebase.

  (This initiative is inspired by the excellent Multicore
  newsletter. Please don't expect that it will be as polished or
  consistent :yo-yo: .)

  Note:

  • Feel free of course to comment or ask questions, but I don't know if
    the people who wrote a small blurb will be looking at the thread, so
    no promises.

  • If you have been working on the OCaml compiler and want to say
    something, please feel free to post! If you would like me to get in
    touch next time I prepare a newsletter issue (some random point in
    the future), please let me know by email at (gabriel.scherer at
    gmail).


[Pull Requests] <https://github.com/ocaml/ocaml/pulls>

@dra27 (David Allsopp)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Compiler relocation patches now exist. There's still a few left to
  write, and they need splitting into reviewable PRs, but the core
  features are working. A compiler installation can be copied to a new
  location and still work, meaning that local switches in opam may in
  theory be renamed and, more importantly, we can cache previously-built
  compilers in an opam root to allow a new switch's compiler to be a
  copy. This probably won't be reviewed in time for 4.13, although it's
  intended that once merged opam-repository will carry back-ports to
  earlier compilers.

  A whole slew of scripting pain has lead to some possible patches to
  reduce the use of scripts in the compiler build to somewhat closer to
  none.

  FlexDLL bootstrap has been completely overhauled, reducing build time
  considerably. This will be in 4.13 (#[10135])


[10135] <https://github.com/ocaml/ocaml/pull/10135>


@nojb (Nicolás Ojeda Bär)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I am working on #[10159], which enables debug information in
  `-output-complete-exe' binaries. It uses [incbin] under Unix-like
  system and some other method under Windows.


[10159] <https://github.com/ocaml/ocaml/pull/10159>

[incbin] <https://github.com/graphitemaster/incbin>


@gasche (Gabriel Scherer)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I worked on bringing more PRs to a decision (merge or close). The
  number of open PRs has gone from 220-ish to 180, which feels nice.

  I have also contributed to @Ekdohibs' project [camlboot], which is a
  "bootstrap-free" implementation of OCaml able to compile the OCaml
  compiler itself. It currently targets OCaml 4.07 for various
  reasons. We were able to do a full build of the OCaml compiler, and
  check that the result produces bootstrap binaries that coincide with
  upstream bootstraps. This gives extremely strong confidence that the
  OCaml bootstrap is free from "trusting trust" attacks. For more
  details, see our [draft paper].


[camlboot] <https://github.com/Ekdohibs/camlboot>

[draft paper] <http://gallium.inria.fr/~scherer/drafts/camlboot.pdf>

with @Octachron (Florian Angeletti)
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  I worked with Florian Angeletti on deprecating certain command-line
  warning-specifier sequences, to avoid usability issues with (new in
  4.12) warning names. Before `-w -partial-match' disables warning 4,
  but `-w -partial' is interpreted as the sequence `w -p -w a -w r -w t
  -w i -w a -w l', most of which are ignored but `-w a' silences all
  warnings. Now multi-letter sequences of "unsigned" specifiers (`-p' is
  signed, `a' is unsigned) are deprecated. (We first deprecated all
  unsigned specifiers, but Leo White tested the result and remarked that
  `-w A' is common, so now we only warn on multi-letter sequences of
  unsigned specifiers.

  I am working with @Octachron (Florian Angeletti) on grouping signature
  items when traversing module signatures. Some items are "ghost items"
  that are morally attached in a "main item"; the code mostly ignores
  this and this creates various bugs in corner cases. This is work that
  Florian started in September 2019 with #[8929], to fix a bug in the
  reprinting of signatures. I only started reviewing in May-September
  2020 and we decided to do sizeable changes, he split it in several
  smaller changes in January 2021 and we merged it in April 2021. Now we
  are looking are fixing other bugs with his code (#[9774],
  #[10385]). Just this week Florian landed a nice PR fixing several
  distinct issues related to signature item grouping: #[10401].


[8929] <https://github.com/ocaml/ocaml/pull/8929>

[9774] <https://github.com/ocaml/ocaml/pull/9774>

[10385] <https://github.com/ocaml/ocaml/pull/10385>

[10401] <https://github.com/ocaml/ocaml/pull/10401>


@xavierleroy (Xavier Leroy)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I fixed #[10339], a mysterious crash on the new Macs with "Apple
  silicon".  This was due to a ARM (32 and 64 bits)-specific
  optimization of array bound checking, which was not taken into account
  by the platform-independent parts of the back-end, leading to
  incorrect liveness analysis and wrong register allocation.  #[10354]
  fixes this by informing the platform-independent parts of the back-end
  that some platform-specific instructions can raise.  In passing, it
  refactors similar code that was duplicating platform-independent
  calculations (of which instructions are pure) in platform-dependent
  files.

  I spent quality time with the Jenkins continuous integration system at
  Inria, integrating a new Mac Mini M1.  For unknown reasons, Jenkins
  ran the CI script in x86-64 emulation mode, so we were building and
  testing an x86-64 version of OCaml instead of the intended ARM64
  version.  A bit of scripting later (8b1bc01c3) and voilà, arm64-macos
  is properly tested as part of our CI.

  Currently, I'm reading the "safe points" proposal by Sadiq Jaffer
  (#[10039]) and the changes on top of this proposed by Damien Doligez.
  It's a necessary step towards Multicore OCaml, so we really need to
  move forward on this one.  It's a nontrivial change involving a new
  static analysis and a number of tweaks in every code emitter, but
  things are starting to look good here.


[10339] <https://github.com/ocaml/ocaml/pull/10339>

[10354] <https://github.com/ocaml/ocaml/pull/10354>

[10039] <https://github.com/ocaml/ocaml/pull/10039>


@mshinwell (Mark Shinwell)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I did a first pass of review on the safe points PR (#[10039]) and
  significantly simplified the proposed backend changes.  I've also been
  involved in discussions about a new function-level attribute to cause
  an error if safe points (including allocations) might exist within a
  function's body, to make code that currently assumes this robust.
  There will be a design document for this coming in due course.

  I fixed the random segfaults that were occurring on the RISC-V Inria
  CI worker (#[10349]).

  In Flambda 2 land we spent two person-days debugging a problem
  relating to Infix_tag!  We discovered that the code in OCaml 4.12
  onwards for traversing GC roots in static data ("caml_globals") is not
  correct if any of the roots are closures.  This arises in part because
  the new compaction code (#[9728]) has a hidden invariant: it must not
  see any field of a static data root more than once (not even via an
  Infix_tag).  As far as we know, these situations do not arise in the
  existing compiler, although we may propose a patch to guard against
  them.  They arise with Flambda 2 because in order to compile
  statically-allocated inconstant closures (ones whose environment is
  partially or wholly computed at runtime) we register closures directly
  as global roots, so we can patch their environments later.


[10039] <https://github.com/ocaml/ocaml/pull/10039>

[10349] <https://github.com/ocaml/ocaml/pull/10349>

[9728] <https://github.com/ocaml/ocaml/pull/9728>


@garrigue (Jacques Garrigue)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I have been working on a number of PRs fixing bugs in the type system,
  which are now merged:
  • #[10277] fixes a theoretical bug in the principality of GADT type
     inference (#[10383] applies only in -principal mode)
  • #[10308] fixes an interaction between local open in patterns and the
     new syntax for introducing existential type variables
  • #[10322] is an internal change using a normal reference inside of a
     weak one for backtracking; the weak reference was an optimization
     when backtracking was a seldom used feature, and was not useful
     anymore
  • #[10344] fixes a bug in the delaying of the evaluation of optional
     arguments
  • #[10347] cleans up some code in the unification algorithm, after a
     strengthening of universal variable scoping
  • #[10362] fixes a forgotten normalization in the type checking
     algorithm

  Some are still in progress:
  • #[10348] improves the way expansion is done during unification, to
     avoid some spurious GADT related ambiguity errors
  • #[10364] changes the typing of the body of the cases of
     pattern-matchings, allowing to warn in some non-principal
     situations; it also uncovered a number of principality related bugs
     inside the the type-checker

  Finally, I have worked with Takafumi Saikawa (@t6s) on making the
  representation of types closer to its logical meaning, by ensuring
  that one always manipulate a normalized view in #[10337] (large
  change, evaluation in progress).


[10277] <https://github.com/ocaml/ocaml/pull/10277>

[10383] <https://github.com/ocaml/ocaml/pull/10383>

[10308] <https://github.com/ocaml/ocaml/pull/10308>

[10322] <https://github.com/ocaml/ocaml/pull/10322>

[10344] <https://github.com/ocaml/ocaml/pull/10344>

[10347] <https://github.com/ocaml/ocaml/pull/10347>

[10362] <https://github.com/ocaml/ocaml/pull/10362>

[10348] <https://github.com/ocaml/ocaml/pull/10348>

[10364] <https://github.com/ocaml/ocaml/pull/10364>

[10337] <https://github.com/ocaml/ocaml/pull/10337>


@let-def (Frédéric Bour)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  For some time, I have been working on new approaches to generate error
  messages from a Menhir parser.

  My goal at the beginning was to detect and produce a precise message
  for the ‘let ;’ situation:
  ┌────
  │ let x = 5;
  │ let y = 6
  │ let z = 7
  └────
  LR detects an error at the third ‘let’ which is technically correct,
  although we would like to point the user at the ‘;’ which might be the
  root cause of the error. This goal has been achieved, but the
  prototype is far from being ready for production.

  The main idea to increase the expressiveness and maintainability of
  error context identification is to use a flavor of regular
  expressions.  The stack of a parser defines a prefix of a sentential
  form. Our regular expressions are matched against it. Internal details
  of the automaton does not leak (no reference to states), the regular
  language is defined by the grammar alone.  With appropriate tooling,
  specific situations can be captured by starting from a coarse
  expression and refining it to narrow down the interesting cases.

  Now I am focusing on one specific point of the ‘error message’
  development pipeline: improving the efficiency of ‘menhir
  –list-errors’.  This command is used to enumerate sentences that cover
  all erroneous situations (as defined by the LR grammar). On my
  computer and with the OCaml grammar, it takes a few minutes and quite
  a lot of RAM. Early results are encouraging and I hope to have a PR
  for Menhir soon. The performance improvement we are aiming for is to
  make the command almost real time for common grammars and to tackle
  bigger grammars by reducing the memory needs.  For instance, in the
  OCaml case, the runtime is down from 3 minutes to 2–3 seconds and
  memory consumption goes from a few GiB down to 200 MiB.


Daniel Bünzli asked and gasche replied
──────────────────────────────────────

        > […] @Ekdohibs’ project [camlboot ], which is a
          “bootstrap-free”
        > implementation of OCaml able to compile the OCaml
          compiler itself. It currently targets OCaml 4.07 for
          various
        > reasons. We were able to do a full build of the OCaml
          compiler, and check that the result produces bootstrap
        > binaries that coincide with upstream bootstraps. This
          gives extremely strong confidence that the OCaml
          bootstrap is
        > free from “trusting trust” attacks. For more details,
          see our [draft paper].

        Something that is not clear to me (but I read quickly) is
        the impact of `guile` itself being not bootstrapped yet.
        Could there be a *very* elaborate attack (with probability
        0 of existing) on both the guile and ocaml bootstrap or is
        there something in the whole scheme that prevents it ?

  Yes, currently Guile needs to be trusted, and it would be possible
  that a bootstrapping virus in Guile would break our correctness
  result. (It would need to reproduce itself through our compiler and
  interpreter that were written after Guile itself, but I think in
  theory this could be done with an almost-infinitely clever program
  analysis.) Of course, an attack at the source level (inserting
  malicious source, instead of malicious binaries) is also possible
  anywhere in the chain.  Our main reason for using Guile is that this
  is the high-level language community most active on
  debootstrapping-towards-the-metal (through the Guix connection), so we
  believe it is more likely to manage debootstrapping and maintain it in
  the longer run.

  (The seed that Guile depends on is its macro-expander, which is
  written using macros itself. In theory one may perform the
  macro-expansion of the expander, and then manually review the two
  versions to verify the absence of attack there.)


[camlboot ] <https://github.com/Ekdohibs/camlboot>

[draft paper] <http://gallium.inria.fr/~scherer/drafts/camlboot.pdf>


After so many years, I discover 'Str.bounded_full_split regexp str n'
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/after-so-many-years-i-discover-str-bounded-full-split-regexp-str-n/7838/1>


UnixJunkie said
───────────────

  This is so useful and powerful:
  ┌────
  │ #require "str";;
  │ Str.bounded_full_split (Str.regexp "[()]") "toto (titi, tata (et tutu)) vont au parc (en courant)" 1024;;
  │ - : Str.split_result list =
  │ [Str.Text "toto "; Str.Delim "("; Str.Text "titi, tata "; Str.Delim "(";
  │  Str.Text "et tutu"; Str.Delim ")"; Str.Delim ")"; Str.Text " vont au parc ";
  │  Str.Delim "("; Str.Text "en courant"; Str.Delim ")"]
  └────

  Still finding hidden pearls in the stdlib after so many years!
  :slight_smile:


Parser for the Scala programming language?
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/parser-for-the-scala-programming-language/7541/18>


Deep in this thread, Yoann Padioleau announced
──────────────────────────────────────────────

  I ended up porting the recursive descent parser in the Scala compiler
  to OCaml …  I think it was the fastest way to get a working parser
  from OCaml …

  <https://github.com/returntocorp/pfff/blob/develop/lang_scala/parsing/Parser_scala_recursive_descent.ml>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-05-04  8:57 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-05-04  8:57 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 6297 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of April 27 to May
04, 2021.

Table of Contents
─────────────────

Ocaml-solidity, a new OCaml library for Solidity
Release of ocaml-pandoc 0.1.0
Stdlib vs Containers vs Batteries vs Base : Core functions comparison
Martin Jambon presentation on Semgrep, Wed April 21 @ 7pm Central
ocaml-lsp-server 1.6.0
Other OCaml News
Old CWN


Ocaml-solidity, a new OCaml library for Solidity
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-solidity-a-new-ocaml-library-for-solidity/7746/2>


Continuing the thread from last week, Fabrice Le Fessant announced
──────────────────────────────────────────────────────────────────

  I should add that the project is now available in the opam-repository,
  see [solidity-parser] and [solidity-typechecker].


[solidity-parser] <https://opam.ocaml.org/packages/solidity-parser/>

[solidity-typechecker]
<https://opam.ocaml.org/packages/solidity-typechecker/>


Release of ocaml-pandoc 0.1.0
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-ocaml-pandoc-0-1-0/7759/1>


Samuel Mimram announced
───────────────────────

  I have just released [ocaml-pandoc], a native OCaml library to write
  filters for [pandoc], which is a markdown-to-anything converter. It
  has allowed me to write some simple filters I needed (such as for
  including code snippets, which is not supported natively).

  The support is not complete yet however, I might add more if needed
  (and pull-requests are of course accepted :slight_smile:).


[ocaml-pandoc] <https://github.com/smimram/ocaml-pandoc>

[pandoc] <https://pandoc.org/>


Stdlib vs Containers vs Batteries vs Base : Core functions comparison
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/stdlib-vs-containers-vs-batteries-vs-base-core-functions-comparison/7766/1>


Jp R announced
──────────────

  You want to compare the main core functions found in the OCaml Stdlib
  (v4.12.0), Containers (v3.3), Batteries (v3.3.0) and Base (v0.14.1)
  libraries ?

  Check it out !

  <https://github.com/Fourchaux/ocaml-stdlib-containers-batteries-base-comparisons>


Vladimir Keleshev then added
────────────────────────────

  Someone reading this might be also interested in my (less formal)
  comparison between OCaml Stdlib and Base:
  <https://gist.github.com/keleshev/764edad011a6a7a40da11716b19ddb75>


Martin Jambon presentation on Semgrep, Wed April 21 @ 7pm Central
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/martin-jambon-presentation-on-semgrep-wed-april-21-7pm-central/7709/5>


Claude Jager-Rubinson announced
───────────────────────────────

  The recording of Martin's talk is now available:
  <https://hfpug.org/2021/05/01/martin-jambon-9-languages-how-we-built-semgrep-a-polyglot-static-analysis-tool/>


Martin Jambon then added
────────────────────────

  Thanks Claude! The talk [starts at 1:45].


[starts at 1:45] <https://www.youtube.com/watch?v=H6TgK-LMA4Y&t=105s>


Ryan Slade then said
────────────────────

  [Comby] may also be of interest, it's a similar project also written
  in OCaml.


[Comby] <https://comby.dev/>


ocaml-lsp-server 1.6.0
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-lsp-server-1-6-0/7774/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the ocaml-lsp team, I'd like to announce version 1.6.0 of
  ocaml-lsp-server. The highlight of this release is the updated version
  of merlin which brings lots of new bug fixes.


1.6.0 (04/30/2020)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Features
┄┄┄┄┄┄┄┄

  • Code action to annotate a value with its type (#397)


Fixes
┄┄┄┄┄

  • Fix interface/implementation switching on Windows (#427)

  • Correctly parse project paths with spaces and other special
    characters that must be escaped.

  • Print types with `-short-paths' even if the project wasn't built yet


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Cryptography updates in OCaml and MirageOS]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Cryptography updates in OCaml and MirageOS]
<https://hannes.nqsb.io/Posts/EC>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-04-27 14:26 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-04-27 14:26 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 26103 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of April 20 to 27,
2021.

Table of Contents
─────────────────

docs.ocaml.pro : an OCaml Documentation Hub
Decompress 1.4.0
elliptic curves - maintainable and verified (full stack, from primitives to TLS)
First release of Docteur, an opiniated read-only file-system for MirageOS
Ocaml-solidity, a new OCaml library for Solidity
Migrating to floatarray (blog post)
Old CWN


docs.ocaml.pro : an OCaml Documentation Hub
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-docs-ocaml-pro-an-ocaml-documentation-hub/7718/1>


Fabrice Le Fessant announced
────────────────────────────

  We are pleased to announce that we just published the first version of
  the OCaml Documentation Hub on:

  <https://docs.ocaml.pro>

  The OCaml Documentation Hub can be used to browse the sources and the
  documentations of more than 2000 opam packages, following links
  between them when useful. This is a work-in-progress, and we are
  working on improving it with many more features, such as source
  annotations with types, full-text and type-driven searches,
  improvements in the general readability of documentation, etc.

  The site is generated using an open-source tool called digodoc,
  available on:

  <https://github.com/OCamlPro/digodoc>

  Digodoc is able to build a map of an opam switch, with links between
  files, opam packages, ocaml libraries, meta packages and ocaml
  modules. It is also able to generate documentation using odoc with
  cross-indexes between all these kinds of packages.

  We welcome feedback and contributions!  Enjoy !


Simon Cruanes said and Anil Madhavapeddy added
──────────────────────────────────────────────

  Great work on this site, and I love the domain name as well ;-)

        The cross linking between packages is fantastic.

  As a bit of background on why documentation cross-linking has taken so
  long, there is a lonnnggg history intertwined with many people's
  contributions to opam, build systems (ocamlbuild and dune),
  conventions (findlib and odig) and of course [odoc] itself.  The major
  milestones along the way have been:

  • [odoc 1.0], first began in 2014 as a quick project to pull together
    typing information from cmt[i] files, but which ran into the problem
    that it needs a consistent set of compiled cmt files to actually
    work, and so needs help from external tools to pull that set of
    compiled libraries together.
  • [odig], which pulls together multiple opam packages (and a
    filesystem layout for metadata) and runs odoc on then. This allowed
    for the creation of <https://docs.mirage.io> a few years ago which
    cross-references a smaller number of packages
  • opam-repo itself has had better and better bulk builds over the
    years to ensure that we can actually automatically compile all the
    artefacts needed for docs builds, thanks to efforts like [health
    check] and [ocurrent].
  • odoc 2.0, which featured a multi-year [rewrite] of the OCaml module
    resolver and introduced a new [output IR].  This forthcoming release
    was presented in this [OCaml 2020 talk] by @jonludlam.

  And now with all these pieces in place, the OCaml documentation spring
  has arrived! The OCamlPro one posted here as the first of the "new
  batch" of mass documentation indexers, and I'm aware of concurrent
  efforts by the odoc/ocaml.org maintainer teams to push a central one
  out to ocaml.org, as well as by the MirageOS team who are refreshing
  docs.mirage.io with the latest and greatest.  I'm sure when the dust
  has settled on all these indexers we can look for common pieces, but
  for now it's lovely to see so much innovation happening at pace.

  For the community: now is the time to fix your docstrings in your
  libraries, as there will many cool tools parsing and processing them,
  and rendering them into all kinds of output formats!

  To the [odoc contributors], thank you! The journey to get to this
  documentation site started here seven years ago:

  ┌────
  │ commit ef91571cab31d9ece7af965ed52eaaff57a12efc
  │ Author: Leo White <lpw25@cl.cam.ac.uk>
  │ Date:   Thu Oct 16 19:20:18 2014 +0100
  │ 
  │     Initial commit
  └────

  @lefessan one thing I'm not sure about in your site is the "copyright
  library authors" claim. That's murky legal ground – it's worth
  establishing if the odoc HTML has gone through a compilation process
  and so is no longer copyright the authors (just as a binary output is
  not copyright the original source code). If the output _is_ copyright
  the authors, then they have reasonable grounds to claim that you
  should also reproduce the copyright notice and other license
  restrictions. Personally, I prefer to claim that there is no copyright
  to the original authors in odoc output, and sidestep this issue.


[odoc] <https://github.com/ocaml/odoc>

[odoc 1.0] <https://github.com/ocaml/odoc>

[odig] <https://github.com/dbuenzli/odig>

[health check] <https://github.com/ocurrent/opam-health-check>

[ocurrent] <https://github.com/ocurrent/overview>

[rewrite] <https://github.com/ocaml/odoc/pull/439>

[output IR] <https://github.com/ocaml/odoc/pull/423>

[OCaml 2020 talk] <https://www.youtube.com/watch?v=wVyZ-KveN-w&t=3s>

[odoc contributors] <https://github.com/ocaml/odoc/graphs/contributors>


Fabrice Le Fessant replied
──────────────────────────

  Thanks @avsm , all these projects were indeed important milestones
  towards the creation of this site. However, I wouldn't want this
  history perspective to give the wrong feeling that building this site
  was easy, it is the result of a very good, long and hard work by the
  team at OCamlPro to make it work despite a road paved with many
  obstacles. It also benefited from OCamlPro's long history of
  innovative projects for the OCaml community, that lead for example in
  the past to Opam, [Try-OCaml], Memprof/[Memthol,] [Opam-builder],
  [Learn-OCaml], the Typerex tools (ocp-indent, ocp-index, ocp-build,
  etc.) and more recently [opam-bin] and [drom].

  As I said, this is a work-in-progress, and there are many features
  that we will be adding in the next months to make this website much
  easier to navigate, for users to rapidely reach the information that
  matters for them. We hope it will be inspirational for all the other
  developers who are working on similar projects, and we are looking
  forward to using their projects soon too!


[Try-OCaml] <https://try.ocamlpro.com/>

[Memthol,]
<https://www.ocamlpro.com/2020/12/01/memthol-exploring-program-profiling/>

[Opam-builder] <https://hal.inria.fr/hal-01352008>

[Learn-OCaml] <https://github.com/ocaml-sf/learn-ocaml>

[opam-bin] <https://github.com/OCamlPro/opam-bin>

[drom] <https://github.com/OCamlPro/drom/>


Daniel Bünzli said
──────────────────

  I'd just like to stress that `odig' documents OCaml package installs
  regardless of the package manager used as long the install structure
  follows [these conventions] (which are automatically followed by [dune
  installs]) .

  Also for people using my packages, I'd just like to mention they may
  miss important documentation bits on [https://docs.ocaml.pro] until
  [that issue] is resolved.


[these conventions]
<https://erratique.ch/software/odig/doc/packaging.html>

[dune installs]
<https://dune.readthedocs.io/en/stable/opam.html#odig-conventions>

[https://docs.ocaml.pro] <https://docs.ocaml.pro/>

[that issue] <https://github.com/OCamlPro/digodoc/issues/33>


Much later in the thread, Kiran Gopinathan said
───────────────────────────────────────────────

  It's not quite the same as hoogle, but merlin has a functionality to
  search for functions by type signature - the feature doesn't seem to
  get much attention apparently - probably the interface is a little
  lacking, but with some extra elisp tuning, it can work quite smoothly:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/3/3c2d1c63fac7cbd7dd1bb5b9a406589e031cb795.gif>


Yawar Amin then added
─────────────────────

  The command line for this:

  ┌────
  │ ocamlmerlin single search-by-polarity -position 0 -query '-int +string'
  └────

  (To search for values of type `int -> string'.)


Decompress 1.4.0
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-decompress-1-4-0/7724/1>


Charles Edouard Lecat announced
───────────────────────────────

Greetings everyone,
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I am happy to announce the new release of [decompress 1.4.0],
  available for installation via OPAM. Decompress is a library
  containing a pure OCaml implementation of several compression
  algorithms:
  • RFC1951
  • Zlib
  • Gzip
  • LZO

  It's goal is to provide several algorithms for both the inflation and
  the deflation of objects, in the form of a stream API allowing to call
  the chosen algorithm one bit at a time. Such behavior allows for an
  easy use of decompress in situations where we would not be able to
  have the input in one go, or where we would like to output the result
  in a non blocking way. This new release comes with several
  improvements to the documentation and bug fixes, but even more, with a
  whole new implementation for the rfc 1951 and zlib algorithms.


[decompress 1.4.0]
<https://github.com/mirage/decompress/releases/tag/v1.4.0>


Non-stream implementation for rfc 1951 and zlib
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Up to this day, decompress was used in several projects like
  ocaml-git. However, as time passed by, it appeared that in some cases,
  the current implementation of decompress was not the optimal solution:
  As useful as a stream implementation is, it requires to save a lot of
  information about the state of the compression, in order to resume it
  once we have enough input.

  This is why, in some cases where we would be sure that we have our
  whole input in one go, we might want to avoid all of these side-costs,
  and directly go to the point.


State of the art: libdeflate
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  This new problematic in mind, we have started thinking about the
  existing implementations of these algorithms which were also bypassing
  the stream behavior. One implementation that proved to be a suitable
  example for our problem, was the library `libdeflate', an
  implementation in C. It's main advantages being: a better compression
  ratio than zlib and with faster runtime.

  It was used as the solid base for the OCaml implementation provided by
  this new release.


OCaml version of libdeflate, performances and use cases
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Inheriting the logic of libdeflate, the new implementation now has a
  better compression ratio, while being slightly faster at it. On the
  other side, the decompression is way faster, with `33% of speed
  increase in most tested cases: On the ~book2' (from the Calgary
  corpus) file:
  • `decompress' (stream): 15 Mb/s (deflation), 76 Mb/s (inflation),
    ratio: 42.46 %
  • `decompress' (non-stream): 17 Mb/s (deflation), 105 Mb/s
    (inflation), ratio: 34.66 %

  Now that this is in place, the users of decompress will be able to
  choose between the two versions, according to their needs. In the case
  of ocaml-git, the vast majority of the git objects are small and will
  be compressed in one go. This is why we updated with the new
  implementation when possible.


Writing optimized code and profiling it
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  One of the biggest concerns of this release was to be able to produce
  optimized code. The base code being coded in C, a lot of sub-optimal
  behavior where ported in the OCaml version: `for' and `while' loops,
  references everywhere, mixes of `struct' and `union.', it needed a lot
  of clean up.

  This is why once the main iteration was done, we have spent several
  weeks profiling the code base, using the OCaml library `landmarks',
  `flamegraph' or simply the linux binary `perf'. This work, sometimes
  tedious, proved to be helpful and healthy for both the harmonization
  of the code and it's performances.


Decompress & MirageOS
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  Compression algorithms are a really important piece in many projects,
  and operating systems do not avoid this.  `decompress' was coded from
  the start with the idea of being used in the much larger project
  MirageOS.

  This release is another opportunity to broaden MirageOS’s reach, by
  providing one more algorithm to it’s stack, allowing us to specialise
  even more the unikernels that would have a need for
  inflation/deflation algorithms. This more restrictive implementation,
  as we need to have the whole input in one go, will allow us to take
  advantage of the situation and give more flexibility for the user.

  The positive aspects of this release will most likely show up soon
  enough, as we make use of decompress to its full potential


elliptic curves - maintainable and verified (full stack, from primitives to TLS)
════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-elliptic-curves-maintainable-and-verified-full-stack-from-primitives-to-tls/7729/1>


Hannes Mehnert announced
────────────────────────

  over the last month I worked on upgrading the cryptography stack for
  OCaml and MirageOS. I just published a [blog post]. Enhancments of
  [OCaml-TLS] ([usenix security paper from 2015]) and [X.509] are in
  place.

  The main achievement after TLS 1.3 support (since May 2020, 0.12.0) is
  that elliptic curve certificates are now supported. Elliptic curve
  cryptography uses [fiat]. The X509 implementation now supports PKCS 12
  (used by browsers and other software (e.g. OpenVPN) to bundle
  certificates and private keys).

  Get mirage-crypto-ec, x509 0.13.0 and tls 0.13.1 (all available in the
  opam-repository). Discussion and feedback appreciated.


[blog post] <https://hannes.robur.coop/Posts/EC>

[OCaml-TLS] <https://github.com/mirleft/ocaml-tls>

[usenix security paper from 2015] <https://usenix15.nqsb.io>

[X.509] <https://github.com/mirleft/ocaml-x509>

[fiat] <https://github.com/mit-plv/fiat-crypto>


First release of Docteur, an opiniated read-only file-system for MirageOS
═════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-docteur-an-opiniated-read-only-file-system-for-mirageos/7743/1>


Calascibetta Romain announced
─────────────────────────────

  I'm glad to announce the first release of [`docteur'], a simple tool
  to make and use (in read-only) a "file-system" for [MirageOS]. As you
  know, with MirageOS, we don't have _sockets_, _kernel space_ or even
  _file-descriptor_. It's not possible to manipulate files
  _standalonely_ and many _primitives_ commonly available with the
  `unix' module don't exists in our space.

  Therefore, it is difficult to imagine making a website that displays
  local files or a database system. But in our spirit of separation of
  services, it becomes possible for your unikernel to communicate over
  the network to a "file system" or a database.

  For quite some time we have been experimenting with a file system
  external to our unikernel called Git. This is the case of [`pasteur']
  which saves the pastes in a Git repository. It is also the case of
  [`unipi'] or [Canopy] which display the content of a Git repository
  and can resynchronize with it using a hook. Or the case of [our
  primary DNS server] whose zone file comes from a Git repository - we
  can then trace all the changes on this file.

  However, we have several limitations:
  1) it requires the Git repository to load into memory in your
     unikernel
  2) it requires a communication (external with GitHub or internal in a
     private network)

  The persistent aspect is very important. We should always be able to
  launch a unikernel and not lose the data if our system shuts down.

  The mutable aspect (modify a file) is useful in some cases but not in
  others. As for `unipi' for example (a simple static web site), the
  difference between resynchronizing with a hook or restarting the
  unikernel with a new version of your filesystem is minor.


[`docteur'] <https://github.com/dinosaure/docteur>

[MirageOS] <https://mirage.io/>

[`pasteur'] <https://github.com/dinosaure/pasteur>

[`unipi'] <https://github.com/roburio/unipi>

[Canopy] <https://github.com/Engil/Canopy>

[our primary DNS server] <https://github.com/roburio/dns-primary-git>

Docteur as a second solution
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This is where Doctor comes in. It solves both of our problems by
  offering the generation of a file system from scratch:
  • a Git repository (local or available on a service)
  • a specific folder

  Doctor is able to create a complete representation of a folder and to
  compress it at such a ratio that a generation of the documentation of
  several OPAM packages with all their versions making 14 Gb is reduced
  to an image of only 280 Mb!

  Such a high compression ratio is in particular due to a double level
  of compression by [`decompress'] and [`duff']. For more details,
  Docteur just generates a slightly modified PACK file with [carton].

  Then, Docteur proposes a simple library which makes available 2 ways
  to manipulate this image for your unikernel:
  1) a way that is fast but with a consequent boot time
  2) a slower way but with no cost to the boot time

  The first way will simply "analyze" the image to re-extract the layout
  of your file system. Then it uses the [ART data-structure] to save
  this layout. So, whenever you want a specific file and according to
  [ART benchmarks], you have access to the content very quickly.

  The problem remains the analysis which takes place at boot time and
  which can take a very long time (it depends essentially on the number
  of files you have). There can also be an impact on memory usage as the
  ART data structure is in memory - the more files there are, the bigger
  the structure is.

  The second method is more "silly". Each time you request a file, we
  will have to rebuild the entire path and therefore deserialize several
  objects (like folders). The advantage is that we don't analyze the
  image and we don't try to maintain a layout of your file system.


[`decompress'] <https://github.com/mirage/decompress>

[`duff'] <https://github.com/mirage/duff>

[carton] <https://github.com/mirage/ocaml-git/tree/master/src/carton>

[ART data-structure] <https://github.com/dinosaure/art>

[ART benchmarks] <https://dinosaure.github.io/art/bench/find.html>


Example
╌╌╌╌╌╌╌

  Docteur is meant to be simple. The generation of the image is done
  very simply by the command `make':
  ┌────
  │ $ docteur.make -b refs/heads/main https://github.com/dinosaure/docteur disk.img
  │ $ docteur.make -b refs/heads/main git@github.com:dinosaure/docteur disk.img
  │ $ docteur.make -b refs/heads/main git://github.com/dinosaure/docteur disk.img
  │ $ docteur.make -b refs/heads/main file://$(pwd)/dev/docteur disk.img
  └────

  Then, Docteur proposes 2 supports: Unix & [Solo5]. For Unix, you just
  have to name explicitly the image file to use. For the case of Solo5
  (and thus of virtualization). You just have to find a name for a
  "block device" and to reuse this name with the Solo5 "tender"
  specifying where the image is.
  ┌────
  │ $ cd unikernel
  │ $ mirage configure -t unix --disk disk.img
  │ $ make depends
  │ $ mirage build
  │ $ ./simple --filename README.md
  └────

  ┌────
  │ $ cd unikernel
  │ $ mirage configure -t hvt --disk docteur
  │ $ make depends
  │ $ mirage build
  │ $ solo5-hvt --block:docteur=disk.img -- simple.hvt --filename README.md
  └────

  Finally, Docteur proposes another tool that checks (and analyzes) an
  image to give you the version of the commit used (if the image comes
  from a Git repository) or the hash of your file system produced by the
  calculation of a [Merkle tree].
  ┌────
  │ $ docteur.verify disk.img
  │ commit	: ad8c418635ca6683177c7ff3b583e1ea5afea78f
  │ author	: "Calascibetta Romain" <romain.calascibetta@gmail.com>
  │ root	: bea10b6874f51e3f6feb1f9bcf3939933b2c4540
  │ 
  │ Merge pull request #11 from dinosaure/fix-tree-expanding
  │ 
  │ Fix how we expand our file-system
  └────


[Solo5] <https://github.com/Solo5/solo5>

[Merkle tree] <https://en.wikipedia.org/wiki/Merkle_tree>


Conclusion
╌╌╌╌╌╌╌╌╌╌

  Many times people ask me for a purpose in MirageOS such as a website
  or a particular service. I think that Docteur shows one essential
  thing about MirageOS, it is a tool and an ecosystem. But it's not an
  endpoint that is concretized in a specific application.

  Docteur is not THE solution to our problems and answers a specific use
  case. What is important to note is not what Docteur does but the
  possibility for our ecosystem and our tools to allow the development
  of Docteur. As it allows the development of a trillion applications!

  As such, I say to those people to "play" with MirageOS if they want to
  learn more. Our goal is not to show you applications that you could
  then deploy easily (even if we are working on this aspect too) but to
  give you the possibility to imagine your OS (independently from our
  vision)!

  And if you try, we'll be happy to help you!


Ocaml-solidity, a new OCaml library for Solidity
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-solidity-a-new-ocaml-library-for-solidity/7746/1>


OCamlPro announced
──────────────────

  We are pleased to announce our new OCaml library, ocaml-solidity !
  [Ocaml-solidity] is a program manipulation library that provides a
  Solidity parser and typechecker.

  Our library is made for developers on Solidity code analysis, it
  builds a typechecked AST that can be analyzed with a provided
  visitor. Please note that our parser and typecheck conforms mostly to
  Solidity 0.7, inline assembly is not supported. Take a look at [our
  documentation].

  You can test it and report bugs just [here]!


[Ocaml-solidity] <https://github.com/OCamlPro/ocaml-solidity>

[our documentation] <https://ocamlpro.github.io/ocaml-solidity/>

[here] <https://github.com/OCamlPro/ocaml-solidity/issues>


Migrating to floatarray (blog post)
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/migrating-to-floatarray-blog-post/7749/1>


Nicolás Ojeda Bär announced
───────────────────────────

  At LexiFi we recently migrated our codebase to use `floatarray' in
  place of `float array' in order to disable the "flat float array" mode
  in the compiler. If you are interested in finding out more about how
  we did it, we wrote a blog post about it
  <https://www.lexifi.com/blog/ocaml/floatarray-migration/>. Enjoy!


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-04-20  9:07 Alan Schmitt
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From: Alan Schmitt @ 2021-04-20  9:07 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of April 13 to 20,
2021.

Table of Contents
─────────────────

Preface (initial release)
OCaml Users and Developers Workshop 2021
Timere 0.1.3 - Dealing with time and time zones has never been easier
Release of `multipart_form.0.2.0'
Engineer position for the development of the Squirrel prover
Martin Jambon presentation on Semgrep, Wed April 21 @ 7pm Central
Old CWN


Preface (initial release)
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-preface-initial-release/7669/1>


Xavier Van de Woestyne announced
────────────────────────────────

  Hello, @d-plaindoux and @pytre and I are very happy to present
  *Preface*, a project that has occupied part of our free time for
  almost 2 years. We received a lot of help from various people (as
  mentioned in the [CREDITS] page), including some present on this forum
  (@gasche, @octachron and @snowleopard)

        Preface is an opinionated library designed to facilitate
        the handling of recurring functional programming idioms in
        [OCaml]. Many of the design decisions were made in an
        attempt to calibrate, as best as possible, to the OCaml
        language. Trying to get the most out of the module
        language. *The name "preface" is a nod to "Prelude"* .

  • [Github repository]
  • [Online documentation]


[CREDITS]
<https://github.com/xvw/preface/blob/master/CREDITS.md#warm-thanks-and-help>

[OCaml] <https://ocaml.org>

[Github repository] <https://github.com/xvw/preface>

[Online documentation]
<https://ocaml-preface.github.io/preface/Preface/index.html>

About the project, and motivation
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  When learning functional programming, one is often confronted with
  constructs derived (or not) from category theory.  Languages such as
  Haskell offer very complete libraries to use them, and thus,
  facilitate their learning. In OCaml, it often happens that these
  abstractions are buried in the heart of certain libraries/projects
  ([Lwt], [Cmdliner], [Bonsai], [Dune] etc.). This is why one of the
  objectives of Preface is to propose tools for concretising these
  abstractions, at least as a pedagogical tool.


[Lwt] <https://ocsigen.org/lwt/latest/manual/manual>

[Cmdliner] <https://erratique.ch/logiciel/cmdliner>

[Bonsai] <https://github.com/janestreet/bonsai>

[Dune] <https://dune.build>


Is Preface useful
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Since OCaml allows for efficient imperative programming, Preface is
  probably not really useful for building software.  However, we (the
  maintainers) think that Preface can be useful for a few things:

  • technical experimentation with abstractions (especially those from
    the Haskell world) that allow programming in a fun style.
  • As an educational tool. Many teaching aids generally only offer the
    minimal interfaces to these abstractions. Preface tries to be as
    complete as possible.
  • It was a lot of fun to make. The last point is obviously the
    lightest but building Preface was really fun! So even if some people
    won't see the point… *we had fun making it*!

  Let's imagine this scenario! Oh, there's this article that seems to
  describe quite precisely how to solve `this complex problem',
  elegantly, using this `collection of abstractions'. After reading, the
  article is clear and I know how to use this `collection of
  abstractions' in practice. I would like to test it. Not having enough
  RAM to install Cabal, I decided to do it in OCaml. But as one
  abstraction leads to another, I am obliged to build an armada of
  things and I abandon my experimentation.

  So now, rather than doing it, locally, for the understanding of an
  article, I add it in Preface.


Additional links
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The [README] is quite expansive on motivations and some design
  choices, but we have tried to add some concrete guides:
  • [ Understanding the module breakdown of Preface]
  • [Effect handling using Freer]
  • [Error handling with Result/Validation and a Free Applicative]

  And in addition here is a project, by a friend of ours, that uses
  Preface, to build static blog generators (very original isn't it :P),
  the code is highly documented and can be an entry point into how to
  use it: [Github repository of the project]


[README] <https://github.com/xvw/preface#preface>

[ Understanding the module breakdown of Preface]
<https://github.com/xvw/preface/blob/master/guides/option_instantiation.md>

[Effect handling using Freer]
<https://github.com/xvw/preface/blob/master/guides/freer_effect_handling.md>

[Error handling with Result/Validation and a Free Applicative]
<https://github.com/xvw/preface/blob/master/guides/error_handling.md>

[Github repository of the project]
<https://github.com/xhtmlboi/wordpress>


Conclusion
╌╌╌╌╌╌╌╌╌╌

  Preface does not offer much that is new, but we have tried to make it
  user-friendly and to document as much as possible the code and design
  choices. It's a lot of fun to build… and it will probably be just as
  much fun to maintain.

  *We are extremely open to contributions and feedback.*

  And my last words will be a warm thank you to the OCaml ecosystem that
  has facilitated so much of our development: Testing with [Alcotest]
  and [QCheck] is a pleasure. [Dune] is a fast and pleasant build
  system. [ODoc] has allowed us to have more control over the generation
  of documentation, especially with the `@inline' comment (on includes)
  which allows signatures from different modules to be merged. And [MDX]
  which I did not know at all and which is used extensively for guides.

  I hope you can find interest in this project! Good luck with the rest
  of the containment (for those concerned).


[Alcotest] <https://github.com/mirage/alcotest>

[QCheck] <https://github.com/c-cube/qcheck>

[Dune] <https://dune.build>

[ODoc] <https://github.com/ocaml/odoc>

[MDX] <https://github.com/realworldocaml/mdx>


OCaml Users and Developers Workshop 2021
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-users-and-developers-workshop-2021/7673/1>


Frédéric Bour announced
───────────────────────

  It is my pleasure to invite submissions to the OCaml Users and
  Developers Workshop 2021, which is again co-located with ICFP and will
  be held virtually this year.

  The OCaml Users and Developers Workshop brings together industrial
  users of OCaml with academics and hackers who are working on extending
  the language, type system, and tools. Previous editions have been
  co-located with ICFP 2012 in Copenhagen, ICFP 2013 in Boston, ICFP
  2014 in Gothenburg, ICFP 2015 in Vancouver, ICFP 2016 in Nara, ICFP
  2017 in Oxford, ICFP 2018 in St Louis, ICFP 2019 in Berlin, and was
  virtual for ICFP 2020, following the OCaml Meetings in Paris in 2010
  and 2011.


Important Links
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [https://icfp21.sigplan.org/home/ocaml-2021 ]
  • [https://ocaml2021.hotcrp.com ]


[https://icfp21.sigplan.org/home/ocaml-2021 ]
<https://icfp21.sigplan.org/home/ocaml-2021>

[https://ocaml2021.hotcrp.com ] <https://ocaml2021.hotcrp.com>


Important dates
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Thursday 20th May (any time zone): Abstract submission deadline
  • Friday 18th July: Author notification
  • Friday 27th August: OCaml Workshop


Scope
╌╌╌╌╌

  Presentations and discussions focus on the OCaml programming language
  and its community. We aim to solicit talks on all aspects related to
  improving the use or development of the language and its programming
  environment, including, for example (but not limited to):

  • compiler developments, new backends, runtime and architectures
  • practical type system improvements, such as GADTs, first-class
    modules, generic programming, or dependent types
  • new library or application releases, and their design rationales
  • tools and infrastructure services, and their enhancements
  • prominent industrial or experimental uses of OCaml, or deployments
    in unusual situations.


Presentations
╌╌╌╌╌╌╌╌╌╌╌╌╌

  Presentations will be held in the online format. Each presentation
  comprise a prerecorded presentation and an interactive live Q&A
  session after the talk. Each talk will be re-translated three times in
  different time zones.  Session chairs and volunteers will assist the
  authors in preparing and casting the presentation. Each presentation
  will be made available through the ocaml.org website.


Submission
╌╌╌╌╌╌╌╌╌╌

  To submit a presentation, please register a description of the talk
  (about 2 pages long) at <https://ocaml2021.hotcrp.com/> providing a
  clear statement of what will be provided by the presentation: the
  problems that are addressed, the solutions or methods that are
  proposed.

  LaTeX-produced PDFs are a common and welcome submission format. For
  accessibility purposes, we ask PDF submitters to also provide the
  sources of their submission in a textual format, such as .tex
  sources. Reviewers may read either the submitted PDF or the text
  version.


Camera ready presentations
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  A pre-recorded versions of accepted presentation shall be provided
  before August, 13th. Volunteers will provide technical assistance to
  authors as well as provide necessary feedback and ensure that all
  videos match our quality standards.


ML family workshop
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The ML family workshop, held on the previous day, deals with general
  issues of the ML-style programming and type systems, focuses on more
  research-oriented work that is less specific to a language in
  particular. There is an overlap between the two workshops, and we have
  occasionally transferred presentations from one to the other in the
  past. Authors who feel their submission fits both workshops are
  encouraged to mention it at submission time and/or contact the Program
  Chairs.


Program Commitee
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Frédéric Bour, Tarides, France
  • Cristina Rosu, Janestreet, UK
  • Hakjoo Oh, Korea University, Korea
  • Hugo Heuzard, Janestreet, UK
  • Jeffrey A. Scofield, Formalsim, USA
  • Jonathan Protzenko, MSR, USA
  • Joris Giovanangeli, Ahrefs, Singapore
  • Jun Furuse, Dailambda, Japan
  • Kihong Heo, KAIST, Korea
  • Kate Deplaix, OCaml Labs, UK
  • Medhi Bouaziz, Nomadic Labs, France
  • Simon Castellan, INRIA, France
  • Ryohei Tokuda, Idein, Japan
  • Vaivaswatha Nagaraj, Zilliqa, India
  • Youyou Cong, Tokyo Institute of Technology, Japan


Questions and contact
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Please contact the PC Chair ([Frédéric Bour]) for any questions.


[Frédéric Bour] <mailto:frederic.bour@lakaban.net>


Timere 0.1.3 - Dealing with time and time zones has never been easier
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-timere-0-1-3-dealing-with-time-and-time-zones-has-never-been-easier/7173/2>


Darren announced
────────────────

  Timere 0.2.1 has landed!

  This release adds nanosecond precision support to timere (and
  fractional second support at various places), along with other small
  improvements.


Release of `multipart_form.0.2.0'
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-multipart-form-0-2-0/7704/1>


Calascibetta Romain announced
─────────────────────────────

  I am pleased to announce the release of [`multipart_form']. Throughout
  the development of [mrmime], we have gained a thorough knowledge of
  the RFCs about email. However, these RFCs also describe mechanisms
  that are found in HTTP/1.1.


[`multipart_form'] <https://github.com/dinosaure/multipart_form>

[mrmime] <https://github.com/mirage/mrmime>

Genesis
╌╌╌╌╌╌╌

  More specifically, a lot of work has been done on [RFC 2045] & [RFC
  2046] (see [RFC 7578 § 4]) which describe the `multipart' format
  (found in emails and in `HTTP/1.{0,1}' requests when serializing a
  `<form>').

  From this work (~ 2 years), we decided to extract the parts allowing
  to manipulate a `multipart/form-data' content for `HTTP/1.{0,1}'
  responses (plus [RFC 2183]). This resulted in the creation of
  `multipart_form'.

  This project is a cross between what many users have been waiting for
  (for [CoHTTP] and [http/af]), a knowledge of what exists and its
  limitations, and finally a development in the spirit of MirageOS.

  The result is an API that is _"full stream"_. Indeed. a question arose
  from the beginning, how to manipulate this format while:
  • not having access to a file system (MirageOS)
  • not exploding memory usage for file uploads


[RFC 2045] <https://tools.ietf.org/html/rfc2045>

[RFC 2046] <https://tools.ietf.org/html/rfc2046>

[RFC 7578 § 4] <https://tools.ietf.org/html/rfc7578#section-4>

[RFC 2183] <https://tools.ietf.org/html/rfc2183>

[CoHTTP] <https://github.com/mirage/ocaml-cohttp>

[http/af] <https://github.com/inhabitedtype/httpaf>


Memory bound implementation
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  With the help of @Armael and the [`memtrace'] tool, we were able to
  implement and extend `multipart_form' so that it is easier to use and
  really ensures our original assumption about memory consumption.

  So we experimented with use cases like uploading very large
  files. Here is the result that `memtrace' gives us with a 100Mb file:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/9/92ee2ab6fa1d4da62d894749aa4b161a95b53fb2_2_1034x590.png>

  The application tries to save the games in files. We use [opium] (and
  thus http/af) but tests were also done with CoHTTP. The code is
  available [here] for people who want to reproduce.


[`memtrace']
<https://blog.janestreet.com/finding-memory-leaks-with-memtrace/>

[opium] <https://github.com/rgrinberg/opium>

[here]
<https://gist.github.com/dinosaure/299c421c95cec4255df7b9289eb53815>


Documentation & encoding
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Finally, a major effort has been made in the documentation to explain
  in detail how to use `multipart_form'. Version `0.2.0' also adds a way
  to produce a `multipart/form-data' document (experimental) with the
  same constraints on memory usage.

  I hope this work will be useful to a lot of people. The documentation
  is available [here].


[here]
<https://dinosaure.github.io/multipart_form/multipart_form/index.html>


Engineer position for the development of the Squirrel prover
════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-04/msg00022.html>


David Baelde announced
──────────────────────

  We are looking for an engineer to support the development of Squirrel,
  an interactive theorem prover for security protocols. The position
  will be funded by ERC POPSTAR. You may find more details here:

  <https://people.irisa.fr/Stephanie.Delaune/internship/sujet-engineer-squirrel.pdf>

  Skilled OCaml developers would be most welcome!


Martin Jambon presentation on Semgrep, Wed April 21 @ 7pm Central
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/martin-jambon-presentation-on-semgrep-wed-april-21-7pm-central/7709/1>


Claude Jager-Rubinson announced
───────────────────────────────

  Please join us this coming Wednesday at 7pm Central when @mjambon will
  talk about Semgrep, an open-source ployglot static analysis tool
  written in OCaml.

  Details and connection info are available at [Houston Functional
  Programmers].


[Houston Functional Programmers] <https://hfpug.org>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-04-06  9:42 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-04-06  9:42 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of March 30 to April
06, 2021.

Table of Contents
─────────────────

Ecosystem Engineer and Technical Writer positions
Release of cohttp 4.0.0
Timere-parse 0.0.2, natural language parsing of date, time and duration
agrid 0.1
State of OCaml and web assembly
containers 3.3
New OCaml books?
Old CWN


Ecosystem Engineer and Technical Writer positions
═════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-ecosystem-engineer-and-technical-writer-positions/7571/1>


Celine announced
────────────────

  [Tarides] is hiring an [Ecosystem Engineer] and a [Technical Writer].

  Tarides is a tech startup based in Paris and founded in 2018. We
  develop a software infrastructure platform to deploy secure,
  distributed applications with strict resource contraints and
  low-latency performance requirements.

  We welcome applications from people of all backgrounds. We are working
  hard to create a representative, inclusive and friendly team, because
  we know that different experiences, perspectives and backgrounds make
  for a better place.

  Please, don't hesitate to contact me if you have any question, I'll be
  more than happy to reply! :)


[Tarides] <https://tarides.com/>

[Ecosystem Engineer] <https://tarides.com/jobs/ecosystem-engineer>

[Technical Writer] <https://tarides.com/jobs/technical-writer>


Release of cohttp 4.0.0
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-cohttp-4-0-0/7537/2>


Continuing this thread, Calascibetta Romain said
────────────────────────────────────────────────

        The work on the new conduit is steadily progressing and
        will be integrated in a new major release of cohttp in the
        future, once we will be confident that the API is
        settled. If you want to try using it immediately, then it
        is available as the [mimic ] library in ocaml-git.

  I just take the opportunity to show up a tutorial about `mimic' which
  is now available into the distribution of it: see [here]. Thanks for
  your work about the release process.


[mimic ] <https://github.com/mirage/ocaml-git/tree/master/src/mimic>

[here] <https://mirage.github.io/ocaml-git/mimic/index.html>


Timere-parse 0.0.2, natural language parsing of date, time and duration
═══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-timere-parse-0-0-2-natural-language-parsing-of-date-time-and-duration/7532/2>


Continuing this thread, Darren said
───────────────────────────────────

  The demo site has been updated to use Timere-parse, you can now try
  interacting with `Timere_parse.timere' in web browser at
  <https://daypack-dev.github.io/timere-parse-demo/>


agrid 0.1
═════════

  Archive: <https://discuss.ocaml.org/t/ann-agrid-0-1/7587/1>


zapashcanon announced
─────────────────────

  I'm pleased to announce the first release of [agrid].

  Agrid stands for *Adjustable Grid*. Adjustable grids are basically two
  dimensional arrays whose width/height can be changed by adding or
  removing row/column at either end (one at a time).

  Here's a very short example :

  ┌────
  │ let () =
  │   let grid = Agrid.of_list [[1; 2]; [3; 4]] in
  │   let grid = Agrid.snoc_row grid (Flex_array.of_list [5; 6]) in
  │   Agrid.pp Format.pp_print_int Format.std_formatter grid
  │   (* prints:
  │    * 1; 2
  │    * 3; 4
  │    * 5; 6
  │    *)
  └────

  It's based on the great [flex-array] library by [Jean-Christophe
  Filliâtre] and is mainly a wrapper around it to make it easier for the
  special case of two dimensional arrays.

  It's been developped at [OCamlPro] while working on [mosaic] when we
  wanted to ease the dataset input process, switching from a basic
  textarea based input to something which looks like a spreadsheet (this
  work is not yet published on the online version).


[agrid] <https://ocamlpro.github.io/agrid>

[flex-array] <https://github.com/backtracking/flex-array>

[Jean-Christophe Filliâtre] <https://www.lri.fr/~filliatr/>

[OCamlPro] <https://www.ocamlpro.com/>

[mosaic] <https://mosaic.univ-lyon1.fr/>


gasche asked and zapashcanon replied
────────────────────────────────────

        Out of curiosity: In a spreadsheet, I would assume that
        inserting/removing rows or columns in the middle is also a
        useful operation. Would you be able to add this operation?

  It's not really a spreadsheet, it's more something [like this]. I
  don't think it would be really useful in the case of mosaic because
  for big inputs, users are more likely to import the data from a file.

  Anyway, it's possible to add this operation, but I can't think of an
  efficient way to do it. I'll think about it and may add such an
  operation. Actually, if it's added to flex-array, it would be trivial
  to add it to agrid, so I'll probably try to add it there.


[like this] <https://www.zapashcanon.fr/~leo/atable/>


State of OCaml and web assembly
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/state-of-ocaml-and-web-assembly/2725/15>


Deep in this thread, Emilio Jesús Gallego Arias announced
─────────────────────────────────────────────────────────

  Yup, we didn't make it yet the "official" release, but it has been
  used by quite a few people to avoid lack of tail-call optimization in
  jsoo, live versions:
  • <https://jscoq.github.io/wa/>
  • <https://jscoq.github.io/wa/scratchpad.html>

  It literally flies.

  I guess @corwin-of-amber is the right person to comment more on his
  superb efforts.


Shachar Itzhaky then added
──────────────────────────

  Hi there @camarick; ocaml-wasm is very much bleeding-edge but it
  already works surprisingly well and I have used it to run Coq,
  esp. for the purpose of making the interactive version of Vols. I,II
  from the Software Foundations textbook (see
  <https://jscoq.github.io/ext/sf> and
  <https://jscoq.github.io/ext/sf/tools/jscoq-tester.html>).

  Of course @ejgallego is exaggerating when he says that it flies, it
  still runs OCaml bytecode in interpreted mode on top of the WASM
  JIT. Performance is pretty reasonable still, except in the case some
  intensive Coq tactics (in which case this is a third level of
  interpreter… :man_facepalming: ). The main gap right now is the
  standard libraries `str', `unix', and `threads', for which I have
  compiled empty stubs, because dynamic loading of libraries in WASI is
  still immature. I *have* been able to compile `num' and it works
  correctly because it does not depend on anything else. I am currently
  investigating how to build `zarith' (which requires `gmp') because Coq
  8.13 depends on it.

  So yeah, this is not at all the coveted WASM backend for `ocamlc', but
  it's one existing solution and you can hack on it right now. Any help
  or comments are welcome!


containers 3.3
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-containers-3-3/7594/1>


Simon Cruanes announced
───────────────────────

  I'm glad to announce the release of containers 3.3. Containers is an
  extension to OCaml's standard library that strives to be compatible
  with it, with more features and a few additional modules to get
  dynamic arrays, heaps, S-expression parser/printer, etc.

  In this release, we have new support for parsing/printing canonical
  S-expressions (a simple binary-safe format), a code-generation module
  for bitfields, and many improvements to existing modules in particular
  in the interface between maps/set/hashtbl and iterators.

  More details [in the github release].

  Many thanks to the contributors, in particular @Fardale for his work
  on CI and auto-doc-generation.


[in the github release]
<https://github.com/c-cube/ocaml-containers/releases/tag/v3.3>


New OCaml books?
════════════════

  Archive: <https://discuss.ocaml.org/t/new-ocaml-books/5789/6>


Deep in this thread, Damien Guichard announced
──────────────────────────────────────────────

  I’m also working on a free culture book. The preview is at
  <https://damien-guichard.developpez.com/downloads/Algorithmic-with-OCaml.pdf>

  It’s under CC-BY-SA.

  Planned chapters include : Records, Type polymorphism, Modules as
  functions, Conceptual graphs.

  The reason why i don't contribute to @dmbaturin's effort is that my
  main topic is algorithmic, ocaml is more a good way than a goal.


Damien Guichard later added
───────────────────────────

  Sorry, you have to be a member of <https://www.developpez.com/> to
  access this link.

  Here is my 2nd try. I hope you don't need to be a member of
  <https://www.aeriesguard.com/> this time.
  <https://www.aeriesguard.com/media/get/504bfbe34d3f517c8acf37ffbe200f84698aca0c/Algorithmic-with-_OCaml.pdf>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-03-30 14:55 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-03-30 14:55 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 21208 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 23 to 30,
2021.

Table of Contents
─────────────────

Theorem Proving with Coq and Ocaml
ocaml-aws 1.2
Release of `fmlib.0.2.0'
soupault: a static website generator based on HTML rewriting
Timere-parse 0.0.2, natural language parsing of date, time and duration
ocamlnet-4.1.9
Release of cohttp 4.0.0
New Try-Alt-Ergo website
Other OCaml News
Old CWN


Theorem Proving with Coq and Ocaml
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/theorem-proving-with-coq-ocaml/7524/1>


Gregory Malecha announced
─────────────────────────

  I lead the formal methods team at Bedrock Systems
  (<https://bedrocksystems.com>) and we are looking to hire a full-time
  engineer working on automation in the Coq proof assistant (which is
  written in Ocaml). We're very interested in candidates with strong
  Ocaml background especially in topics related to automated theorem
  proving, e.g. SAT/SMT solvers, datalog, superposition, resolution,
  etc. While Coq experience is great, you do not need to be a Coq expert
  to apply to this position, we're happy to marry your Ocaml expertise
  with our Coq expertise.

  Formal methods are at the core of BedRock's business and we are deeply
  committed to solving problems of system verification at industrial
  scale. We get FM techniques and insights into the code early on and
  use them to build, maintain, and evolve code. This includes developing
  more agile techniques to keep evolving verified systems once they're
  built.

  We have eight folks on the formal methods team today, hailing from
  MPI-SWS, MIT CSAIL, Princeton, and other leading research groups. If
  you're interested, send me an email or you can inquire more broadly at
  jobs@bedrocksystems.com.

  *Company overview:*

  BedRock is building a *trustworthy compute base for mission-critical
  applications* . The foundation of the platform is an open source,
  multi-core, capability-based micro-hypervisor that we are developing
  and verifying. On top of these deep specifications we are writing and
  verifying applications to provide an extensible and configurable core.

  Our contention is that the *time is ripe for verifiably trustworthy
  systems*, for everything from secure phones and industrial IoT to
  autonomous systems and financial infrastructure. With significant seed
  funding, great investors, and commercial projects underway, we are
  growing our team in Boston, the Bay Area, DC, and Germany.


ocaml-aws 1.2
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocaml-aws-1-2/7526/1>


Tim Mc Gilchrist announced
──────────────────────────

  I'm pleased to announce the release of [ocaml-aws] 1.2.

  ocaml-aws aims to provide generated bindings to many AWS services
  using the botocore specifications. In this version we've bumped
  version bounds on a bunch of depedencies and also added new bindings
  for:
  • RDS
  • Route53
  • SDB
  • SQS

  Please check it out and report any issues.


[ocaml-aws] <https://opam.ocaml.org/packages/aws/>


Release of `fmlib.0.2.0'
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-fmlib-0-2-0/7527/1>


Hbr announced
─────────────

  I am pleased to announce the second release (0.2.0) of fmlib, a
  functional library with managed effects.

  The library has up to now 4 components:

  • [Some standard datatypes]
  • [Pretty printing functions]
  • [Parsing combinator library]
  • [Primitives to compile to javascript]

  The last component is the new one in version 0.2.0. Internally it uses
  `js_of_ocaml' to compile to javascript. It is an easy to use library
  of primitive functions to access mainly browser functionality from
  ocaml and some rudimentary functions to access nodejs functionality.

  It can be installed via opam by

  ┌────
  │ opam update
  │ opam install fmlib
  │ opam install fmlib_js
  └────

  It is located at [github]


[Some standard datatypes]
<https://hbr.github.io/fmlib/odoc/fmlib/Fmlib_std/index.html>

[Pretty printing functions]
<https://hbr.github.io/fmlib/odoc/fmlib/Fmlib_pretty/Print/index.html>

[Parsing combinator library]
<https://hbr.github.io/fmlib/odoc/fmlib/Fmlib_parse/index.html>

[Primitives to compile to javascript]
<https://hbr.github.io/fmlib/odoc/fmlib_js/index.html>

[github] <https://github.com/hbr/fmlib>


Hbr added
─────────

  Hint: `fmlib' is still a bundle of three libraries i.e. three toplevel
  modules `Fmlib_std', `Fmlib_pretty' and `Fmlib_parse'. Therefore they
  have to be used in a `dune' file with

  ┌────
  │ (libraries fmlib.fmlib_std fmlib.fmlib_pretty fmlib.fmlib_parse ...)
  └────

  while the new library can be used with

  ┌────
  │ (libraries fmlib_js ...)
  └────

  This inconvenience will be corrected in the next release.


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/14>


Daniil Baturin announced
────────────────────────

  [soupault 2.5.0] offers some features that are unique among SSGs.

  There are two new built-in widgets for rewriting internal links, which
  is useful if you don't host your website at the server root. For
  example, if you host it at `example.com/~user', you cannot just write
  `<img src="/header.png">': it will point to `example.com/header.png'
  while you want `example.com/~user/header.png' instead.

  The `relative_links' widget will convert all internal links to
  relative links according to their depth in the directory tree. For
  example, suppose you have `<img src="/header.png">' in your page
  template. Then in `about/index.html' that link will become `<img
  src="../header.png">'; in `books/magnetic-fields/index.html' it will
  be `<img src="../../header.png">' and so on. This way you can move the
  website to a subdirectory and it will still work.

  The `absolute_links' widget prepends a prefix to every internal
  link. Conceptually similar to the site URL option in other SSGs and
  CMSes, but works for all links, not only links generated by the SSG
  itself.


[soupault 2.5.0] <https://soupault.app/blog/soupault-2.5.0-release/>


Timere-parse 0.0.2, natural language parsing of date, time and duration
═══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-timere-parse-0-0-2-natural-language-parsing-of-date-time-and-duration/7532/1>


Darren announced
────────────────

  I'm happy to announce the release of Timere-parse 0.0.2, the natural
  language parsing component of Timere, a date time handling and
  reasoning library. Both packages are under the [Timere repo].

  Timere-parse allows interpretation of common descriptions of date,
  time and duration.


[Timere repo] <https://github.com/daypack-dev/timere>

Date time examples
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Input strings are in `""', indented lines are pretty printed output.

  ┌────
  │ "2020 jun 6 10am"
  │   Ok 2020-06-06T10:00:00Z
  │ "2020 jun 6th 10:15"
  │   Ok 2020-06-06T10:15:00Z
  │ "Australia/Sydney 2020 jun 6 10am"
  │   Ok 2020-06-06T10:00:00+10:00
  │ "01-06-2020 10:10"
  │   Ok 2020-06-01T10:10:00Z
  │ "2020/06/01 10am"
  │   Ok 2020-06-01T10:00:00Z
  │ "jul 6 2021 9:15am"
  │   Ok 2021-07-06T09:15:00Z
  │ "2020/06/01"
  │   Ok 2020-06-01T00:00:00Z
  └────


Duration examples
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ "24h"
  │   Ok 1 days 0 hours 0 mins 0 secs
  │ "16.5 hours"
  │   Ok 16 hours 30 mins 0 secs
  │ "1h20min"
  │   Ok 1 hours 20 mins 0 secs
  │ "1 hour 2.5 minutes"
  │   Ok 1 hours 2 mins 30 secs
  │ "100 seconds"
  │   Ok 1 mins 40 secs
  │ "2.25 minutes 1 seconds"
  │   Ok 2 mins 16 secs
  │ "5 days 6.5 hours"
  │   Ok 5 days 6 hours 30 mins 0 secs
  └────


Timere object examples
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ "2020 jun"
  │   Ok (pattern (years 2020) (months Jun))
  │ "jan"
  │   Ok (pattern (months Jan))
  │ jan 6 12pm to 2pm"
  │   Ok (bounded_intervals whole (duration 366 0 0 0) (points (pick mdhms Jan 6 12 0 0)) (points (pick hms 14 0 0)))
  │ "12th, 13 to 15, 20"
  │   Ok (pattern (month_days 12 13 14 15 20))
  │ "16th 7:30am"
  │   Ok (pattern (month_days 16) (hours 7) (minutes 30) (seconds 0))
  │ "16th 8am to 10am, 11am to 12pm"
  │   Ok (inter (pattern (month_days 16)) (union (bounded_intervals whole (duration 1 0 0 0) (points (pick hms 8 0 0))
  │ (points (pick hms 10 0 0))) (bounded_intervals whole (duration 1 0 0 0) (points (pick hms 11 0 0)) (points (pick hms
  │ 12 0 0)))))
  │ "2020 jun 16th 10am to jul 1 12pm"
  │   Ok (bounded_intervals whole (duration 366 0 0 0) (points (pick ymdhms 2020 Jun 16 10 0 0)) (points (pick mdhms Jul
  │ 1 12 0 0)))
  └────


Corpus
╌╌╌╌╌╌

  For the full corpus/examples, see [corpus/] for code and
  [corpus-outputs/] for generated outputs.


[corpus/] <https://github.com/daypack-dev/timere/tree/main/corpus>

[corpus-outputs/]
<https://github.com/daypack-dev/timere/blob/main/corpus-outputs>


ocamlnet-4.1.9
══════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-03/msg00028.html>


Gerd Stolpmann announced
────────────────────────

  there is now ocamlnet-4.1.9 available:

  • compatibility with upcoming OCaml-4.12
  • some fixes regarding TLS (https)
  • a few build-related details

  See the project page for download, documentation, a detailed
  changelog, and the mailing list:
  <http://projects.camlcity.org/projects/ocamlnet.html>

  The repository is at

  <https://gitlab.com/gerdstolpmann/lib-ocamlnet3/>

  opam follows soon.


Release of cohttp 4.0.0
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-cohttp-4-0-0/7537/1>


Marcello Seri announced
───────────────────────

  We are glad to announce the [upcoming release] of [`cohttp 4.0.0'], a
  low-level OCaml library for HTTP clients and servers.

  This release comes with a big update of the documentation and the
  examples, both in the [README] and in the codebase, and improvements
  and bug fixes from many contributors 🙇 which you will find listed
  below.

  A huge thank you to all the people that helped to get this release
  ready by raising issues, participating in discussions, sending PRs,
  and otherwise using our library.


[upcoming release] <https://github.com/ocaml/opam-repository/pull/18385>

[`cohttp 4.0.0'] <https://github.com/mirage/ocaml-cohttp>

[README] <https://github.com/mirage/ocaml-cohttp>

The future of cohttp
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  To quote @avsm from [another post]

        The development process […] is driven by a simple
        principle that is inspired by OCaml itself: don't
        needlessly break backwards compatibility without good
        reason, and when it is necessary, justify it. Our tools
        are embedded in projects that have lifespans measured in
        the decades, and we take compatibility seriously. That’s
        why we take pains to provide migration paths […] that are
        as invisible as possible.

  Since in this release we have decided to include a number of fixes and
  improvements which modified Cohttp module signatures, we decided to
  signal the potential breackage by bumping the major version of the
  library. In most cases, however, you don't need to do anything and
  your code will keep working with the latest cohttp.

  Moving forward, we have agreed to start working on the API and the
  internals of cohttp to modernize it and get it ready for multicore
  support and also for eventual unification with the h2 stack that
  offers HTTP2/3 support.

  To be able to move forward and avoid stalling improvements for months,
  we will be less shy of major releases.  However, to remain true to the
  principle above, we will be careful to introduce one breakage at a
  time, carefully justify its need and provide a clear upgrade path in
  the changelog.

  The version history is:
  • cohttp 2.5.5: security backports (changelog below)
  • cohttp 3.0.0: skipped (explained below)
  • cohttp 4.0.0: the next release (changelog below)
  • cohttp 5.0.0: will include a long-awaited change in [how headers are
    treated]: which fixes a multitude of past issues and simplifies the
    internals of the module.

  For the people that need stability, *we have decided to keep
  backporting important security fixes to the `2.5.x' branch of the
  project*. In fact, `cohttp 2.5.5', released just a few days ago was
  the first release with the backport of a security issue.


[another post]
<https://discuss.ocaml.org/t/defining-standard-ocaml-development-lifecycle-processes/7486/5>

[how headers are treated]
<https://github.com/mirage/ocaml-cohttp/pull/747>


What happened to 3.0.0?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The release of `cohttp 3.0.0' has been long awaited, and we are
  extremely grateful to @dinosaure for the enormous work that went into
  designing and implementing `conduit 3.0.0' and `cohttp 3.0.0' (part of
  which remained in `4.0.0' as bug fixes and API improvements).

  However, a discussion started soon after the release pointing out that
  there could be further room of improvement also with the new design,
  particularly with respect to backwards compatibility. Since the design
  discussion did not reach consensus, these changes were reverted to
  preserve better compatibility with existing cohttp users and `cohttp
  3.0.0' was [marked as unavailable] on the opam repository.  As
  maintainers, our "lesson learnt" is to not do releases incrementally
  when they span multiple libraries: we were caught in an awkward spot
  when conduit 3 was released, but without cohttp 3.

  The work on the new conduit is steadily progressing and will be
  integrated in a new major release of cohttp in the future, once we
  will be confident that the API is settled. If you want to try using it
  immediately, then it is available as the [mimic] library in ocaml-git.


[marked as unavailable]
<https://github.com/mirage/ocaml-cohttp/issues/736>

[mimic] <https://github.com/mirage/ocaml-git/tree/master/src/mimic>


Change Log
╌╌╌╌╌╌╌╌╌╌

v4.0.0
┄┄┄┄┄┄

  • cohttp.response: fix malformed status header for custom status codes
    (@mseri @aalekseyev #752)
  • remove dependency to base (@samoht #745)
  • add GitHub Actions workflow (@smorimoto #739)
  • `cohttp-lwt-jsoo': Forward exceptions to caller when response is
    null (@mefyl #738)
  • Use implicit executable dependency for generate.exe (@TheLortex
    #735)
  • cohttp: update HTTP codes (@emillon #711)
  • cohttp: fix chunked encoding of empty body (@mefyl #715)
  • cohttp-async: fix body not being uploaded with unchunked Async.Pipe
    (@mefyl #706)
  • cohttp-{async, lwt}: fix suprising behaviours of Body.is_empty
    (@anuragsoni #714 #712 #713)
  • refactoring of tests (@mseri #709, @dinosaure #692)
  • update documentation (@dinosaure #716, @mseri #720)
  • fix deadlock in logging (@dinosaure #722)
  • improve media type parsing (@seliopou #542, @dinosaure #725)
  • [reverted] breaking changes to client and server API to use conduit
    3.0.0 (@dinosaure #692). However, as the design discussion did not
    reach consensus, these changes were reverted to preserve better
    compatibility with existing cohttp users. (#741, @samoht)

  *Potentially breaking changes*

  • remove `wrapped false' from the codebase (@rgrinberg #734)
  • cohttp: add Uti.t to uri scheme (@brendanlong #707)
  • cohttp-lwt-jsoo: rename Cohttp_lwt_xhr to Cohttp_lwt_jsoo for
    consistency (@mseri #717)
  • cohttp: fix transfer-encoding ordering in headers (@mseri #721)
  • lower-level support for long-running cohttp-async connections
    (@brendanlong #704)
  • add of_form and to_form functions to body (@seliopou #440, @mseri
    #723)
  • cohttp-lwt: partly inline read_response, fix body stream leak
    (@madroach @dinosaure #696).  Note: there is a new warning that may
    show up in your logs when bodies are leaked, see also [#730].
  • add comparison functions for Request.t and Response.t via
    ppx_compare (@msaffer-js @dinosaure #686)


[#730] <https://github.com/mirage/ocaml-cohttp/issues/730>


v2.5.5
┄┄┄┄┄┄

  • `Cohttp_async.resolve_local_file', `Cohttp_lwt.resolve_local_file'
    and `Cohttp_lwt_unix.resolve_file' are now the same code under the
    hood (`Cohttp.Path.resolve_local_file'). The old names have been
    preserved for compatibility, but will be marked as deprecated in the
    next release. This changes the behavior of
    `Cohttp_lwt_unix.resolve_file': it now percent-decodes the paths and
    blocks escaping from the docroot correctly. This also fixes and
    tests the corner cases in these methods when the docroot is
    empty. (@ewanmellor #755)

    *Double check your code base for uses of
     `Cohttp_lwt_unix.resolve_file': it is unsafe with respect to path
     handling*. If you cannot upgrade to `cohttp 2.5.5', you should
     modify your code to call `Cohttp_lwt.resolve_local_file' instead.


New Try-Alt-Ergo website
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-try-alt-ergo-website/7555/1>


OCamlPro announced
──────────────────

  We are pleased to announce the new version of the [Try Alt-Ergo
  website]!

  As a reminder, Try Alt-Ergo allows you to write and run your problems
  in your browser without any server computation.  It was designed to be
  a powerful and simple tool to use.

  Updates concern these parts of the site:
  • A new back end in JavaScript
  • Front end with news features (Ace editor, top panel, right panel,
    etc.)

  Take a look at [our blogpost] to read how we have updated the Try
  Alt-Ergo website and what's new! You can also visit the [Try Alt-Ergo
  website] directly. As usual, do not hesitate to report bugs, to ask
  questions, or to give your feedback.


[Try Alt-Ergo website] <https://try-alt-ergo.ocamlpro.com/>

[our blogpost] <https://www.ocamlpro.com/2021/03/29/new-try-alt-ergo/>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [New Try-Alt-Ergo]
  • [TZComet's New Token Viewer]


[OCaml Planet] <http://ocaml.org/community/planet/>

[New Try-Alt-Ergo]
<https://www.ocamlpro.com/2021/03/29/new-try-alt-ergo/>

[TZComet's New Token Viewer]
<https://seb.mondet.org/b/0012-tzcomet-token-viewer.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-03-23  9:05 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-03-23  9:05 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of March 16 to 23,
2021.

Table of Contents
─────────────────

findlib-1.9.1
Conformist 0.2.1
Compiler Explorer now supports OCaml 4.12.0
Annoucement of OFLAT, a web-based platform to support courses on Formal Languages and Automata Theory
Old CWN


findlib-1.9.1
═════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-03/msg00014.html>


Gerd Stolpmann announced
────────────────────────

  a couple of installation problems slipped into findlib-1.9, mostly
  missing files in the release tarball, but also a FreeBSD
  incompatibility. For that reason, there is now findlib-1.9.1 fixing
  the problems (so far known, and I hope we caught them all).

  Same link as before:

  <http://projects.camlcity.org/projects/findlib.html>


Conformist 0.2.1
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-conformist-0-2-1/7482/1>


jerben announced
────────────────

  I am happy to announce the release of conformist 0.2.1.

  [Conformist] deals with schema definition and validation. It supports
  decoding to bridge the gap between runtime types and static types
  without ppx.

  ┌────
  │ type occupation =
  │   | Mathematician
  │   | Engineer
  │ 
  │ type user =
  │   { occupation : occupation
  │   ; email : string
  │   ; birthday : int * int * int
  │   ; nr_of_siblings : int
  │   ; comment : string option
  │   ; wants_premium : bool
  │   }
  │ 
  │ let user occupation email birthday nr_of_siblings comment wants_premium =
  │   { occupation; email; birthday; nr_of_siblings; comment; wants_premium }
  │ ;;
  │ 
  │ let occupation_decoder = function
  │   | "mathematician" -> Ok Mathematician
  │   | "engineer" -> Ok Engineer
  │   | _ -> Error "Unknown occupation provided"
  │ ;;
  │ 
  │ let occupation_encoder = function
  │   | Mathematician -> "mathematician"
  │   | Engineer -> "engineer"
  │ ;;
  │ 
  │ let user_schema =
  │   Conformist.(
  │     make
  │       Field.
  │ 	[ custom
  │ 	    occupation_decoder
  │ 	    occupation_encoder
  │ 	    "occupation"
  │ 	    ~meta:()
  │ 	; string "email"
  │ 	; date "birthday"
  │ 	; int ~default:0 "nr_of_siblings"
  │ 	; optional (string "comment")
  │ 	; bool "wants_premium"
  │ 	]
  │       user)
  │ ;;
  │ 
  │   let input =
  │     [ "occupation", [ "engineer" ]
  │     ; "email", [ "test@example.com" ]
  │     ; "birthday", [ "2020-12-01" ]
  │     ; "nr_of_siblings", [ "3" ]
  │     ; "comment", [ "hello" ]
  │     ; "wants_premium", [ "true" ]
  │     ]
  │ 
  │ let user =
  │   Conformist.decode Schema.user_schema input
  │ 
  │ let validation_errors =
  │   Conformist.validate Schema.user_schema input
  └────

  The `user_schema' and the `user' create function are guaranteed to be
  in sync at compile time.


[Conformist] <https://github.com/oxidizing/conformist>


Compiler Explorer now supports OCaml 4.12.0
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-compiler-explorer-now-supports-ocaml-4-12-0/7479/3>


Continuing this thread, Sora Morimoto announced
───────────────────────────────────────────────

  Today we deployed 4.12.0 flambda. It must already be available!


Annoucement of OFLAT, a web-based platform to support courses on Formal Languages and Automata Theory
═════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-03/msg00026.html>


Antonio Ravara announced
────────────────────────

  <http://ctp.di.fct.unl.pt/FACTOR/OFLAT/>

  To support students’ autonomous work on topics related with Formal
  Languages and Automata Theory (FLAT), interactive tools that allow
  them to experiment with examples and solve exercises are very
  important - several studies demonstrate this.

  There are applications with this aim. While some are impressively
  complete, but are mainly Desktop applications (like JFLAP), others
  that can be used via a web browser are under-developed. Moreover,
  these applications are often not fully interactive - illustrations or
  even step-by-step execution is key to understand the algorithms - and,
  due to the programming languages used, implement the concepts in a way
  quite distant from the textbook Mathematical definitions. Code that
  implements closely the definitions is also a relevant pedagogical
  tool.

  With three concerns in mind - availability in mobile devices,
  interactive run of the algorithms (or at least presenting clear
  explanations), and code following closely the definitions - we
  developed OFLAT, a web-based tool to represent and illustrate
  graphically classical mechanisms and algorithms of Formal Languages
  and Automata Theory. It includes not only exercises evaluated
  automatically and providing feedback, but also allows students to
  create their own exercises. An integration with a grading platform
  like Learn-OCaml is underway.

  The tool is implemented in OCaml and is organised in two parts: a
  library - OCamlFLAT - which concentrates the logic of FLAT concepts,
  and the interactive applicational part - OFLAT. To run on browsers,
  the application uses the OCaml to Javascript translator
  Js_of_OCaml. To implement the interactive graphics, it uses Cytoscape,
  a Javascript library for graphs. All code is available in the Git of
  the project: <https://gitlab.com/releaselab/leaf/OCamlFlat>,
  <https://gitlab.com/releaselab/leaf/OFLAT>.

  The development of new functionalities is ongoing (we're now working
  more animations and on Context-Free Grammar and Pushdown Automata).
  Comments most welcome.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-03-16 10:31 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-03-16 10:31 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 5376 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 09 to 16,
2021.

Table of Contents
─────────────────

Links from the OCaml Discourse
findlib-1.9
Compiler Explorer now supports OCaml 4.12.0
Old CWN


Links from the OCaml Discourse
══════════════════════════════

The editor says
───────────────

  Due to a [global Discourse change] that disabled the mailing list
  mode, I was no able to collect the bodies of the news from the OCaml
  Discourse for several days. This has now been fixed and next week’s
  OCaml Weekly News should be as usual. In the meantime, here are links
  to the main announcements. Do not hesitate to [contact me] if you want
  to give feedback about this newsletter.

  • [Release 1.0.0 of bag]
  • [Plan for Dune 3.0]
  • [lascar 0.7.0 - a library for manipulating Labeled Transition
    Systems in OCaml]
  • [dirsift 0.0.3 - Search for directories by type]
  • [FSML 0.3.0 - an OCaml library for describing and describing
    synchronous finite state machines]
  • [Multicore OCaml: February 2021]
  • [VSCode OCaml Platform v1.7.0 - v1.8.0]
  • [ca-certs and ca-certs-nss]
  • [Js_of_Ocaml position at TrustInSoft]
  • [Senior Developer vacancy at Cryptosense, France (or remote)]
  • [hxd.0.3.1 - A simple hexdump tool in OCaml]
  • [Release of Gopcaml-mode (0.0.2) - Unicode & Compatibility Update]


[global Discourse change]
<https://meta.discourse.org/t/mailing-list-mode-mysteriously-deactivated/182650>

[contact me] <mailto:alan.schmitt@polytechnique.org>

[Release 1.0.0 of bag]
<https://discuss.ocaml.org/t/ann-release-1-0-0-of-bag/7464>

[Plan for Dune 3.0] <https://discuss.ocaml.org/t/plan-for-dune-3-0/7414>

[lascar 0.7.0 - a library for manipulating Labeled Transition Systems in
OCaml]
<https://discuss.ocaml.org/t/ann-lascar-0-7-0-a-library-for-manipulating-labeled-transition-systems-in-ocaml/7443>

[dirsift 0.0.3 - Search for directories by type]
<https://discuss.ocaml.org/t/ann-dirsift-0-0-3-search-for-directories-by-type/7435>

[FSML 0.3.0 - an OCaml library for describing and describing synchronous
finite state machines]
<https://discuss.ocaml.org/t/ann-fsml-0-3-0-an-ocaml-library-for-describing-and-describing-synchronous-finite-state-machines/7445>

[Multicore OCaml: February 2021]
<https://discuss.ocaml.org/t/multicore-ocaml-february-2021/7449>

[VSCode OCaml Platform v1.7.0 - v1.8.0]
<https://discuss.ocaml.org/t/ann-vscode-ocaml-platform-v1-7-0-v1-8-0/7424>

[ca-certs and ca-certs-nss]
<https://discuss.ocaml.org/t/ann-ca-certs-and-ca-certs-nss/6804/7>

[Js_of_Ocaml position at TrustInSoft]
<https://discuss.ocaml.org/t/js-of-ocaml-position-at-trustinsoft/7429>

[Senior Developer vacancy at Cryptosense, France (or remote)]
<https://discuss.ocaml.org/t/senior-developer-vacancy-at-cryptosense-france-or-remote/7431>

[hxd.0.3.1 - A simple hexdump tool in OCaml]
<https://discuss.ocaml.org/t/ann-hxd-0-3-1-a-simple-hexdump-tool-in-ocaml/7417>

[Release of Gopcaml-mode (0.0.2) - Unicode & Compatibility Update]
<https://discuss.ocaml.org/t/ann-release-of-gopcaml-mode-0-0-2-unicode-compatibility-update/7425>


findlib-1.9
═══════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-03/msg00012.html>


Gerd Stolpmann announced
────────────────────────

  findlib-1.9 is out. Changes:

  • Overhaul how separately installed packages (e.g. num) are handled
    (by David Allsopp).
  • Switch to opam-2.0 file format (by David Allsopp).
  • Fix an incomaptibility with ocaml-4.13 (by David Allsopp).
  • Expose the native toplevel (by Louis Gesbert).
  • Fix an incompatibility with "Jane Street Style" (by Mark Laws).
  • Switch from m4 to sed (by kit-ty-kate).

  For manual, download, manuals, etc. see here:

  <http://projects.camlcity.org/projects/findlib.html>

  An updated OPAM package will follow soon.


Compiler Explorer now supports OCaml 4.12.0
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-compiler-explorer-now-supports-ocaml-4-12-0/7479/1>


Sora Morimoto announced
───────────────────────

  Sorry to the OCaml hacker using Compiler Explorer for the late update
  (it took some time to deploy the infrastructure, etc.), but it now
  supports OCaml 4.12.0, but also 4.10.2 and 4.11.2!

  <https://godbolt.org>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-03-09 10:58 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-03-09 10:58 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 10261 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 02 to 09,
2021.

Table of Contents
─────────────────

Working on an app to learn and execute OCaml on iPhone/iPad/Mac for beginners
ERic (Entity-Relation interactive calculator) version 0.3
OCaml Café: Tue, March 9 @ 7-9pm (CST)
Functional Programming User Study (Specifically in OCaml)
OCaml 4.12.0 released (with 4.11.2 too)
Other OCaml News
Old CWN


Working on an app to learn and execute OCaml on iPhone/iPad/Mac for beginners
═════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/working-on-an-app-to-learn-and-execute-ocaml-on-iphone-ipad-mac-for-beginners/7392/1>


Nathan Fallet announced
───────────────────────

  I started to work on a new project recently: My goal is to provide an
  iOS app for beginners to learn OCaml and practice on their device.  I
  think it is a good idea to get started easily.

  Here are some screenshots of what I’ve done so far:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/e/ef66cf62d1ab605542033f09040cc964787cbb65_2_462x1000.jpeg>

  I’m open to feedback and opinion about this project idea


Nathan Fallet then added
────────────────────────

  I made it available for pre order on the App Store - I will keep
  improving it with time, and I think it can be a great tool for
  beginners

  [https://apps.apple.com/app/ocaml-learn-code/id1547506826]


[https://apps.apple.com/app/ocaml-learn-code/id1547506826]
<https://apps.apple.com/app/ocaml-learn-code/id1547506826>


Yawar Amin replied
──────────────────

  This is really cool. I just want to point out that your app is the
  sole search result for 'OCaml' in the App Store.  So that's a first
  :-)

  Incidentally, there is an 'OCaml Toplevel' app on the Android Play
  Store:
  <https://play.google.com/store/apps/details?id=fr.vernoux.ocaml>

  Your app looks more sophisticated though. Hopefully one day we have
  something like [Swift Playgrounds] and people can start learning OCaml
  interactively on their devices directly.


[Swift Playgrounds] <https://www.apple.com/ca/swift/playgrounds/>


ERic (Entity-Relation interactive calculator) version 0.3
═════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-eric-entity-relation-interactive-calculator-version-0-3/7408/1>


Damien Guichard announced
─────────────────────────

  The [programming languages zoo] is a great resource for wanna-be
  interpreter/compiler writers. The [ICFP 2000 programming contest] is
  another great resource for wanna-be ray tracers. However until now
  there has been no OCaml resource for wanna-be Knowledge Representation
  tool-ers. This makes sound like KR tool is a more difficult area than
  other projects. ERic v0.3 demonstrates the opposite as it's about 1200
  lines size (lexer & hand-written parser included) and reads/writes a
  [Conceptual Graph] Interchange Format (CGIF) notation.

  • ERic v0.3 [Zip archive]
  • ERic v0.3 [SVN repository]


[programming languages zoo] <http://plzoo.andrej.com/>

[ICFP 2000 programming contest]
<https://www.cs.cornell.edu/icfp/contest_results.htm>

[Conceptual Graph] <https://en.wikipedia.org/wiki/Conceptual_graph>

[Zip archive]
<http://damien-guichard.developpez.com/downloads/ERic-0.3.zip>

[SVN repository] <http://subversion.developpez.com/projets/ERic/trunk/>


OCaml Café: Tue, March 9 @ 7-9pm (CST)
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-cafe-tue-march-9-7-9pm-cst/7409/1>


Claude Jager-Rubinson announced
───────────────────────────────

  Please join us next Tuesday at 7pm Central time for the second meeting
  of OCaml Café.  Zoom connection info is available at [Houston
  Functional Programmers].

  OCaml Café offers a friendly, low stakes opportunity to ask questions
  about the OCaml language and ecosystem, work through programming
  problems that you’re stuck on, and get feedback on your code.
  Especially geared toward new and intermediate users, experienced OCaml
  developers will be available to answer your questions.

  Whether you’re still trying to make sense of currying or can spot
  non-tail-recursive code from across the room, we hope that you’ll join
  us with your questions about OCaml, or just to hang out with the OCaml
  community.


[Houston Functional Programmers] <https://hfpug.org>


Functional Programming User Study (Specifically in OCaml)
═════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/functional-programming-user-study-specifically-in-ocaml/7410/1>


Ahan Malhotra announced
───────────────────────

  We are doing user studies to help us understand how to help people
  understand and navigate complex information about programming
  documentation, *specifically in OCaml*. You will complete a series
  tasks that help us understand working memory and how you navigate a
  new interface. After examining a layout of the data (interface) for a
  short, predetermined amount of time, you will be asked a set of
  comprehension and/or qualitative questions to measure whether the
  methods of presenting this information has any impact on your
  performance.

  *The study will take around 55 minutes, and you will be entered into a
  lottery for a $150 Amazon gift card as compensation for your time.*

  *A bit more about this study*

  The user study will be done virtually on Zoom. You will be asked to
  various tasks with the interface. The interface is deployed as a
  public web application so you don’t have to install anything. This
  research is governed by Harvard University's Committee on the Use of
  Human Subjects.

  *Eligibility*

  You also don’t have to be an expert in anything to participate. You
  just need to be fluent in English and over 18 years of age.

  If you are interested, please fill out this survey to confirm your
  eligibility, and we will follow up to schedule the study session:
  <https://forms.gle/q6vkyEE2tSjjZoiSA>

  If you have any questions, please email
  ahanmalhotra@college.harvard.edu.


OCaml 4.12.0 released (with 4.11.2 too)
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-12-0-released-with-4-11-2-too/7358/13>


Continuing this thread from last week, Hannes Mehnert said
──────────────────────────────────────────────────────────

  Congratulations to the new release. For the curious who intend to
  install a flambda version of 4.12 and are surprised that
  `ocaml-variants.4.12.0+flambda' does not exist, from [this thread] the
  opam layout has changed, and now the following works:

  ┌────
  │ $ opam sw create <my-switch-name> --packages=ocaml-variants.4.12.0+options,ocaml-options-only-flambda
  └────

  There are more configuration options available, take a look at the
  output of `opam search ocaml-option' for all options. (I've not been
  involved with this development. I don't quite understand why there is
  for each `Y' a `ocaml-option-Y' and a `ocaml-options-only-Y'.) I also
  have not figured out whether there's a way to pass `-O3' in the just
  created switch.

  Maybe it is worth to embed such information in the very nicely styled
  OCaml manual (considering that opam got quite some traction over the
  years and is recommended for OCaml developers)?


[this thread]
<https://discuss.ocaml.org/t/ocaml-4-12-0-first-release-candidate/7294>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Release of Frama-Clang 0.0.10]
  • [Qubes-lite with KVM and Wayland]
  • [Florence and beyond: the future of Tezos storage]
  • [The ReScript Association]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Release of Frama-Clang 0.0.10]
<https://frama-c.com/fc-plugins/frama-clang.html>

[Qubes-lite with KVM and Wayland]
<https://roscidus.com/blog/blog/2021/03/07/qubes-lite-with-kvm-and-wayland/>

[Florence and beyond: the future of Tezos storage]
<https://tarides.com/blog/2021-03-04-florence-and-beyond-the-future-of-tezos-storage>

[The ReScript Association]
<https://rescript-lang.org/blog/rescript-association-rebranding>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-02-23  9:51 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-02-23  9:51 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 15261 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of February 16 to 23,
2021.

Table of Contents
─────────────────

OCamlFormat 0.17.0
Set up OCaml 1.1.8
Set up OCaml 1.1.9
OCaml 4.12.0, first release candidate
Ppxlib.0.22: an update on the state of ppx
OCaml-based trading firm is hiring remote devs
ocamlearlybird 1.0.0 beta1
OCaml for ARM MacOS
Old CWN


OCamlFormat 0.17.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocamlformat-0-17-0/7287/1>


Guillaume Petiot announced
──────────────────────────

  On behalf of the OCamlFormat development team I am pleased to announce
  the release of [ocamlformat.0.17.0] :tada:.

  OCamlformat is an auto-formatter for OCaml code, writing the parse
  tree and comments in a consistent style, so that you do not have to
  worry about formatting it by hand, and to speed up code review by
  focusing on the important parts.

  OCamlFormat is beta software. We expect the program to change
  considerably before we reach version 1.0.0. In particular, upgrading
  the `ocamlformat' package will cause your program to get
  reformatted. Sometimes it is relatively pain-free, but sometimes it
  will make a diff in almost every file. We are working towards having a
  tool that pleases most usecases in the OCaml community, please bear
  with us!

  To make sure your project uses the last version of ocamlformat, please
  set
  ┌────
  │ version=0.17.0
  └────
  in your `.ocamlformat' file.

  Main changes in `ocamlformat.0.17.0' are:

  • the `let-open' option, deprecated since 0.16.0, has been removed
  • support for OCaml 4.06 and 4.07 has been removed, minimal version
    requirement bumped to OCaml 4.08
  • the `extension-sugar' option, deprecated since 0.14.0, has been
    removed
  • the syntax of infix set/get operators is now preserved (`String.get'
    and similar calls used to be automatically rewritten to their
    corresponding infix form `.()', that was incorrect when using the
    `-unsafe' compilation flag. Now the concrete syntax of these calls
    is preserved)
  • all sugared extension points are now preserved
  • injectivity type annotations (OCaml 4.12 feature) are now supported
  • various fixes about comments positions

  We encourage you to try ocamlformat, that can be installed from opam
  directly ( `opam install ocamlformat' ), but please remember that it
  is still beta software. We have a [FAQ for new users ] that should
  help you decide if ocamlformat is the right choice for you.


[ocamlformat.0.17.0] <https://github.com/ocaml-ppx/ocamlformat>

[FAQ for new users ]
<https://github.com/ocaml-ppx/ocamlformat#faq-for-new-users>


Set up OCaml 1.1.8
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-8/7288/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • The Windows opam wrapper is fractionally less-archaically named
    opam.cmd, with no loss in arcaneness.
  • Export `CYGWIN_ROOT' on the Windows runners, allowing bash to be
    invoked as `%CYGWIN_ROOT%\bin\bash~/~$env:CYGWIN_ROOT\bin\bash' (and
    similarly for Cygwin `setup-x86_64.exe').
  • The Windows runner no longer prepends `%CYGWIN_ROOT%\bin' to `PATH'.


Fixed
╌╌╌╌╌

  • Switches in Unix are now properly initialized before running depext.

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.8>


Set up OCaml 1.1.9
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-9/7293/1>


Sora Morimoto announced
───────────────────────

Fixed
╌╌╌╌╌

  • Further fix to switch initialisation.

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.9>


OCaml 4.12.0, first release candidate
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-12-0-first-release-candidate/7294/1>


octachron announced
───────────────────

  The release of OCaml 4.12.0 is expected next week. We have created a
  release candidate that you can test. Most opam packages should work
  with this release candidate (without the need for an alpha
  repository).

  Compared to the last beta, this new release only contains one fix for
  Solaris and illumos.

  If you find any bugs, please report them here:
   <https://github.com/ocaml/ocaml/issues>

  Happy hacking,

  – Florian Angeletti for the OCaml team.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.12.0~rc1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can pick
  configuration options with
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.12.0~rc1+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where `<option_list>' is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and afl enabled switch:
  ┌────
  │ opam switch create 4.12.0~rc1+flambda+afl --packages=ocaml-variants.4.12.0~rc1+options,ocaml-option-flambda,ocaml-option-afl
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with `opam search ocaml-option'.

  The source code is available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.12.0-rc1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.12/ocaml-4.12.0~rc1.tar.gz>


Ppxlib.0.22: an update on the state of ppx
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ppxlib-0-22-an-update-on-the-state-of-ppx/7296/1>


Nathan Rebours announced
────────────────────────

  We're happy to announce the release of ppxlib.0.22.0, the fist release
  of ppxlib fully compatible with OCaml 4.12.  The main and only feature
  of this release is the bump of the internal OCaml AST used by ppxlib
  from 4.11 to 4.12, allowing you to use 4.12 language features with
  ppxlib and any ppxlib-based ppx.  Note that ppxlib was compatible with
  the 4.12 compiler since 0.19.0 but that you couldn't use 4.12 language
  features until now.

  This is the third such AST bump release since we announced our plan to
  improve the state of the PPX ecosystem [here] and we though it'd be a
  good time to report back to you and tell you how things are going on
  this front.

  For those of you who aren't familiar with this plan, the goal is to
  upstream a minimal, stable, ocaml-migrate-parsetree-like API on top of
  the compiler-libs called `Astlib'. It will allow us to keep ppxlib and
  any ppx based on ppxlib compatible with OCaml trunk at all time.  To
  allow better performances and a clear compisition semantic, all the
  ppxlib-based ppx-es need to use the same AST (as opposed to
  ocaml-migrate-parsetree based ppx-es) so from a certain perspective,
  this plan simply moves the breaking API up one step, from
  compiler-libs to ppxlib.  In order to greatly ease the maintainenance
  of ppx-es and to prevent opam-universe splits we decided that
  everytime we cut a breaking ppxlib release, we will send patches to
  keep the existing ppx-es compatible with the latest version and
  therefore with the latest OCaml compilers and language features.

  While this seems like a tremendous task and a huge amount of work,
  dune and other tools that raised in its wake such as [opam-monorepo]
  incredibly simplified this kind of work.

  Ahead of OCaml releases, we prepare a branch of ppxlib with the
  upgraded AST. We then fetch opam-repository to gather a list of
  sensible reverse dependencies (i.e. packages whose latest version
  depends on ppxlib and is compatible with ppxlib's latest version) and
  assemble a dune workspace with a clone of each of those reverse
  dependencies, our ppxlib branch and all of their dependencies thanks
  to opam-monorepo.  We then use dune to build all the packages we're
  interested in and simply follow the compilation errors until
  everything builds successfully with the new ppxlib.  What remains is
  to create PRs on the relevant repositories to upstream those changes,
  after which maintainers have everything they need to cut a new
  compatible release.

  Most of this process is automated using scripts but it still requires
  a bit of handiwork. We aim at extracting tools to further improve this
  workflow and reduce the time and effort required but it has been
  surprisingly smooth. Our experience with the 4.10, 4.11 and 4.12
  upgrades so far is that most reverse dependencies don't need an
  upgrade and that it's far less demanding for one person to upgrade all
  the packages that need it than it would be for each individual
  maintainers to understand the changes in the AST and do the upgrade
  themselves.

  It's worth noting that for this to work well, the ppx-es and all their
  dependencies have to build with dune. We do maitain a separate
  opam-repository with dune ports of commonly used packages so in
  practice most projects fall into this category but a few exceptions
  remain and they are therefore not taken into account for this upgrade
  process.

  We're also trying to improve the tracking of the upgrade's progress
  and for the 4.12 compatible release we created a [github project] to
  have a list of all the packages we considered and see where they
  are. We also keep track of the packages we had to exclude and why.
  During this upgrade, we considered 80 opam packages, out of which only
  4 needed to be patched and 6 had to be excluded from the process as we
  couldn't reasonably get them to build in our workspace.

  Once we have a better idea of what makes a package easy to upgrade we
  plan on releasing a set of reasonable rules to follow to benefit from
  those upgrades, we'll keep you updated on this!

  All in all we're pretty happy with this new process and although it
  needs to be refined, we're confident it can grow into something
  sustainable by creating tools and CI to support it. Hopefully these
  will also benefit the wider community and help grow a healthier Opam
  universe.


[here] <https://discuss.ocaml.org/t/ppx-omp-2-0-0-and-next-steps/6231>

[opam-monorepo] <https://github.com/ocamllabs/opam-monorepo>

[github project] <https://github.com/ocaml-ppx/ppxlib/projects/2>


Jason Nielsen asked
───────────────────

  Curious about the current status of `Astlib'.  I was closely following
  [ppx] at one point but it hasn't seen much activity recently.  Thanks
  for all your hard work.


[ppx] <https://github.com/ocaml-ppx/ppx>


Jérémie Dimino
──────────────

  It's in progress. Not much happened in the past couple of months while
  we were finishing the port of a few projects to ppxlib and doing the
  4.12 upgrade. But @pitag re-started working `Astlib' as of a week
  ago. You can follow our progression via [the public meeting notes].

  Note however that the [ppx] project was for our original goal or
  providing a "forever stable" API for ppx rewriters. It has been in
  pause since August 2020 while were trying the "upgrade the world"
  method, which as @NathanReb pointed out is working pretty well
  practice. At this point, it's looking more and more likely that we
  won't resurect the ppx project.


[the public meeting notes] <https://github.com/ocaml-ppx/ppxlib/wiki>

[ppx] <https://github.com/ocaml-ppx/ppx>


OCaml-based trading firm is hiring remote devs
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-based-trading-firm-is-hiring-remote-devs/7298/1>


Michael Bacarella announced
───────────────────────────

  BTG is a trading firm founded by ex-Jane Street devs looking to hire
  some more devs.

  The role is primarily remote, working with the rest of our mostly
  remote team, though we hope to resume regular on-sites in Puerto Rico.

  We operate 24/7 and will consider employees anywhere in the world.

  Prior experience with OCaml is a plus, though any solid programming
  experience with an interest in functional programming and strong
  static types is also fine.

  Comfort navigating Linux is essential.

  Shoot me a message with a copy of your résumé or C.V. to discuss the
  opportunity further: [michael.bacarella@gmail.com]

  Feel free to re-post this elsewhere.


[michael.bacarella@gmail.com] <mailto:michael.bacarella@gmail.com>


ocamlearlybird 1.0.0 beta1
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamlearlybird-1-0-0-beta1/7180/21>


文宇祥 announced
────────────────

  Hi, all. All the issues of beta1 have been fixed. Beta2 will be
  released soon.

  <https://github.com/ocaml/opam-repository/pull/18191>


OCaml for ARM MacOS
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-for-arm-macos/6019/24>


Aaron L. Zeng announced
───────────────────────

  I noticed that opam 2.08 is now available for ARM Macs using
  [Homebrew], and I was able to confirm on my machine.

  `brew install opam' away :)


[Homebrew] <https://github.com/Homebrew/homebrew-core/pull/71605>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-02-16 13:53 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-02-16 13:53 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of February 09 to 16,
2021.

Table of Contents
─────────────────

opam 2.0.8 release
opam 2.1.0~beta4
Set up OCaml 1.1.6
Set up OCaml 1.1.7
Old CWN


opam 2.0.8 release
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-0-8-release/7242/1>


R. Boujbel announced
────────────────────

  We are pleased to announce the minor release of [opam 2.0.8].

  This new version contains some fixes, mainly for sandbox and fish
  scripts. You can find more information in this [blog post], and more
  detailed in the [release note].

  /opam is a source-based package manager for OCaml. It supports
  multiple simultaneous compiler installations, flexible package
  constraints, and a Git-friendly development workflow./


[opam 2.0.8] <https://github.com/ocaml/opam/releases/tag/2.0.8>

[blog post] <https://opam.ocaml.org/blog/opam-2-0-8>

[release note] <https://github.com/ocaml/opam/releases/tag/2.0.8>


opam 2.1.0~beta4
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-1-0-beta4/7252/1>


David Allsopp announced
───────────────────────

  On behalf of the opam team, it gives me great pleasure to announce the
  third beta release of opam 2.1. Don’t worry, you didn’t miss beta3 -
  we had an issue with a configure script that caused beta2 to report as
  beta3 in some instances, so we skipped to beta4 to avoid any further
  confusion!

  We encourage you to try out this new beta release: there are
  instructions for doing so in [our wiki]. The instructions include
  taking a backup of your `~/.opam' root as part of the process, which
  can be restored in order to wind back. _Please note that local
  switches which are written to by opam 2.1 are upgraded and will need
  to be rebuilt if you go back to opam 2.0_. This can either be done by
  removing `_opam' and repeating whatever you use in your build process
  to create the switch, or you can use `opam switch export
  switch.export' to backup the switch to a file before installing new
  packages. Note that opam 2.1 _shouldn’t_ upgrade a local switch unless
  you upgrade the base packages (i.e. the compiler).


[our wiki]
<https://github.com/ocaml/opam/wiki/How-to-test-an-opam-feature>

What’s new in opam 2.1?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Switch invariants
  • Improved options configuration (see the new `option' and expanded
    `var' sub-commands)
  • Integration of system dependencies (formerly the opam-depext
    plugin), increasing their reliability as it integrates the solving
    step
  • Creation of lock files for reproducible installations (formerly the
    opam-lock plugin)
  • CLI versioning, allowing cleaner deprecations for opam now and also
    improvements to semantics in future without breaking
    backwards-compatibility
  • Performance improvements to opam-update, conflict messages, and many
    other areas
  • New plugins: opam-compiler and opam-monorepo


Switch invariants
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  In opam 2.0, when a switch is created the packages selected are put
  into the “base” of the switch. These packages are not normally
  considered for upgrade, in order to ease pressure on opam’s
  solver. This was a much bigger concern early on in opam 2.0’s
  development, but is less of a problem with the default mccs solver.

  However, it’s a problem for system compilers. opam would detect that
  your system compiler version had changed, but be unable to upgrade the
  ocaml-system package unless you went through a slightly convoluted
  process with `--unlock-base'.

  In opam 2.1, base packages have been replaced by switch
  invariants. The switch invariant is a package formula which must be
  satisfied on every upgrade and install. All existing switches’ base
  packages could just be expressed as `package1 & package2 & package3'
  etc. but opam 2.1 recognises many existing patterns and simplifies
  them, so in most cases the invariant will be `"ocaml-base-compiler" {=
  4.11.1}', etc. This means that `opam switch create my_switch
  ocaml-system' now creates a _switch invariant_ of `"ocaml-system"'
  rather than a specific version of the `ocaml-system' package. If your
  system OCaml package is updated, `opam upgrade' will seamlessly switch
  to the new package.

  This also allows you to have switches which automatically install new
  point releases of OCaml. For example:

  ┌────
  │ opam switch create ocaml-4.11 --formula='"ocaml-base-compiler" {>= "4.11.0" & < "4.12.0~"}'
  │ --repos=old=git+https://github.com/ocaml/opam-repository#a11299d81591
  │ opam install utop
  └────

  Creates a switch with OCaml 4.11.0 (the `--repos=' was just to select
  a version of opam-repository from before 4.11.1 was released). Now
  issue:

  ┌────
  │ opam repo set-url old git+https://github.com/ocaml/opam-repository
  │ opam upgrade
  └────

  and opam 2.1 will automatically offer to upgrade OCaml 4.11.1 along
  with a rebuild of the switch. There’s not yet a clean CLI for
  specifying the formula, but we intend to iterate further on this with
  future opam releases so that there is an easier way of saying “install
  OCaml 4.11.x”.


opam depext integration
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  opam has long included the ability to install system dependencies
  automatically via the [depext plugin]. This plugin has been promoted
  to a native feature of opam 2.1.0 onwards, giving the following
  benefits:

  • You no longer have to remember to run `opam depext', opam always
    checks depexts (there are options to disable this or automate it for
    CI use). Installation of an opam package in a CI system is now as
    easy as `opam install .', without having to do the dance of `opam
    pin add -n/depext/install'. Just one command now for the common
    case!
  • The solver is only called once, which both saves time and also
    stabilises the behaviour of opam in cases where the solver result is
    not stable. It was possible to get one package solution for the
    `opam depext' stage and a different solution for the `opam install'
    stage, resulting in some depexts missing.
  • opam now has full knowledge of depexts, which means that packages
    can be automatically selected based on whether a system package is
    already installed. For example, if you have *neither* MariaDB nor
    MySQL dev libraries installed, `opam install mysql' will offer to
    install `conf-mysql' and `mysql', but if you have the MariaDB dev
    libraries installed, opam will offer to install `conf-mariadb' and
    `mysql'.


[depext plugin] <https://github.com/ocaml-opam/opam-depext>


opam lock files and reproducibility
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  When opam was first released, it had the mission of gathering together
  scattered OCaml source code to build a [community repository]. As time
  marches on, the size of the opam repository has grown tremendously, to
  over 3000 unique packages with over 18000 unique versions. opam looks
  at all these packages and is designed to solve for the best
  constraints for a given package, so that your project can keep up with
  releases of your dependencies.

  While this works well for libraries, we need a different strategy for
  projects that need to test and ship using a fixed set of
  dependencies. To satisfy this use-case, opam 2.0.0 shipped with
  support for _using_ `project.opam.locked' files. These are normal opam
  files but with exact versions of dependencies. The lock file can be
  used as simply as `opam install . --locked' to have a reproducible
  package installation.

  With opam 2.1.0, the creation of lock files is also now integrated
  into the client:
  • `opam lock' will create a `.locked' file for your current switch and
    project, that you can check into the repository.
  • `opam switch create . --locked' can be used by users to reproduce
    your dependencies in a fresh switch.

  This lets a project simultaneously keep up with the latest
  dependencies (without lock files) while providing a stricter set for
  projects that need it (with lock files).


[community repository] <https://github.com/ocaml/opam-repository>


CLI Versioning
┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  A new `--cli' switch was added to the first beta release, but it’s
  only now that it’s being widely used. opam is a complex enough system
  that sometimes bug fixes need to change the semantics of some
  commands. For example:

  • `opam show --file' needed to change behaviour
  • The addition of new controls for setting global variables means that
    the `opam config' was becoming cluttered and some things want to
    move to `opam var'
  • `opam switch create 4.11.1' still works in opam 2.0, but it’s really
    an OPAM 1.2.2 syntax.

  Changing the CLI is exceptionally painful since it can break scripts
  and tools which themselves need to drive `opam'.  CLI versioning is
  our attempt to solve this. The feature is inspired by the `(lang dune
  ...)' stanza in `dune-project' files which has allowed the Dune
  project to rename variables and alter semantics without requiring
  every single package using Dune to upgrade their `dune' files on each
  release.

  Now you can specify which version of opam you expected the command to
  be run against. In day-to-day use of opam at the terminal, you
  wouldn’t specify it, and you’ll get the latest version of the CLI. For
  example: `opam var --global' is the same as `opam var --cli=2.1
  --global'. However, if you issue `opam var --cli=2.0 --global', you
  will told that `--global' was added in 2.1 and so is not available to
  you. You can see similar things with the renaming of `opam upgrade
  --unlock-base' to `opam upgrade --update-invariant'.

  The intention is that `--cli' should be used in scripts, user guides
  (e.g. blog posts), and in software which calls opam. The only decision
  you have to take is the _oldest_ version of opam which you need to
  support. If your script is using a new opam 2.1 feature (for example
  `opam switch create --formula=') then you simply don’t support opam
  2.0. If you need to support opam 2.0, then you can’t use `--formula'
  and should use `--packages' instead. opam 2.0 does not have the
  `--cli' option, so for opam 2.0 instead of `--cli=2.0' you should set
  the environment variable `OPAMCLI' to `2.0'. As with _all_ opam
  command line switches, `OPAMCLI' is simply the equivalent of `--cli'
  which opam 2.1 will pick-up but opam 2.0 will quietly ignore (and, as
  with other options, the command line takes precedence over the
  environment).

  Note that opam 2.1 sets `OPAMCLI=2.0' when building packages, so on
  the rare instances where you need to use the `opam' command in a
  _package_ `build:' command (or in your build system), you _must_
  specify `--cli=2.1' if you’re using new features.

  There’s even more detail on this feature [in our wiki]. We’re still
  finalising some details on exactly how `opam' behaves when `--cli' is
  not given, but we’re hoping that this feature will make it much easier
  in future releases for opam to make required changes and improvements
  to the CLI without breaking existing set-ups and tools.


[in our wiki]
<https://github.com/ocaml/opam/wiki/Spec-for-opam-CLI-versioning>


What’s new since the last beta?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • opam now uses CLI versioning ([#4385])
  • opam now exits with code 31 if all failures were during fetch
    operations ([#4214])
  • `opam install' now has a `--download-only' flag ([#4036]), allowing
    opam’s caches to be primed
  • `opam init' now advises the correct shell-specific command for `eval
    $(opam env)' ([#4427])
  • `post-install' hooks are now allowed to modify or remove installed
    files ([#4388])
  • New package variable `opamfile-loc' with the location of the
    installed package opam file ([#4402])
  • `opam update' now has `--depexts' flag ([#4355]), allowing the
    system package manager to update too
  • depext support NetBSD and DragonFlyBSD added ([#4396])
  • The format-preserving opam file printer has been overhauled
    ([#3993], [#4298] and [#4302])
  • pins are now fetched in parallel ([#4315])
  • `os-family=ubuntu' is now treated as `os-family=debian' ([#4441])
  • `opam lint' now checks that strings in filtered package formulae are
    booleans or variables ([#4439])

  and many other bug fixes as listed [on the release page].


[#4385] <https://github.com/ocaml/opam/pull/4385>

[#4214] <https://github.com/ocaml/opam/issues/4214>

[#4036] <https://github.com/ocaml/opam/issues/4036>

[#4427] <https://github.com/ocaml/opam/pull/4427>

[#4388] <https://github.com/ocaml/opam/pull/4388>

[#4402] <https://github.com/ocaml/opam/pull/4402>

[#4355] <https://github.com/ocaml/opam/issues/4355>

[#4396] <https://github.com/ocaml/opam/pull/4396>

[#3993] <https://github.com/ocaml/opam/issues/3993>

[#4298] <https://github.com/ocaml/opam/pull/4298>

[#4302] <https://github.com/ocaml/opam/pull/4302>

[#4315] <https://github.com/ocaml/opam/issues/4315>

[#4441] <https://github.com/ocaml/opam/pull/4441>

[#4439] <https://github.com/ocaml/opam/issues/4439>

[on the release page]
<https://github.com/ocaml/opam/releases/tag/2.1.0-beta4>


New Plugins
╌╌╌╌╌╌╌╌╌╌╌

  Several features that were formerly plugins have been integrated into
  opam 2.1.0. We have also developed some _new_ plugins that satisfy
  emerging workflows from the community and the core OCaml team. They
  are available for use with the opam 2.1 beta as well, and feedback on
  them should be directed to the respective GitHub trackers for those
  plugins.


opam compiler
┄┄┄┄┄┄┄┄┄┄┄┄┄

  The [`opam compiler'] plugin can be used to create switches from
  various sources such as the main opam repository, the ocaml-multicore
  fork, or a local development directory. It can use Git tag names,
  branch names, or PR numbers to specify what to install.

  Once installed, these are normal opam switches, and one can install
  packages in them. To iterate on a compiler feature and try opam
  packages at the same time, it supports two ways to reinstall the
  compiler: either a safe and slow technique that will reinstall all
  packages, or a quick way that will just overwrite the compiler in
  place.


[`opam compiler'] <https://github.com/ocaml-opam/opam-compiler>


opam monorepo
┄┄┄┄┄┄┄┄┄┄┄┄┄

  The [`opam monorepo'] plugin lets you assemble standalone dune
  workspaces with your projects and all of their opam dependencies,
  letting you build it all from scratch using only Dune and OCaml. This
  satisfies the “monorepo” workflow which is commonly requested by large
  projects that need all of their dependencies in one place. It is also
  being used by projects that need global cross-compilation for all
  aspects of a codebase (including C stubs in packages), such as the
  MirageOS unikernel framework.


[`opam monorepo'] <https://github.com/ocamllabs/opam-monorepo>


Next Steps
╌╌╌╌╌╌╌╌╌╌

  This is anticipated to be the final beta in the 2.1 series, and we
  will be moving to release candidate status after this. We could really
  use your help with testing this release in your infrastructure and
  projects and let us know if you run into any blockers. If you have
  feature requests, please also report them on [our issue tracker] – we
  will be planning the next release cycle once we ship opam 2.1.0
  shortly.


[our issue tracker] <https://github.com/ocaml/opam/issues>


Set up OCaml 1.1.6
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-6/7276/1>


Sora Morimoto announced
───────────────────────

  This release includes a change to make the OCaml CI workflow on
  Windows faster!

        I tested this on one of my repos where the build itself is
        mere seconds. Before this change, setup-ocaml needed an
        average of 5:39 to install OCaml+opam and 1:53 to build
        the dependencies of the library. After this change, it
        needs an average of 3:15 for the installation and 1:27 for
        the deps.


Changed
╌╌╌╌╌╌╌

  • Windows installs Cygwin to `D:\cygwin', using faster Azure temporary
    storage.

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.6>


Set up OCaml 1.1.7
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-7/7279/1>


Sora Morimoto announced
───────────────────────

Changed
╌╌╌╌╌╌╌

  • Ubuntu and macOS runners no longer display "No switch is currently
    installed." before building the compiler.
  • Ubuntu no longer installs the system ocaml packages.
  • macOS no longer builds two compilers on every run.
  • Upgrade opam to 2.0.8 for Linux VMs.

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.7>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-02-02 13:56 Alan Schmitt
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From: Alan Schmitt @ 2021-02-02 13:56 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of January 26 to
February 02, 2021.

Table of Contents
─────────────────

release 0.2.2 of ppx_deriving_encoding
OCaml 4.12.0, second beta release
OCaml Office Hours?
Timere 0.1.3 - Dealing with time and time zones have never been easier
Interesting OCaml Articles
json-data-encoding 0.9
ocamlearlybird 1.0.0 beta1
Cmdliner cheatsheet
containers 3.2
OCaml Café: Thu, Feb 11 @ 7pm (U.S. Central)
Dependency graph of some OCaml source files
Other OCaml News
Old CWN


release 0.2.2 of ppx_deriving_encoding
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-0-2-2-of-ppx-deriving-encoding/7169/1>


levillain.maxime announced
──────────────────────────

  Following the release of [json-data-encoding.0.9], I am happy to
  announce the release of ppx_deriving_encoding.0.2.2.

  The code source and some documentation is available on [gitlab], and
  the package can be installed with opam (`opam install
  ppx_deriving_encoding').

  This ppx allows to derive encoding of json-data-encoding library from
  most of ocaml types.

  Have fun!


[json-data-encoding.0.9]
<https://discuss.ocaml.org/t/ann-json-data-encoding-0-9/7157>

[gitlab] <https://gitlab.com/o-labs/ppx_deriving_encoding>


OCaml 4.12.0, second beta release
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-12-0-second-beta-release/7171/1>


octachron announced
───────────────────

  The release of OCaml 4.12.0 is on the horizon. We have created a new
  beta version to help you adapt your software to the new features ahead
  of the release.

  Compared to the first beta release, this new release contains one fix
  for the Thread library (for a race condition on Windows), and
  experimentally re-enables building the compiler on illumos and Oracle
  Solaris.

  We are expecting this beta to be the last one before the release.

  If you find any bugs, please report them here:
   <https://github.com/ocaml/ocaml/issues>

  Happy hacking,

  – Florian Angeletti for the OCaml team.


Installation instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.12.0~beta2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can pick
  configuration options with
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.12.0~beta2+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where <option_list> is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and afl enabled switch:
  ┌────
  │ opam switch create 4.12.0~beta2+flambda+afl
  │ --packages=ocaml-variants.4.12.0~beta2+options,ocaml-option-flambda,ocaml-option-afl
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with "opam search ocaml-option".

  The source code is available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.12.0-beta2.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.12/ocaml-4.12.0~beta2.tar.gz>

  If you want to test this version, you may want to install the alpha
  opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This alpha repository contains various packages patched with fixes in
  the process of being upstreamed. Once the repository installed, these
  patched packages will take precedence over the non-patched version.


Changes from the first beta
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Thread library
┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • *additional fixes* [9757], [9846], +[10161]: check proper ownership
     when operating over mutexes. Now, unlocking a mutex held by another
     thread or not locked at all reliably raises a Sys_error exception.
     Before, it was undefined behavior, but the documentation did not
     say so. Likewise, locking a mutex already locked by the current
     thread reliably raises a Sys_error exception.  Before, it could
     deadlock or succeed (and do recursive locking), depending on the
     OS. (Xavier Leroy, report by Guillaume Munch-Maccagnoni, review by
     Guillaume Munch-Maccagnoni, David Allsopp, and Stephen Dolan)


[9757] <https://github.com/ocaml/ocaml/issues/9757>

[9846] <https://github.com/ocaml/ocaml/issues/9846>

[10161] <https://github.com/ocaml/ocaml/issues/10161>


Build system
┄┄┄┄┄┄┄┄┄┄┄┄

  • [10063]: (Re-)enable building on illumos (SmartOS, OmniOS, …) and
    Oracle Solaris; x86_64/GCC and 64-bit SPARC/Sun PRO C
    compilers. (partially revert [2024]). (Tõivo Leedjärv and Konstantin
    Romanov, review by Gabriel Scherer, Sébastien Hinderer and Xavier
    Leroy)


[10063] <https://github.com/ocaml/ocaml/issues/10063>

[2024] <https://github.com/ocaml/ocaml/issues/2024>


Documentation
┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [9755]: Manual: post-processing the html generated by ocamldoc and
    hevea. Improvements on design and navigation, including a mobile
    version, and a quick-search functionality for the API. (San Vũ Ngọc,
    review by David Allsopp and Florian Angeletti)

  • [10142], [10154]: improved rendering and latex code for toplevel
    code examples. (Florian Angeletti, report by John Whitington, review
    by Gabriel Scherer)


[9755] <https://github.com/ocaml/ocaml/issues/9755>

[10142] <https://github.com/ocaml/ocaml/issues/10142>

[10154] <https://github.com/ocaml/ocaml/issues/10154>


OCaml Office Hours?
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-office-hours/7132/9>


Deep in this thread, Orbifx said
────────────────────────────────

  And there is XMPP: <xmpp:ocaml@conference.orbitalfox.eu?join>


Timere 0.1.3 - Dealing with time and time zones have never been easier
══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-timere-0-1-3-dealing-with-time-and-time-zones-have-never-been-easier/7173/1>


Darren announced
────────────────

  I am happy to announce first release of [Timere], a time handling and
  reasoning library, which @Drup and I have been working on recently.


[Timere] <https://github.com/daypack-dev/timere>

Examples
╌╌╌╌╌╌╌╌

  Christmases which fall on Wednesday from now
  ┌────
  │ let () =
  │   let open Timere in
  │   match
  │     resolve (
  │       after (Date_time.now ())
  │       & months [`Dec]
  │       & days [25]
  │       & weekdays [`Wed]
  │     )
  │   with
  │   | Error msg -> failwith msg
  │   | Ok s ->
  │     Fmt.pr "%a@." (pp_intervals ~sep:(Fmt.any "@.") ()) s
  └────
  gives
  ┌────
  │ [2024 Dec 25 00:00:00 +00:00:00, 2024 Dec 26 00:00:00 +00:00:00)
  │ [2030 Dec 25 00:00:00 +00:00:00, 2030 Dec 26 00:00:00 +00:00:00)
  │ [2041 Dec 25 00:00:00 +00:00:00, 2041 Dec 26 00:00:00 +00:00:00)
  │ [2047 Dec 25 00:00:00 +00:00:00, 2047 Dec 26 00:00:00 +00:00:00)
  │ [2052 Dec 25 00:00:00 +00:00:00, 2052 Dec 26 00:00:00 +00:00:00)
  │ [2058 Dec 25 00:00:00 +00:00:00, 2058 Dec 26 00:00:00 +00:00:00)
  │ ...
  └────

  See [here] for more examples


[here] <https://github.com/daypack-dev/timere/tree/main/examples>


Features
╌╌╌╌╌╌╌╌

  • Timestamp and date time handling with platform independent time zone
    support
    • Subset of the IANA time zone database is built into this library
  • Reasoning over time intervals via timere objects/expressions,
    examples:
    • Pattern matching time and intervals. These work across DST
      boundaries.
    • Intersection and union
    • Chunking at year or month boundary, or in fixed sizes
    • Evaluate (sub)expressions with a different time zone
      (e.g. intersection of 9am to 5pm of Sydney and 9am to 5pm of New
      York)


Links
╌╌╌╌╌

  • Repo: <https://github.com/daypack-dev/timere>
  • API doc:
    <https://daypack-dev.github.io/timere/timere/Timere/index.html>


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/92>


Yawar Amin announced
────────────────────

  Not primarily a programming article but I thought this is an
  interesting exception because it may be the first time OCaml has been
  mentioned in the Financial Times:
  <https://www.ft.com/content/81811f27-4a8f-4941-99b3-2762cae76542>


json-data-encoding 0.9
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-json-data-encoding-0-9/7157/2>


Raphaël Proust announced
────────────────────────

  On behalf of Nomadic Labs, it is my pleasure to release
  json-data-encoding.0.9.1. The code of this packaging-fix release is
  identical to the recent json-data-encoding.0.9 but the license
  information has been corrected.

  The previous release had _LGPL with linking exception_ headers in the
  source files, LICENSE file in the repository, and license field in the
  opam file. However, the code was actually under MIT as per agreement
  of the copyright holders. Release 0.9.1 has the correct license
  headers, LICENSE file and license field in the opam files.

  The code of 0.9/0.9.1 is in dual license. Future releases will be
  under MIT license only.


ocamlearlybird 1.0.0 beta1
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamlearlybird-1-0-0-beta1/7180/1>


文宇祥 announced
────────────────

  I'm pleased to annonce that [ocamlearlybird] 1.0.0~beta1 just
  released.  Will soon be available on opam.

  This is a big step that we toward 1.0.0. We solved lots of issues and
  tested with realy ocaml projects such as utop, ocamlformat, and so
  on. And certainly, it can debug ocamlearlybird itself.

  Try yourself!


[ocamlearlybird] <https://github.com/hackwaly/ocamlearlybird>

NOTES.
╌╌╌╌╌╌

  • New version only support OCaml 4.11. If you need other versions
    support, please let me know.
  • Dune-release do not support `1.0.0~beta1' version string. So we
    released 1.0.0 as 1.0.0~beta1 on opam.


KNOWN ISSUES:
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Continue run command may hit on last removed breakpoint once when
    debug utop.


文宇祥
──────

  Since the post has edited over 3 times. I can't edit it anyway. I
  uploaded demo video here:

  [Debug utop]


[Debug utop]
<https://media.githubusercontent.com/media/hackwaly/ocamlearlybird/master/_assets/utop.webp>


Cmdliner cheatsheet
═══════════════════

  Archive: <https://discuss.ocaml.org/t/cmdliner-cheatsheet/7185/1>


Martin Jambon announced
───────────────────────

  As a follow-up to [an earlier conversation], I made a [cheatsheet and
  a template] for using cmdliner by @dbuenzli. It was done quickly and I
  don't know everything about cmdliner, so please let me know if you see
  mistakes.


[an earlier conversation]
<https://discuss.ocaml.org/t/what-are-some-libraries-you-almost-always-use/7165/17?u=mjambon>

[cheatsheet and a template]
<https://github.com/mjambon/cmdliner-cheatsheet>


Christian Lindig then said
──────────────────────────

  Good to see this. I believe a common use case is to add are sub
  commands as popularised by `git'. It looks like this in my code:

  ┌────
  │ module C = Cmdliner
  │ 
  │ let report =
  │   let doc = "generate HTML or JSON report for an outing" in
  │   let man = ..   in
  │   C.Term.
  │     (ret (const make $ common_options $ json $ path), info "report" ~doc ~man)
  │ 
  │ let default =
  │   let help = `Help (`Pager, None) in
  │   let doc = "GPS analysis for rowers" in
  │  C.Term.(ret @@ const help, info "eightplus" ~doc ~man)
  │ 
  │ let cmds = [ export; report; topspeed; debug; summary; help ]
  │ let main () = C.Term.(eval_choice default cmds |> exit)
  │ let () = if !Sys.interactive then () else main ()
  └────


Martin Jambon later said
────────────────────────

  I just added a demo/template for subcommand handling. There are now
  [two demo programs]. One is focused on the different kinds of
  arguments and the other one on subcommands.


[two demo programs]
<https://github.com/mjambon/cmdliner-cheatsheet/tree/main/src>


Shon also replied
─────────────────

  In this same vein, I've been compiling "executable notes" whenever I
  find myself needing a certain Cmdlner recipe. I took took these recent
  discussion as an occasion to document the module a bit:
  <https://github.com/shonfeder/kwdcmd>

  The aim is to provide "self-documenting" constructors that encode the
  composition of common CLI terms into module namespaces, labeled args,
  and type aliases. The hope being that I can have the type signature of
  a combinator give me all the hints I need to avoid having to look up
  the documentation every time :laughing:

  It's just a very rough (and quite imperfect) collection of idioms I've
  found useful, but it could be worth a look!  When i get a chance, I
  hope to look through your cheat sheet to make sure I have a
  representative constructor for each idiom you've documented.


containers 3.2
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-containers-3-2/7196/1>


Simon Cruanes announced
───────────────────────

  I'm happy to announce that containers 3.2 has just been [released]. It
  should arrive on opam soon. It notably contains an `Either'
  compatibility wrapper, more formatting functions, list functions, and
  a bunch of fixes. Many thanks to @darrenldl for contributing some
  initial fuzzing support.


[released]
<https://github.com/c-cube/ocaml-containers/releases/tag/v3.2>


OCaml Café: Thu, Feb 11 @ 7pm (U.S. Central)
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-cafe-thu-feb-11-7pm-u-s-central/7197/1>


Claude Jager-Rubinson announced
───────────────────────────────

  Join us with your questions about the OCaml language, or just to hang
  out with the OCaml community. Especially geared toward new and
  intermediate users, experienced OCaml developers will be available to
  answer your questions about the language and ecosystem.

  Whether you’re still trying to make sense of currying or can spot
  non-tail-recursive code from across the room, we hope that you’ll join
  us on Thursday, February 11 at 7pm (U.S. Central time). Meeting info
  and additional details can be found at [https://hfpug.org].


[https://hfpug.org] <https://hfpug.org>


Dependency graph of some OCaml source files
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/dependency-graph-of-some-ocaml-source-files/7198/6>


Deep in this thread, Jun FURUSE said
────────────────────────────────────

  You may be interested in [cmgraph] which scrapes the compiled modules
  (`*.cmi/*.cmo/*.cmx') instead of the source code.  It needs no
  compilation switch options since it does not scrape source code.


[cmgraph] <https://gitlab.com/camlspotter/cmgraph>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Recent and upcoming changes to Merlin]
  • [The road ahead for MirageOS in 2021]
  • [Release of Alt-Ergo 2.4.0]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Recent and upcoming changes to Merlin]
<https://tarides.com/blog/2021-01-26-recent-and-upcoming-changes-to-merlin>

[The road ahead for MirageOS in 2021] <https://hannes.nqsb.io/Posts/NGI>

[Release of Alt-Ergo 2.4.0]
<https://www.ocamlpro.com/2021/01/22/release-of-alt-ergo-2-4-0/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <https://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-01-26 13:25 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-01-26 13:25 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 31437 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 19 to 26,
2021.

Table of Contents
─────────────────

How to get pleasant documentation for a library using Dune?
Alt-Ergo 2.4.0 release
First release of Art - Adaptive Radix Tree in OCaml
perf demangling of OCaml symbols (and a short introduction to perf)
Decimal 0.2.1 - arbitrary-precision decimal floating point
Basic GitLab CI configuration
OCaml Office Hours?
json-data-encoding 0.9
VSCode OCaml Platform v1.6.0
release 0.3.0 of drom, the OCaml project creator
Old CWN


How to get pleasant documentation for a library using Dune?
═══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/how-to-get-pleasant-documentation-for-a-library-using-dune/7121/1>


gasche announced
────────────────

  I'm working to publish a small library using Dune. The documentation
  automatically generated by `dune build @doc' looks fairly unpleasant
  to me, as I don't see an easy way to explain what the library is
  about. I'm creating this topic in case I am missing something simple,
  and to get other people to share their library-documentation practices
  or examples.


Problem description
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  For the sake of the example let's imagine that the library is called
  `Foo' and contains three modules `A', `B' and `C'. I'm using the
  standard dune approach of wrapped modules, so I get three compilation
  units `Foo.A', `Foo.B', `Foo.C'. Each module has a `.mli' file with
  documentation comments.

  When I run `dune build @doc', dune generates an `index.html' file with
  basically no content, pointing to a `foo/index.html' file with
  basically no content, pointing to a `foo/Foo/index.html' looking like
  this:

        Up – foo » Foo

        *Module `Foo'*

        `module A : sig ... end'

        `module B : sig ... end'

        `module C : sig ... end'

  It's easy to skip the first two pages, and use the third page as a
  landing page for the documentation of my library.  However, this
  landing page is not very pleasant:
  1. It should explain what the library is about.
  2. It should briefly describe what each module does, so that users
     know which module they want to look at first.

  (Point 2 is especially important with "wrapped libraries", where it's
  not necessarily obvious which of the several modules is the main entry
  point with the important functions to look at first. In comparison, in
  a design where the "entry point" is in the `Foo' module, with `Foo.A'
  and `Foo.B' as more advanced submodules (or `Foo_A' and `Foo_B' in the
  old days) the user is guided to look at `Foo' first.)

  My problem is: what should I change in my Dune setup to be able to do
  this?

  I have read the [dune documentation on documentation], but I could not
  find an answer to this question.


[dune documentation on documentation]
<https://dune.readthedocs.io/en/stable/documentation.html>


Rough ideas
╌╌╌╌╌╌╌╌╌╌╌

  Roughly I see two ways to get what I want, that I have not tried yet:
  1. I could write my own landing page for the library as a separate
     `doc.mld' file, use the `(documentation)' stanza to get it included
     in the built documentation, and use this as the entry point into my
     library.
  2. In could write my own `foo.ml' module instead of using Dune's
     default wrapped-module scaffolding, inserting my own `module A =
     Foo__A' aliases, with documentation comments in the standard
     style. Then I suppose that `foo/Foo/index.html' would get this
     content in the way I expect.

  They feel a bit complex to me, and (2) involves the tedious work of
  redoing the wrapping logic myself. I guess that (1) is not so bad, and
  I would be inclined to do this if it was documented somewhere as the
  recommended approach.

  (Maybe there is some odoc option that would help solve this problem?)


Examples from other people?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Do you have a library built using dune with nice documentation? If so,
  can you show the documentation and the corresponding sources (in
  particular dune setup)?


Thibaut Mattio replied
──────────────────────

  I think the documentation of [Streaming] is a great example of the
  option 1 you describe.

  The corresponding Dune setup can be found [here]

  That's also the approach we took for [Opium's documentation], although
  the index page is certainly not as impressive as Streaming's.


[Streaming] <https://odis-labs.github.io/streaming/streaming/index.html>

[here]
<https://github.com/odis-labs/streaming/blob/master/streaming/dune>

[Opium's documentation]
<https://rgrinberg.github.io/opium/opium/index.html>


gasche then said
────────────────

  Thanks! It looks like these systems rely on an undocumented feature of
  the `(documentation)' stanza (or odoc), which is that a user-provided
  `index.mld' file will implicitly replace the automatically-generated
  `index.mld' file, giving a reasonably natural result.

  The opium documentation also [uses] the `{!modules: modulename ...}'
  markup directive, which is a way to include the module index within
  this manually-written landing page without having to duplicate the
  markup. Streaming¹ uses [inline html] instead to get a nicer-looking
  result, but it is too much effort. Maybe there is a better way, or the
  tools could be improved to make this easier.

  ¹: I'm ashamed to admit that I wasn't aware of this very nice library
  [Streaming], am I consuming the wrong sources of information on the
  OCaml ecosystem?

  Finally, the Opium documentation manifestly has a short synopsis for
  each module in its listing, which corresponds to my "It should briefly
  describe what each module does" requirement. I believe that this comes
  from the first line of the first documentation comment of the
  module. There are module-global documentation comments in the library
  I'm working on, but they do not include such first-line headers.

  Once I have the impression of understanding what is a good way to do
  this, I may try to contribute better documentation in `dune'.


[uses]
<https://github.com/rgrinberg/opium/blob/2a89e35/opium/doc/index.mld#L72-L74>

[inline html]
<https://github.com/odis-labs/streaming/blob/ee5d82a/streaming/index.mld#L32-L68>

[Streaming] <https://odis-labs.github.io/streaming/streaming/index.html>


Gabriel Radanne replied
───────────────────────

        It looks like these systems rely on an undocumented
        feature of the `(documentation)' stanza (or odoc), which
        is that a user-provided `index.mld' file will implicitly
        replace the automatically-generated `index.mld' file,
        giving a reasonably natural result.

  I confirm this feature is here to stay, is the right one to customize
  your index page, and in the future will benefit from good support from
  odoc directly.

        The opium documentation also [uses] the `{!modules:
        modulename ...}' markup directive, which is a way to
        include the module index within this manually-written
        landing page without having to duplicate the
        markup. Streaming¹ uses [inline html] instead to get a
        nicer-looking result, but it is too much effort. Maybe
        there is a better way, or the tools could be improved to
        make this easier.

  I would strongly advise to use the `modules' markup directive, and to
  suggests output improvements on odoc's bug instead of hacking HTML
  together. We could absolutely add the synopsis of the module here, for
  instance.


[uses]
<https://github.com/rgrinberg/opium/blob/2a89e35/opium/doc/index.mld#L72-L74>

[inline html]
<https://github.com/odis-labs/streaming/blob/ee5d82a/streaming/index.mld#L32-L68>


Daniel Bünzli then said
───────────────────────

        which is that a user-provided `index.mld' file will
        implicitly replace the automatically-generated `index.mld'
        file, giving a reasonably natural result.

  This is also the correct way to customize the landing page of your
  package for `odig' generated doc sets, see [here] for more
  information.

        I confirm this feature is here to stay, is the right one
        to customize your index page, and in the future will
        benefit from good support from odoc directly.

  There's an open issue about that [here].


[here]
<https://erratique.ch/software/odig/doc/packaging.html#odoc_api_and_manual>

[here] <https://github.com/ocaml/odoc/issues/297>


Alt-Ergo 2.4.0 release
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-alt-ergo-2-4-0-release/7134/1>


OCamlPro announced
──────────────────

  We are pleased to announce a new release of Alt-Ergo!

  Alt-Ergo 2.4.0 is now available from [Alt-Ergo’s website]. An
  associated opam package will be published in the next few days.

  This release contains some major novelties:

  • Alt-Ergo supports incremental commands (push/pop) from the[ smt-lib]
    standard.
  • We switched command line parsing to use[ cmdliner]. You will need to
    use –<option name> instead of -<option name>. Some options have also
    been renamed, see the manpage or the documentation.
  • We improved the online documentation of your solver, available[
    here].

  This release also contains some minor novelties:

  • .mlw and .why extension are depreciated, the use of .ae extension is
    advised.
  • Add –input (resp –output) option to manually set the input (resp
    output) file format
  • Add –pretty-output option to add better debug formatting and to add
    colors
  • Add exponentiation operation, ** in native Alt-Ergo syntax. The
    operator is fully interpreted when applied to constants
  • Fix –steps-count and improve the way steps are counted (AdaCore
    contribution)
  • Add –instantiation-heuristic option that can enable lighter or
    heavier instantiation
  • Reduce the instantiation context (considered foralls / exists) in
    CDCL-Tableaux to better mimic the Tableaux-like SAT solver
  • Multiple bugfixes

  The full list of changes is available [here]. As usual, do not
  hesitate to report bugs, to ask questions, or to give your feedback!


[Alt-Ergo’s website] <https://alt-ergo.ocamlpro.com/>

[ smt-lib] <https://smtlib.cs.uiowa.edu/>

[ cmdliner] <https://erratique.ch/software/cmdliner>

[ here] <https://ocamlpro.github.io/alt-ergo/>

[here] <https://ocamlpro.github.io/alt-ergo/About/changes.html>


First release of Art - Adaptive Radix Tree in OCaml
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-art-adaptive-radix-tree-in-ocaml/7142/1>


Calascibetta Romain announced
─────────────────────────────

  I'm glad to announce the first release of [`art'], an implementation
  of [the Adaptive Radix Tree] in OCaml. The goal of this library is to
  provide a data-structure such as `Map.S' (and keep the order) with
  performances of `Hashtbl.t'.


[`art'] <https://github.com/dinosaure/art>

[the Adaptive Radix Tree] <https://db.in.tum.de/~leis/papers/ART.pdf>

Performances
╌╌╌╌╌╌╌╌╌╌╌╌

  `art' uses [Bechamel] as a tool for micro-benchmarking and it compares
  performances about [insertion] and [lookup]. As you can see, about
  insertion, `art' is definitely more fast than `Hashtbl.t'.

  For the _lookup_ operation, we are slightly more fast than the
  `Hashtbl.t'. The main advantage comparing to `Hashtbl.t' is the
  ability to use `maximum~/~minimum' or to `iter' over the whole
  data-structure with a certain order.

  On details, benchmarks use a normal distribution of `strings' about
  their lengths. As a practical example where `art' will be better than
  `Hashtbl.t' is when you want to _index_ several words (such as email
  addresses).


[Bechamel] <https://github.com/mirage/bechamel>

[insertion] <https://dinosaure.github.io/art/bench/insert.html>

[lookup] <https://dinosaure.github.io/art/bench/find.html>


Tests
╌╌╌╌╌

  Of course, the library provide [a fuzzer] and tests have a coverage
  of: 91.93 %


[a fuzzer] <https://github.com/dinosaure/art/blob/master/fuzz/fuzz.ml>


Read Optimized Write Exclusion - ROWEX
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Even if it's not a part of the package, the distribution comes with
  _lock-free_ implementation of `art': `rowex'.  This implementation
  comes from [a research paper] about data-structure and atomic
  operations.

  ROWEX provides a _persistent_ implementation which manipulates a file
  to store the whole data-structure. The goal is to provide an _indexer_
  free to be manipulated by several processes in parallel.

  Currently, the implementation of ROWEX in OCaml is not well-tested and
  it is no distributed. It does not take the advantage of
  [ocaml-multicore] (but it should) but outcomes are good and the
  development will be more focus on this part.

  So feel free to play with it a bit :+1:.


[a research paper] <https://db.in.tum.de/~leis/papers/artsync.pdf>

[ocaml-multicore] <https://github.com/ocaml-multicore/ocaml-multicore>


perf demangling of OCaml symbols (and a short introduction to perf)
═══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-perf-demangling-of-ocaml-symbols-a-short-introduction-to-perf/7143/1>


Fabian announced
────────────────

  As a project sponsored by the [OCaml software foundation], I've worked
  on demangling OCaml symbols in [perf]. Some screenshots are below. The
  work is currently being upstreamed. In the meantime, it can be used as
  follows:

  ┌────
  │ git clone --depth=1 https://github.com/copy/linux.git
  │ # or:
  │ # wget https://github.com/copy/linux/archive/master.tar.gz && tar xfv master.tar.gz
  │ cd linux/tools/perf
  │ make
  │ alias perf=$PWD/perf
  │ # or copy perf to somewhere in your PATH
  └────

  Your distribution's version of perf will also work for the examples
  below, but will have less readable symbols :-)


[OCaml software foundation] <https://ocaml-sf.org/>

[perf] <https://perf.wiki.kernel.org/index.php/Main_Page>

Short intruction to perf
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Perf is a Linux-only sampling profiler (and more), which can be used
  to analyse the performance profile of OCaml and other
  executables. When compiling with ocamlopt, add `-g' to include debug
  information in the executable. dune does this automatically, even in
  the release profile. To start a program and record its profile:
  ┌────
  │ perf record --call-graph dwarf program.exe
  └────
  Or record a running program:
  ┌────
  │ perf record --call-graph dwarf -p `pidof program.exe`
  └────

  Then, view a profile using:
  ┌────
  │ perf report # top-down
  │ perf report --no-children # bottom-up
  └────

  Within the report view, the following keybindings are useful:

  • `+': open/close one callchain level
  • `e': open/close entire callchain
  • `t': Toggle beween current thread and all threads (e.g., only
    `dune', `ocamlopt', etc.)

  Or generate a flamegraph:

  ┌────
  │ git clone https://github.com/brendangregg/FlameGraph
  │ cd FlameGraph
  │ perf script -i path/to/perf.data | ./stackcollapse-perf.pl | ./flamegraph.pl > perf-flamegraph.svg
  └────

  You may need to run the following command to allow recording by
  non-root users ([more infos]):
  ┌────
  │ echo 0 | sudo tee /proc/sys/kernel/perf_event_paranoid
  └────


[more infos]
<https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html#unprivileged-users>


Sources
╌╌╌╌╌╌╌

  • [Profiling OCaml code]
  • <https://perf.wiki.kernel.org/index.php/Tutorial#Sampling_with_perf_record>
  • <http://www.brendangregg.com/perf.html#FlameGraphs>

  Before:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/9/95433869e4d55c6c822a096a901483304d44338d_2_1380x602.png>

  After:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/3/3bf847ea23608973644175927e09d4d039ab720e_2_1380x602.png>

  Bottom-up:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/0/01042663ccf66e8b955723fae3cd1c6ff9e0b029_2_1380x602.png>

  Flamegraph (cropped):

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/c/c8e3e0f5b9e1d879198892395529ebb3c339c791_2_1380x602.png>


[Profiling OCaml code]
<https://github.com/ocaml-bench/notes/blob/master/profiling_notes.md>


Decimal 0.2.1 - arbitrary-precision decimal floating point
══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/decimal-0-2-1-arbitrary-precision-decimal-floating-point/7144/1>


Yawar Amin announced
────────────────────

  Happy to announce that `decimal' 0.2.1 has been [pubished on opam].

  `decimal' is a port of [Python's `decimal' module] to OCaml and
  implements the [General Decimal Arithmetic Specification]. However
  note that it is a port in progress–basic arithmetic and rounding
  functions have been ported, but I am still working on powers and
  logs. The ported functions pass the same unit test suite that the
  Python version does (with some minor modifications).

  Another caveat: currently the library is only supported on 64-bit
  architectures due to (exponent) overflow issues on 32-bit. If anyone
  is willing to test and fix overflows on 32-bit, I am more than happy
  to accept PRs.

  Here's an example of using the module:

  ┌────
  │ (* Rosetta Code Currency Example *)
  │ 
  │ (* Demo purposes, normally you'd prefix module name or local open *)
  │ open Decimal
  │ 
  │ let hamburger_qty = of_string "4_000_000_000_000_000"
  │ let hamburger_amt = of_string "5.50"
  │ let milkshake_qty = of_int 2
  │ let milkshake_amt = of_string "2.86"
  │ 
  │ (* Shortcut to divide 7.65 by 100 *)
  │ let tax_rate = of_string "7.65e-2"
  │ 
  │ let subtotal = hamburger_qty * hamburger_amt + milkshake_qty * milkshake_amt
  │ let tax = round ~n:2 (subtotal * tax_rate)
  │ let total = subtotal + tax
  │ 
  │ let () = Format.printf "Subtotal: %a
  │      Tax:  %a
  │    Total: %a\n" pp subtotal pp tax pp total
  └────

  You can get the package with: `opam install decimal'. Minimum OCaml
  version 4.08.


[pubished on opam] <http://opam.ocaml.org/packages/decimal/>

[Python's `decimal' module]
<https://docs.python.org/3/library/decimal.html>

[General Decimal Arithmetic Specification]
<http://speleotrove.com/decimal/decarith.html>


Basic GitLab CI configuration
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/basic-gitlab-ci-configuration/3327/25>


gasche announced
────────────────

  After a long ci-golfing adventure (83 tests), I got a `.gitlab-ci.yml'
  file that I think is reusable and useful for small projects /
  libraries:
  • project: <https://gitlab.com/gasche/gitlab-ocaml-ci-example>
  • configuration file:
    <https://gitlab.com/gasche/gitlab-ocaml-ci-example/-/blob/main/.gitlab-ci.yml>

  Features:
  • It is project-agnostic, so it should work unchanged for your own
    (simple) projects.
  • It caches the opam dependencies.
  • It builds the project, runs the tests and builds the documentation.
  • Several compiler versions can be tested in parallel.
  • It provides an easy way to upload the documentation as "Gitlab
    project Pages".

  CI times are satisfying: on very small libraries I observe a 11mn job
  time on the first run (or when cleaning the opam cache), and 2mn job
  time on following runs.

  The expected usage-mode of this CI configuration is that you copy it
  in your own project. If you find that you need/want additional
  features, ideally you would try to write them in a project-agonistic
  way and contribute them back to the example repository.

  This configuration does not use @smondet's trick of generating a
  docker image on the fly. I think this would be an excellent idea to
  get more reliable caching, but it is too complex for me and I don't
  see how to do it in a maintainable and project-agnostic way.


Current status
╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I wrote this CI configuration over the week-end, and have not used it
  much. I expect it to keep evolving somewhat before it
  stabilizes. Feedback from other people trying to use the configuration
  would be warmly welcome.


Aside on `_build' caching
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I also implemented caching of dune's `_build' data, inspired by the
  [data-encoding] example of @raphael-proust. I don't need it for my
  small projects (dune build is 3s, compared to 1m setting up the Docker
  image), but I thought it would make the CI configuration scale better
  to larger projects.

  When I tested this CI configuration, I discovered that caching the
  dune `_build' data does not work as well as I had expected. (Tracking
  issue: [dune#4150]).

  I can tell because I am asking dune to tell me about what it is
  rebuilding (`dune build --display short'). I suspect that projects
  that cache the `_build' data *without* logging what dune (re)builds
  are also not caching as much as they think they are.

  (But then maybe the use of a fixed-compiler OPAM image, as
  data-encoding is using, solves the issue.)


[data-encoding]
<https://gitlab.com/nomadic-labs/data-encoding/-/blob/master/.gitlab-ci.yml>

[dune#4150] <https://github.com/ocaml/dune/issues/4150>


official CI template?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I considered submitting this CI configuration as an "OCaml Gitlab CI
  template" to go with the official list of "blessed" CI templates in
  [the documentation]. But reading the [Development guide for Gitlab
  CI/CD templates] convinced me that my CI configuration is nowhere
  ready to serve this role.

  Gitlab developers apparently expect that users will be able to
  "include" those CI templates by pointing to their URL, and then tune
  it for their own use-case (without modifying it) by performing some
  (unreasonable?) inheritance tricks using whatever those configurations
  offers as abstraction/inheritance/extension/overriding
  mechanism. Let's just say that this is next-level CI configuration
  writing, and that my script is not ready for this.


[the documentation]
<https://docs.gitlab.com/ee/ci/examples/README.html#cicd-templates>

[Development guide for Gitlab CI/CD templates]
<https://gitlab.com/gitlab-org/gitlab/-/blob/master/doc/development/cicd/templates.md>


OCaml Office Hours?
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-office-hours/7132/4>


Deep in this thread, UnixJunkie said
────────────────────────────────────

  In addition to mailing lists and discuss, there is also an IRC channel
  where people can interact with some ocaml experts in a more
  "interactive" manner (<irc://irc.freenode.net/#ocaml>)


json-data-encoding 0.9
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-json-data-encoding-0-9/7157/1>


Raphaël Proust announced
────────────────────────

  On behalf of [Nomadic Labs], I'm happy to announce the release of
  json-data-encoding version 0.9.

  The code is hosted on Gitlab:
  <https://gitlab.com/nomadic-labs/json-data-encoding> It is distributed
  under GNU LGPL with linking exception.  The documentation is available
  online: <https://nomadic-labs.gitlab.io/json-data-encoding/> The
  package is available under opam: `opam install json-data-encoding'

  json-data-encoding is a library to define encoder/decoder values to
  translate OCaml values to JSON and back. It also generates JSON
  schemas so you can document the value representation. It can use
  either Ezjsonm or Yojson as backends.

  The version 0.9 has the following new features:
  • more tests
  • memoisation of fixpoint encoding to avoid repeated computations
  • support for `format' field for string schemas (see
    <https://json-schema.org/understanding-json-schema/reference/string.html#format>)
    (contributed by @levillain.maxime)
  • fixed integer bound printing in schemas (bug report by @pw374)
  • support for json-lexeme streaming (see details below)
  • support for inclusion/exclusion of default-value fields during
    serialisation (contributed by @levillain.maxime)
  • improved union-of-object schemas (contributed by @levillain.maxime)

  One major difference with the previous release is the inclusion of a
  lexeme-streaming JSON constructor. Specifically, the function

  ┌────
  │ val construct_seq : 't encoding -> 't -> jsonm_lexeme Stdlib.Seq.t
  └────

  generates a sequence of `Jsonm.lexeme' (the . This sequence is lazy
  (in the sense of `Stdlib.Seq' not of `Stdlib.Lazy') and it paves the
  way to a similar feature in `data-encoding'. An interesting feature of
  sequences is that they can be used in Vanilla OCaml settings as well
  as Lwt/Async settings where they allow user-driven yielding in between
  elements.


[Nomadic Labs] <https://nomadic-labs.com/>


VSCode OCaml Platform v1.6.0
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-vscode-ocaml-platform-v1-6-0/7164/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the vscode-ocaml-platform team, I'm pleased to announce
  1.6.0. This release contains a new activity tab for managing opam
  switches developed by @tmattio. We hope you find it useful.

  Change log:

  ┌────
  │ - Highlight token aliases in Menhir associativity declarations (#473)
  │ 
  │ - Activate the extension when workspace contains OCaml, Reason sources or
  │   project marker files. (#482)
  │ 
  │ - Add `ocaml.useOcamlEnv` setting to determine whether to use `ocaml-env` for
  │   opam commands from OCaml for Windows (#481)
  │ 
  │ - Fix terminal creation when using default shell and arguments (#484)
  │ 
  │ - Add an OCaml activity tab.
  │ 
  │   The activity tab provides three views: the available switches, the build
  │   commands and an Help and Feedback section with links to community channels.
  │ 
  │ - Support `eliom` and `eliomi` file extensions (#487)
  │ 
  │ - Fix ocaml/ocaml-lsp#358: automatic insertion of an inferred interface was
  │   inserting code incorrectly on the second switch to the newly created (unsaved)
  │   `mli` file. If the new `mli` file isn't empty, we don't insert inferred
  │   interface (#498)
  └────


release 0.3.0 of drom, the OCaml project creator
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-0-3-0-of-drom-the-ocaml-project-creator/7166/1>


Fabrice Le Fessant announced
────────────────────────────

  We are pleased to release version 0.3.0 of `drom', the OCaml project
  creator.

  `drom' is born from a simple observation: every time you create a new
  OCaml project, you spend time searching and copy-pasting files from
  other projects, adapting them to the new one. `drom' does that for
  you: it comes with a set of predefined skeleton projects, that you can
  easily configure and adapt to your goal.

  It's as easy as:
  ┌────
  │ $ drom new
  │   # check the list of skeletons
  │ $ drom new PROJECT_NAME --skeleton SKELETON_NAME
  │ $ cd PROJECT_NAME
  │ $ emacs drom.toml
  │    # ... edit basic description, dependencies, etc. ...
  │ $ drom project
  │ $ drom build
  └────
  Thanks to contributors (Maxime Levillain and David Declerck), the list
  of project skeletons for drom 0.3.0 has grown:
  • OCaml projects: library menhir mini_lib mini_prg ppx_deriver
    ppx_rewriter program
  • C Bindings: c_binding ctypes_foreign ctypes_stubs
  • Javascript projects: js_lib js_prg vue wasm_binding

  and you can easily contribute your own: for example,
  `gh:USER/SKELETON' will trigger the download of the `USER/SKELETON'
  project from Github as a template for your new project.

  `drom' is available from `opam': `opam update && opam install
  drom.0.3.0'

  <https://github.com/ocamlpro/drom>

  Enjoy !


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-01-19 14:28 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-01-19 14:28 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 22382 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 12 to 19,
2021.

Table of Contents
─────────────────

Irmin 2.3.0
Dune 2.8.0
lwt-canceler.0.3
Interesting OCaml Articles
OCaml 4.12.0, first beta release
OCaml for ARM MacOS
Talk on OCaml Batteries at Houston Functional Programmers
Other OCaml News
Old CWN


Irmin 2.3.0
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-irmin-2-3-0/7084/1>


Craig Ferguson announced
────────────────────────

  I'm very happy to announce the release of the Irmin 2.3.0 family of
  packages, including:

  • [`irmin-pack.2.3.0'], a storage backend for Irmin designed for and
    used by Tezos. This release contains a host of performance
    improvements as well as offline CLI features such as integrity
    checking. It also contains a number of high-level design changes,
    which were discussed in a recent [Tarides blog post].

    Finally, `irmin-pack.2.3.0' also contains a prototype of the
    [_layered_] `irmin-pack' store, which provides an [OverlayFS]-esque
    mode of operation for `irmin-pack' in which the causal history of
    the store can be chunked into independently-accessable
    substores. This feature will eventually be deployed in a [future
    version of Tezos].

  • [`irmin-containers'], a collection of pre-defined mergeable data
    structures built using Irmin and compatible with any backend. These
    were originally provided by @kayceesrk as part of [`ezirmin'], and
    has since been modernised and upstreamed by Anirudh S.

  • `irmin-bench', a suite of benchmarks for Irmin for use with
    [`current-bench'], an experimental continuous benchmarking
    infrastructure for OCaml projects. Lots of work has been going on
    behind the scenes to make this a general benchmarking infrastructure
    for the Mirage ecosystem, including a recent [fancy UI overhaul] by
    new contributor @rizo.

  • [`repr'], an extraction of the `Irmin.Type' type representation
    library for use in other packages. This package contains a set of
    combinators for building run-time representations of types, along
    with various generic operations defined over those representations,
    including: equality, comparison, pretty-printing, JSON / binary
    codecs, etc. The API of this library is currently a
    work-in-progress, but we hope to use it more widely in the Mirage
    ecosystem soon.

  • [`semaphore-compat'], an extraction of the `Semaphore' library in
    OCaml 4.12, for libraries that want to maintain compatibility with
    earlier versions of OCaml.

  The full list of changes to Irmin can be found [here].

  Many thanks to our open-source contributors and collaborators. Happy
  hacking!


[`irmin-pack.2.3.0'] <https://www.youtube.com/watch?v=v1lfMUM332w>

[Tarides blog post]
<https://tarides.com/blog/2020-09-08-irmin-september-2020-update>

[_layered_]
<https://gist.github.com/icristescu/1afb7f9f862f8e989b8b6c195908e7d0>

[OverlayFS] <https://en.wikipedia.org/wiki/OverlayFS>

[future version of Tezos]
<https://gitlab.com/tezos/tezos/-/merge_requests/2127>

[`irmin-containers']
<https://mirage.github.io/irmin/irmin-containers/Irmin_containers/index.html>

[`ezirmin'] <https://github.com/kayceesrk/ezirmin>

[`current-bench'] <https://github.com/ocurrent/current-bench/>

[fancy UI overhaul] <https://github.com/ocurrent/current-bench/pull/20>

[`repr'] <https://github.com/mirage/repr>

[`semaphore-compat'] <https://github.com/mirage/semaphore-compat>

[here]
<https://github.com/mirage/irmin/blob/master/CHANGES.md#230-2020-01-12>


Dune 2.8.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-8-0/7090/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune, I'm pleased to announce the release of dune
  2.8.0. This release contains many bug fixes, performance improvements,
  and interesting new features. I'll point out two new features that I'm
  most excited about.

  First is the experimental `dune_site' extension that makes it possible
  to register and load plugins at runtime. This feature is quite
  involved, but we've documented it extensively [in the manual].

  Another cool feature is that we've eliminated the need for .merlin
  files and all the caveats that came with them.  Now, merlin talks to
  dune directly to get precise configuration for every module. Say
  goodbye to all those "approximate .merlin file" warnings!

  I encourage everyone to upgrade as soon as possible, as earlier
  versions are not compatible with OCaml 4.12. Happy Hacking.

  Full change log:


[in the manual] <https://dune.readthedocs.io/en/stable/sites.html>

2.8.0 (13/01/2021)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • `dune rules' accepts aliases and other non-path rules (#4063,
    @mrmr1993)

  • Action `(diff reference test_result)' now accept `reference' to be
    absent and in that case consider that the reference is empty. Then
    running `dune promote' will create the reference file. (#3795,
    @bobot)

  • Ignore special files (BLK, CHR, FIFO, SOCKET), (#3570, fixes #3124,
    #3546, @ejgallego)

  • Experimental: Simplify loading of additional files (data or code) at
    runtime in programs by introducing specific installation sites. In
    particular it allow to define plugins to be installed in these
    sites. (#3104, #3794, fixes #1185, @bobot)

  • Move all temporary files created by dune to run actions to a single
    directory and make sure that actions executed by dune also use this
    directory by setting `TMPDIR' (or `TEMP' on Windows). (#3691, fixes
    #3422, @rgrinberg)

  • Fix bootstrap script with custom configuration. (#3757, fixes #3774,
    @marsam)

  • Add the `executable' field to `inline_tests' to customize the
    compilation flags of the test runner executable (#3747, fixes #3679,
    @lubegasimon)

  • Add `(enabled_if ...)' to `(copy_files ...)' (#3756, @nojb)

  • Make sure Dune cleans up the status line before exiting (#3767,
    fixes #3737, @alan-j-hu)

  • Add `{gitlab,bitbucket}' as options for defining project sources
    with `source' stanza `(source (<host> user/repo))' in the
    `dune-project' file.  (#3813, @rgrinberg)

  • Fix generation of `META' and `dune-package' files when some targets
    (byte, native, dynlink) are disabled. Previously, dune would
    generate all archives for regardless of settings. (#3829, #4041,
    @rgrinberg)

  • Do not run ocamldep to for single module executables &
    libraries. The dependency graph for such artifacts is trivial
    (#3847, @rgrinberg)

  • Fix cram tests inside vendored directories not being interpreted
    correctly.  (#3860, fixes #3843, @rgrinberg)

  • Add `package' field to private libraries. This allows such libraries
    to be installed and to be usable by other public libraries in the
    same project (#3655, fixes #1017, @rgrinberg)

  • Fix the `%{make}' variable on Windows by only checking for a `gmake'
    binary on UNIX-like systems as a unrelated `gmake' binary might
    exist on Windows.  (#3853, @kit-ty-kate)

  • Fix `$ dune install' modifying the build directory. This made the
    build directory unusable when `$ sudo dune install' modified
    permissions. (fix #3857, @rgrinberg)

  • Fix handling of aliases given on the command line (using the `@' and
    `@@' syntax) so as to correctly handle relative paths. (#3874, fixes
    #3850, @nojb)

  • Allow link time code generation to be used in preprocessing
    executable. This makes it possible to use the build info module
    inside the preprocessor.  (#3848, fix #3848, @rgrinberg)

  • Correctly call `git ls-tree' so unicode files are not quoted, this
    fixes problems with `dune subst' in the presence of unicode
    files. Fixes #3219 (#3879, @ejgallego)

  • `dune subst' now accepts common command-line arguments such as
    `--debug-backtraces' (#3878, @ejgallego)

  • `dune describe' now also includes information about executables in
    addition to that of libraries. (#3892, #3895, @nojb)

  • instrumentation backends can now receive arguments via
      `(instrumentation (backend <name> <args>))'. (#3906, #3932, @nojb)

  • Tweak auto-formatting of `dune' files to improve
    readability. (#3928, @nojb)

  • Add a switch argument to opam when context is not default. (#3951,
    @tmattio)

  • Avoid pager when running `$ git diff' (#3912, @AltGr)

  • Add `(root_module ..)' field to libraries & executables. This makes
    it possible to use library dependencies shadowed by local modules
    (#3825, @rgrinberg)

  • Allow `(formatting ...)' field in `(env ...)' stanza to set
    per-directory formatting specification. (#3942, @nojb)

  • [coq] In `coq.theory', `:standard' for the `flags' field now uses
    the flags set in `env' profile flags (#3931 , @ejgallego @rgrinberg)

  • [coq] Add `-q' flag to `:standard' `coqc' flags , fixes #3924,
    (#3931 , @ejgallego)

  • Add support for Coq's native compute compilation mode (@ejgallego,
    #3210)

  • Add a `SUFFIX' directive in `.merlin' files for each dialect with no
    preprocessing, to let merlin know of additional file extensions
    (#3977, @vouillon)

  • Stop promoting `.merlin' files. Write per-stanza Merlin
    configurations in binary form. Add a new subcommand `dune
    ocaml-merlin' that Merlin can use to query the configuration
    files. The `allow_approximate_merlin' option is now useless and
    deprecated. Dune now conflicts with `merlin < 3.4.0' and
    `ocaml-lsp-server < 1.3.0' (#3554, @voodoos)

  • Configurator: fix a bug introduced in 2.6.0 where the configurator
    V1 API doesn't work at all when used outside of dune. (#4046,
    @aalekseyev)

  • Fix `libexec' and `libexec-private' variables. In cross-compilation
    settings, they now point to the file in the host context. (#4058,
    fixes #4057, @TheLortex)

  • When running `$ dune subst', use project metadata as a fallback when
    package metadata is missing. We also generate a warning when `(name
    ..)' is missing in `dune-project' files to avoid failures in
    production builds.

  • Remove support for passing `-nodynlink' for executables. It was
    bypassed in most cases and not correct in other cases in particular
    on arm32.  (#4085, fixes #4069, fixes #2527, @emillon)

  • Generate archive rules compatible with 4.12. Dune longer attempt to
    generate an archive file if it's unnecessary (#3973, fixes #3766,
    @rgrinberg)

  • Fix generated Merlin configurations when multiple preprocessors are
    defined for different modules in the same folder. (#4092, fixes
    #2596, #1212 and #3409, @voodoos)

  • Add the option `use_standard_c_and_cxx_flags' to `dune-project' that
    1.  disables the unconditional use of the `ocamlc_cflags' and
    `ocamlc_cppflags' from `ocamlc -config' in C compiler calls, these
    flags will be present in the `:standard' set instead; and 2. enables
    the detection of the C compiler family and populates the `:standard'
    set of flags with common default values when building CXX
    stubs. (#3875, #3802, fix #3718 and #3528, @voodoos)


lwt-canceler.0.3
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-lwt-canceler-0-3/7092/1>


Raphaël Proust announced
────────────────────────

  On behalf of [Nomadic Labs], I'm happy to announce the release of
  Lwt-canceler version 0.3. Lwt-canceler is a small library to help
  programs written using Lwt to synchronise promises around resource
  clean-up. This library was developed as part of the [Tezos codebase]
  before being released.

  With this version, the code has matured significantly (including
  tests, documentation and some refactoring); the next release will
  probably be a version 1.0 at which point a more robust versioning
  scheme will be used.

  The documentation is available online:
  <https://nomadic-labs.gitlab.io/lwt-canceler/lwt-canceler/Lwt_canceler/index.html>
  The code is released under MIT License and hosted on Gitlab:
  <https://gitlab.com/nomadic-labs/lwt-canceler> The new version is
  available on opam: `opam install lwt-canceler'

  Happy hacking!


[Nomadic Labs] <https://nomadic-labs.com/>

[Tezos codebase] <https://gitlab.com/tezos/tezos>


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/90>


Weng Shiwei announced
─────────────────────

  Let me share my new blog post on understanding `format6' with
  examples.  <https://blog.tail.moe/2021/01/13/format6.html>

  It's almost my reading note for the paper Format Unraveled (on module
  Format) and experiments on utop. I tried not to be too verbose though.


Weng Shiwei later said
──────────────────────

  Well, I made a sequel of `format6' post, *Understanding `format6' in
  OCaml by diagrams*
  <https://blog.tail.moe/2021/01/15/format6-diagram.html>

  This time I just use four examples with four diagrams e.g. it's the
  one for `Scanf.sscanf'

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/f/f18093391072f739d70c68c2ccf4be92441078c2_2_1034x432.png>

  p.s. It's a pity that I missed Gabriel's post [The 6 parameters of
  (’a, ’b, ’c, ’d, ’e, ’f) format6] after writing that one.


[The 6 parameters of (’a, ’b, ’c, ’d, ’e, ’f) format6]
<http://gallium.inria.fr/blog/format6/>


OCaml 4.12.0, first beta release
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-12-0-first-beta-release/7099/1>


octachron announced
───────────────────

  The release of OCaml 4.12.0 is close.

  The set of new features has been stabilized, and core opam packages
  already work with this release. After three alpha releases, we have
  created a first beta version to help you adapt your software to the
  new features ahead of the release. Compared to the last alpha, this
  beta contains only three new bug fixes and one change to the standard
  library.

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.12.0~beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────

  If you want to tweak the configuration of the compiler, you can pick
  configuration options with
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.12.0~beta1+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where <option_list> is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and afl enabled switch:
  ┌────
  │ opam switch create 4.12.0~beta1+flambda+afl
  │ --packages=ocaml-variants.4.12.0~beta1+options,ocaml-option-flambda,ocaml-option-afl
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with "opam search ocaml-option".

  The source code is available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.12.0-beta1.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.12/ocaml-4.12.0~beta1.tar.gz>

  If you want to test this version, you may want to install the alpha
  opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with

  opam repo add alpha
  git://github.com/kit-ty-kate/opam-alpha-repository.git

  This alpha repository contains various packages patched with fixes in
  the process of being upstreamed. Once the repository installed, these
  patched packages will take precedence over the non-patched version.

  If you find any bugs, please report them here:
   <https://github.com/ocaml/ocaml/issues>


Changes from the third alpha release
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

Postponed features
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [9533], [10105], [10127] : Added String.starts_with and
    String.ends_with. (Bernhard Schommer, review by Daniel Bünzli,
    Gabriel Scherer and Alain Frisch)


[9533] <https://github.com/ocaml/ocaml/issues/9533>

[10105] <https://github.com/ocaml/ocaml/issues/10105>

[10127] <https://github.com/ocaml/ocaml/issues/10127>


Additional bug fixes
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  • [9096], [10096]: fix a 4.11.0 performance regression in
    classes/objects declared within a function (Gabriel Scherer, review
    by Leo White, report by Sacha Ayoun)

  • [10106], [10112]: some expected-type explanations where forgotten
    after some let-bindings (Gabriel Scherer, review by Thomas Refis and
    Florian Angeletti, report by Daniil Baturin)

  • [9326], [10125]: Gc.set incorrectly handles the three `custom_*'
    fields, causing a performance regression (report by Emilio Jesús
    Gallego Arias, analysis and fix by Stephen Dolan, code by Xavier
    Leroy, review by Hugo Heuzard and Gabriel Scherer)


[9096] <https://github.com/ocaml/ocaml/issues/9096>

[10096] <https://github.com/ocaml/ocaml/issues/10096>

[10106] <https://github.com/ocaml/ocaml/issues/10106>

[10112] <https://github.com/ocaml/ocaml/issues/10112>

[9326] <https://github.com/ocaml/ocaml/issues/9326>

[10125] <https://github.com/ocaml/ocaml/issues/10125>


OCaml for ARM MacOS
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-for-arm-macos/6019/23>


Deep in this thread, Xavier Leroy said
──────────────────────────────────────

  It's quite easy to get up to speed using the precompiled OPAM binary
  for macOS/ARM64.

  • Download [opam-2.0.7-arm64-macos].

  • Move it to some directory in your PATH, rename it to `opam', and
    make it executable.  From a Terminal window:
  ┌────
  │ mv ~/Downloads/opam-2.0.7-arm64-macos /usr/local/bin/opam
  │ chmod +x /usr/local/bin/opam
  └────

  • Try to execute it: `opam init'.  You will be blocked by the macOS
    security checks, as the binary is not signed.

  • Open Preferences / Security and Privacy.  There should be a notice
    "opam was blocked because…" and an "Allow Anyway" button.  Click on
    that button.

  • Try again to execute `opam init'.  You will be blocked again, but
    now there is an "Open" button.  Click on that button. `opam init'
    should run and install the OCaml 4.10.2 compiler.

  • From now on, you can run `opam' without being blocked.  Use this
    freedom to `opam install' the packages you need.

  • Some packages that depend on external C libraries may fail to
    install because these C libraries are not available. Normally we
    would rely on Homebrew or MacPorts to provide these C libraries, but
    these package collections are still being ported to macOS/ARM64.

  As a reward for these minor inconveniences, you'll get excellent
  performance running OCaml software such as Coq.  Single-core
  performance on a MacBook Air M1 is 20% better than the best x86
  workstation I have access to.


[opam-2.0.7-arm64-macos]
<https://github.com/ocaml/opam/releases/download/2.0.7/opam-2.0.7-arm64-macos>


Talk on OCaml Batteries at Houston Functional Programmers
═════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/talk-on-ocaml-batteries-at-houston-functional-programmers/7103/1>


Claude Jager-Rubinson announced
───────────────────────────────

  @UnixJunkie will be speaking (virtually, of course) on *OCaml
  Batteries Included* at Houston Functional Programmers, this coming
  Wednesday, Jan 20 at 7pm (U.S. Central time).  His talk will cover
  Batteries' history, place within the OCaml ecosystem, and comparisons
  with OCaml's other alternative standard libraries.  All are welcome to
  join us, even if you're not from Houston.  Complete details and Zoom
  info are at [hfpug.org].


[hfpug.org] <https://hfpug.org>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Coq 8.13.0 is out]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Coq 8.13.0 is out] <https://coq.inria.fr/news/coq-8-13-0-is-out.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-01-12  9:47 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-01-12  9:47 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of January 05 to 12,
2021.

Table of Contents
─────────────────

Marshal determinism and stability
Sedlex + Menhir parser for both tty and file parsing
First release of awa-ssh
Introducing Feather: A lightweight shell-scripting library for OCaml
postdoc researcher and research engineer positions for CHERI and Arm verification
First ocb (OCaml Badgen) release
Release of OCaml-Git v3.0 and co
Other OCaml News
Old CWN


Marshal determinism and stability
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/marshal-determinism-and-stability/7041/28>


Continuing this thread, David Allsopp said
──────────────────────────────────────────

  A couple of notes on `Marshal', which I don't think have been covered
  • Although the guarantee is only between identical versions of OCaml,
    the implementation actually goes to considerable lengths to maintain
    backwards compatibility (so a value _written_ by older OCaml remains
    _readable_ in newer OCaml). Our own testsuite, for example,
    indirectly [includes a test which unmarshals a 3.12.1 value]. I
    don't know exactly how far back the support goes.
  • As it happens, the change which affected Unison in 4.08 was the
    first breaking change to Marshal since either 4.00 or 4.01. The fact
    that it doesn't break often (and that the two code paths - at least
    at present - are small) meant I have suggested a few months back
    that we could in future add an additional flag in the style of
    `Compat_32' to allow values to be written in a way which should be
    readable on older versions of OCaml. Indeed, it's small enough that
    flags could be added for the changes in 4.08 ([PR#1683]) and in 4.11
    ([PR#8791]).
  • Neither point undermines using alternative formats either for
    network serialisation or persistent storage, for the many reasons
    discussed above!


[includes a test which unmarshals a 3.12.1 value]
<https://github.com/ocaml/ocaml/blob/trunk/testsuite/tests/lib-hashtbl/compatibility.ml>

[PR#1683] <https://github.com/ocaml/ocaml/pull/1683>

[PR#8791] <https://github.com/ocaml/ocaml/pull/8791>


Sedlex + Menhir parser for both tty and file parsing
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/sedlex-menhir-parser-for-both-tty-and-file-parsing/7055/1>


Bernard Sufrin announced
────────────────────────

  I am a great fan of Menhir, and have used it in several private
  language projects, using the ulexing scanner generator to provide
  Unicode-capable scanners.

  Alarmed by the obsolescence of ulexing, and needing a utf8-capable
  scanner in a hurry I decided to (teach myself to) use Sedlex. On the
  whole the experience was very satisfactory, and I found it
  straightforward to produce a variant of the sedlexing library which
  supports buffers with variable chunk sizes, thereby enabling efficient
  lexing on channels connected to files as well as immediately
  responsive lexing on channels connected to terminals.

  I also wanted to teach myself how to use the error-reporting,
  incremental, interfaces to Menhir-generated parsers. In the hope that
  it might be useful to others facing the same learning task, or the
  problem of adapting Sedlex for efficient interactive use, I have
  placed the example mock-S-Expression parser that resulted from this
  excursion in:

  [Git Repository: github.com/sufrin/InteractiveSedlexMenhirExample]


[Git Repository: github.com/sufrin/InteractiveSedlexMenhirExample]
<https://github.com/sufrin/InteractiveSedlexMenhirExample>


First release of awa-ssh
════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-awa-ssh/7057/1>


Hannes Mehnert announced
────────────────────────

  I'm happy to announce that `awa-ssh'
  (<https://github.com/mirage/awa-ssh>) has just been merged into
  opam-repository. It is a pure OCaml implementation of the ssh (secure
  shell, <https://en.wikipedia.org/wiki/SSH_(Secure_Shell)>) protocol.

  This is the initial release, please report issues you encounter.

  It was initially developed by Christiano Haesbaert in 2016, and
  revived mid-2019 by myself and in 2020 it was migrated to the MirageOS
  organization on GitHub for further development and maintenance.

  Both client and server code are present in the library (pure code in
  the main awa package), though the awa-lwt package implements only a
  server, and the awa-mirage package implements only a client. Tests and
  examples are in the test subdirectory.

  The MirageOS client has been successfully used to clone git
  repositories (on private servers, on GitHub, etc.). It supports apart
  from RSA keys also ED25519 keys (and key exchanges).


Introducing Feather: A lightweight shell-scripting library for OCaml
════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/introducing-feather-a-lightweight-shell-scripting-library-for-ocaml/7059/1>


Charles announced
─────────────────

  I wrote a shell scripting library called [Feather]. I like idea of
  writing bash-like code quickly, later being able to intersperse OCaml
  to add more typeful components as needed. It's kind of like [Shexp]
  but without the monadic interface and with Async
  support. ([Feather_async])

  There's a tutorial and some examples in the link above but here's a
  quick taste:

  ┌────
  │ open Feather
  │ 
  │ let lines = find "." ~name:"*.ml"
  │   |. tr "/" "\n"
  │   |. map_lines ~f:String.capitalize
  │   |. sort
  │   |. process "uniq" [ "-c" ]
  │   |. process "sort" [ "-n" ]
  │   |. tail 4
  │   |> collect_lines
  │ in
  │ String.concat ~sep:", " lines |> print_endline
  └────
  Let me know if you have any feedback! And feel free to file bug
  reports [here]. Hope it ends up being useful, entertaining, or both!


[Feather] <https://hg.sr.ht/~etc/feather>

[Shexp] <https://github.com/janestreet/shexp/>

[Feather_async] <https://hg.sr.ht/~etc/feather_async>

[here] <https://todo.sr.ht/~etc/feather>


postdoc researcher and research engineer positions for CHERI and Arm verification
═════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2021-01/msg00023.html>


Peter Sewell announced
──────────────────────

  We are looking for postdoctoral researchers and postdoctoral or
  postgraduate research engineers to help develop semantics and
  verification to improve the foundations and security of mainstream
  computer systems, for CHERI and Arm system software verification, at
  the University of Cambridge.  OCaml expertise to help develop
  verification tools will be especially welcome. Closing date 13 January
  2021 - see the advert <http://www.jobs.cam.ac.uk/job/28012/>.


First ocb (OCaml Badgen) release
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-ocb-ocaml-badgen-release/7073/1>


zapashcanon announced
─────────────────────

  A few days ago, I released [ocb]. It's a library and a command-line
  tool to generate SVG badges.

  To get started quickly:

  ┌────
  │ ocb --label Hello --color green --style flat --labelcolor white --status Goodbye
  └────

  Will gives this result: [SVG example].

  My first use case was [To.ml] where I'm using [bisect_ppx] to generate
  and deploy a [coverage report]. I wanted to display the coverage
  percentage in the README and tried existing tools but wasn't fully
  satisfied as they didn't work or were failing randomly. Now, [I'm
  generating the badge directly in a GitHub action].

  The project was inspired by [badgen]. I still have to add support for
  icons and to improve the documentation but it's usable.


[ocb] <https://github.com/ocamlpro/ocb>

[SVG example]
<https://raw.githubusercontent.com/OCamlPro/ocb/master/example/cli.svg>

[To.ml] <https://github.com/ocaml-toml/To.ml>

[bisect_ppx] <https://github.com/aantron/bisect_ppx>

[coverage report] <https://ocaml-toml.github.io/To.ml/coverage/>

[I'm generating the badge directly in a GitHub action]
<https://github.com/ocaml-toml/To.ml/blob/6ac580848ad1d34ec3032da8672bbd9aca203cc4/.github/workflows/deploy.yml#L34>

[badgen] <https://github.com/badgen/badgen>


Release of OCaml-Git v3.0 and co
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-of-ocaml-git-v3-0-and-co/7076/1>


Ulugbek Abdullaev announced
───────────────────────────

  We, the [`ocaml-git'] team, are happy to announce a new major release
  of `ocaml-git v3.0' and related libraries.


[`ocaml-git'] <https://github.com/mirage/ocaml-git>

Release Notes
╌╌╌╌╌╌╌╌╌╌╌╌╌

OCaml-Git v3.0
┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  [*OCaml-Git*] is a library that implements `git' format and protocol
  implementation in pure OCaml. The library is used by libraries such as
  [`irmin'], a git-like distributed database, or [`pasteur'], a MirageOS
  unikernel-based snippet storage service.


[*OCaml-Git*] <https://github.com/mirage/ocaml-git>

[`irmin'] <https://github.com/mirage/irmin>

[`pasteur'] <https://github.com/dinosaure/pasteur>

Changes
┈┈┈┈┈┈┈

  The main goal behind this major release was to get better
  compatibility with various platforms, including
  [~MirageOS~](mirage.io), 32-bit platforms, and `js_of_ocaml'. In order
  to achieve that, we broke down `ocaml-git' into several components,
  which are represented as sub-libraries. We will describe some of those
  components later in this post.

  Along with better support for various platforms, `ocaml-git 3.0' also
  comes with SSH support for `fetch/push' and various bug fixes.

  The rest of the changes are mostly internal and pave a way for
  interesting features such as a full-blown `git' [garbage collector]
  and wire protocol v2 ([announcment] and [spec]).

  *References:*

  • Full [changes list]
  • [PR] that introduced the major rewrite of `ocaml-git'

  —

  In the new version of `ocaml-git', we try to have better separation of
  concerns by breaking some of the `ocaml-git' components into
  sub-libraries, which do not contain `git'-specific logic and can be
  reused for other purposes.


[garbage collector] <https://git-scm.com/docs/git-gc>

[announcment]
<https://opensource.googleblog.com/2018/05/introducing-git-protocol-version-2.html>

[spec]
<https://github.com/git/git/blob/master/Documentation/technical/protocol-v2.txt>

[changes list]
<https://github.com/mirage/ocaml-git/blob/master/CHANGES.md>

[PR] <https://github.com/mirage/ocaml-git/pull/395>


Carton
┄┄┄┄┄┄

  Git uses [PACK files] to store old git objects such as commits and
  transfer objects over wire using git's wire protocols (`git-nss'
  library mentioned below implements [v1] of the protocol; [v2]
  implementation is in progress).

  [*Carton*] is a library to work with PACK files. The library does not
  contain git-specific code, so one can easily reuse the library and
  PACK format for non-git objects. One can see how `ocaml-git' uses
  `carton' for its purposes [here].

  *References:*

  • [PR] that introduces `carton'


[PACK files]
<https://github.com/git/git/blob/master/Documentation/technical/pack-format.txt>

[v1]
<https://github.com/git/git/blob/master/Documentation/technical/pack-protocol.txt>

[v2]
<https://github.com/git/git/blob/master/Documentation/technical/protocol-v2.txt>

[*Carton*] <https://github.com/mirage/ocaml-git/tree/master/src/carton>

[here] <https://github.com/mirage/ocaml-git/tree/master/src/carton-git>

[PR] <https://github.com/mirage/ocaml-git/issues/375>


Git-NSS (Not So Smart)
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  When one wants to synchronize with a remote repository using git, they
  need to use `git fetch/push'.  Communication and
  synchronization/negotiation is defined by git *wire protocol*, which
  has two versions: older version 1 and newer leaner version 2. The
  protocols are defined for four wire transports: HTTP(S), SSH, and
  `git://' (TCP).

  [`Not-So-Smart'] library is a library that allows for such
  synchronization based on the git wire protocols but without
  git-specific code, meaning that files being fetched do not need to be
  git objects or that there is no assumptions on the "repository" that
  one is synchronizing with. So, as well as `carton', the library aims
  to be reusable for other purposes.

  This release features support for SSH using [awa-ssh] by @hannesm (see
  [the release]), support for [partial-clone] (of various `depth'), and
  memory consumption fixes for unikernels.

  *Note 1:* The library's name "Not so smart" is a play on the git's
  "smart" protocol, a part of wire protocol v1 over HTTP(S) transport.

  *Note 2:* only client side logic is implemented for wire
  protocols. The server-side is planned but not yet implemented. One can
  use `git' as the server for now.


[`Not-So-Smart']
<https://github.com/mirage/ocaml-git/tree/master/src/not-so-smart>

[awa-ssh] <https://github.com/mirage/awa-ssh>

[the release]
<https://discuss.ocaml.org/t/ann-first-release-of-awa-ssh/7057>

[partial-clone] <https://git-scm.com/docs/partial-clone>


Mimic
┄┄┄┄┄

  [*Mimic*] is a small reimplementation of [`conduit'], a library that
  helps to abstract over a transport protocol such as HTTP(S) or SSH. In
  other words, the code using `mimic' can deal not with different types
  that represent an HTTP or SSH connection, but just deal, e.g., read
  from or write to, with a `flow' value, which hides protocol-specific
  details under its hood.

  —

  There are several independent libraries that were upgraded along with
  `ocaml-git 3.0'.


[*Mimic*] <https://github.com/mirage/ocaml-git/tree/master/src/mimic>

[`conduit'] <https://github.com/mirage/ocaml-conduit>


Duff v0.3
┄┄┄┄┄┄┄┄┄

  [*Duff*] is a library that implements git's [`libXdiff'] (`xdiff'
  algorithm) in OCaml. PACK files use a binary diff algorithm, `xdiff',
  to compress binary data. More on the project [page] and release
  [notes] for `ocaml-git 2.0'.


[*Duff*] <https://github.com/mirage/duff>

[`libXdiff'] <http://www.xmailserver.org/xdiff-lib.html>

[page] <https://github.com/mirage/duff>

[notes] <https://discuss.ocaml.org/t/ann-ocaml-git-2-0/2740>

Changes
┈┈┈┈┈┈┈

  This release fixes the support for 32-bit architecture platforms.


Encore v0.7
┄┄┄┄┄┄┄┄┄┄┄

  [*Encore*] is a library that can create an encoder/decoder based on
  the format given. It also ensures isomorphism by construction.


[*Encore*] <https://github.com/mirage/encore>

Changes
┈┈┈┈┈┈┈

  Extensive changes to the API. See the project page.


Decompress v1.2.0
┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄┄

  [*Decompress*] is an OCaml implementation of certain decompression
  algorithms such as `Zlib', `Gzip', etc.


[*Decompress*] <https://github.com/mirage/decompress>

Changes
┈┈┈┈┈┈┈

  `ocaml-git 3.0' uses new version of `decompress' with extensive
  performance improvements documented in *Tarides's* blog [API changes]
  and [performance improvements].

  We'd be happy to get your feedback or questions! :-)


[API changes]
<https://tarides.com/blog/2019-08-26-decompress-the-new-decompress-api>

[performance improvements]
<https://tarides.com/blog/2019-09-13-decompress-experiences-with-ocaml-optimization>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [How We Lost at The Delphi Oracle Challenge]
  • [Tarides sponsors the Oxbridge Women in Computer Science Conference
    2020]
  • [Coq 8.12.2 is out]
  • [First release of MetAcsl plugin]
  • [Announcing MirageOS 3.10]
  • [ ReScript 8.4]
  • [Coq 8.13+beta1 is out]


[OCaml Planet] <http://ocaml.org/community/planet/>

[How We Lost at The Delphi Oracle Challenge]
<https://seb.mondet.org/b/0010-delphi-challenge-post-vivum.html>

[Tarides sponsors the Oxbridge Women in Computer Science Conference
2020]
<https://tarides.com/blog/2020-12-14-tarides-sponsors-the-oxbridge-women-in-computer-science-conference-2020>

[Coq 8.12.2 is out] <https://coq.inria.fr/news/coq-8-12-2-is-out.html>

[First release of MetAcsl plugin]
<https://frama-c.com/fc-plugins/metacsl.html>

[Announcing MirageOS 3.10]
<https://mirage.io/blog/announcing-mirage-310-release>

[ ReScript 8.4]
<https://rescript-lang.org/blog/bucklescript-release-8-4>

[Coq 8.13+beta1 is out]
<https://coq.inria.fr/news/coq-8-13beta1-is-out.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2021-01-05 11:22 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2021-01-05 11:22 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of December 29, 2020
to January 05, 2021.

Table of Contents
─────────────────

First release of Feat
OCluster and OBuilder
Plotting 3D vectors
Marshal determinism and stability
It there a tutorial for `js_of_ocaml' with simple graphics?
Interesting OCaml exercises from François Pottier available online
Old CWN


First release of Feat
═════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-feat/7033/1>


François Pottier announced
──────────────────────────

  A brief note to announce the first release of Feat:

  ┌────
  │ opam update
  │ opam install feat
  └────

  Feat is a library that offers support for counting, enumerating, and
  sampling objects of a certain kind, such as (say) the inhabitants of
  an algebraic data type.

  Feat was inspired by the paper "Feat: Functional Enumeration of
  Algebraic Types" by Jonas Duregård, Patrik Jansson and Meng Wang
  (2012).

  More details can be found here:

  <https://gitlab.inria.fr/fpottier/feat/>


OCluster and OBuilder
═════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocluster-and-obuilder/7035/1>


Thomas Leonard announced
────────────────────────

  I'm pleased to announce the first release of [OCluster]. A user can
  submit a build job (either a Dockerfile or an OBuilder spec) to the
  scheduler, which then runs the build on a worker machine, streaming
  the logs back to the client.

  This is the build scheduler / cluster manager that we use for e.g.
  [opam-repo-ci] (which you may have seen in action if you submitted a
  package to opam-repository recently).

  See [ocurrent/overview] for a quick overview of the various other CI
  services using it too.

  To install and run the scheduler use e.g.

  ┌────
  │ opam depext -i ocluster
  │ mkdir capnp-secrets
  │ ocluster-scheduler \
  │   --capnp-secret-key-file=./capnp-secrets/key.pem \
  │   --capnp-listen-address=tcp:0.0.0.0:9000 \
  │   --capnp-public-address=tcp:127.0.0.1:9000 \
  │   --state-dir=/var/lib/ocluster-scheduler \
  │   --pools=linux-arm32,linux-x86_64
  └────

  It will generate `key.pem' on the first run, as well as various
  capability files granting access for workers and clients. You then
  copy each generated pool capability (e.g. `pool-linux-x86_64.cap') to
  each machine you want in that pool, and run `ocluster-worker
  pool-linux-x86_64.cap' to start the worker agent. See the [README] for
  full details.

  [OBuilder] is an alternative to `docker build'. The main differences
  are that it takes a spec in S-expression format, which is easier to
  generate than a Dockerfile, handles concurrent builds reliably, and
  keeps copies of the logs so that you still see the output even if
  someone else performed the same build step earlier and the result is
  therefore taken from the cache.

  It currently supports ZFS and Btrfs for storage (it needs cheap
  snapshots) and `runc' for sandboxing builds. [macos support] is under
  development, but not yet upstreamed. It should be fairly easy to add
  support for any platform that has some form of secure chroot.

  OCluster supports monitoring with Prometheus, so you can see what the
  cluster is doing:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/d/d5ff5aaa0259d7b59445b156e6b642a421040b64_2_920x750.png>


[OCluster] <https://github.com/ocurrent/ocluster>

[opam-repo-ci] <https://github.com/ocurrent/opam-repo-ci>

[ocurrent/overview] <https://github.com/ocurrent/overview>

[README] <https://github.com/ocurrent/ocluster/blob/master/README.md>

[OBuilder] <https://github.com/ocurrent/obuilder>

[macos support] <https://github.com/ocurrent/obuilder/issues/57>


Plotting 3D vectors
═══════════════════

  Archive: <https://discuss.ocaml.org/t/plotting-3d-vectors/7038/1>


Andreas Poisel asked
────────────────────

  I'm doing linear algebra with Owl.  Owl-plplot works great for
  visualizing 2D vectors, but it doesn't seem to capable of plotting 3D
  vectors.

  I took a (fast) look at vanilla [Plplot], [Oplot], and the [GNUplot
  bindings], but I didn't find a simple way to plot 3D vectors.

  I don't need high quality plots, 3D surfaces, a lot of control or
  fancy features, just a coordinate system and some function to draw
  geometric primitives (points, lines, circles, etc.).

  Did I miss anything or do I have to build this myself with the good
  old Graphics module?


[Plplot] <http://plplot.org/>

[Oplot] <https://github.com/sanette/oplot>

[GNUplot bindings] <https://github.com/c-cube/ocaml-gnuplot>


Marshall Abrams replied
───────────────────────

  What kind of vector representation do you want?  Just lines/arrows in
  3D?  That's just a curve in 3D, so it should be possible with Owl and
  plplot, at least.  Looks like it should be easy with oplot, too (but I
  haven't used oplot).  There are some 3D Owl plplot examples, with
  source code, on these pages:

  <https://ocaml.xyz/book/visualisation.html>

  <https://github.com/owlbarn/owl/wiki/Tutorial:-How-to-Plot-in-Owl%3F>

  <https://github.com/owlbarn/owl/wiki/Plot-Gallery>

  I don't know whether it will be easy to adapt them to your needs.  I
  wrote the last example on the last page above.  It's a plot of a
  series 2D curves in 3D.  Maybe some of the techniques can be adapted
  to your needs.  (The code is a few years old.  I'm not sure whether it
  works with the current version of Owl.)

  (If you end up having to use low-level bindings to plplot, oplot,
  etc. from Owl, you might consider contributing a wrapper module that
  makes it easy to do the kind of plot you want.)


Andreas Poisel then said
────────────────────────

  Thank you for your answer.

  I'd just like to draw 3D vectors in a cartesian coordinate system.  A
  plot should look similar to this:

  <https://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/3D_Vector.svg/800px-3D_Vector.svg.png>

  I wouldn't even need arrows, simple lines would be ok.

  Maybe there is a way to use one of the 3D functions (`Plot.surf',
  `Plot.mesh', `Plot.contour'), but I can't figure it out.


Hezekiah Carty replied
──────────────────────

  It's been a while since I worked with plplot but what you showed
  should be possible. The [plline3] function allows you to plot line
  segments in 3d space. The function is setup to take multiple segments
  in a single call. For a single segment each array would hold a single
  value. Colors can be set between draw calls.


[plline3]
<http://plplot.org/docbook-manual/plplot-html-5.15.0/plline3.html>


sanette also replied
────────────────────

  in oplot, there is the Curve3d object that should do it,
  <https://sanette.github.io/oplot/oplot/Oplot/Plt/index.html#type-plot_object.Curve3d>
  although it is quite rudimentary


Marshal determinism and stability
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/marshal-determinism-and-stability/7041/25>


Deep in this thread, Bikal Lem mentioned and Raphaël Proust described
─────────────────────────────────────────────────────────────────────

        [Binary module of data-encoding]

  Quick notes about this approach:

  • It is used extensively in the Tezos codebase. For data exchange (in
    the p2p layer), for data at rest (configuration files), and for a
    mix of the two (serialisation of economic protocol data which is
    both exchanged by peers and stored on disk).
  • It is flexible in that you have great control over the
    representation of data and the serialisation/deserialisation
    procedure. There is a medium-term plan to allow even more
    control. For now you can decide, say, if 8 booleans are represented
    as one byte, 8 bytes, or 8 words (or something else altogether) (see
    code below).
  • Some of the responsibility for correctness rests upon your shoulders
    as a user. E.g., when you encode a tuple, the left element must have
    either a fixed length (e.g., be an int8, int32, etc., be a
    fixed-length string, or be a tuple of fixed-length values) or be
    prefixed by a length marker (which the library provides a combinator
    for). Most of the errors for this are raised when you declare the
    encoding and a few are raised when you use the encoding. I recommend
    writing some tests to check that your encodings accept the range of
    values that you are going to throw at them.
  • The library is well tested: there are tests using crowbar to check
    that encoding and decoding are actual inverse of each others.

  Let me know if you have more questions. And in the meantime, here's
  two different encodings for a tuple of 8 booleans:

  ┌────
  │ (* easy-encoding, produces 8 bytes *)
  │ let boolsas8bytes =
  │    tup8 bool bool bool bool bool bool bool bool
  │ 
  │ (* very-compact encoding, produces 1 byte *)
  │ let boolsas1byte =
  │    conv
  │       (fun (b1, b2, b3, b4, b5, b6, b7, b8) ->
  │ 	 let acc = 0 in
  │ 	 let acc = if b1 then acc lor 0b10000000 else acc in
  │ 	 let acc = if b2 then acc lor 0b01000000 else acc in
  │ 	 let acc = if b3 then acc lor 0b00100000 else acc in
  │ 	 …
  │ 	 acc)
  │       (fun i ->
  │ 	 let b1 = i land 0b10000000 <> 0 in
  │ 	 let b1 = i land 0b01000000 <> 0 in
  │ 	 let b1 = i land 0b00100000 <> 0 in
  │ 	 …
  │ 	 (b1, b2, b3, b4, b5, b6, b7, b8))
  │       uint8
  └────

  In general, data-encoding is probably slower than marshal, but its
  strong points are:
  • it offers some type guarantees,
  • it gives you some control over the representation of the data,
  • it allows you to define representations that are easy to parse in
    other languages or in other versions of the same language,
  • it generates documentation about the data-representation.


[Binary module of data-encoding]
<https://gitlab.com/nomadic-labs/data-encoding>


It there a tutorial for `js_of_ocaml' with simple graphics?
═══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/it-there-a-tutorial-for-js-of-ocaml-with-simple-graphics/4636/7>


Deep in this thread, Phat Ky said
─────────────────────────────────

  This is a really, really late reply but this youtube video was very
  helpful to me …  <https://www.youtube.com/watch?v=h_e5pPKI0K4>


Interesting OCaml exercises from François Pottier available online
══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-exercises-from-francois-pottier-available-online/7050/1>


gasche announced
────────────────

  The recent URL
  <https://ocaml-sf.org/learn-ocaml-public/#activity%3Dexercises>
  contains auto-graded OCaml exercises, in particular a bunch of
  advanced and fairly interesting exercices written by François Pottier,
  which I would recommend for anyone knowledgeable in OCaml and curious
  about algorithms and functional programming. (You have to scroll down
  to see those, the exercises at the top come from the OCaml MOOC.)

  See for example François' exercises on:
  • [Alpha-Beta Search],
  • [Parser combinators],
  • [Huffman Compression],
  • [Implementing backtracking with continuations], or
  • my personal favorite, [reimplementing the core of a pretty-printer].

  Context: the exercise platform is [LearnOCaml], initially written by
  OCamlPro for the OCaml MOOC and maintaing by Yann Régis-Gianas
  (@yurug) on behalf of the [OCaml Software Foundation]. We (at the
  Foundation) are trying to assemble a corpus of nice OCaml exercises
  for teachers and people self-studying, and the nice exercises by
  François Pottier (@fpottier) were written as part of this initiative.


[Alpha-Beta Search]
<https://ocaml-sf.org/learn-ocaml-public/exercise.html#id%3Dfpottier/alpha_beta%26tab%3Dtext%26prelude%3Dshown>

[Parser combinators]
<https://ocaml-sf.org/learn-ocaml-public/exercise.html#id%3Dfpottier/parser_combinators%26tab%3Dtext>

[Huffman Compression]
<https://ocaml-sf.org/learn-ocaml-public/exercise.html#id%3Dfpottier/huffman%26tab%3Dtext%26prelude%3Dshown>

[Implementing backtracking with continuations]
<https://ocaml-sf.org/learn-ocaml-public/exercise.html#id%3Dfpottier/nondet_monad_cont%26tab%3Dtext%26prelude%3Dshown>

[reimplementing the core of a pretty-printer]
<https://ocaml-sf.org/learn-ocaml-public/exercise.html#id%3Dfpottier/pprint%26tab%3Dtext%26prelude%3Dshown>

[LearnOCaml] <https://github.com/ocaml-sf/learn-ocaml>

[OCaml Software Foundation] <http://ocaml-sf.org/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-12-29  9:59 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-12-29  9:59 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 9463 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of December 22 to 29,
2020.

Table of Contents
─────────────────

ppx_deriving_yaml 0.1.0
A Heroku buildpack for OCaml
opam-dune-lint - keep opam and dune dependencies in sync
Scirep, a utility for literate programming
Camel Calendar for 2021
Old CWN


ppx_deriving_yaml 0.1.0
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ppx-deriving-yaml-0-1-0/7007/1>


Patrick Ferris announced
────────────────────────

  I'm proud to announce the first release (and my first release) of
  [ppx_deriving_yaml]. If you are familiar with the excellent
  [ppx_deriving_yojson] then this library should come as no surprise. In
  fact it helped me a lot in writing this ppx, so thank you to its
  creators/maintainers.


[ppx_deriving_yaml] <https://github.com/patricoferris/ppx_deriving_yaml>

[ppx_deriving_yojson] <https://github.com/ocaml-ppx/ppx_deriving_yojson>

Installation
╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ $ opam update
  │ $ opam install ppx_deriving_yaml
  └────


Usage
╌╌╌╌╌

  Ppx_deriving_yaml converts your OCaml types to the "basic" [OCaml Yaml
  value type] (the one that is currently compatible with ezjsonm). So
  for example you can have:

  ┌────
  │ type t = { title: string; authors: string list } [@@deriving yaml]
  │ 
  │ let () =
  │   let v = { title = "Yaml PPX!"; authors = [ "Patrick Ferris" ] } in
  │   let yaml = to_yaml v in
  │   Yaml.pp Format.std_formatter yaml;
  │   match of_yaml yaml with
  │     | Ok t -> Format.print_string t.title
  │     | Error (`Msg m) -> failwith m
  └────

  The ppx generates two functions:

  ┌────
  │ val of_yaml : Yaml.value -> t Yaml.res
  │ val to_yaml : t -> Yaml.value
  └────

  And when built with this dune file:

  ┌────
  │ (executable
  │  (name main)
  │  (libraries yaml)
  │  (preprocess
  │   (pps ppx_deriving_yaml)))
  └────

  The following output is generated:

  ┌────
  │ title: Yaml PPX!
  │ authors:
  │ - Patrick Ferris
  │ Yaml PPX!
  └────

  The [README] contains some more information and the library is still a
  little rough around the edges, especially with error reporting, but
  I'm currently using it in a few places such as an "ocaml-ified"
  [github actions] library (ppx_deriving_yaml's [test workflow] was
  automatically generated with it :sparkles:). This is a nice example of
  how it can be used in a fairly straightforward way to generate OCaml
  versions of the many projects that use Yaml for configuration files.

  Happy yaml-ing :)


[OCaml Yaml value type]
<https://github.com/avsm/ocaml-yaml/blob/6de8fa6926d391334b945754619a64857d352e5d/lib/types.ml#L44>

[README]
<https://github.com/patricoferris/ppx_deriving_yaml#implementation-details>

[github actions] <https://github.com/patricoferris/opam-github-workflow>

[test workflow]
<https://github.com/patricoferris/ppx_deriving_yaml/blob/main/.github/workflows/test.yml>


A Heroku buildpack for OCaml
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-a-heroku-buildpack-for-ocaml/7012/1>


roddy announced
───────────────

  I wrote [a Heroku buildpack] for OCaml web apps that use opam/dune.


[a Heroku buildpack]
<https://github.com/roddyyaga/heroku-buildpack-ocaml>


opam-dune-lint - keep opam and dune dependencies in sync
════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-opam-dune-lint-keep-opam-and-dune-dependencies-in-sync/7014/1>


Thomas Leonard announced
────────────────────────

  We're pleased to announce the first release of [opam-dune-lint]. This
  little tool checks that every ocamlfind dependency listed in your
  `dune' files has the corresponding opam package listed as a dependency
  in your `*.opam' file(s).

  e.g.

  ┌────
  │ $ cd charrua
  │ $ opam dune-lint
  │ charrua-client.opam: changes needed:
  │   "tcpip" {with-test & >= 6.0.0}           [from test/client, test/client/lwt]
  │ charrua-server.opam: changes needed:
  │   "ppx_cstruct" {with-test & >= 6.0.0}     [from (ppx), test]
  │   "tcpip" {with-test & >= 6.0.0}           [from test]
  │ charrua-unix.opam: changes needed:
  │   "cstruct-lwt" {>= 6.0.0}                 [from unix]
  │   "ipaddr" {>= 5.0.1}                      [from unix]
  │   "tcpip" {>= 6.0.0}                       [from unix]
  │ charrua.opam: OK
  │ Note: version numbers are just suggestions based on the currently installed version.
  │ Write changes? [y] y
  │ Wrote "./charrua-client.opam"
  │ Wrote "./charrua-server.opam"
  │ Wrote "./charrua-unix.opam"
  └────

  If your project generates the opam files from `dune-project', then it
  will update your `dune-project' instead.

  It can also be useful to run this in CI. It will exit with a non-zero
  exit status if anything needs to be changed. [ocaml-ci] runs this
  automatically as part of the "lint-opam" check.


[opam-dune-lint] <https://github.com/ocurrent/opam-dune-lint>

[ocaml-ci] <https://ci.ocamllabs.io/>


Scirep, a utility for literate programming
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/scirep-a-utility-for-literate-programming/7016/1>


Philippe announced
──────────────────

  I wrote a utility called [scirep] to render a markdown file with OCaml
  code blocks as an HTML document, which provides some support for
  graphics. Here are some examples of generated documents: [one based on
  vg], and [another using owl-plplot].

  It can also be used downstream of [mdx] as a markdown-to-html
  converter that detects pictures in the toplevel's standard output and
  renders them in the final document.

  It is really a hack, and it is poorly documented, but I'm advertising
  it in case it might be useful to others.


[scirep] <https://github.com/pveber/scirep>

[one based on vg] <http://pveber.github.io/scirep/fold.html>

[another using owl-plplot] <http://pveber.github.io/scirep/damped.html>

[mdx] <https://github.com/realworldocaml/mdx>


Camel Calendar for 2021
═══════════════════════

  Archive: <https://discuss.ocaml.org/t/camel-calendar-for-2021/7020/1>


Florent Monnier announced
─────────────────────────

  I would like to share with you a [camel calendar for 2021 in pdf] with
  the nice theme from ocaml dot org.

  It was generated from an ocaml script that you can find in this repo:
  [svg calendar generator].

  Several scripts are available, you can find some results on this [web
  page].

  At the beginning of 2020 I was searching for a free software to
  generate calendars in SVG that I could customise for my own use, but I
  was unable to install the Perl script that exists (it has a lot of
  dependencies and the error message when I try to install it didn't
  help us to find what's wrong with it).

  This explains the design of these scripts, that are made to work
  without any dependencies and without any compilation. There's code
  duplication, but every script only need the ocaml interpreter to be
  run, so most people comfortable with the command line should be able
  to use it.

  (I also tried to sell some [on Etsy] but didn't sold a single one.)

  By default 12 languages are included in every script, but you can
  generate the calendars for more than 200 languages if you use [these
  dates locales] that come from the CLDR repository.

  You can also switch monday first or sunday first.

  These generators are provided under Zlib license.

  I hope some will enjoy!


[camel calendar for 2021 in pdf]
<http://decapode314.free.fr/cal/cal-camel/cal-camel-2021-en.pdf>

[svg calendar generator] <https://github.com/fccm/ocaml-cal-svg>

[web page] <http://decapode314.free.fr/cal/>

[on Etsy] <https://www.etsy.com/fr/shop/Decapode>

[these dates locales] <https://github.com/fccm/DateLocale-ocaml>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-12-22  8:48 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-12-22  8:48 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 12455 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of December 15 to 22,
2020.

Table of Contents
─────────────────

ocaml-lsp-server 1.4.0
OCaml 4.12.0, third alpha release
Lwt 5.4.0, Lwt_ppx 2.0.2, Lwt_react 1.1.4 releases
Senior software engineer at Docent, France - Remote OK
Old CWN


ocaml-lsp-server 1.4.0
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-lsp-server-1-4-0/6996/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the ocaml-lsp team, it is my pleasure to announce version
  1.4.0. This release introduces support for [automatic signature help].
  Signature help is not yet present in all possible contexts. We intend
  to improve to support as many relevant language constructs as possible
  in the future. Many thanks to @mnxn for implementing this feature.

  The full change log is replicated at the end of this post for your
  convenience.

  Happy Holidays!

  • Support cancellation notifications when possible. (#323)

  • Implement signature help request for functions (#324)

  • Server LSP requests & notifications concurrently. Requests that
    require merlin are still serialized. (#330)


[automatic signature help]
<https://code.visualstudio.com/api/language-extensions/programmatic-language-features#help-with-function-and-method-signatures>


OCaml 4.12.0, third alpha release
═════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-12-0-third-alpha-release/6997/1>


octachron announced
───────────────────

  The release of OCaml 4.12.0 is approaching. We have released a third
  alpha version to help fellow hackers join us early in our bug hunting
  and opam ecosystem fixing fun.

  Beyond the usual bug fixes, this new alpha version contains two small
  API fixes for statmemprof and the Unix module. (Keen-eyed readers
  might notice a breaking change in the change log below but this
  concerns a corner case of a corner case of the type system that should
  not affect anyone.)

  The base compiler can be installed as an opam switch with the
  following commands
  ┌────
  │ opam update
  │ opam switch create 4.12.0~alpha3
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  If you want to tweak the configuration of the compiler, you can pick
  configuration options with
  ┌────
  │ opam update
  │ opam switch create <switch_name> --packages=ocaml-variants.4.12.0~alpha3+options,<option_list>
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where <option_list> is a comma separated list of ocaml-option-*
  packages. For instance, for a flambda and afl enabled switch:
  ┌────
  │ opam switch create 4.12.0~alpha3+flambda+afl
  │ --packages=ocaml-variants.4.12.0~alpha3+options,ocaml-option-flambda,ocaml-option-afl
  │ --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  All available options can be listed with "opam search ocaml-option".

  The source code for the alpha is also available at these addresses:

  • <https://github.com/ocaml/ocaml/archive/4.12.0-alpha3.tar.gz>
  • <https://caml.inria.fr/pub/distrib/ocaml-4.12/ocaml-4.12.0~alpha3.tar.gz>

  If you want to test this version, it is advised to install the alpha
  opam repository

  <https://github.com/kit-ty-kate/opam-alpha-repository>

  with
  ┌────
  │ opam repo add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This alpha repository contains various packages patched with fixes in
  the process of being upstreamed. Once the repository installed, these
  patched packages will take precedence over the non-patched version.

  If you find any bugs, please report them here:
   <https://github.com/ocaml/ocaml/issues>


Changes from the second alpha:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • *additional fixes* [1128], [7503], [9036], [9722], +[10069]:
     EINTR-based signal handling. When a signal arrives, avoid running
     its OCaml handler in the middle of a blocking section. Instead,
     allow control to return quickly to a polling point where the signal
     handler can safely run, ensuring that

  • [9907]: Fix native toplevel on native Windows. (David Allsopp,
    review by Florian Angeletti)

  • [10056]: Memprof: ensure young_trigger is within the bounds of the
    minor heap in caml_memprof_renew_minor_sample (regression from
    [8684]) (David Allsopp, review by Guillaume Munch-Maccagnoni and
    Jacques-Henri Jourdan)

  • [10062]: set ARCH_INT64_PRINTF_FORMAT correctly for both modes of
    mingw-w64 (David Allsopp, review by Xavier Leroy)

  • [10025]: Track custom blocks (e.g. Bigarray) with Statmemprof
    (Stephen Dolan, review by Leo White, Gabriel Scherer and
    Jacques-Henri Jourdan)

  • [10070]: Fix Float.Array.blit when source and destination arrays
    coincide. (Nicolás Ojeda Bär, review by Alain Frisch and Xavier
    Leroy)

  • *additional fixes* [9869], +[10073]: Add Unix.SO_REUSEPORT (Yishuai
     Li, review by Xavier Leroy, amended by David Allsopp)

  • [9877]: manual, warn that multi-index indexing operators should be
    defined in conjunction of single-index ones. (Florian Angeletti,
    review by Hezekiah M. Carty, Gabriel Scherer, and Marcello Seri)

  • [10046]: Link all DLLs with -static-libgcc on mingw32 to prevent
    dependency on libgcc_s_sjlj-1.dll with mingw-w64 runtime 8.0.0
    (previously this was only needed for dllunix.dll). (David Allsopp,
    report by Andreas Hauptmann, review by Xavier Leroy)

  • [9896]: Share the strings representing scopes, fixing some
    regression on .cmo/.cma sizes (Alain Frisch and Xavier Clerc, review
    by Gabriel Scherer)

  • [10044]: Always report the detected ARCH, MODEL and SYSTEM, even for
    bytecode- only builds (fixes a "configuration regression" from 4.08
    for the Windows builds) (David Allsopp, review by Xavier Leroy)

  • [10071]: Fix bug in tests/misc/weaklifetime.ml that was reported in
    [10055] (Damien Doligez and Gabriel Scherer, report by David
    Allsopp)

  • *breaking change* [8907], [9878]: `Typemod.normalize_signature' uses
     wrong environment Does not treat submodules differently when
     normalizing conjunctive types in polymorphic variants. This may
     break code that expose conjunctive types in inferred
     interface. (Jacques Garrigue, report and review by Leo White)

  • [9739], [9747]: Avoid calling type variables, types that are not
    variables in recursive occurence error messages (for instance, "Type
    variable int occurs inside int list") (Florian Angeletti, report by
    Stephen Dolan, review by Armaël Guéneau)

  • [10048]: Fix bug with generalized local opens. (Leo White, review by
    Thomas Refis)


[1128] <https://github.com/ocaml/ocaml/issues/1128>

[7503] <https://github.com/ocaml/ocaml/issues/7503>

[9036] <https://github.com/ocaml/ocaml/issues/9036>

[9722] <https://github.com/ocaml/ocaml/issues/9722>

[10069] <https://github.com/ocaml/ocaml/issues/10069>

[9907] <https://github.com/ocaml/ocaml/issues/9907>

[10056] <https://github.com/ocaml/ocaml/issues/10056>

[8684] <https://github.com/ocaml/ocaml/issues/8684>

[10062] <https://github.com/ocaml/ocaml/issues/10062>

[10025] <https://github.com/ocaml/ocaml/issues/10025>

[10070] <https://github.com/ocaml/ocaml/issues/10070>

[9869] <https://github.com/ocaml/ocaml/issues/9869>

[10073] <https://github.com/ocaml/ocaml/issues/10073>

[9877] <https://github.com/ocaml/ocaml/issues/9877>

[10046] <https://github.com/ocaml/ocaml/issues/10046>

[9896] <https://github.com/ocaml/ocaml/issues/9896>

[10044] <https://github.com/ocaml/ocaml/issues/10044>

[10071] <https://github.com/ocaml/ocaml/issues/10071>

[10055] <https://github.com/ocaml/ocaml/issues/10055>

[8907] <https://github.com/ocaml/ocaml/issues/8907>

[9878] <https://github.com/ocaml/ocaml/issues/9878>

[9739] <https://github.com/ocaml/ocaml/issues/9739>

[9747] <https://github.com/ocaml/ocaml/issues/9747>

[10048] <https://github.com/ocaml/ocaml/issues/10048>


Lwt 5.4.0, Lwt_ppx 2.0.2, Lwt_react 1.1.4 releases
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-lwt-5-4-0-lwt-ppx-2-0-2-lwt-react-1-1-4-releases/7001/1>


Raphaël Proust announced
────────────────────────

  We are glad to announce the release of version 5.4.0 of Lwt, version
  2.0.2 of Lwt_ppx, and version 1.1.4 of Lwt_react.

  <https://github.com/ocsigen/lwt/releases/tag/5.4.0>

  It can be installed from opam as usual:

  ┌────
  │ opam update
  │ opam upgrade lwt lwt_ppx lwt_react
  └────


OCaml 4.12 compatibility
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  With this release, Lwt is now compatible with OCaml 4.12. Thanks
  @kit-ty-kate for the contribution towards this support.

  Thanks as well to all the other contributors for all the other
  improvements that made it into this release. Check-out the release's
  changelog (link above) for a full list of bugfixes and additions.


Maintainers' notes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  As per [a previous announce] I am a co-maintainer of Lwt. With this
  release I'm taking on a more and more central role in the maintenance
  effort. Whilst I've received a lot of help getting this release
  together, I'm most likely the one responsible for any issues in the
  process.

  I'd like to thank @antron who is as stellar with maintenance of the
  project as he is with guiding me through the learning process. I'd
  also like to thank the opam-repository team who stepped up very
  quickly to fix some CI-related build-issues. And I'd like to thank my
  employer, [Nomadic Labs], who agreed to make Lwt maintenance part of
  my day job.

  I'm looking forward to all your bug reports, pull requests, comments,
  ideas, questions, remarks, as well as any sort of feedback. Don't
  hesitate to get in touch!


[a previous announce]
<https://discuss.ocaml.org/t/announcing-a-new-maintainer-for-lwt/6192>

[Nomadic Labs] <https://nomadic-labs.com/>


Senior software engineer at Docent, France - Remote OK
══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/senior-software-engineer-at-docent-france-remote-ok/7002/1>


Thibaut Mattio announced
────────────────────────

  Docent, a company I'm working with, is recruiting an OCaml
  developer. You can see the job post [here]

  The team and project are really nice, I would definitely recommend it!

  I've built the current version of the backend, so don't hesitate to
  reach out (thibaut.mattio@gmail.com) if you have any questions on the
  tech (or other).


[here]
<https://www.notion.so/docentart/OCaml-Developer-bc047ff6c80b448e814943f7116fa14b>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-12-15  9:51 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-12-15  9:51 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 20085 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of December 08 to 15,
2020.

Table of Contents
─────────────────

MirageOS 3.10 released
Exception vs Result
Release: scikit-learn, Numpy, Scipy for OCaml, 0.3.1
OCaml 4.10.2
BAP 2.2.0 Release
Liquidshop 1.0, Jan. 17th and 18th, 2021
Opium 0.20.0
Set up OCaml 1.1.5
Other OCaml News
Old CWN


MirageOS 3.10 released
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-mirageos-3-10-released/6941/1>


Hannes Mehnert announced
────────────────────────

  we're pleased to announce MirageOS 3.10:

  IPv6 and dual (IPv4 and IPv6) stack support
  <https://github.com/mirage/mirage/pull/1187>
  <https://github.com/mirage/mirage/issues/1190>

  Since a long time, IPv6 code was around in our TCP/IP stack (thanks to
  @nojb who developed it in 2014).  Some months ago, @hannesm and
  @MagnusS got excited to use it. After we managed to fix some bugs and
  add some test cases, and writing more code to setup IPv6-only and dual
  stacks, we are eager to share this support for MirageOS in a released
  version. We expect there to be bugs lingering around, but duplicate
  address detection (neighbour solicitation and advertisements) has been
  implemented, and (unless "–accept-router-advertisement=false") router
  advertisements are decoded and used to configure the IPv6 part of the
  stack. Configuring a static IPv6 address is also possible (with
  "–ipv6=2001::42/64").

  While at it, we unified the boot arguments between the different
  targets: namely, on Unix (when using the socket stack), you can now
  pass "–ipv4=127.0.0.1/24" to the same effect as the direct stack: only
  listen on 127.0.0.1 (the subnet mask is ignored for the Unix socket
  stack).

  A dual stack unikernel has "–ipv4-only=BOOL" and "–ipv6-only=BOOL"
  parameters, so a unikernel binary could support both Internet Protocol
  versions, while the operator can decide which protocol version to
  use. I.e. now there are both development-time (stackv4 vs stackv6 vs
  stackv4v6) choices, as well as the run-time choice (via boot
  parameter).

  I'm keen to remove the stackv4 & stackv6 in future versions, and
  always develop with dual stack (leaving it to configuration & startup
  time to decide whether to enable ipv4 and ipv6).

  Please also note that the default IPv4 network configuration no longer
  uses 10.0.0.1 as default gateway (since there was no way to unset the
  default gateway <https://github.com/mirage/mirage/issues/1147>).

  For unikernel developers, there are some API changes in the Mirage
  module
  • New "v4v6" types for IP protocols and stacks
  • The ipv6_config record was adjusted in the same fashion as the
    ipv4_config type: it is now a record of a network (V6.Prefix.t) and
    gateway (V6.t option)

  Some parts of the Mirage_key module were unified as well:
  • Arp.ip_address is available (for a dual Ipaddr.t)
  • Arg.ipv6_address replaces Arg.ipv6 (for an Ipaddr.V6.t)
  • Arg.ipv6 replaces Arg.ipv6_prefix (for a Ipaddr.V6.Prefix.t)
  • V6.network and V6.gateway are available, mirroring the V4 submodule

  If you're ready to experiment with the dual stack: below is a diff for
  our basic network example (from mirage-skeleton/device-usage/network)
  replacing IPv4 with a dual stack, and the tlstunnel unikernel commit
  <https://github.com/roburio/tlstunnel/commit/2cb3e5aa11fca4b48bb524f3c0dbb754a6c8739b>
  changed tlstunnel from IPv4 stack to dual stack.

  ┌────
  │ diff --git a/device-usage/network/config.ml b/device-usage/network/config.ml
  │ index c425edb..eabc9d6 100644
  │ --- a/device-usage/network/config.ml
  │ +++ b/device-usage/network/config.ml
  │ @@ -4,9 +4,9 @@ let port =
  │    let doc = Key.Arg.info ~doc:"The TCP port on which to listen for
  │ incoming connections." ["port"] in
  │    Key.(create "port" Arg.(opt int 8080 doc))
  │ 
  │ -let main = foreign ~keys:[Key.abstract port] "Unikernel.Main" (stackv4
  │ @-> job)
  │ +let main = foreign ~keys:[Key.abstract port] "Unikernel.Main"
  │ (stackv4v6 @-> job)
  │ 
  │ -let stack = generic_stackv4 default_network
  │ +let stack = generic_stackv4v6 default_network
  │ 
  │  let () =
  │    register "network" [
  │ diff --git a/device-usage/network/unikernel.ml
  │ b/device-usage/network/unikernel.ml
  │ index 5d29111..1bf1228 100644
  │ --- a/device-usage/network/unikernel.ml
  │ +++ b/device-usage/network/unikernel.ml
  │ @@ -1,19 +1,19 @@
  │  open Lwt.Infix
  │ 
  │ -module Main (S: Mirage_stack.V4) = struct
  │ +module Main (S: Mirage_stack.V4V6) = struct
  │ 
  │    let start s =
  │      let port = Key_gen.port () in
  │ -    S.listen_tcpv4 s ~port (fun flow ->
  │ -        let dst, dst_port = S.TCPV4.dst flow in
  │ +    S.listen_tcp s ~port (fun flow ->
  │ +        let dst, dst_port = S.TCP.dst flow in
  │ 	 Logs.info (fun f -> f "new tcp connection from IP %s on port %d"
  │ -                  (Ipaddr.V4.to_string dst) dst_port);
  │ -        S.TCPV4.read flow >>= function
  │ +                  (Ipaddr.to_string dst) dst_port);
  │ +        S.TCP.read flow >>= function
  │ 	 | Ok `Eof -> Logs.info (fun f -> f "Closing connection!");
  │ Lwt.return_unit
  │ -        | Error e -> Logs.warn (fun f -> f "Error reading data from
  │ established connection: %a" S.TCPV4.pp_error e); Lwt.return_unit
  │ +        | Error e -> Logs.warn (fun f -> f "Error reading data from
  │ established connection: %a" S.TCP.pp_error e); Lwt.return_unit
  │ 	 | Ok (`Data b) ->
  │ 	   Logs.debug (fun f -> f "read: %d bytes:\n%s" (Cstruct.len b)
  │ (Cstruct.to_string b));
  │ -          S.TCPV4.close flow
  │ +          S.TCP.close flow
  │        );
  │ 
  │      S.listen s
  └────

  Other bug fixes include <https://github.com/mirage/mirage/issues/1188>
  (in <https://github.com/mirage/mirage/pull/1201>) and adapt to charrua
  1.3.0 and arp 2.3.0 changes
  (<https://github.com/mirage/mirage/pull/1199>).


Exception vs Result
═══════════════════

  Archive: <https://discuss.ocaml.org/t/exception-vs-result/6931/18>


Continuing this thread, Vladimir Keleshev announced
───────────────────────────────────────────────────

  A bit late to the party, but here's an overview of error handling
  methods that I did a while ago:

  [Composable Error Handling in OCaml (keleshev.com)]

  It compares the following approaches:
  • Exceptions
  • Result type with strings for errors
  • Result type with custom variants for errors
  • Result type with polymorphic variants for errors


[Composable Error Handling in OCaml (keleshev.com)]
<https://keleshev.com/composable-error-handling-in-ocaml>


Release: scikit-learn, Numpy, Scipy for OCaml, 0.3.1
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-release-scikit-learn-numpy-scipy-for-ocaml-0-3-1/6942/1>


Ronan Le Hy announced
─────────────────────

  I've just released an update of OCaml wrappers for scikit-learn:
  • documentation: <https://lehy.github.io/ocaml-sklearn/>
  • code: <https://github.com/lehy/ocaml-sklearn>
  • `opam install sklearn'

  These bindings also come with bindings for Numpy (`opam install np')
  and Scipy (`opam install scipy').

  Scikit-learn is all of these things:
  • Simple and efficient tools for predictive data analysis
  • Accessible to everybody, and reusable in various contexts
  • Built on NumPy, SciPy, and matplotlib
  • Open source, commercially usable - BSD license

  Scikit-learn is robust, well-engineered and covers most basic machine
  learning use cases. As a professional data scientist I use it
  extensively from Python. I built these wrappers because I felt
  challenged by my friend @UnixJunkie's funny R wrappers.

  I don't depend personally on these packages and maintain/improve them
  without any guarantees. They have many unpolished corners. However,
  they have tests and I don't expect them to add too many bugs to
  scikit-learn. Contributions and bug reports are welcome (but be aware
  that the bindings are generated from a big hairy Python script).

  Many thanks to everybody involved in opam!


OCaml 4.10.2
════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocaml-4-10-2/6945/1>


octachron announced
───────────────────

  The OCaml team has the pleasure of celebrating the birthday of Grace
  Hopper by announcing the release of OCaml version 4.10.2.

  This exceptional release makes OCaml 4.10 available on the new
  macOS/arm64 platform, and fixes some compatibility issues for the
  mingw64 and FreeBSD/amd64 platform.

  If OCaml 4.10.1 already works on your platform of choice, this release
  should be completely transparent to you (and can be safely ignored).

  Note that those fixes were backported from OCaml 4.12: further
  improvement to the support of the macOS/arm64 platform will happen on
  the 4.12 branch.

  The release is available as a set of OPAM switches, and as a source
  download here:

  <https://github.com/ocaml/ocaml/archive/4.10.2.tar.gz>
  <https://caml.inria.fr/pub/distrib/ocaml-4.10/>


OCaml 4.10.2
╌╌╌╌╌╌╌╌╌╌╌╌

  • [9938], [9939]: Define __USE_MINGW_ANSI_STDIO=0 for the mingw-w64
    ports to prevent their C99-compliant snprintf conflicting with
    ours. (David Allsopp, report by Michael Soegtrop, review by Xavier
    Leroy)


[9938] <https://github.com/ocaml/ocaml/issues/9938>

[9939] <https://github.com/ocaml/ocaml/issues/9939>

◊ Supported platforms:

  • [9699], [10026]: add support for iOS and macOS on ARM 64 bits
    Backported from OCaml 4.12.0 (GitHub user @EduardoRFS, review by
    Xavier Leroy, Nicolás Ojeda Bär and Anil Madhavapeddy, additional
    testing by Michael Schmidt)


  [9699] <https://github.com/ocaml/ocaml/issues/9699>

  [10026] <https://github.com/ocaml/ocaml/issues/10026>


◊ Code generation and optimization

  • [9752], [10026]: Revised handling of calling conventions for
    external C functions. Provide a more precise description of the
    types of unboxed arguments, so that the ARM64 iOS/macOS calling
    conventions can be honored. Backported from OCaml 4.12.0 (Xavier
    Leroy, review by Mark Shinwell and Github user @EduardoRFS)

  • [9969], [9981]: Added mergeable flag tqo ELF sections containing
    mergeable constants.  Fixes compatibility with the integrated
    assembler in clang 11.0.0. Backported from OCaml 4.12.0 (Jacob
    Young, review by Nicolás Ojeda Bär)


  [9752] <https://github.com/ocaml/ocaml/issues/9752>

  [10026] <https://github.com/ocaml/ocaml/issues/10026>

  [9969] <https://github.com/ocaml/ocaml/issues/9969>

  [9981] <https://github.com/ocaml/ocaml/issues/9981>


Anil Madhavapeddy
─────────────────

  There is also a [macos/arm64 binary of opam] available from the
  releases page for your convenience, and opam repository has been
  updated to understand the new tier-1 constraints imposed by macos/arm
  (i.e. the only working compilers there are 4.10.2 and 4.12.0~dev, and
  `opam init' will now do the right thing).

  There will be a number of packages that are broken due to the shift to
  `/opt/homebrew' from `/usr/local' for Homebrew/ARM (due to the need to
  keep them simultaneously installed on the same Mac), so please feel
  free to submit PRs to opam-repository to fix this stuff.

  We'll shortly have Mac (both Intel and ARM) testing up and running on
  opam-repository, so CI will catch up with reality once more, thanks to
  furious hacking by @patricoferris to extend our ocurrent-based CI
  infrastructure to support the unique vagaries of the Mac environment
  (notably, a total lack of native containers).  We have it working
  locally, and are just upstreaming it now.


[macos/arm64 binary of opam]
<https://github.com/ocaml/opam/releases/tag/2.0.7>


BAP 2.2.0 Release
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-bap-2-2-0-release/6950/1>


Ivan Gotovchits announced
─────────────────────────

  We are proud to announce the 2.2.0 release of the Carnegie Mellon
  University [Binary Analysis Platform]. BAP is the framework and
  toolkit for analyzing programs in their machine code
  representation. This update has a lot of [new features] despite that
  originally it was more as a maintenance version. Special thanks to
  @XVilka and [@Phosphorus15] for contributing Thumb/ThumbV2 lifter and
  radare2 integration. We would also like to thank [ForAllSecure] for
  open-sourcing and contributing to us their x86 floating-point
  lifter. The new version of BAP is also much more efficient and we now
  have a much better symbolization facility (so we're no longer really
  dependent on the presence of external tools). Another nice addition is
  a new REPL powered by [ocaml-linenoise], see the demo below.

  <https://asciinema.org/a/358996>


[Binary Analysis Platform]
<https://github.com/BinaryAnalysisPlatform/bap>

[new features]
<https://github.com/BinaryAnalysisPlatform/bap/releases/tag/v2.2.0>

[@Phosphorus15] <https://github.com/Phosphorus15>

[ForAllSecure] <https://forallsecure.com/>

[ocaml-linenoise] <https://github.com/ocaml-community/ocaml-linenoise>


Liquidshop 1.0, Jan. 17th and 18th, 2021
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-liquidshop-1-0-jan-17th-18th-2021/6951/1>


Romain Beauxis announced
────────────────────────

  We are happy to announce that we'll be holding Liquidshop 1.0 these
  coming Jan. 17th & 18th, our first ever (online) conference and
  workshops on liquidsoap and other related technologies and projects!

  Liquidsoap is a statically typed scripting language with specialized
  primitives and operators for creating media streams used for media
  processing, online streaming and a lot more. It is written in OCaml
  and has been maintained for over a decade now.

  We will have 3 different tracks for the event, namely:
  • Showcases: short presentations about a website / radio / art
    installation that you built using Liquidsoap or other related tools
  • Tech talks: in-depth presentation of a technology related to
    Liquidsoap and streaming in general
  • Workshops: user-centered freeform discussions about your project or
    issues around Liquidsoap and streaming

  If you're interested to participate, wether as an attendee or a
  presenter, make sure to register via our website at:
  <http://www.liquidsoap.info/liquidshop/> or directly via the form
  available at: <https://forms.gle/HdGNLz5qM3HVU1ub7>

  We are super excited for this event. We have already secured a couple
  of interesting speakers and we would love to get to know the community
  better, see what y'all are doing with liquidsoap and other releated
  projects, community radios, live video, weird installations, etc. and
  meet with everyone.

  Also, if you have any suggestion about the best technical solutions to
  organize such an event, we'd be happy to hear about them.

  Finally, if any of y'all have some specific topics to discuss and
  would like to learn more about liquidsoap, this will be a great place
  to connect!


Opium 0.20.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-opium-0-20-0/6955/1>


Thibaut Mattio announced
────────────────────────

  I'm pleased to announce a new version of [Opium] web framework
  (0.20.0) is available on Opam.

  Here's the changelog:


[Opium] <https://github.com/rgrinberg/opium>

Added
╌╌╌╌╌

  • New `Auth' module to work with `Authorization' header ([#238])

  • New `basic_auth' middleware to protect handlers with a `Basic'
    authentication method ([#238])

  • New `Response.of_file' API for conveniently creating a response of a
    file ([#244])

  • Add a package `opium-graphql' to easily create GraphQL server with
    Opium ([#235])

  • Add a function `App.run_multicore' that uses pre-forking and spawns
    multiple processes that will handle incoming requests ([#239])


[#238] <https://github.com/rgrinberg/opium/pull/238>

[#244] <https://github.com/rgrinberg/opium/pull/244>

[#235] <https://github.com/rgrinberg/opium/pull/235>

[#239] <https://github.com/rgrinberg/opium/pull/239>


Fixed
╌╌╌╌╌

  • Fix reading cookie values when multiple cookies are present in
    `Cookie' header ([#246])

  Happy hacking :slight_smile:


[#246] <https://github.com/rgrinberg/opium/pull/246>


Set up OCaml 1.1.5
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-5/6971/1>


Sora Morimoto announced
───────────────────────

  This release reduces build time by up to 2 minutes by exporting
  modified `OPAMJOBS' environment variable.

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.5>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Memthol: exploring program profiling]
  • [Growing the Hardcaml toolset]
  • [ Editor Plugin for VSCode and Vim Officially Released!]
  • [Announcing Our Market Prediction Kaggle Competition]
  • [Every proof assistant: introducing homotopy.io – a proof assistant
    for geometrical higher category theory]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Memthol: exploring program profiling]
<https://www.ocamlpro.com/2020/12/01/memthol-exploring-program-profiling/>

[Growing the Hardcaml toolset]
<https://blog.janestreet.com/growing-the-hardcaml-toolset-index/>

[ Editor Plugin for VSCode and Vim Officially Released!]
<https://rescript-lang.org/blog/editor-support-release-1-0>

[Announcing Our Market Prediction Kaggle Competition]
<https://blog.janestreet.com/announcing-our-market-prediction-kaggle-competition-index/>

[Every proof assistant: introducing homotopy.io – a proof assistant for
geometrical higher category theory]
<http://math.andrej.com/2020/11/24/homotopy-io/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-12-01  8:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-12-01  8:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of November 24 to
December 01, 2020.

Table of Contents
─────────────────

drom.0.2.0: OCaml Project Manager, beta release
OCaml on the BEAM webinar
ocaml-lsp-server 1.3.0
OCaml User Survey 2020
http-cookie 2.0.0
reparse 2.0.0
VSCode OCaml Platform v1.5.0
Database modelling
Opium 0.19.0
Operator lookup tool for OCaml
Other OCaml News
Old CWN


drom.0.2.0: OCaml Project Manager, beta release
═══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-drom-0-2-0-ocaml-project-manager-beta-release/6841/1>


Fabrice Le Fessant announced
────────────────────────────

  I am happy to announce the first release of `drom', version 0.2.0, a
  tool to create and manage OCaml projects. `drom' is a simple layer on
  top of `opam' and `dune', with project and package descriptions
  written in TOML syntax. It is an attempt at providing a `cargo'-like
  experience for developers, with builtin support for standard OCaml
  tools (`opam', `dune', `odoc', etc.) and source managers (Github for
  now, with Github Actions and Github Pages).

  There are mainly 2 use-cases of `drom':

  • Scafolding tool: `drom' makes it easy to create OCaml projects by
    generating all the files needed for a standard OCaml project. It
    creates files for `opam' and `dune', formatters (`ocp-index' and
    `ocamlformat'), documentation (`sphinx' and `odoc'), testing
    directories and Github CI. Once these files have been created,
    `drom' is not needed anymore and you can keep using your preferred
    tools.

  • Management tool: `drom' can also be used to keep managing the
    project afterwards. It has commands like `drom build' to build the
    project, automatically installing a local switch with all needed
    dependencies, `drom doc' to generate the documentation and `drom
    test' to execute tests. `drom' works as a simple interface over
    `opam' and `dune' so you almost never need to use them directly.

  <https://ocamlpro.github.io/drom>

  (this site and the documentation was mostly generated by `drom'
  itself)

  `drom' is available in the official opam repository.

  Examples:

  ┌────
  │ $ drom new mylib --skeleton library // generate library project
  │                                     //           or
  │ $ drom new hello                    // generate program project
  │ 
  │ $ cd hello
  │ $ emacs drom.toml // edit the project description
  │ $ drom project    // update files
  │ $ drom build                  // create local switch and build
  │                               //      or
  │ $ drom build --switch 4.10.0  // use global switch and build
  │ $ ./hello         // run the executable
  │ $ drom test       // run tests
  │ $ drom install    // install in opam switch
  └────

  This is an early release to get feedback from users. `drom' has been
  tested on several of our internal projects, like `opam-bin' and
  `ez_file'.

  Since `drom' creates local `opam' switches for every project by
  default (though it is possible to use global switches too), it is
  advised to use it with `opam-bin' to speed up switch creation and
  upgrades.

  `drom' works by creating projects using "skeletons", i.e. project and
  package templates. `drom' comes with a few predefined skeletons
  (`program' or `library'), and allows users to add their own
  skeletons. We will of course extend the substitution language to help
  users develop such new skeletons.

  `drom' is a collaborative work between OCamlPro and Origin Labs.


François Bobot asked and Fabrice Le Fessant replied
───────────────────────────────────────────────────

        I'm very happy to see work in the OCaml world in that
        direction. I was currently looking for duniverse for that
        kind of need. Do they fullfil different needs or how do
        they compare?

  My understanding is that `duniverse' tackles the problem of the
  "mono-repo", i.e. when you want to manage many different projects as
  just one project, using `dune' capacity to build them all at once. I
  would say that `drom' tackles an orthogonal problem, which is to
  simplify the creation of simple OCaml projects (generating all the
  standard files you need, like Makefile, dune-project, dune,
  .ocamlformat, .github CI, documentation, license, etc.) and day-to-day
  management (changing dependencies, having a copy of headers that you
  can insert in new files, etc.). It also provides a single interface
  over basic opam/dune commands.

  It would probably be possible to use `duninverse' on a set of projects
  containing projects generated by `dune', but I don't know enough about
  `duniverse' to be sure.

  Of course, `drom' can manage projects composed of multiple libraries
  and executables (called `packages' because `drom' generates one `opam'
  file for every one of them), but I wouldn't call that a mono-repo,
  it's just frequent to have more than one package in a small project.


OCaml on the BEAM webinar
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-on-the-beam-webinar/6851/1>


Yawar Amin announced
────────────────────

  Erlang Solutions is going to do a webinar on Leandro Ostera's new BEAM
  backend for OCaml:
  <https://www2.erlang-solutions.com/webinar-registration-2>

  Should be exciting!


ocaml-lsp-server 1.3.0
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-lsp-server-1-3-0/6856/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the ocaml-lsp team, I’d like to announce version 1.3.0.

  This release an improvement in keyword completion and a new code
  action. Keywords are now filtered by the context the user requested
  the completion, and there's a new code action to quickly populate .mli
  files with the the inferred types from the .ml file.


OCaml User Survey 2020
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-user-survey-2020/6624/28>


Xavier Leroy announced
──────────────────────

  Here is a summary and analysis of the survey results I wrote on behalf
  of the OCaml Software Foundation:
  <https://www.dropbox.com/s/omba1d8vhljnrcn/OCaml-user-survey-2020.pdf?dl=0>
  Enjoy!


http-cookie 2.0.0
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-http-cookie-2-0-0/6866/1>


Bikal Lem announced
───────────────────

  A new version of `cookies' package - now named `http-cookie'- has been
  released to opam. This version has been rewritten to remove all its
  external and ppx dependencies and now only depends on stock ocaml and
  its stdlib.

  `http-cookie' is a [RFC 6265] compliant HTTP cookie library.  RFC 6265
  is a HTTP cookie standard specifying cookie data validity
  requirements.

  Additionally, I have also removed the use of `Result.t' from the
  previous version and have used plain old exceptions to denote any
  cookie data validation errors.

  • [Github - http-cookie]
  • [Docs - http-cookie]


[RFC 6265] <https://tools.ietf.org/html/rfc6265>

[Github - http-cookie] <https://github.com/lemaetech/http-cookie>

[Docs - http-cookie] <https://lemaetech.co.uk/http-cookie/>


reparse 2.0.0
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-reparse-2-0-0/6868/1>


Bikal Lem announced
───────────────────

  A new version of `reparse' 2.0.0 has been released to opam.

  Reparse is a monadic, recursive descent based, comprehensive, parser
  construction library for ocaml.


CHANGES for version 2.0.0:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Rewrite the whole package to use exceptions rather than `result'
    type
  • Adds many more parsing combinators
  • Adds comprehensive unit tests
  • Adds comprehensive documentation, host documentation and add links
    in repo home page
  • Adds abstraction for input source
  • Provides unix file source and string input source
  • Adds separate package `reparse-unix' for unix file input
  • Adds calc.ml and json.ml in examples.

  Additionally, the API is now comprehensively documented with at least
  an example for each API call.

  • [Github Reparse]
  • [API Docs]


[Github Reparse] <https://github.com/lemaetech/reparse>

[API Docs] <https://lemaetech.co.uk/reparse/>


VSCode OCaml Platform v1.5.0
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-vscode-ocaml-platform-v1-5-0/6871/1>


Max Lantas announced
────────────────────

  We are happy to announce the v1.5.0 release of [VSCode OCaml
  Platform], a Visual Studio Code extension for OCaml. It is available
  on the [VSCode Marketplace] and [Open VSX Registry].

  This release has the following changes:
  • Highlight `rec' keyword in OCaml mli files for recursive modules
    ([#434])
  • Highlight `cram' stanza in dune-project files ([#441])
  • Fix reason highlighting of let extensions ([#447])
  • Improve highlighting of Menhir new syntax ([#450])
  • Improve Menhir syntax highlighting ([#455])
  • Add `Alt + P' keyboard shortcut for infer interface code action
    ([#448])
  • Infer interface when switching to a non-existing interface file
    ([#437])

  This is the first release to be automatically published to Open VSX,
  which will benefit users of [VSCodium] and other editors.

  Please feel free to share feedback.


[VSCode OCaml Platform]
<https://github.com/ocamllabs/vscode-ocaml-platform>

[VSCode Marketplace]
<https://marketplace.visualstudio.com/items?itemName=ocamllabs.ocaml-platform>

[Open VSX Registry]
<https://open-vsx.org/extension/ocamllabs/ocaml-platform>

[#434] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/434>

[#441] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/441>

[#447] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/447>

[#450] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/450>

[#455] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/455>

[#448] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/448>

[#437] <https://github.com/ocamllabs/vscode-ocaml-platform/pull/437>

[VSCodium] <https://github.com/VSCodium/vscodium>


Database modelling
══════════════════

  Archive: <https://discuss.ocaml.org/t/database-modelling/1150/2>


Reviving this very old thread, paul announced
─────────────────────────────────────────────

  And a version for postgresql:
  <https://github.com/pat227/ocaml-pgsql-model.git>


Opium 0.19.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-opium-0-19-0/6876/1>


Thibaut Mattio announced
────────────────────────

  On behalf of the Opium team, I am pleased to announce a new version of
  Opium (`0.19.0') is available on Opam.

  This release comes with a complete rewrite of Opium's internals to
  switch from Cohttp to Httpaf (work done by @anuragsoni).

  As demonstrated in several benchmarks, Httpaf's latency is much lower
  than Cohttp's in stress tests, so it is expected that Opium will
  perform better in these high-pressure situations.

  The underlying HTTP server implementation is now contained in a `rock'
  package, that provides a Service and Filter implementation, inspired
  by Finagle's. The architecture is similar to Ruby's Rack library
  (hence the name), so one can compose complex web applications by
  combining Rock applications.

  The `rock' package offers a very slim API, with very few dependencies,
  so it should be an attractive option for other Web frameworks to build
  on, which would allow the re-usability of middlewares and handlers,
  independently of the framework used (e.g. one could use Sihl
  middlewares with Opium, and vice versa).

  Apart from the architectural changes, this release comes with a lot of
  additional utilities and middlewares which should make Opium a better
  candidate for complex web applications, without having to re-write a
  lot of common Web server functionalities.

  The Request and Response modules now provide:
  • JSON encoders/decoders with `Yojson'
  • HTML encoders/decoders with `Tyxml'
  • XML encoders/decoders with `Tyxml'
  • SVG encoders/decoders with `Tyxml'
  • multipart/form encoders/decoders with `multipart_form_data'
  • urlencoded encoders/decoders with `Uri'

  And the following middlewares are now built-in:
  • `debugger' to display an HTML page with the errors in case of
    failures
  • `logger' to log requests and responses, with a timer
  • `allow_cors' to add CORS headers
  • `static' to serve static content given a custom read function
    (e.g. read from S3)
  • `static_unix' to serve static content from the local filesystem
  • `content_length' to add the `Content-Length' header to responses
  • `method_override' to replace the HTTP method with the one found in
    the `_method' field of `application/x-www-form-urlencoded' encoded
    `POST' requests.
  • `etag' to add `ETag' header to the responses and send an HTTP code
    `304' when the computed ETag matches the one specified in the
    request.
  • `method_required' to filter the requests by the HTTP method and
    respond with an HTTP code `405' if the method is not allowed.
  • `head' to add supports for `HEAD' request for handlers that receive
    `GET' requests.

  Lastly, this release also adds a package `opium-testing' that can be
  used to test Opium applications with Alcotest. It provides `Testable'
  modules for every Opium types, and implements helper functions to
  easily get an `Opium.Response' from an `Opium.Request'.

  As this release changes the API drastically, we will keep maintaining
  the `0.18.0' branch for bug fixes, for users who don't want to (or
  can't) migrate to `0.19.0'.


What's next?
╌╌╌╌╌╌╌╌╌╌╌╌

  Recent discussions have shown that building optimized applications was
  not trivial. This is partly due to the lack of documentation, and
  probably because some configurations that should come by default, are
  left to the user to optimize. Therefore, we will keep performance in
  mind for the next release and investigate the current bottlenecks in
  Opium.

  We will also continue adding higher-level functionalities to Opium to
  make users productive with real-world applications. This includes:
  • Sessions support (with signed cookies)
  • Handlers for authentication
  • Adding more middlewares (compression, flash messages, caching, etc.)

  Your feedback is welcome, don't hesitate to open Issues on Github!


Andreas Poisel asked and Anurag Soni replied
────────────────────────────────────────────

        Does Opium + Httpaf support TLS?

  It doesn't at the moment.


Calascibetta Romain then said
─────────────────────────────

  According the interface of `opium', it's possible to have the support
  of TLS (with `ocaml-tls') with the [new version of Conduit] and
  [`paf'] (which is a MirageOS compatible layer of HTTP/AF -
  unreleased):

  ┌────
  │ let stack ip =
  │   Tcpip_stack_socket.UDPV4.connect (Some ip) >>= fun udpv4 ->
  │   Tcpip_stack_socket.TCPV4.connect (Some ip) >>= fun tcpv4 ->
  │   Tcpip_stack_socket.connect [ ip ] udpv4 tcpv4
  │ 
  │ let http_with_conduit (ip, port) error_handler request_handler =
  │   Paf.https httpaf_config ~error_handler ~request_handler:(fun _ -> request_handler)
  │     ({ Paf.TCP.stack= stack ip
  │      ; keepalive= None
  │      ; nodelay= false
  │      ; port= port}, Tls.Config.server ~certificates ())
  │ 
  │ let () = match Lwt_main.run (Opium.run (https_with_conduit (Ipaddr.V4.localhost, 4343)) opium_app) with
  │   | Ok () -> ()
  │   | Error err -> Fmt.epr "%a.\n%!" Conduit_mirage.pp_error err
  └────

  I used it for a long time on my personal unikernels and did some tests
  to ensure that [it does fails when it handles many requests]. Note
  that you are able to use OpenSSL too if you want.


[new version of Conduit]
<https://discuss.ocaml.org/t/ann-new-release-of-conduit/6611>

[`paf'] <https://github.com/dinosaure/paf-le-chien/>

[it does fails when it handles many requests]
<https://github.com/dinosaure/paf-le-chien/pull/12>


Robin Björklin also replied
───────────────────────────

  If you want to use this new version of Opium there are ways around
  this problem. You could have Haproxy (or similar) terminate your TLS
  connections externally and if your environment requires TLS for your
  internal network something like [Consul Connect] can cover that
  use-case for you.


[Consul Connect]
<https://learn.hashicorp.com/tutorials/consul/get-started-service-networking?in=consul/getting-started>


Operator lookup tool for OCaml
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-operator-lookup-tool-for-ocaml/6882/1>


Craig Ferguson announced
────────────────────────

  I'm pleased to announce the initial release of
  craigfe.io/operator-lookup/, a search tool for OCaml operators and
  syntax elements:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/e/ee41569b4426c9b77fd6d367e50ff5ac759f4e46_2_1034x558.png>

  For each operator, the tool provides a short explanation of its
  behaviour, examples of usage and warnings of common misuses and
  misunderstandings:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/8/879ae652a8895fa0258bc288c8d0c819cb9ef314_2_920x1000.png>

  The intent of writing this tool was to give OCaml beginners a quick
  way to find the standard / conventional operators in the language and
  to disambiguate "operator-like" syntax that can be hard to search for
  otherwise. It currently supports:

  • all standard library operators,
  • conventional infix operators (`>>=', `>>|', `>|='),
  • binding operators (`let+', `let*', `and+', etc.),
  • syntax that is often confused for an operator (`#', `;;').

  Please let me know if you have any suggestions for improvements. I
  hope you find it useful!


Acknowledgements
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This tool is heavily based on the [JavaScript operator lookup] utility
  by [Josh Comeau]. Thanks to him for the initial idea and for allowing
  me to re-use his design elements.


[JavaScript operator lookup]
<https://www.joshwcomeau.com/operator-lookup/>

[Josh Comeau] <https://twitter.com/JoshWComeau>


Kakadu asked and Craig Ferguson replied
───────────────────────────────────────

        It's not obvious for me are these operators hardcoded or
        do you scan opam packages from time to time?

  They're hardcoded. The operators fall into three classes:

  • The vast majority of them are from the `Stdlib' module, so I don't
    expect those to change very regularly.

  • A small number of "conventional" operators used in the community
    (`>>=', `let*', etc.). Even for that small set there is some
    divergence in Opam – c.f. `>>|' vs `>|=' for a _map_ operator – so I
    suspect there are not many other candidates for this group.

  • There are a few regexes behind the scenes for catching valid
    operator names that don't fall into the first two
    categories. e.g. many search terms are classified as "_a
    left-associative operator_" with a correspondingly vague
    description.


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [“Universal” Dune Tip: Rebuild Stuff, Sometimes]


[OCaml Planet] <http://ocaml.org/community/planet/>

[“Universal” Dune Tip: Rebuild Stuff, Sometimes]
<https://seb.mondet.org/b/0009-dune-universe-hack.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-11-03 15:15 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-11-03 15:15 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 32510 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of October 27 to
November 03, 2020.

Table of Contents
─────────────────

Brr 0.0.1, a toolkit for programming browsers
New release of Monolith (20201026)
MirageOS 3.9.0 released
An AST typing problem
erlang 0.0.14, a toolkit to manipulate Erlang sources
opam-bin.1.0.0: binary packages for opam
Interesting OCaml Articles
Old CWN


Brr 0.0.1, a toolkit for programming browsers
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-brr-0-0-1-a-toolkit-for-programming-browsers/6608/9>


Continuing this thread, Daniel Bünzli said
──────────────────────────────────────────

  One thing I forgot, is that there is a [todomvc] example in the repo,
  see `todomvc.{html,ml}' in [this directory].

  It doesn't use the UI toolkit you mentioned, just the basic reactive
  DOM support provided by [`Brr_note'] and [`Brr_note_kit']. But you can
  see how quickly you get reusable and composable components like
  [`bool_editor'] and [`string_editor'].

  The program structure in that example is quite similar to the one I
  had in the drawing app. You define a purely functional, non reactive
  [data model], [actions] over the data model, create small UI fragments
  that renders parts of your data model and generate actions events for
  it, gradually glue them together using note combinators and finally
  define a [fixed point signal] that holds the data model as massaged by
  the actions events of your UI (as mentioned I'd like to replace fix
  points by direct `let rec' and a lazy infinitesimal delay combinator).

  There are a few pitfalls like you should avoid retaining parts of your
  data model in the UI otherwise you could get outdated data come back
  in your model (makes for very fun and spooky bugs though).  Identity
  in the data model is also a bit tricky, it seems in todomvc I [used]
  `=='. That didn't work in the drawing app where my surfaces had
  properties that could be updated but they could also be linked
  toghether (that window belongs to that wall etc.) so I needed stable
  identifiers for which I introduced a little abstraction to identify
  values and define relations between them.

  One thing I remember fondly when doing the drawing app is that I would
  still get the odd interaction glitches you get when coding direct
  mouse manipulation interactions (surface
  definition/selection/move/transform) however thanks to the ability to
  denotationally reason and act (left leaning [`E.select']) on the
  simultaneity of events, they were easy to understand and fix in an
  explicit way (that is via a defining *expression*).

  Also if you get into [`Note'] the denotational semantics notation is
  not yet explained there, refer to the [one of react] it's the same.


[todomvc] <http://todomvc.com/>

[this directory] <https://github.com/dbuenzli/brr/tree/master/test>

[`Brr_note'] <https://erratique.ch/software/brr/doc/Brr_note/index.html>

[`Brr_note_kit']
<https://erratique.ch/software/brr/doc/Brr_note_kit/index.html>

[`bool_editor']
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L229>

[`string_editor']
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L213-L214>

[data model]
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L36>

[actions]
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L101>

[fixed point signal]
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L314-L324>

[used]
<https://github.com/dbuenzli/brr/blob/41580885f40bfd184c3d8e5be2ddd56b0712b411/test/todomvc.ml#L84>

[`E.select']
<https://erratique.ch/software/note/doc/Note/E/index.html#val-select>

[`Note'] <https://erratique.ch/software/note/doc/Note/>

[one of react]
<https://erratique.ch/software/react/doc/React/index.html#sem>


Yoann Padioleau asked and Daniel Bünzli replied
───────────────────────────────────────────────

        How hard would it be to build on top of Brr_note something
        like an Elm Architecture-style toolkit? I know there's a
        TEA-Bucklescript library, but I'd rather use something
        relying on dune/jsoo.

        I've read somewhere else that you were a bit skeptical
        about the advantage of MVU (movel-view-update) over MVC,
        but I personnaly find the counter UI example in ELM at
        <https://guide.elm-lang.org/architecture/buttons.html> far
        simpler than the corresponding one in Brr at
        <https://github.com/barko/brr-eg/blob/master/counter/counter.ml>

  I don't know. I didn't look into MVU too much, but to me it's largely
  a remix of MVC – despite what its proponents try to tell you. Since we
  now live in an age of software adverstising it's a bit hard to get
  frank assessments.

  As far as I'm concerned the compositionality story of MVU doesn't look
  great. Basically it enforces state machines on you, and composing
  state machines is a bit meh. In FRP state machines become signals (via
  `S.accum') which are highly composable entities with *fine
  granularity* (and bonus point, a well defined denotational semantics
  for equational reasoning).

  If you are looking for MVU I think you can simply jump on [LexiFI's
  vdom]. But when I see how you get to [compose two models] in that
  paradigm, I'm not convinced.

        There’s no need for those E.select. The UI is IMHO more
        declarative in ELM.

  That example could be rewritten (I didn't write the examples in this
  repo) to be more like the ELM one in it's declarations.

  But I think the ELM example is also more rigid. You may not like that
  `E.select' on this toy example, but you may get to enjoy it you when
  you start composing larger systems from smaller components.


[LexiFI's vdom] <https://github.com/LexiFi/ocaml-vdom>

[compose two models]
<https://github.com/LexiFi/ocaml-vdom/blob/9c5e42888ba72e69d5a018e38a4633e400913bfb/examples/demo/demo.ml#L196-L223>


Yaron Minsky then said
──────────────────────

  You might be interested in Bonsai! At some level, you can think of it
  as a library for building composable state machines. It uses
  [Incremental] as its engine for incrementalizing the computation of
  views, with a virtual-dom implementation underneath.

  <https://github.com/janestreet/bonsai>

  It's the primary tool we use for building UIs inside of Jane Street.

  In some ways, Bonsai is like Elm, but it has its own interesting
  ideas. Some of the concepts are borrowed from this paper:

  <https://www.cl.cam.ac.uk/~jdy22/papers/the-arrow-calculus.pdf>

  though I won't pretend to understand this paper myself!

  Bonsai doesn't yet have enough public-facing documentation, and really
  the bleeding edge version on github is considerably better and more
  usable than the one released into opam. But there's at least one
  public-facing UI that's built with it, if you want a real-world
  example.

  <https://blog.janestreet.com/finding-memory-leaks-with-memtrace/>


[Incremental] <https://github.com/janestreet/incremental>


Yoann Padioleau replied
───────────────────────

  Thx for the links!

  The memtrace viewer example is pretty cool, but Bonsai looks far more
  complicated than ELM.  If you look at the counter example (the hello
  world of UI), here:
  <https://github.com/janestreet/bonsai/blob/master/examples/counters/lib/bonsai_web_counters_example.ml>

  and you compare it to the one in ocaml-vdom (thx @dbuenzli for the
  link) at
  <https://github.com/LexiFi/ocaml-vdom/blob/master/examples/counters/counters.ml>

  there's a huge difference in simplicity.


Ty Overby then said
───────────────────

  Hi Aryx, I wrote the Bonsai example that you linked, and it certainly
  isn't the most concise, but that's because it was built for a tutorial
  on building small components (one counter is a single component), how
  to use more advanced combinators (Bonsai.assoc), and how to move data
  from one component to another (the add_counter_component into the
  associated counters component.)  I think it's a great example of the
  power of structuring an UI as a DAG rather than a tree, but it
  definitely doesn't make for the most concise code!

  In the example, the comments that look like "CODE_EXCERPT_BEGIN" are
  actually preprocessor definitions that are used in the (honestly,
  kinda out of date) [tutorial here].  A bonsai app that wasn't written
  for such a tutorial would look more like [this].


[tutorial here]
<https://github.com/janestreet/bonsai/blob/master/docs/getting_started/open_source/counters.mdx>

[this]
<https://gist.github.com/TyOverby/e0f7e944d002cdf7144aaf0102d16ed5>


New release of Monolith (20201026)
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-monolith-20201026/6667/1>


François Pottier announced
──────────────────────────

  It is my pleasure to announce a major new release of Monolith.

  ┌────
  │ opam update && opam install monolith
  └────

  Monolith offers facilities for testing an OCaml library (for instance,
  a data structure implementation) by comparing it against a reference
  implementation. It can be used to perform either random testing or
  fuzz testing. Fuzz testing relies on the external tool afl-fuzz.

  More information on Monolith is available [here] and in the draft
  paper [Strong Automated Testing of OCaml Libraries].


[here] <https://gitlab.inria.fr/fpottier/monolith>

[Strong Automated Testing of OCaml Libraries]
<http://cambium.inria.fr/~fpottier/publis/pottier-monolith-2021.pdf>


MirageOS 3.9.0 released
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-mirageos-3-9-0-released/6668/1>


Martin Lucina announced
───────────────────────

  We are pleased to announce the release of MirageOS 3.9.0.

  Our last release announcement was for [MirageOS 3.6.0], so we will
  also cover changes since 3.7.x and 3.8.x in this announcement.

  New features:

  • The Xen backend has been [re-written from scratch] to be based on
    Solo5, and now supports PVHv2 on Xen 4.10 or higher, and QubesOS
    4.0.
  • As part of this re-write, the existing Mini-OS based implementation
    has been retired, and all non-UNIX backends now use a unified OCaml
    runtime based on `ocaml-freestanding'.
  • OCaml runtime settings settable via the `OCAMLRUNPARAM' environment
    variable are now exposed as unikernel boot parameters. For details,
    refer to [#1180].

  Security posture improvements:

  • With the move to a unified Solo5 and ocaml-freestanding base
    MirageOS unikernels on Xen gain several notable improvements to
    their overall security posture such as SSP for all C code, W^X, and
    malloc heap canaries. For details, refer to the mirage-xen 6.0.0
    release [announcement].

  API breaking changes:

  • Several Xen-specific APIs have been removed or replaced, unikernels
    using these may need to be updated. For details, refer to the
    mirage-xen 6.0.0 release [announcement].

  Other notable changes:

  • `Mirage_runtime' provides event loop enter and exit hook
    registration ([#1010]).
  • All MirageOS backends now behave similarly on a successful exit of
    the unikernel: they call `exit' with the return value 0, thus
    `at_exit' handlers are now executed ([#1011]).
  • The unix backend used a toplevel exception handler, which has been
    removed. All backends now behave equally with respect to exceptions.
  • Please note that the `Mirage_net.listen' function still installs an
    exception handler, which will be removed in a future release. The
    out of memory exception is no longer caught by `Mirage_net.listen'
    ([#1036]).
  • To reduce the number of OPAM packages, the `mirage-*-lwt' packages
    are now deprecated. `Mirage_net' (and others) now use `Lwt.t'
    directly, and their `buffer' type is `Cstruct.t' ([#1004]).
  • OPAM files generated by `mirage configure' now include opam build
    and installation instructions, and also an URL to the Git `origin'
    ([#1022]).

  Known issues:

  • `mirage configure' fails if the unikernel is under version control
    and no `origin' remote is present ([#1188]).
  • The Xen backend has issues with event delivery if built with an
    Alpine Linux GCC toolchain. As a work-around, please use a Fedora or
    Debian based toolchain.

  Acknowledgements:

  • Thanks to Roger Pau Monné, Andrew Cooper and other core Xen
    developers for help with understanding the specifics of how Xen
    PVHv2 works, and how to write an implementation from scratch.
  • Thanks to Marek Marczykowski-Górecki for help with the QubesOS
    specifics, and for forward-porting some missing parts of PVHv2 to
    QubesOS version of Xen.
  • Thanks to @palainp on Github for help with testing on QubesOS.


[MirageOS 3.6.0] <https://mirage.io/blog/announcing-mirage-36-release>

[re-written from scratch] <https://github.com/mirage/mirage/issues/1159>

[#1180] <https://github.com/mirage/mirage/pull/1180>

[announcement]
<https://github.com/mirage/mirage-xen/releases/tag/v6.0.0>

[#1010] <https://github.com/mirage/mirage/pull/1010>

[#1011] <https://github.com/mirage/mirage/pull/1011>

[#1036] <https://github.com/mirage/mirage/issues/1036>

[#1004] <https://github.com/mirage/mirage/issues/1004>

[#1022] <https://github.com/mirage/mirage/pull/1022>

[#1188] <https://github.com/mirage/mirage/issues/1188>


An AST typing problem
═════════════════════

  Archive: <https://discuss.ocaml.org/t/an-ast-typing-problem/3677/8>


Chet Murthy announced
─────────────────────

  This note discusses the beginnings of an OCaml attribute-grammar
  evaluator generator.  You can find this code on github at
  `camlp5/pa_ppx_ag'.

  All of this code is implemented using `camlp5' and the `pa_ppx' suite
  of PPX rewriters.

  Caveat: this code is less than a week old, so it's changing fast.  In
  the unlkely event that anybody out there is actually interested in
  using this code, I'm happy to help in any way I can.  But just be
  aware that it's changing -really- fast.


Attribute Grammars for the multipass AST analysis problem
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  A year-and-a-half ago, the OP "An AST Typing Problem"
  (<https://discuss.ocaml.org/t/an-ast-typing-problem/3677>) raised the
  problem of how to deal with ASTs, in the presence of multiple passes
  of program-analysis, each of which will want to hang various bits of
  data off nodes.  The author of the OP pointed also at a couple of
  posts on Lambda-the-Ultimate (LtU), discussing related problems.

  The author notes:

        There’s a lot of passes, many of which depend on the
        previous ones, each one making some slight change to the
        AST which might or might not result in having to walk
        through the whole AST to catch all occurrences of that
        particular node. Clearly you’ll want to encode semantic
        errors in the types, so each pass ends up having its own
        unique AST, each depending on the previous one. To change
        a single node deep in the AST I have to write about a
        hundred lines of types and mapping functions’ worth of
        boilerplate. Any change in the lower levels of the AST
        bubbles up to the higher ones, and refactoring becomes a
        nightmare.

  I've been thinking about this problem ever since, and at the time, had
  suggested that while it seemed like attribute-grammars might be a
  workable solution, they were a pretty heavy hammer.  It doesn't help
  (of course) that there exist no attribute-grammar evaluator
  generators, for OCaml.  Also, at least in the LtU threads, there was
  discussion of modifying the AST, and having the analyses automatically
  be updated for the modified AST.  Obviously this would require an
  incremental re-attribution algorithm: more complexity and again,
  something that isn't implemented for OCaml.

  But imagine that there existed an attribute-grammar evaluator
  generator for OCaml.  So for a simple language of expressions, with an
  assignment-operator, we could write an evaluator as an
  attribute-grammar.  Imagine that you could write an ast like this
  (test1_ast.ml):
  ┌────
  │ type expr =
  │     INT of int
  │   | BINOP of binop * expr * expr
  │   | UNOP of unop * expr
  │   | REF of string
  │   | ASSIGN of string * expr
  │   | SEQ of expr * expr
  │ and unop = UPLUS | UMINUS
  │ and binop = PLUS | MINUS | STAR | SLASH | PERCENT
  │ and prog = expr
  └────
  and then (having elsewhere written parser/pretty-printer) declare
  attributes on those types (test1_variants.ml):
  ┌────
  │ module Attributed = struct
  │   [%%import: Test1_ast.expr]
  │   [@@deriving attributed {
  │     attributed_module_name = AT
  │   ; normal_module_name = OK
  │   ; attributes = {
  │       expr = {
  │ 	inh_env = [%typ: (string * int) list]
  │       ; syn_env = [%typ: (string * int) list]
  │       ; value_ = [%typ: int]
  │       }
  │     ; prog = {
  │ 	value_ = [%typ: int]
  │       }
  │     ; binop = {
  │ 	oper = [%typ: int -> int -> int]
  │       }
  │     ; unop = {
  │ 	oper = [%typ: int -> int]
  │       }
  │     }
  │   }]
  │ end
  └────
  and then declare attribute equations (test1_ag.ml):
  ┌────
  │ module REC = struct
  │ [%%import: Test1_variants.Attributed.AT.expr]
  │   [@@deriving ag {
  │     module_name = AG
  │   ; storage_mode = Records
  │   ; axiom = prog
  │   ; attributes = {
  │       expr = {
  │ 	inh_env = [%typ: (string * int) list]
  │       ; syn_env = [%typ: (string * int) list]
  │       ; value_ = [%typ: int]
  │       }
  │     ; prog = {
  │ 	value_ = [%typ: int]
  │       }
  │     ; binop = {
  │ 	oper = [%typ: int -> int -> int]
  │       }
  │     ; unop = {
  │ 	oper = [%typ: int -> int]
  │       }
  │     }
  │   ; attribution = {
  │       expr__INT = (
  │ 	[%nterm 0].syn_env := [%nterm 0].inh_env ;
  │ 	[%nterm 0].value_ := [%prim 1].intval
  │       )
  │     ; expr__BINOP = (
  │ 	[%nterm expr.(1)].inh_env := [%nterm expr].inh_env ;
  │ 	[%nterm expr.(2)].inh_env := [%nterm expr.(1)].syn_env ;
  │ 	[%nterm expr].syn_env := [%nterm expr.(2)].syn_env ;
  │ 	[%nterm expr].value_ := [%nterm binop.(1)].oper [%nterm expr.(1)].value_ [%nterm
  │ expr.(2)].value_
  │       )
  │     ; expr__UNOP = (
  │ 	[%nterm expr.(1)].inh_env := [%nterm expr].inh_env ;
  │ 	[%nterm expr].syn_env := [%nterm expr.(1)].syn_env ;
  │ 	[%nterm expr].value_ := [%nterm unop.(1)].oper [%nterm expr.(1)].value_
  │       )
  │     ; expr__REF = (
  │ 	[%nterm 0].syn_env := [%nterm 0].inh_env ;
  │ 	[%nterm 0].value_ := List.assoc [%prim 1].stringval [%nterm 0].inh_env
  │       )
  │     ; expr__ASSIGN = (
  │ 	[%nterm 0].syn_env := ([%prim 1].stringval, [%nterm expr.(1)].value_) :: [%nterm
  │ expr.(1)].syn_env ;
  │ 	[%nterm expr.(1)].inh_env := [%nterm 0].inh_env ;
  │ 	[%nterm 0].value_ := [%nterm expr.(1)].value_
  │       )
  │     ; expr__SEQ = (
  │ 	[%nterm 1].inh_env := [%nterm 0].inh_env ;
  │ 	[%nterm 2].inh_env := [%nterm 1].syn_env ;
  │ 	[%nterm 0].syn_env := [%nterm 2].syn_env ;
  │ 	[%nterm 0].value_ := [%nterm 2].value_
  │       )
  │     ; prog = (
  │ 	[%nterm 1].inh_env := [] ;
  │ 	[%nterm 0].value_ := [%nterm 1].value_ ;
  │ 	assert True
  │       )
  │     ; unop__UPLUS = (
  │ 	[%nterm unop].oper := fun x -> x
  │       )
  │     ; unop__UMINUS = (
  │ 	[%nterm unop].oper := fun x -> (- x)
  │       )
  │     ; binop__PLUS = (
  │ 	[%nterm binop].oper := (+)
  │       )
  │     ; binop__MINUS = (
  │ 	[%nterm binop].oper := (-)
  │       )
  │     ; binop__STAR = (
  │ 	[%nterm binop].oper := fun a b -> a*b
  │       )
  │     ; binop__SLASH = (
  │ 	[%nterm binop].oper := (/)
  │       )
  │     ; binop__PERCENT = (
  │ 	[%nterm binop].oper := (mod)
  │       )
  │     }
  │   }]
  │ end
  └────
  and then, turning a crank, you would get an evaluator:
  ┌────
  │ let test_records ctxt =
  │   assert_equal 3 ({| x := 1 ; x ; y := 2 ; x + y |} |> pa_prog_attributed |> REC.AG.evaluate)
  │ ; assert_equal 0 ({| x := 1 ; y := 2 ; x / y |} |> pa_prog_attributed |> REC.AG.evaluate)
  └────
  where `pa_prog_attributed' is a parser that parses the surface syntax
  into an AST, which has empty slots for all attributes, and
  `REC.AG.evaluate' evaluates attributes in its argument AST, and then
  returns a tuple of all the synthesized attributes of the root node.


Retaining familiar surface syntax for pattern-matching and constructing ASTs
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Now, we don't want to give up easy pattern-matching and construction
  of the AST, just because the AST has attributes strewn throughout it.
  But we don't have to: with Camlp5's "quotations", once we define a
  surface syntax parser for the basic AST (unadorned with attributes –
  viz. `test1_ast.ml'), we can use that to bootstrap ourselves to a
  surface syntax parser for expressions and patterns over that AST, and
  then in a similar manner we can get them for the AST adorned with
  attributes.

  This has already been done for hashconsed ASTs, and ASTs with built-in
  unique-IDs, and and doing it for "attributed ASTs" isn't any harder.
  Those examples can be found in the github project
  `camlp5/pa_ppx_q_ast'.


Limitations
╌╌╌╌╌╌╌╌╌╌╌

  There are still limitations.

  1. The current code only implements topological-order evaluation.
     That is, it builds the entire dependency-graph, topologically-sorts
     it, and then evaluates attributes.  This is …. suboptimal, when we
     well know that almost all interesting AGs are already in the class
     of ordered attribute-grammars (OAGs).  I plan to implement the OAG
     evaluation strategy next.

  2. Traditionally AGs are defined over "productions" which are
     sequences of nonterminals and terminals.  This doesn't correspond
     to the way we define OCaml constructor data-types.  So instead of a
     constructor like

     ┌────
     │ type expr =
     │   ... | Call of name * arg_list
     │ and arg_list = NoArgs | SomeArgs of expr * arg_list
     └────
     we might want to use ~ 'a list~
     ┌────
     │ type expr =
     │   ... | Call of name * expr list
     └────

     Problem is: defining attribute-equations for (effectively) an array
     of nodes, is not part of the standard lingo of AGs.  But I believe
     we can invent new syntax and make this succinct.

  3. Storage optimization.  A naive implementation of AGs can store all
     attributes ever computed, at all the nodes in the AST.  This can
     use a lot of memory.  But there are well-known techniques to
     discard attributes once they'll never more be needed in the rest of
     the attribute-evaluation, and I plan to implement these techniques.

  There's an entire literature on things like remote-references in
  attribute grammars, aggregates, and other things, all of which can
  probably be usefully employed.


Conclusion
╌╌╌╌╌╌╌╌╌╌

  I think that attribute-grammars could be a useful way to structure
  complex multipass program-analysis, just as they used to do back in
  the good ol' days.

  Maybe worth a look-see!


erlang 0.0.14, a toolkit to manipulate Erlang sources
═════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-erlang-0-0-14-a-toolkit-to-manipulate-erlang-sources/6694/1>


ostera announced
────────────────

  Hej, hope you're staying safe :raised_hands:

  I'm excited to share with you the first release of `erlang'.

  *tl;dr*: _parser/lexer/ast/printer for Erlang_


Description
╌╌╌╌╌╌╌╌╌╌╌

  `erlang' is a toolkit for manipulating Standard Erlang and Core Erlang
  sources and their abstract syntax trees according to the Erlang
  specifications.

  Version 0.0.14 provides:
  • A lexer/parser written in Menhir for Standard Erlang
  • ASTs for Core Erlang and Standard Erlang
  • An AST helper module for constructing Standard Erlang programs
  • A printer for the Standard Erlang AST (of highly volatile
    prettiness)
  • Support to turn ASTs to S-expressions
  • `erldump', a binary tool for reading Erlang sources and printing
    their concrete syntax trees as S-expressions.

  It is distributed under Apache-2.0 license, depends on Menhir and
  Cmdliner, and it is being developed as part of the Caramel project.

  • *PR*: <https://github.com/ocaml/opam-repository/pull/17553> – should
     be on opam.ocaml.org sometime tomorrow :)
  • *Homepage*: <https://github.com/AbstractMachinesLab/caramel>
  • *Install*: `opam install erlang'
  • *API Docs & manuals*: maybe on next release, but _follow the types_,
     and the `Erlang.Ast_helper' module is modeled after the
     `Parsing.Ast_helper' so it should feel familiar.

  I started writing `erlang' to let Caramel do an entirely symbolic
  compilation from the OCaml typedtree that would still allow for other
  passes/checks to be made cleanly. It's come with a decent number of
  tests, and it can parse some OTP modules with small modifications.

  There's [a few outstanding issues] regarding the parsing for the next
  release, but it should be a starting point for anyone wanting to read
  sources and _do something_ with them. I plan on cover these issues in
  the rest of the year, but as with all open source, it may take longer.

  I'd like to add a few other things, like an AST invariants module to
  check that ASTs are actually valid Erlang programs, and
  transformations more suitable for static analyses of the sources.

  My thanks go to @antron, @c-cube, @Drup, @rgrinberg, and @mseri for
  helping me get around the OCaml compiler, Menhir, and eventually to
  get this version split from Caramel and released independently.  Also
  a shoutout to the Js_of_ocaml project that served as a starting point
  for the parser/lexer work here.

  If you can give me some feedback on the design and implementation, I'd
  very much like to hear your thoughts :slight_smile:

  For those of you hoping to start using it, _do not_ let it crash.


[a few outstanding issues]
<https://github.com/AbstractMachinesLab/caramel/issues?q=is%3Aissue+is%3Aopen+label%3Alib%3Aerlang>


opam-bin.1.0.0: binary packages for opam
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-opam-bin-1-0-0-binary-packages-for-opam/6696/1>


Fabrice Le Fessant announced
────────────────────────────

  I am happy to announce the first stable release of `opam-bin', version
  1.0.0, a framework to CREATE, USE and SHARE binary relocatable
  packages with opam, to speed-up installation of packages. It is easily
  installable from opam-repository, and available on Github:

  <https://ocamlpro.github.io/opam-bin>

  With opam-bin, you can :

  • build binary packages while installing their source counterpart with
    opam
  • automatically reuse previously created binary packages instead of
    compiling them again
  • export and share your binary packages as part of opam repositories
    for other users/computers to use

  `opam-bin' is a framework in 3 parts :
  • a tool `opam-bin' to create binary packages:
    <https://ocamlpro.github.io/opam-bin>
  • a set of patches to make some packages relocatable (`opam-bin' will
    apply them automatically when building packages), including patches
    to make the OCaml distribution relocatable from version 4.02.0 to
    4.11.1: <https://github.com/ocamlpro/relocation-patches>
  • a set of contributed repositories of binary packages. For now, there
    is only one contribution, during the summer, by Origin Labs :
    <https://www.origin-labs.com/opam-bin/debian10.4-amd64/> containing
    5 repos, among which the "4.10.0" repo contains more than 1800
    packages. These repos can be used DIRECTLY WITH opam, WITHOUT USING
    opam-bin.

  This is the first stable release:
  • Specific support has been added in the current `master' branch of
    `opam' to make working with this version more convenient, by
    printing pre- and post- installation messages. Yet, it will still
    work with previous version of opam, but with no output on the
    terminal when calling opam.
  • The `sharing' option can be enabled to share files with hard-links
    between switches, making the creation of new local switches almost
    costless in time and disk space.

  `opam-bin' is a collaborative work between OCamlPro and Origin Labs.

  `opam-bin' is particularly useful if you create many local switches,
  as they become unexpensive. Tools like Drom (an OCaml project
  scaffolder, <https://ocamlpro.github.io/drom>) can take advantage of
  that to provide a cargo-like experience.


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/63>


Ryan Slade announced
────────────────────

  Anyone who's been following this blog probably saw this coming:

  <https://blog.darklang.com/leaving-ocaml/>

  It's an interesting read and hopefully can be used as constructive
  criticism in order to improve the state of the OCaml ecosystem.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-10-27  8:43 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-10-27  8:43 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of October 20 to 27,
2020.

Table of Contents
─────────────────

Bisect_ppx, the coverage tool, now has excellent integration with Dune
Js_of_ocaml in the VSCode OCaml Platform
Training Sessions for "Fast Track to OCaml" and "Expert OCaml" in Paris (23-26 November 2020)
Set up OCaml 1.1.2
Set up OCaml 1.1.3
First release of FSML
Qrc 0.1.0, a QR code encoder
cumulus 0.0.1
Brr 0.0.1, a toolkit for programming browsers
Old CWN


Bisect_ppx, the coverage tool, now has excellent integration with Dune
══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/bisect-ppx-the-coverage-tool-now-has-excellent-integration-with-dune/6634/1>


Anton Bachin announced
──────────────────────

  [*Bisect_ppx*], the coverage tool, has just had its [2.5.0] release,
  in which the main addition is a very neat integration with Dune:

  ┌────
  │ dune runtest --instrument-with bisect_ppx --force
  └────

  This uses the new [instrumentation support] added in Dune 2.7.0, and
  is a considerable improvement over the dubious methods Bisect and its
  users were previously forced to rely on :)

  It is no longer necessary to edit `dune' files for a release, as
  Bisect only becomes a dependency of your project when
  `--instrument-with bisect_ppx' is supplied on the Dune command line,
  which is only during development and in CI. This makes projects ready
  for release from any commit. Dune also now knows to rebuild affected
  files when instrumentation is turned on or off, so you don't have to
  manually run `dune clean' in between. Everything just works the way it
  should.

  See the updated [instructions] for all the details on how to use this
  integration.

  I've also adapted [Lambda Soup] as a simple full-project example. See
  its [`opam'], [`dune-project'], [`dune'], and [`Makefile'].

  Bisect_ppx still supports all the older integrations, so if you have
  an existing setup, you don't have to edit it. Support may eventually
  be removed in the future, however, so I encourage users to gradually
  update.

  See the full [changelog] for information on bugs fixed by the release.

  Thanks to the Dune team for adding `--instrument-with', to @undu for
  supporting it on the Bisect side, and to all the Bisect_ppx users and
  contributors!

  Happy testing!

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/1/1911adc6af898b6f4efd7dc69d2c1f90699031ba.gif>

  <https://github.com/aantron/bisect_ppx>


[*Bisect_ppx*] <https://github.com/aantron/bisect_ppx>

[2.5.0] <https://github.com/aantron/bisect_ppx/releases/tag/2.5.0>

[instrumentation support]
<https://dune.readthedocs.io/en/stable/instrumentation.html?highlight=instrument-with>

[instructions] <https://github.com/aantron/bisect_ppx#Dune>

[Lambda Soup] <https://github.com/aantron/lambdasoup>

[`opam']
<https://github.com/aantron/lambdasoup/blob/a0cbf54bf9affda00455c54369e473b905458114/lambdasoup.opam#L17-L22>

[`dune-project']
<https://github.com/aantron/lambdasoup/blob/master/dune-project#L1>

[`dune']
<https://github.com/aantron/lambdasoup/blob/a0cbf54bf9affda00455c54369e473b905458114/src/dune#L7>

[`Makefile']
<https://github.com/aantron/lambdasoup/blob/a0cbf54bf9affda00455c54369e473b905458114/Makefile#L15>

[changelog] <https://github.com/aantron/bisect_ppx/releases/tag/2.5.0>


Js_of_ocaml in the VSCode OCaml Platform
════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/js-of-ocaml-in-the-vscode-ocaml-platform/6635/1>


Max LANTAS announced
────────────────────

  I just finished a write-up about [vscode-ocaml-platform]'s recent
  transition to Js_of_ocaml:
  <https://mnxn.github.io/blog/ocaml/vscode-jsoo/>

  I can answer any questions here.

  This is also my first technical blog post, so any constructive
  criticism or comments about my writing would be very helpful.


[vscode-ocaml-platform]
<https://github.com/ocamllabs/vscode-ocaml-platform/>


Training Sessions for "Fast Track to OCaml" and "Expert OCaml" in Paris (23-26 November 2020)
═════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-10/msg00018.html>


Laurène Gibaud announced
────────────────────────

  At OCamlPro, we will be organizing 2 cross-company training sessions
  in French. Both sessions interleave theory and practice. You'll have
  time to ask your specific questions and get personalized feedback on
  your programs.

  • Our Beginner session will allow developers to build upon their
    experience of other programming languages (such as C, C++, Python,
    C# or Java) to program confidently in OCaml. Feel free to share the
    info with your coworkers or your network!
  • Our “Expert OCaml” training will allow you to master OCaml’s
    advanced features such as its type-system, OCaml’s open source tools
    and libraries, and how to write compact and efficient code.

  More info on the program and prerequisites on
  <http://www.ocamlpro.com/training-ocamlpro/> or ask away (answer this
  email or write at contact@ocamlpro.com).

  When? The Beginner session is scheduled for November 23-24, 2020. The
  Expert session will be on November 25-26, 2020.

  Where? Paris 14, in OCamlPro's office.

  How? Register on:
  <https://www.ocamlpro.com/pre-inscription-a-une-session-de-formation-inter-entreprises/>

  We can also organize custom and on-site sessions upon request.


Set up OCaml 1.1.2
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-2/6643/1>


Sora Morimoto announced
───────────────────────

  This release contains these changes:

  • Add the Cygwin setup to a known location for later steps
  • Check if the switch exists before creating the switch

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.2>


Set up OCaml 1.1.3
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-3/6644/1>


Sora Morimoto announced
───────────────────────

  This release contains these changes:

  • Update the `@actions/core' package to address [CVE-2020-15228]

  <https://github.com/avsm/setup-ocaml/releases/tag/v1.1.3>


[CVE-2020-15228] <https://github.com/advisories/GHSA-mfwh-5m23-j46w>


First release of FSML
═════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-fsml/6645/1>


jserot announced
────────────────

  This is to announce the first public release of FSML, an OCaml library
  for describing and describing synchronous finite state machines.

  FSML is a simplified version of the library provided in the [Rfsm]
  package for which

  • the system is composed of a single FSM

  • this FSM has a single, implicit, triggering event (typically called
    the *clock* , hence the term *synchronous* used in the description)

  The FSML library provides

  • a type `Fsm.t' for describing FSMs
    • possibly having *local variables*
    • for which *transitions* , implicitely triggered by a clock, are
      defined by a set of *boolean guards* and a set of *actions*

  • a set of PPX extensions for building values of type `Fsm.t'

  • functions for producing and viewing graphical representations of
    FSMs in the `.dot' format

  • functions for saving and reading FSM representations in files using
    the JSON format

  • functions for performing single or multi-step simulations of FSMs
    and generating trace files in the `.vcd' format to be viewed by VCD
    viewers such as [gtkwave]

  • functions for generating C or VHDL code from a FSM representation
    (for integration into existing
  code and/or simulation)

  FSML is available from [Github] or as an [OPAM package].


[Rfsm] <http://github.com/jserot/rfsm>

[gtkwave] <http://gtkwave.sourceforge.net/>

[Github] <https://github.com/jserot/fsml>

[OPAM package] <https://opam.ocaml.org/packages/fsml>


Qrc 0.1.0, a QR code encoder
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-qrc-0-1-0-a-qr-code-encoder/6647/1>


Daniel Bünzli announced
───────────────────────

  QR codes are unsightly – a mirror of their specification. But they
  enable all sorts of neat tricks now that scanners for them are in many
  pockets.

  Qrc generate them:

        Qrc encodes your data into QR codes. It has built-in QR
        matrix renderers for SVG, ANSI terminal and text.

        Qrc is distributed under the ISC license. It has no
        dependencies.

  Homepage: <https://erratique.ch/software/qrc>
  API docs: <https://erratique.ch/software/qrc/doc/> or `odig doc qrc'
  Install: `opam install qrc'


cumulus 0.0.1
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-cumulus-0-0-1/6655/1>


Petter A. Urkedal announced
───────────────────────────

  I would like to announce a new FRP library built on the React library.
  The purpose of [cumulus] is to help organize code which work on
  differential updates.  The main type is the *cumulus signal*, which is
  analogous to a react signal, except that information about the
  difference from the previous value is provided to consumers along with
  the new value, when the cumulus signal changes.

  So, why does a cumulus signal provide both the state and the
  difference to downstream signals?  That is, what is the difference
  between the following:?
  ┌────
  │ type t1 = state * change React.E     (* initial value and even of changes *)
  │ type t2 = (state, change) Cumulus.t  (* the cumulus signal *)
  └────
  The former type presumes that after the consumer has received the
  initial state, it will only need to know what changes on successive
  updates.  This seems quite natural.  It works well if, for instance,
  we want to reconstruct a signal holding a set of strings, given an
  initial set and a series of additions and removals:
  ┌────
  │ module String_set = Set.Make (String)
  │ 
  │ type 'a set_patch = [`Add of string | `Remove of string]
  │ type 'a update = 'a -> 'a
  │ 
  │ let patch_string_set : string set_patch -> String_set.t update = function
  │  | `Add x -> String_set.add x
  │  | `Remove x -> String_set.remove x
  │ 
  │ let integrate_strings (init, changes) =
  │   React.E.fold (fun l p -> patch_string_set p l) init changes
  └────
  But what if we want to maintain a signal holding the intersection of
  two sets of strings?  If we try to lift the intersection operation to
  work on patches, we discover that learning about the addition of an
  element to left-hand set is not sufficient to determine whether the
  element shall the added to the resulting set; we also need to know
  whether the element is a member of the right-hand set.  So, in this
  case we would instead use cumulus signals:
  ┌────
  │ let cu : (String_set.t, string set_patch) Cumulus.t = ...
  │ let cv : (String_set.t, string set_patch) Cumulus.t = ...
  │ let cuv =
  │   let init u v = String_set.inter u v in
  │   let patch (u, du) (v, dv) r' =
  │     (match du, dv with
  │      | None, Some x when String_set.mem x u ->
  │ 	Cumulus.Patch (String_set.add x r', `Add1 x)
  │      ...)
  │   in
  │   Cumulus.l2 ~init ~patch cu cv
  └────
  For the complete example, using integers instead of strings, see
  [`test_isecn.ml'] from the testsuite.

  (Footnote: If consumers know how to integrate the states they depend
  on, they could in principle keep their own record of the full states
  of the arguments.  But this would be inefficient if there are many
  consumers, and there is also a simplification of code and possibly
  improved abstraction in letting the producer maintain its own state.)

  Formally, we can understand the difference between `t1' and `t2' in
  terms of calculus.  For instance, the differential of a product
  `d(x·y) = dx·y + x·dy' contains a mix of both the differentials and
  values of the two variables.  But if the expression is linear, only
  differentials will will occur: `d(a·x + b·y + c) = a·dx + b·dy'.  So,
  when `t1' is sufficient, we are dealing with the analogue of a linear
  function.  The above example could be turned into a linear one by
  making `Labels.t' a multiset type and considering the multiset union
  operation.

  Thus far we only considered purely functional code, but a cumulus
  signal may chose to modify and return the same physical state during
  an update.  Also note when designing the differential component of the
  cumulus signal, that we may exploit the fact the consumers also may
  inspect the corresponding new state.  Combining these two points, a
  cumulus signal holding an array might have the type `('a array, [`Set
  of int | `Resize of int])'. Here the state may be reused for ``Set'
  and replaced for ``Resize'.

  On a related not, there is also the [reactiveData] library which deals
  with (linear) patching of containers.

  I must also mention that there there is an [OCaml project with the
  same name] (except casing). Sorry for not checking thoroughly in
  advance. I hope it is not an issue in practise, otherwise there is
  still time to rename while the library is fresh.


[cumulus] <https://github.com/paurkedal/ocaml-cumulus/>

[`test_isecn.ml']
<https://github.com/paurkedal/ocaml-cumulus/blob/master/tests/test_isecn.ml>

[reactiveData] <https://github.com/ocsigen/reactiveData>

[OCaml project with the same name] <https://github.com/Cumulus/Cumulus>


Brr 0.0.1, a toolkit for programming browsers
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-brr-0-0-1-a-toolkit-for-programming-browsers/6608/5>


Continuing this thread, Yoann Padioleau asked Daniel Bünzli replied
───────────────────────────────────────────────────────────────────

        What are the differences with the default bindings
        provided in js_of_ocaml to the browser APIs (e.g., js.mli,
        dom.mli, etc.)?

  I'm not sure exactly what you are asking but:

  1. If you are asking about the way API are exposed: `brr' does not
     type JavaScript's objects as phantom types. It simply relies on
     OCaml's abstract data types and plain functions. More about this
     can be found in brr's [FFI manual] and [FFI cookbook].
  2. If you are asking about binding coverage, you should be able to get
     a sense of what is bound in `brr' [here].

  Regarding 2. `brr''s coverage of more recent browser APIs is broader
  and more consistent than in `js_of_ocaml' – Promise support, Fetch,
  Service workers, Media capture APIs, WebGL2, Webcrypto, WebAudio,
  etc. Conversly older APIs supported in `js_of_ocaml' may not supported
  in `brr' (e.g.  XMLHTTPRequest). Besides `brr''s coverage of some of
  the DOM *element-specific* interfaces may be shallower than in
  `js_of_ocaml'. There is however good coverage for the
  [`HTMLMediaElement'], [`HTMLCanvasElement'], [`HTMLFormElement'] and
  [`HTMLInputElement'] interfaces. For the rest the [attribute and
  property API] and the occasional trivial FFI method binding should be
  able to get you a long way.


[FFI manual] <https://erratique.ch/software/brr/doc/ffi_manual.html>

[FFI cookbook] <https://erratique.ch/software/brr/doc/ffi_cookbook.html>

[here] <https://erratique.ch/software/brr/doc/index.html#supported_apis>

[`HTMLMediaElement']
<https://erratique.ch/software/brr/doc/Brr_io/Media/index.html#el>

[`HTMLCanvasElement']
<https://erratique.ch/software/brr/doc/Brr_canvas/Canvas/index.html>

[`HTMLFormElement']
<https://erratique.ch/software/brr/doc/Brr_io/Form/index.html>

[`HTMLInputElement']
<https://erratique.ch/software/brr/doc/Brr/El/index.html#ifaces>

[attribute and property API]
<https://erratique.ch/software/brr/doc/Brr/El/index.html#ats_and_props>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-10-20  8:15 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-10-20  8:15 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of October 13 to 20,
2020.

Table of Contents
─────────────────

Dialo is hiring frontend and backend OCaml developers (Remote)
Progress 0.1.0
Brr 0.0.1, a toolkit for programming browsers
New release of Conduit
Easy cross compilation using esy
OCaml User Survey 2020
Old CWN


Dialo is hiring frontend and backend OCaml developers (Remote)
══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/dialo-is-hiring-frontend-and-backend-ocaml-developers-remote/6604/1>


Wojtek Czekalski announced
──────────────────────────

  [Dialo] is an early stage company with an experienced founding
  team. Assembling a team that consists of the best and brightest is our
  top priority. In the immediate term we are building a visual
  programming language for conversational AI. Our long term vision is
  that personalized contact we are enabling will cause deeper
  relationships between users and businesses and turn all interactions
  into a unified long term customer journey.

  The work is quite demanding when it comes to both ideation and
  implementation. We are aiming to provide a room for growth both
  technically and/or as a leader. For current open source maintainers we
  are willing to sponsor your work on OSS for 20% of time.

  We use OCaml for frontend and backend (along with Python for machine
  learning, natural language processing). We are hiring people for
  different positions. Both people with extensive experience and
  newcomers are encouraged to apply. We try to find the sharpest people
  rather than checking boxes with particular skills.

  The official job posting:
  <https://dialo.recruitee.com/o/software-developer-ocamlreason> We are
  also hiring for two other (related) positions:
  • <https://dialo.recruitee.com/o/software-developer-frontend>
  • <https://dialo.recruitee.com/o/software-developer-backend>


[Dialo] <https://dialo.ai>


Progress 0.1.0
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-progress-0-1-0/6607/1>


Craig Ferguson announced
────────────────────────

  I'm pleased to announce the first release of [`Progress'], now
  available on Opam.

  <https://raw.githubusercontent.com/CraigFe/progress/main/.meta/example.svg>

  `Progress' is a small library for quickly defining and using progress
  bars in OCaml programs. It aims to provide the following:

  • support for rendering multiple progress bars simultaneously;
  • responds dynamically to changes in terminal size;
  • allows user-defined progress bar layouts.


[`Progress'] <https://github.com/CraigFe/progress/>

Defining your own progress bars
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The example animation above uses a pre-provided progress bar layout
  that should meet many needs ([`Progress_unix.counter']), but it's
  fairly easy to re-define it ourselves using the low-level
  [`Progress.Segment'] API:

  ┌────
  │ let counter filename =
  │   let proportion i = Int64.to_float i /. 1_000_000. in
  │   let open Progress in
  │   Segment.(
  │     list
  │       [
  │ 	const filename;
  │ 	Units.bytes of_pp;
  │ 	Progress_unix.stopwatch ();
  │ 	bar ~mode:`ASCII proportion;
  │ 	using proportion (Units.percentage of_pp);
  │       ]
  │     |> box_winsize ~fallback:80  (* Dynamically scale to window size *)
  │     |> periodic 100              (* Re-render once every 100 updates *)
  │     |> accumulator Int64.add 0L  (* Accumulate progress updates *))
  │   |> make ~init:0L
  └────

  The `Segment' combinators are similar to those of general-purpose
  pretty-printing libraries (e.g.  [`pp'] and [`fmt']), but are equipped
  with extra logic for "stateful" segments and segments that can have
  dynamic width. Together, these make for a convenient way to express
  common patterns when pretty-printing progress bars. For instance, the
  stateful segment `periodic' seen above can be used to ensure that very
  frequent updates from a hot-loop do not result in too much time spent
  re-rendering the output.

  The library is not yet feature-complete, but should still be
  reasonably useful :slightly_smiling_face: Happy hacking!


[`Progress_unix.counter']
<https://craigfe.github.io/progress/progress/Progress_unix/index.html#val-counter>

[`Progress.Segment']
<https://craigfe.github.io/progress/progress/Progress/Segment/index.html>

[`pp'] <https://github.com/ocaml-dune/pp>

[`fmt'] <https://erratique.ch/software/fmt>


Brr 0.0.1, a toolkit for programming browsers
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-brr-0-0-1-a-toolkit-for-programming-browsers/6608/1>


Daniel Bünzli announced
───────────────────────

  I'd like to announce the first release of Brr.

  The TL; DR is:
        If you are looking for a productive way to program
        browsers with js_of_ocaml but without ppx and ghost OCaml
        objects, give Brr a try.

  The details:

        Brr is a toolkit for programming browsers in OCaml with
        the [`js_of_ocaml'] compiler. It provides:
        • Interfaces to a [selection] of browser APIs.
        • Note based reactive support (optional and experimental).
        • An [OCaml console] developer tool for live interaction
          with programs running in web pages.
        • A JavaScript FFI for idiomatic OCaml programming.

        Brr is distributed under the ISC license. It depends on
        [Note] and on the `js_of_ocaml' compiler and runtime – but
        not on its libraries or syntax extension.

  • Homepage: <https://erratique.ch/software/brr>
  • API Docs & manuals: <https://erratique.ch/software/brr/doc/> or
    `odig doc brr'
  • Install: `opam install brr'

  Brr is essentially what I need to be productive for browser
  programming with js_of_ocaml: an obvious FFI with JavaScript objects
  as abstract data types without OCaml object phantom types and binding
  documentation precisely linking into MDN.

  The OCaml console is the hack on the cake. In the past I often found
  it frustrating to have OCaml programs running in my webpages and be
  greeted with a JavaScript prompt in the browser dev tools.  Quite a
  bit of polishing could be done on that though. Some of which should
  likely directly be done upstream in the toplevel machinery
  (e.g. identifier completion, a better toploop API and support for easy
  pretty printer installation). It would also be nice if we could cut
  down on `js_of_ocaml''s toplevel compilation times ;–)

  Parts of Brr have been seriously dogfooded in the past but that new
  incarnation is largely untested for now and certain APIs might need
  adjustements. Early adopters should study actual binding coverage,
  expect glitches and little breakages in the future.

  The Note reactive functionality was also seriously used in the past
  but Note itself needs a new design round and I don't have the
  ressources to do it right now, expect breakage, don't pay too much
  attention to it for now.

  My thanks to the `js_of_ocaml' developers for the nice ocaml to
  javascript compiler and a special shootout to Hugo Heuzard for not
  getting mad at me when pinging him directly for questions.

  Happy browser compatibility bug hunting,


[`js_of_ocaml'] <https://ocsigen.org/js_of_ocaml>

[selection]
<https://erratique.ch/software/brr/doc/index.html#supported_apis>

[OCaml console]
<https://erratique.ch/software/brr/doc/ocaml_console.html>

[Note] <https://erratique.ch/software/note>


gasche asked
────────────

  It's not really released, but I'm curious about [Note] now: this is a
  new FRP library from you, the author of [React] (the FRP library for
  OCaml, not the Javascript framework of the same name).

  Would you say a few words on why you went for a different library? My
  guess would be that React depends on runtime mechanisms (weak
  pointers) that are not well-supported in Javascript-lang; but even if
  the guess is right, I'm not sure what would be the impact on the API
  or properties of the library.


[Note] <https://erratique.ch/software/note>

[React] <https://erratique.ch/software/react>


Daniel Bünzli replied
─────────────────────

        Would you say a few words on why you went for a different
        library?

  `Note' is the result from seeing people (and myself) struggling to use
  ~React~/FRP "correctly" over the years.

  Some of this, I largely attribute to ergonomic problems with the
  API. It's my hope for `Note' to address most of these points (one
  thing that still needs to be done is replace fix points by a simple
  lazy infinitesimal delay combinator).

  I don't think I could have made all these changes in `React' itself so
  I found it better to start a new library. Also I lost the trademark on
  the name :–)

  `Note' also tries to provide a much simpler implementation. `React''s
  implementation was based on the [FrTime Phd thesis]. It's quite subtle
  and involved and, as you suggested, uses weak pointer. `Note' tries to
  avoid them since those are not available in the browser (but you have
  things like [MutationObservers] which I use as gc in Brr's Note-based
  [reactive dom support]).

  However not using weak pointers has a semantic uncleanness cost whose
  impact I'm unsure yet – without discipline from the programmer it may
  lead to subtle and hard to track bugs when the reactive graph changes
  dynamically, which I'm a bit wary of.

  When my brain dumped `Note' I wrote a few more technical points in the
  readme you can read them [here].


[FrTime Phd thesis] <http://cs.brown.edu/people/ghcooper/thesis.pdf>

[MutationObservers]
<https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver>

[reactive dom support]
<https://erratique.ch/software/brr/doc/Brr_note/Elr/index.html>

[here] <https://github.com/dbuenzli/note#history>


New release of Conduit
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-conduit/6611/1>


Calascibetta Romain announced
─────────────────────────────

  *Conduit 3.0.0*

  Hello everyone,

  We're glad to announce the new release of [`conduit'], a framework
  that allows to _abstract_ over transfer protocols. One of its main
  advantages is allowing the implemententation of _free-dependencies_
  protocols.


[`conduit'] <https://github.com/mirage/ocaml-conduit>

Introduction
╌╌╌╌╌╌╌╌╌╌╌╌

  There are several ways to abstract over an implementation in
  OCaml. However, those solutions are often lost deep in the stack of
  protocols and allowing the user to choose the implementations of the
  sub-procotols implies growing complexity as we move up through the
  stack. (For example, allowing to abstract over the implementation of
  the TLS protocol from the implementation of the HTTP protocol)

  One of those solutions, the _functors_, can rapidly become a hellish
  nightmare for the end-user. This is especially true in the case of
  MirageOS, which literally wants to abstract over everything!

  This is why Conduit was implemented: it aims to provide to the user a
  cleaner abstraction mechanism which would allow the protocol
  developers to get rid of most of the responsibilities concerning the
  choice of sub-protocols (Like which TLS implementation use between
  OpenSSL or our great [ocaml-tls] library), while giving the end-users
  an easy way to compose the protocols of their choice and inject them
  in the stack via conduit.


[ocaml-tls] <https://github.com/mirleft/ocaml-tls>


Usage of Conduit
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Such a framework allows us to separate the logic of a protocol from
  underlying implementation needed to communicate with a peer. The
  distribution of Conduit comes with [a simple tutorial] which explains
  step by step how to implement a _ping-pong_ client & server and, most
  importantly, how to upgrade them with TLS.

  With Conduit, we ensure the compatibility with MirageOS (and specially
  [mirage-tcpip]) while being useful for others. Of course, Conduit is
  not mandatory to ensure this compatibility, but it helps us for
  _higher_ libraries such as [ocaml-git]/[Irmin] or [Cohttp].


[a simple tutorial]
<https://mirage.github.io/ocaml-conduit/conduit/howto.html>

[mirage-tcpip] <https://github.com/mirage/mirage-tcpip>

[ocaml-git] <https://github.com/mirage/ocaml-git>

[Irmin] <https://github.com/mirage/irmin>

[Cohttp] <https://github.com/mirage/ocaml-cohttp>


Specific improvements
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

◊ Abstract and destruct it!

  The most requested feature on the new version of Conduit is the
  ability to _destruct_ the [Conduit.flow][conduit-flow]. The ability to
  abstract the protocol comes with the _abstract_ type
  `Conduit.flow'. The new version permits to _destruct_ it to a
  well-known value (such as an UNIX socket):

  ┌────
  │ let handler flow = match flow with
  │   | Conduit_lwt.TCP.T (Value file_descr) ->
  │     let peer = Lwt_unix.getpeername file_descr in
  │     ...
  │   | flow -> ... (* other kind of protocol *)
  │ 
  │ let run =
  │   Cohttp_lwt_unix.serve ~handler
  │     { sockaddr= Unix.inet_addr_loopback }
  └────


◊ The dispatch of the protocol

  The second most interesting feature of Conduit is the full control
  over the dispatch between protocols by the end-user. From a concrete
  information such as an `Uri.t', the end-user is able to describe how
  Conduit should choose the protocol (and with which value it should try
  to initiate the connection):

  ┌────
  │ let my_tls_config = Tls.Config.client ...
  │ 
  │ let connect uri =
  │   let edn = Conduit.Endpoint.of_string
  │     (Uri.host_with_default ~default:"localhost" uri) in
  │   let resolvers = match Uri.scheme uri with
  │     | Some "https" ->
  │       let port = Option.value ~default:443 (Uri.port uri) in
  │       Conduit_lwt.add
  │ 	Conduit_lwt_tls.TCP.protocol
  │ 	(Conduit_lwt_tls.TCP.resolve ~port ~config:my_tls_config)
  │ 	Conduit.empty
  │     | Some "http" | None ->
  │       let port = Option.value ~default:80 (Uri.port uri) in
  │       Conduit_lwt.add
  │ 	Conduit_lwt.TCP.protocol
  │ 	(Conduit_lwt.TCP.resolve ~port)
  │ 	Conduit.empty in
  │   Conduit_lwt.resolve ~resolvers edn >>= fun flow ->
  │   ...
  └────


◊ An explicit way to launch a server

  Conduit comes with a new API for the server-side, where everything
  becomes explicit: no dispatch, no hidden choice. It proposes now a
  simple function to start the usual server loop:

  ┌────
  │ let run handler =
  │   Conduit_lwt.serve ~handler
  │     Conduit_lwt.TCP.service
  │     { Conduit_lwt.TCP.sockaddr= Unix.(ADDR_INET (inet_addr_loopback, 8080)
  │     ; capacity= 40 }
  └────


Reverse-dependencies
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Conduit is used by many libraries (~150 packages) and we spend 2
  months to track this breaking-change.  Currently, it's mostly about
  [Cohttp] and [Irmin] and both have a PR according the new version of
  Conduit. These packages will be released as soon as we can with the
  new version of Conduit.


[Cohttp] <https://github.com/mirage/ocaml-cohttp>

[Irmin] <https://github.com/mirage/irmin>


Conclusion
╌╌╌╌╌╌╌╌╌╌

  Conduit is a piece required by many libraries but nobody really uses
  it. This new version wants to replace and redefine more concretely
  what Conduit is. The update is [huge] for us but small for people
  where we tried to keep the same global idea of the abstraction.

  I would like to thank many people (MirageOS core team, Cohttp peoples,
  some not so famous guys of the Reason/OCaml eco-system) who followed
  us on this deep development (and tried and iterated on our
  version). It does not change too much our world, but it paves the way
  for a better MirageOS/OCaml eco-system.

  As a french guy, I just would like to say: Conduit est mort, Vive
  Conduit!


[huge] <https://github.com/mirage/ocaml-conduit/pull/311>


Easy cross compilation using esy
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-easy-cross-compilation-using-esy/6612/1>


EduardoRFS announced
────────────────────

  I've been working on this for a couple of months now, and now it is
  ready for an initial announcement of my tools to cross compiling OCaml
  and ReasonML Native.

  <https://github.com/EduardoRFS/reason-mobile>


What it can do
╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Out of box it can cross compile most dune and topkg, packages
  available on opam for a couple of platforms, there is also patches for
  popular packages.

  You can also compile opam packages by making an wrapper, like

  <https://github.com/mirage/mirage-crypto/pull/84/files>


Limitations
╌╌╌╌╌╌╌╌╌╌╌

  Your package should build with OCaml 4.10, and all the packages that
  are built for the `host' will also be build for the `target', so
  sometimes you need to fix a package that you will not use directly.

  Some packages you will need to pin to a `dune-universe' fork version


How to use it
╌╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ ## compile your project
  │ esy
  │ 
  │ ## generate the wrapper
  │ esy add -D generate@EduardoRFS/reason-mobile:generate.json
  │ esy generate android.arm64
  │ 
  │ ## build for android.arm64
  │ esy @android.arm64
  └────


Platforms
╌╌╌╌╌╌╌╌╌

  All of the following are tested from Linux and macOS, but I would
  suppose that FreeBSD should be also working as a build system.

  ━━━━━━━━━━━━━━━━━━━━━━
   Targets              
  ──────────────────────
   android.arm64        
   android.x86_64       
   ios.arm64            
   ios.simulator.x86_64 
   linux.musl.arm64     
   linux.musl.x86_64    
  ━━━━━━━━━━━━━━━━━━━━━━


What I tested
╌╌╌╌╌╌╌╌╌╌╌╌╌

  In the past I was able to build `Revery' the UI framework for
  `Android' and `iOS'

  But recently I did compile `esy' the package manager itself for all of
  the following platforms above from an `Arch Linux x86_64' and `macOS
  Catalina x86_64'. Including `iOS', with the right version of OCaml it
  will run inside of the new `macOS ARM64' and inside of a jailbroken
  iPhone.


OCaml User Survey 2020
══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-user-survey-2020/6624/1>


gasche announced
────────────────

  We are happy to announce the [OCaml User Survey 2020]. We are trying
  to get a better picture of the OCaml community and its needs. It would
  be very useful if you could fill the survey (10-15 minutes), and share
  it widely with other OCaml programmers!

  The survey is run by the [OCaml Software Foundation]. Thanks in
  particular to our sponsors OCamlPro (@MuSSF) for preparing many of the
  questions, Jane Street (@Yaron_Minsky) for excellent feedback, and to
  Kim @K_N Nguyễn for his technical help.

  This is our first year running the survey, we hope to continue in
  following years. There are many things to improve; please feel free to
  give us feedback! (There is a feedback question at the end of the
  survey, or you can post here, or send me a message/email.)

  The survey was inspired by programming-language surveys ran by other
  communities. See for example past survey results for [Go], [Haskell],
  [Rust], and [Scala].


[OCaml User Survey 2020] <https://forms.gle/MAT7ZE7RtxTWuNgK7>

[OCaml Software Foundation] <https://ocaml-sf.org/>

[Go] <https://blog.golang.org/survey2019-results>

[Haskell] <https://taylor.fausak.me/2019/11/16/haskell-survey-results/>

[Rust] <https://blog.rust-lang.org/2020/04/17/Rust-survey-2019.html>

[Scala] <https://scalacenter.github.io/scala-developer-survey-2019/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-10-06  7:22 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-10-06  7:22 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of September 29 to
October 06, 2020.

Table of Contents
─────────────────

vue-jsoo 0.2
Rehabilitating packs using functors and recursivity, part 2
Clap 0.1.0 (Command-Line Argument Parsing)
Old CWN


vue-jsoo 0.2
════════════

  Archive: <https://discuss.ocaml.org/t/ann-vue-jsoo-0-2/6522/1>


levillain.maxime announced
──────────────────────────

  I'd like to announce the second release of vue-jsoo (vue-jsoo.0.2). A
  js_of_ocaml binding and helpers to use the vue-js framework with
  js_of_ocaml.


Xavier Van de Woestyne added
────────────────────────────

  Here is the link: <https://gitlab.com/o-labs/vue-jsoo>

  (Congratulation!)


Rehabilitating packs using functors and recursivity, part 2
═══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/rehabilitating-packs-using-functors-and-recursivity-part-2/6525/1>


OCamlPro announced
──────────────────

  Following the publication of [the first part] of our blogpost about
  the redemption of packs in the OCaml ecosystem, we are pleased to
  share "[Rehabilitating packs using functors and recursivity, part 2.]"

        This blog post and the previous one about functor packs
        covers two RFCs currently developed by OCamlPro and Jane
        Street. We previously introduced functor packs, a new
        feature adding the possiblity to compile packs as
        functors, allowing the user to implement functors as
        multiple source files or even parameterized libraries.

        In this blog post, we will cover the other aspect of the
        packs rehabilitation: allowing anyone to implement
        recursive compilation units using packs (as described
        formally in the RFC#20). Our previous post introduced
        briefly how packs were compiled and why we needed some
        bits of closure conversion to effectively implement big
        functors. Once again, to implement recursive packs we will
        need to encode modules through this technique, as such we
        advise the reader to check at least the introduction and
        the compilation part of functor packs.


[the first part]
<https://www.ocamlpro.com/2020/09/24/rehabilitating-packs-using-functors-and-recursivity-part-1/>

[Rehabilitating packs using functors and recursivity, part 2.]
<https://www.ocamlpro.com/2020/09/30/rehabilitating-packs-using-functors-and-recursivity-part-2/>


Clap 0.1.0 (Command-Line Argument Parsing)
══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-clap-0-1-0-command-line-argument-parsing/6544/1>


rbardou announced
─────────────────

  I am happy to announce the first release of Clap.

  Clap is a library for command-line argument parsing. Clap works by
  directly consuming arguments in an imperative way. Traditionally,
  argument parsing in OCaml is done by first defining a specification
  (an OCaml value defining the types of arguments), and then parsing
  from this specification. The "impure" approach of Clap skips the need
  to define a specification and results in code which is quite simple in
  practice, with limited boilerplate.

  Clap is available as an opam package (`opam install clap').

  Source code, API documentation and a full commented example are
  available at: <https://github.com/rbardou/clap/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-09-29  7:02 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-09-29  7:02 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of September 22 to
29, 2020.

Table of Contents
─────────────────

Opam-repository: security and data integrity posture
jsonoo 0.1.0
Interesting OCaml Articles
Rehabilitating Packs using Functors and Recursivity
the OCaml Software Foundation
dual 0.1.0
Old CWN


Opam-repository: security and data integrity posture
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/opam-repository-security-and-data-integrity-posture/6478/1>


Chas Emerick said, spawning a huge thread
─────────────────────────────────────────

  In connection with [another thread] discussing the fact that
  Bitbucket's closure of mercurial support had affected the availability
  of around 60+ projects' published versions, I learned of a number of
  facts about how the opam repository is arranged, and how it is managed
  that are concerning.

  In summary, it seems that opam / opam-repository:

  1. Never retains "published" artifacts, only links to them as provided
     by library authors.
  2. Allows very weak hashes (even md5).
  3. Allows authors to _update_ artifact URLs and hashes of previously
     "published" versions.
  4. Offers scant support for individually signing artifacts or
     metadata.

  All of these are quite dangerous. As a point of reference, the
  ecosystems I am most familiar with using prior to OCaml (JVM and
  Javascript) each had very serious documented failures and exploits
  (and many many more quiet ones) until their respective package
  managers (Maven Central et al., and npm) plugged the above
  vulnerabilities that opam-repository suffers from.

  To make things concrete, without plugging the above (and especially
  items 1-3):

  • the availability and integrity of published libraries can be
    impacted by third-party hosting services changing or going offline
    (as in the case of the Bitbucket closure)
  • the integrity of libraries can be impacted by authors
    non-maliciously publishing updates to already-released versions,
    affecting functionality, platform compatibility, build
    reproducibility, or all of the above (anecdotes of which were shared
    with me when talking about this issue earlier today)
  • the integrity of libraries can be impacted by malicious authors
    publishing updates to already-released versions
  • the integrity of libraries can be impacted by malicious non-authors
    changing the contents at tarball URLs to include changed code that
    could e.g. exfiltrate sensitive data from within the organizations
    that use those libraries. This is definitely the nuclear nightmare
    scenario, and unfortunately opam is wide open to it thanks to
    artifacts not being retained authoritatively and [essential
    community libraries] continuing to use md5 in 2020.

  Seeing that this has been well-established policy for years was
  honestly quite shocking (again, in comparison to other languages'
  package managers that have had these problems licked for a very very
  long time). I understand that opam and its repository probably have
  human-decades of work put into them, and that these topics have been
  discussed here and there (in somewhat piecemeal fashion AFAICT), so
  I'm certain I have not found (nevermind read) all of the prior art,
  but I thought it reasonable to open a thread to gauge what the
  projects' posture is in general.


[another thread]
<https://discuss.ocaml.org/t/bitbucket-stopped-supporting-mercurial-repositories/6324/3?u=cemerick>

[essential community libraries]
<https://github.com/ocaml/opam-repository/blob/master/packages/core/core.v0.14.0/opam>


Hannes Mehnert replied
──────────────────────

  first of all thanks for your post raising this issue, which is
  important for me as well.

  I've been evaluating and working on improving the security of the
  opam-repository over the years, including to not use `curl –insecure`
  (i.e. properly validate TLS certificates) - the WIP result is [conex],
  which aims at cryptographically signed community repositories without
  single points of failures (threshold signatures for delegations,
  built-in key rollover, …) - feel free to read the blog posts or OCaml
  meeting presentations. Unfortunately it still has not enough traction
  to be deployed and mandatory for the main opam repository. Without
  cryptopgraphic signatures (and an established public key
  infrastructure), the hashes used in opam-repository and opam are more
  checksums (i.e. integrity protection) than for security. Threat models
  - I recommend to read section [1.5.2 "goals to protect against
  specific attacks"] - that's what conex above is based on and attempts
  to mitigate. I'll most likely spend some time on improving conex over
  the next year, and finally deploying it on non-toy repositories.

  In the meantime, what you're mentioning:
  1. "Never retains 'published' artifacts" <- this is not true, the
     opam.ocaml.org host serves as an artifact cache, and is used by
     opam when you use the default repository. This also means that the
     checksums and the tarballs are usually taken from the same host ->
     the one who has access there may change anything arbitrarily for
     all opam users.
  2. "Weak hashes" <- this is true, I'd appreciate if (a) opam would
     warn (configurable to error out) if a package which uses weak
     checksum algorithms, and (b) Camelus or some other CI step would
     warn when md5/sha1 are used
  3. "Authors can modify URLs and hashes" <- sometimes (when a
     repository is renamed or moved on GitHub) the GitHub auto-generated
     tarball has a different checksum. I'd appreciate to, instead of
     updating that meta-data in the opam-repository to add new
     patch-versions (1.2.3-1 etc.) with the new URL & hash - there could
     as well be a CI job / Camelus check what is allowed to be modified
     in an edit of a package (I think with the current state of the
     opam-repository, "adding upper bounds" on dependencies needs to be
     allowed, but not really anything else).
  4. I'm not sure I understand what you mean - is it about cryptographic
     signatures and setting up a public key infrastructure?


[conex] <https://github.com/hannesm/conex>

[1.5.2 "goals to protect against specific attacks"]
<https://github.com/theupdateframework/specification/blob/master/tuf-spec.md#the-update-framework-specification>


Anton Kochkov said
──────────────────

  Closely related issue is
  <https://discuss.ocaml.org/t/how-to-setup-local-opam-mirror/4423>,
  since the integrity checks and verification will become even more
  important if there will be multiple mirrors in the future.


jsonoo 0.1.0
════════════

  Archive: <https://discuss.ocaml.org/t/ann-jsonoo-0-1-0/6480/1>


Max LANTAS announced
────────────────────

  Hello! I am announcing the first release of `jsonoo', a JSON library
  for Js_of_ocaml.

  <https://github.com/mnxn/jsonoo>
  <https://opam.ocaml.org/packages/jsonoo>

  This library provides a very similar API to the excellent BuckleScript
  library, [bs-json] by [glennsl]. Unlike bs-json, this port of the
  library tries to follow OCaml naming conventions and be easier to
  interface with other OCaml types like `Hashtbl.t' . This library
  passes a nearly equivalent test suite.

  This project is part of ongoing work to port [vscode-ocaml-platform]
  to Js_of_ocaml.

  Generated documentation can be found [here].


[bs-json] <https://github.com/glennsl/bs-json>

[glennsl] <https://github.com/glennsl>

[vscode-ocaml-platform]
<https://github.com/ocamllabs/vscode-ocaml-platform>

[here] <https://mnxn.github.io/jsonoo/jsonoo/Jsonoo/index.html>


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/62>


Ryan Slade announced
────────────────────

  <https://blog.darklang.com/fizzboom-benchmark/>


Rehabilitating Packs using Functors and Recursivity
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/rehabilitating-packs-using-functors-and-recursivity/6497/1>


OCamlPro announced
──────────────────

  Our new blogpost is about the redemption of packs in the OCaml
  ecosystem. This first part shows our work to generate functor units
  and functor packs : [Rehabilitating Packs using Functors and
  Recursivity, part 1.]

        Packs in the OCaml ecosystem are kind of an outdated
        concept (options `-pack' and `-for-pack' the OCaml manual,
        and their main utility has been overtaken by the
        introduction of module aliases in OCaml 4.02. What if we
        tried to redeem them and give them a new youth and utility
        by adding the possibility to generate functors or
        recursive packs?

        This blog post covers the functor units and functor packs,
        while the next one will be centered around recursive
        packs. Both RFCs are currently developed by JaneStreet and
        OCamlPro. This idea was initially introduced by functor
        packs (Fabrice Le Fessant) and later generalized by
        functorized namespaces (Pierrick Couderc /et al/.).


[Rehabilitating Packs using Functors and Recursivity, part 1.]
<https://www.ocamlpro.com/2020/09/24/rehabilitating-packs-using-functors-and-recursivity-part-1/>


the OCaml Software Foundation
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-the-ocaml-software-foundation/4476/19>


gasche announced
────────────────

  We were all very busy during the last semester, and have been mostly
  quiet on the foundation activities, but of course our actions were
  running in the background. Some highlights:

  • Kate @kit-ty-kate Deplaix has worked on opam-repository QA for the
    OCaml 4.11 release, and the work and results are just as superb as
    for 4.10. We will fund Kate to work again on the upcoming 4.12
    release.

  • We are funding ongoing maintenance work on [ocaml-rs] (a port of the
    OCaml FFI library from C to Rust) by its author and maintainer, Zach
    @zshipko Shipko. Zach did a big round of cleanup changes this
    summer, improving the overall design of the library and completing
    its feature set.

  • We are funding @JohnWhitington (the author of [OCaml from the Very
    Beginning]) to do some technical writing work for OCaml
    documentation. His contributions so far have been very diverse, from
    a script to harmonize the documentation of List and ListLabels (and
    Array and ArrayLabels, etc.) in the standard library, to small
    cleanups and improvement to ocaml.org web pages. One focus of his
    work is the upcoming documentation page "Up and running with OCaml",
    taking complete newcomers through the basic setup, using the
    toplevel and building and running a Hello World. ([ocaml.org#1165],
    [rendered current state])

  • Two [Outreachy] internships were supervised this summer, focusing on
    the compiler codebase. Florian @Octachron Angeletti (INRIA)
    supervised an intern on adding a JSON format for some compiler
    messages (we expect PRs to be submitted soon). Vincent @vlaviron
    Laviron and Guillaume @zozozo Bury (OCamlPro) supervised an intern
    on reducing mutable state in the internal implementation.

  • Inspired by [this Discuss thread], we are funding experimental work
    by @sanette on the HTML rendering of the OCaml manual. This work is
    in the process of being reviewed for upstreaming in the OCaml
    compiler distribution. ([#9755].) This is a better end-result than I
    had initially expected.

  (We also had a couple non-highlights. For example, we funded a sprint
  (physical development meeting) for the [Owl] contributors, with
  Marcello @mseri Seri doing all the organization work; it was planned
  for the end of March, and had to be postponed due to the pandemic.)


[ocaml-rs] <https://github.com/zshipko/ocaml-rs/>

[OCaml from the Very Beginning] <http://ocaml-book.com/>

[ocaml.org#1165] <https://github.com/ocaml/ocaml.org/pull/1165>

[rendered current state]
<https://github.com/johnwhitington/ocaml.org/blob/up-and-running/site/learn/tutorials/up_and_running.md>

[Outreachy] <https://outreachy.org>

[this Discuss thread]
<https://discuss.ocaml.org/t/suggestions-for-ocaml-documentation/4504>

[#9755] <https://github.com/ocaml/ocaml/pull/9755>

[Owl] <https://github.com/owlbarn>


dual 0.1.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dual-0-1-0/6512/1>


Jason Nielsen announced
───────────────────────

  I’ve released [dual] which is now up on opam.  It is a dual numbers
  library which includes a one dimensional root finder (via Newton's
  method).


[dual] <https://github.com/drjdn/ocaml_dual>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-09-22  7:27 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-09-22  7:27 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 15579 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of September 15 to
22, 2020.

Table of Contents
─────────────────

Liquidsoap 1.4.3
Simple63 v1: compression of integer sequences
bentov v1: streaming estimation of 1D histograms
opam-compiler 0.1.0
lua_parser 1.0.0
Merlin 3.4.0 : introducing external configuration readers
gRPC server and client in OCaml
Bitstring (and ppx_bitstring) 4.0.0
Old CWN


Liquidsoap 1.4.3
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-liquidsoap-1-4-3/6429/1>


Romain Beauxis announced
────────────────────────

  I'm happy to announce that liquidsoap `1.4.3' is out at:
  <https://github.com/savonet/liquidsoap/releases/tag/v1.4.3>

  This is the 3rd bugfix release for the `1.4.x' branch. It contains
  important fixes and a couple of new minor features. Update is
  recommended and should be fairly safe.

  Along we this release, we have now added builds for `arm64' debian
  packages and docker-ready production images for `amd64' and `arm64'
  architectures available at:
  <https://hub.docker.com/repository/docker/savonet/liquidsoap>

  Again, we would like to warmly thank all users, contributors and
  reporters for helping us bring liquidsoap to the next step!

  Also, please note that a couple of issues had to be left out to make
  sure that the release comes out on time. These are listed [here] and
  will be tackled as soon as possible.

  Next for liquidsoap, we will focus on getting the current `2.x' branch
  finalized and polished. We already have support for encoded content
  and ffmpeg raw frames. We need to write a couple of inline encoders
  and decoders and we'll have 90% of the features ready. This will be a
  major update for us!


[here] <https://github.com/savonet/liquidsoap/milestone/7>


Simple63 v1: compression of integer sequences
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-simple63-v1-compression-of-integer-sequences/6431/1>


Mika Illouz announced
─────────────────────

  This is to announce Simple63, an opam package for compression of
  integer sequences; similar to Anh and Moffat's Simple-8b. More details
  found in:

  • github: [https://github.com/barko/simple63]
  • documentation: [https://barko.github.io/simple63/]

  Feedback and bug reports welcome.


[https://github.com/barko/simple63] <https://github.com/barko/simple63>

[https://barko.github.io/simple63/] <https://barko.github.io/simple63/>


bentov v1: streaming estimation of 1D histograms
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-bentov-v1-streaming-estimation-of-1d-histograms/6434/1>


Mika Illouz announced
─────────────────────

  This is to announce bentov, a opam package that implements a 1D
  histogram-sketching algorithm. For more details:

  • github: [https://github.com/barko/bentov]
  • documentation: [https://barko.github.io/bentov]

  Feedback and bug reports welcome.


[https://github.com/barko/bentov] <https://github.com/barko/bentov>

[https://barko.github.io/bentov] <https://barko.github.io/bentov>


opam-compiler 0.1.0
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-compiler-0-1-0/6442/1>


Etienne Millon announced
────────────────────────

  On behalf of the opam maintainers, I'd like to announce the first
  release of opam-compiler, a plugin to work with compiler variants,
  branches and forks.

  This can cover a pretty wide range of use cases, so the first version
  is starting small with a single command to create a switch from a
  branch or github PR:

  ┌────
  │ % opam compiler create '#9921'
  │ Opam plugin "compiler" is not installed. Install it on the current switch? [Y/n] y
  │ 
  │ ...
  │ 
  │ <><> Carrying on to "opam compiler create #9921" ><><><><><><><><><><><><><><><>
  │ 
  │ [ocaml-variants.4.12.0+trunk+no-flat-float-array] synchronised from
  │ git+https://github.com/gasche/ocaml#Atomic.create
  │ ocaml-variants is now pinned to git+https://github.com/gasche/ocaml#Atomic.create (version
  │ 4.12.0+trunk)
  │ % opam switch
  │ ...
  │ →  ocaml-ocaml-9921
  │           [opam-compiler] ocaml/ocaml#9921 - stdlib: rename Atomic.make into Atomic.create
  └────

  You can also override the arguments passed to `--configure'.

  As you can see in the above snippet, it's an opam plugin so it will
  auto-install if needed (assuming you ran `opam update' recently) and
  will be available across all switches. Its sources and issue tracker
  are available [here].

  For the next releases, our plan is to add a user-friendly way to setup
  a switch based on a local git clone, so that it's easy to test your
  compiler fork with opam packages. You can find the other features we'd
  like to add in the future in [the relevant part of the opam roadmap].

  Thanks and have fun compiling compilers!


[here] <https://github.com/ocaml-opam/opam-compiler>

[the relevant part of the opam roadmap]
<https://github.com/ocaml/opam/wiki/Spec-for-working-with-the-OCaml-compiler>


lua_parser 1.0.0
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-lua-parser-1-0-0/6445/1>


Jason Nielsen announced
───────────────────────

  I've release [lua_parser] which is now up on opam.  It is a parser and
  pretty-printer for lua 5.2.  Actually it was developed with luajit in
  mind which is lua 5.1 plus goto/labels (which syntactically for the
  purposes of parsing and pretty-printing is lua 5.2).


[lua_parser] <https://github.com/drjdn/ocaml_lua_parser>


Merlin 3.4.0 : introducing external configuration readers
═════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-merlin-3-4-0-introducing-external-configuration-readers/6446/1>


vds announced
─────────────

  I am glad to announce, on behalf of the Merlin team, the release of
  Merlin `3.4.0' which brings some major changes in the way
  configuration is handled.

  As you might know, Merlin reads its configuration from the closest
  `.merlin' file to the source file being edited. These files tell
  merlin where to find other source files and build artifacts, but also
  which flags should be passed to the compiler, which syntax extensions
  are enabled and which packages are used by the project.

  In this setting the configuration is the same for all the source files
  of a folder, regardless of their specificities. In other words, the
  configuration loaded for a single source file contains the union of
  the dependencies of this file and of all its siblings which is not an
  optimal behavior.

  Starting with version `3.4.0' merlin will ship with two packages:
  `merlin' and `dot-merlin-reader' which, as the name suggests, reads
  configuration from `.merlin' files. Both are necessary for proper
  function.

  When a `.merlin' file is present in the source folder the Merlin
  server will start a `dot-merlin-reader' process and communicate with
  it via standard input and output following a simple protocol. These
  processes are halted with the server.

  *This change should not have any visible impact on users' workflows as
  long as the `dot-merlin-reader' binary is correctly installed and in
  the path*. (which should be the case in opam-based setups)

  This change in itself will not solve the granularity problem mentioned
  earlier, but it paves the way for such improvements: in a near-future
  Dune will stop generating `.merlin' files and Merlin will obtain
  file-based configuration directly from the build system using the same
  protocol as the one used by `dot-merlin-reader'.


Changelog
╌╌╌╌╌╌╌╌╌

  ⁃ merlin binary
    • fix completion of pattern matchings with exception patterns
      (#1169)
    • delegate configuration reading to external programs via a simple
      protocol and create a new package `dot-merlin-reader' with a
      binary that reads `.merlin' files. (#1123, #1152)


gRPC server and client in OCaml
═══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/grpc-server-and-client-in-ocaml/6465/1>


blandinw announced
──────────────────

  TL;DR <https://github.com/blandinw/ocaml-grpc-envoy/>

  Hey, I'm new to OCaml after writing some Clojure, C++ and Haskell in
  various contexts, including working at FB (relevant below).

  After browsing this forum and Reddit for a bit, the assumption seems
  to be that OCaml is not a good fit for gRPC, since there's no pure
  implementation today. Now, this is something I have experience with,
  so I thought I'd try and challenge this assumption.

  As you may know, services inside FB use Thrift (both the format and
  protocol) to communicate. The Thrift team worked primarily in C++ (for
  good reasons), causing support for other languages to lag behind
  despite their best efforts. Now, the interchange format (equivalent to
  Protobuf) does not change very often so it's fine to have a
  per-language implementation, but the client and server (equivalent to
  HTTP2 + gRPC) frequently receive new features, optimizations and
  fixes. After a valiant and continued effort to support most languages
  used internally, the Thrift team came up with an idea. Instead of
  maintaining multiple implementations and dealing with obscure FFI
  bugs, ~FingerprintTrustManagerFactory~s and whatnot, they would focus
  solely on the C++ implementation and provide a daemon to be ran
  alongside whatever code you were trying to run. You could then use
  simple IPC to exchange Thrift (the format) messages with that daemon,
  and it would handle all the nitty-gritty of running a service at scale
  (load balancing, connection pooling, service discovery, security,
  retries, timeouts, network stats, hot restarts, etc.). Needless to
  say, it worked remarkably well even at very high scale and everybody
  was much happier.

  I wanted to replicate this idea with OCaml and gRPC. We already have
  support for protobuf thanks to the excellent `ocaml-protoc'. All we
  need is a way to exchange protobuf messages reliably on the wire.
  Instead of having an OCaml implementation that will have to stay
  up-to-date and have its own set of bugs (the official `grpc/grpc-java'
  repo has 4450 commits and 2400 issues at the moment), can we reuse
  existing infra with already massive support and production time?

  Fortunately, the people at Lyft built just that, open-sourced it and
  contributed it to the Cloud Native Computing Foundation in late
  2017. It is called Envoy and it is bliss.

  I demonstrate how to fit these pieces together at
  [blandinw/ocaml-grpc-envoy] to build a simple KV store, including a
  gRPC client and server in 200 lines of OCaml code. The idea is to
  spawn an Envoy process that will handle all gRPC communication for our
  OCaml code. We use HTTP/1.1 to exchange Protobuf messages with it,
  using for example `httpaf' and `Lwt'. This solution has the added
  benefit that it is highly scalable from the start, allowing you for
  instance to spawn one OCaml process per core and load balance between
  them. You can also use Envoy (with proper config!) as your web reverse
  proxy instead of say, nginx.

  At the very least, this solution allows us to start writing gRPC code
  today, and gracefully evolve towards HTTP/2, Multicore and maybe a
  native OCaml implementation later.

  I'm curious to hear your perspective on the future of building
  services with OCaml, or your past experience like what went well, what
  was missing, etc.


[blandinw/ocaml-grpc-envoy]
<https://github.com/blandinw/ocaml-grpc-envoy/>


Yawar Amin asked and blandinw replied
─────────────────────────────────────

        Fantastic idea. So if I understand correctly, the only
        thing that Envoy (server-side) is doing is translating the
        Protobuf from gRPC HTTP2 transport to HTTP1, and
        forwarding these Protobuf objects over HTTP1 to the OCaml
        server? Envoy doesn't know to know about the actual gRPC
        schema, because it doesn't touch the Protobuf objects
        themselves, right?

  That's correct. Envoy is only concerned with transporting bytes (along
  with load balancing, routing, etc, etc). Only OCaml knows about the
  Protobuf schemas.

  In the OCaml server case, Envoy listens for HTTP/2 gRPC requests,
  accesses the bytes payload with no knowledge of the actual
  schema/layout and repackages these same bytes in a HTTP/1.1 request
  that OCaml can process. OCaml then responds with bytes (an encoded
  Protobuf response message) that Envoy sends back on the original HTTP2
  connection.


Bitstring (and ppx_bitstring) 4.0.0
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-bitstring-and-ppx-bitstring-4-0-0/6471/1>


xrguerin announced
──────────────────

Features
╌╌╌╌╌╌╌╌

  • Add support for let bindings introduced in 4.08
  • Switch to PPXLIB


Deprecations
╌╌╌╌╌╌╌╌╌╌╌╌

  As PPXLIB requires `ocaml >= 4.04' support for earlier versions has
  been dropped.


Breaking changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This release splits the library from the PPX to reduce runtime
  dependencies. Projects using the PPX from bitstring will need to also
  depends on ppx_bitstring from now on.


Rudi Grinberg added
───────────────────

  The project is hosted [here] for those who are interested.There's also
  some excellent [docs]


[here] <https://github.com/xguerin/bitstring>

[docs] <https://bitstring.software/documentation/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-09-08 13:11 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-09-08 13:11 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 29657 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of September 01 to
08, 2020.

Table of Contents
─────────────────

OCaml 4.11.1: early bugfix release
textmate-language 0.1.0
Batteries v3.1.0
Job offer in Paris - Be Sport
Some SIMD in your OCaml
A PPX Rewriter approach to ocaml-migrate-parsetree
telltime - when is when exactly?
Ocamlunit emacs minor-mode
Sihl 0.1.0
promise_jsoo 0.1.0
Other OCaml News
Old CWN


OCaml 4.11.1: early bugfix release
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-11-1-early-bugfix-release/6337/1>


octachron announced
───────────────────

  A serious bug has been discovered last week in OCaml 4.11.0: explicit
  polymorphic annotations are checked too permissively.  Some incorrect
  programs (possibly segfaulting) are accepted by the compiler in
  4.11.0.

  Programs accepted by OCaml 4.10 are unchanged.

  We are thus releasing OCaml 4.11.1 as an early bugfix version.  You
  are advised to upgrade to this new version if you were using OCaml
  4.11.0.

  It is (or soon will be) available as a set of OPAM switches with
  ┌────
  │ opam switch create 4.11.1
  └────

  and as a source download here:
    <https://caml.inria.fr/pub/distrib/ocaml-4.11/>

  This bug was introduced when making polymorphic recursion easier to
  use. We are working on making the typechecker more robust and more
  exhaustively tested to avoid such issues in the future.


Bug fixes:
╌╌╌╌╌╌╌╌╌╌

  • [#9856], [#9857]: Prevent polymorphic type annotations from
    generalizing weak polymorphic variables. (Leo White, report by
    Thierry Martinez, review by Jacques Garrigue)

  • [#9859], [#9862]: Remove an erroneous assertion when inferred
    function types appear in the right hand side of an explicit :>
    coercion (Florian Angeletti, report by Jerry James, review by Thomas
    Refis)


[#9856] <https://github.com/ocaml/ocaml/issues/9856>

[#9857] <https://github.com/ocaml/ocaml/issues/9857>

[#9859] <https://github.com/ocaml/ocaml/issues/9859>

[#9862] <https://github.com/ocaml/ocaml/issues/9862>


Rwmjones then said
──────────────────

  We've now got 4.11.1 in Fedora 33 & Fedora 34.  No apparent problems
  so far.


textmate-language 0.1.0
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-textmate-language-0-1-0/6339/1>


dosaylazy announced
───────────────────

  I am pleased to announce [textmate-language 0.1.0]. Textmate-language
  is a library for tokenizing code using TextMate grammars. Therefore,
  it may be useful for implementing syntax highlighters. Please report
  any bugs or API inconveniences you find.


[textmate-language 0.1.0]
<https://opam.ocaml.org/packages/textmate-language/textmate-language.0.1.0/>


Batteries v3.1.0
════════════════

  Archive: <https://discuss.ocaml.org/t/batteries-v3-1-0/6347/1>


UnixJunkie announced
────────────────────

  OCaml Batteries Included is a community-maintained extended standard
  library for OCaml.

  The latest API can be found here:
  <https://ocaml-batteries-team.github.io/batteries-included/hdoc2/>

  This minor release adds support for OCaml 4.11.  It has been available
  in opam for some days.

  Special thanks to all the contributors!

  The changelog follows:

  • Compatibility fixes for OCaml-4.11 [#962] (Jerome Vouillon)
  • BatEnum: added combination [#518] (Chimrod, review by hcarty)
  • fix benchmarks [#956] (Cedric Cellier)
  • BatFile: added count_lines [#953] (Francois Berenger, review by
    Cedric Cellier)
  • BatArray: use unsafe_get and unsafe_set more often [#947] (Francois
    Berenger, review by Cedric Cellier)
  • fix some tests for ocaml-4.10.0 [#944] (kit-ty-kate)
  • BatResult: BatPervasives.result is now equal to Stdlib.result
    instead of sharing constructors without being the same type [#939],
    [#957] (Clément Busschaert, Cedric Cellier).


[#962]
<https://github.com/ocaml-batteries-team/batteries-included/pull/962>

[#518]
<https://github.com/ocaml-batteries-team/batteries-included/pull/518>

[#956]
<https://github.com/ocaml-batteries-team/batteries-included/pull/956>

[#953]
<https://github.com/ocaml-batteries-team/batteries-included/pull/953>

[#947]
<https://github.com/ocaml-batteries-team/batteries-included/pull/947>

[#944]
<https://github.com/ocaml-batteries-team/batteries-included/pull/944>

[#939]
<https://github.com/ocaml-batteries-team/batteries-included/pull/939>

[#957]
<https://github.com/ocaml-batteries-team/batteries-included/pull/957>


Job offer in Paris - Be Sport
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-offer-in-paris-be-sport/6355/1>


Vincent Balat announced
───────────────────────

  Be Sport is looking to hire an OCaml developer with skills in

  • Mobile/web feature design
  • Team management
  • Use of Social networks

  She/he will take part in the development of our Web and mobile apps,
  entirely written in OCaml with Ocsigen, and participate in reflections
  on features.

  Please contact me for more information or send an email to
  jobs@besport.com.


Some SIMD in your OCaml
═══════════════════════

  Archive: <https://discuss.ocaml.org/t/some-simd-in-your-ocaml/6367/1>


Anmol Sahoo announced
─────────────────────

  Fresh from a weekend of hacking, I would like to share some results of
  an experiment I conducted of creating a library for exposing Intel
  AVX2 intrinsics to OCaml code. AVX2 is an instruction set subset that
  adds data-parallel operations in hardware.

  I chose to fork the amazing [bigstringaf] library and modified it. You
  can find the additions to the code here - [bigstringaf_simd].


[bigstringaf] <https://github.com/inhabitedtype/bigstringaf>

[bigstringaf_simd]
<https://github.com/anmolsahoo25/bigstringaf/blob/8df94c4fb5607317ee9634611784eea65368a270/lib/bigstringaf_simd.mli#L287>

Overview
╌╌╌╌╌╌╌╌

  Given a type `Bigstring.t' (1 dimensional byte arrays) there now exist
  functions such as -
  ┌────
  │ val cmpeq_i8 : (t * int) -> (t * int) -> (t * int) -> unit
  └────
  So `cmpeq_i8 (x,o1) (y,o2) (z,03)' will compare 32 bytes starting at
  `o1' and `o2' from `x' and `y' respectively and store the result in
  `z' at `o3'.


Why?
╌╌╌╌

  This was mainly an exercise in curiosity. I just wanted to learn
  whether something like this is viable.  I also want to see if adding
  some type-directed magic + ppx spells can let us write data parallel
  code much more naturally similar to what `lwt / async' did for async
  code.

  At the same time, you might ask - why not use something like Owl
  (which already has good support for data-parallel operations)? Apart
  from the fact that such libraries are oriented towards numerical code,
  I would also like to explore if we can operate directly on OCaml types
  and cast them into data parallel algorithms. Like how `simdjson'
  pushed the boundaries of JSON parsing, it would be nice to port
  idiomatic code to data-parallel versions in OCaml. Can we, at some
  point, have generic traversals of data-types, which are actually
  carried out in a data-parallel fashion?


Does it work?
╌╌╌╌╌╌╌╌╌╌╌╌╌

  Given the limitation of the current implementation (due to foreign
  function calls into C), I still found some preliminary results to be
  interesting! Implementing the `String.index' function, which returns
  the first occurence of a char, the runtime for finding an element at
  the `n-1' position in an array with `320000000' elements is -
  ┌────
  │ serial: 1.12 seconds
  │ simd: 0.72 seconds (1.5x)
  └────
  I still have to do the analysis what the overhead of the function call
  into C is (even with `[@@noalloc]'!


Future directions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  It would be interesting to see, if we can create a representation
  which encapsulates the various SIMD ISA's such as AVX2, AVX512, NEON,
  SVE etc. Further more, it would be really interesting to see if we can
  use ppx to automatically widen `map` functions to operate on blocks of
  code, or automatically cast data types in a data parallel
  representation.


Disclaimer
╌╌╌╌╌╌╌╌╌╌

  This was mostly a hobby project, so I cannot promise completing any
  milestones or taking feature requests etc. I definitely do not
  recommend using this in production, because of the lack of testing
  etc.


A PPX Rewriter approach to ocaml-migrate-parsetree
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-ppx-rewriter-approach-to-ocaml-migrate-parsetree/6369/1>


Chet Murthy announced
─────────────────────

TL;DR
╌╌╌╌╌

  Based on `camlp5' and the `pa_ppx' PPX rewriters, I've written a new
  one, `pa_deriving_plugins.rewrite', that automates almost all the work
  of writing a migration from one version of OCaml's AST to another.
  1. It took a few days (b/c of laziness) to write the initial PPX
     rewriter
  2. A day to get 4.02->4.03 AST migration working
  3. a couple of hours to get 4.03->4.02 working
  4. and a few more hours to get 4.03<->4.04 and 4.04<->4.05 working

  At this point, I fully expect that the other version-pairs will not be
  difficult.

  You can find this code [warning: very much a work-in-progress] at
  <https://github.com/chetmurthy/pa_ppx/tree/migrate-parsetree-hacking>

  The file `pa_deriving.plugins/pa_deriving_rewrite.ml' contains the
  source for the PPX rewriter.

  The directory `pa_omp' contains the migrations, typically named
  `rewrite_NNN_MMM.ml'.


A slightly longer-winded explanation
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  If you think about it, `ppx_deriving.map' isn't so different from what
  we need for `ocaml-migrate-parsetree'.  `ppx_deriving.map', from a
  type definition for ~ 'a t~, will automatically generate a function
  ┌────
  │ map_t : ('a -> 'b) -> 'a t -> 'b t
  └────
  If you think about it, if we could just substitute our own type for
  the second occurrence of `t' (somehow …. yeah *grin*) then it would be
  almost like what we want for o-m-p, yes?

  With 11 versions of the Ocaml AST so far, maybe it's worth thinking
  about how to automate more of the migration task.  Also, since so much
  of it is type-structure-driven, one would think that it would be an
  excellent opportunity to apply PPX rewriting technology.  *Indeed, one
  might think that a good test of PPX rewriting, is the ability to
  automate precisely such tasks.*

  So what's hard about this migration task?  Here are some issues (maybe
  there are more):
  1. the types are slightly differently-organized in different versions
     of the AST.  Types might move from one module to another.
  2. sometimes new types are introduced and old ones disappear
  3. constructor data-types may get new branches, or lose them
  4. record-types may get new fields, or lose them
  5. sometimes the analogous types in two consecutive versions are just
     really, really different [but this is rare]: we need to supply the
     code directly
  6. when mapping from one version to another, sometimes features are
     simply not mappable, and an error needs to be raised; that error
     ought to contain an indication of where in the source that
     offending feature was found
  7. And finally, when all else fails, we might need to hack on the
     migration code directly

  But morally, the task is really straightforward (with problems listed
  in-line):

  1. use `ppx_import' to copy over types from each of the AST times of
     each Ocaml version
     • `ppx_import' works on `.cmi' files, and those have different
       formats in different versions of Ocaml.  Wouldn't it be nice if
       it worked on `.mli' files, whose syntax (b/c OCaml is
       well-managed) doesn't change much?
  2. build a single OCaml module that has all the AST types in it (from
     all the versions of OCaml)
     • but without the form
       ┌────
       │ type t = M.t = A of .. | B of ....
       └────
       that is, without the "type equation" that allows for a new
       type-definition to precisely repeat a previous one.
  3. Then use `ppx_import' against this single module to construct a
     recursive type-declaration list of all the AST types for a
     particular version of OCaml, and apply a "souped-up" version of
     ppx_deriving.map to it, to map the types to *another* version of
     the AST types.
     • but `ppx_deriving.map' doesn't do this today, and besides, it
       would have to provide a bunch of "escape hatches" for all the
       special-cases I mentioned above.

  But this is in principle doable, and it has the nice feature that all
  the tedious boilerplate is mechanically-generated from
  type-definitions, hence likely to not contain errors (assuming the PPX
  rewriter isn't buggy).

  So I decided to do it, and this little post is a result.


Discussion
╌╌╌╌╌╌╌╌╌╌

  I think this is a quite viable approach to writing
  `ocaml-migrate-parsetree', and I would encourage the PPX community to
  consider it.  One of the nice things about this approach, is that it
  relies *heavily* on PPX rewriting itself, to get the job done.  I
  think one of the important things we've learned in programming
  languages research, is that our tools need to be largely sufficient to
  allow us to comfortably implement those same tools.  It's a good test
  of the PPX infrastructure, to see if you can take tedious tasks and
  automate them away.

  I'm not going to describe anymore of how this works, b/c I'd rather
  get the rest of the migrations working, start figuring out how to
  test, and get this code integrated with camlp5.

  But for anybody who's interested, I'd be happy to interactively
  describe the code and walk them thru how it works.


Louis Roché then asked
──────────────────────

  For a person who hasn't digged into OMP, can you explain how it is
  different from what is done currently? Because the idea I had of OMP
  is basically what you describe, a set of functions transformation an
  AST from vX to vX-1 and vX+1. So I am obviously missing something.


Chet Murthy replied
───────────────────

  Yes, you're right: imagine a series of modules M2…M11.  Each declares
  the same set of types, but with different definitions, yes?  Then
  you'd have migration modules, `migrate_i_j' (j=i+1 or j=i-1) that have
  functions that convert between the analogously-named types.  The
  entire question is: how are these functions implemented?  By hand?
  With significant mechanized support?  They can't be implemented
  fully-mechanically, because there are decisions to be made about how
  to bridge differences in type-definitions.  For instance, look at the
  4.02 type `label' and the 4.03 type `arg_label'.  Sometimes these are
  analogous (and sometimes they're not).  When they're analogous, the
  code that converts between -cannot- be automatically inferred: a human
  has to write it.  But -most- of the code of these migration functions
  can be inferred automatically from the type-definitions themselves.

  And that's really all that my little experiment does: automatically
  infer the migration code (most of the time) with some hints for those
  cases where it's not possible to automatically infer.

  Now, why would one do this?  Well, two reasons:

  1. it should be more maintainable to automatically generate most of
     the code from types, and it should be quicker to bring online a
     migration for a new version of the Ocaml AST.
  2. this should be a good test of PPX rewriting.  That is, if we're
     going to build a macro-preprocessing support system, shouldn't it
     be able to make solving such straightforward, but very tedious,
     problems much, much easier?


Chet Murthy then added
──────────────────────

  I forgot to add a third reason why this PPX-rewriter-based approach is
  better:

  1. If you look at ocaml-migrate-parsetree "migrations", you'll find
     that they're almost all boilerplate code.  But sprinkled
     here-and-there, is actual logic, actual decisions about how to come
     up with values for new fields, about which fields, when non-trivial
     (e.g. not "[]") should lead to migration-failure, etc.  It is this
     code, that is the actual meat of the migration, and it's not at all
     obvious, when sprinkled thru the mass of mechanically-produclble
     boilerplate.

  A mechanized production of that boilerplate would mean that we
  retained explicitly only this nontrivial code, and hence for
  maintenance we could focus on it, and make sure it does the right
  thing.


Josh Berdine asked
──────────────────

  Figuring out ways to make maintaining this stuff more efficient would
  be great! One aspect that isn't clear to me is how this approach
  compares to the process currently used to generate the omp code. I
  haven't done it myself, but at first glance the tools to generate the
  omp code (e.g. gencopy) seem to also accurately be describable as
  heavily using ppx infrastructure in order to implement the map code
  from one version to another. Is there an executive summary that
  compares and contrasts that and this proposal?


Chet Murthy replied
───────────────────

  From the README, gencopy is used to generate a prototype file for each
  migration, and then a human goes in and fixes up the code.  A way to
  put my point is: gencopy should be provided the fixups in some compact
  form, and apply them itself.


telltime - when is when exactly?
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-telltime-when-is-when-exactly/6372/1>


Darren announced
────────────────

  I'm happy to announce release of [telltime] 0.0.1, a small cli tool
  for interacting with Daypack-lib (a schedule, time, time slots
  handling library) components.

  It primarily answers time related queries, with support for union
  (`||'), intersect (`&&') and "ordered select" (`>>', explanation of
  this is at the bottom).

  The query language, time expression, aims to mimic natural language,
  but without ambiguity. The grammar is only documented in the online
  demo [here] at the moment.

  Some examples copied from the README are as follows.


[telltime] <https://github.com/daypack-dev/telltime>

[here] <https://daypack-dev.github.io/time-expr-demo/>

Search for time slots matching Daypack time expression
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  "Hm, I wonder what years have Febuary 29th?"

  ┌────
  │ $ telltime search --time-slots 5 --years 100 "feb 29 00:00"
  │ Searching in time zone offset (seconds)            : 36000
  │ Search by default starts from (in above time zone) : 2020 Sep 03 19:24:15
  │ 
  │ Matching time slots (in above time zone):
  │ [2024 Feb 29 00:00:00, 2024 Feb 29 00:00:01)
  │ [2028 Feb 29 00:00:00, 2028 Feb 29 00:00:01)
  │ [2032 Feb 29 00:00:00, 2032 Feb 29 00:00:01)
  │ [2036 Feb 29 00:00:00, 2036 Feb 29 00:00:01)
  │ [2040 Feb 29 00:00:00, 2040 Feb 29 00:00:01)
  └────

  "Would be handy to know what this cron expression refers to"
  ┌────
  │ $ telltime search --time-slots 5 "0 4 8-14 * *"
  │ Searching in time zone offset (seconds)            : 36000
  │ Search by default starts from (in above time zone) : 2020 Sep 06 17:39:56
  │ 
  │ Matching time slots (in above time zone):
  │ [2020 Sep 08 04:00:00, 2020 Sep 08 04:01:00)
  │ [2020 Sep 09 04:00:00, 2020 Sep 09 04:01:00)
  │ [2020 Sep 10 04:00:00, 2020 Sep 10 04:01:00)
  │ [2020 Sep 11 04:00:00, 2020 Sep 11 04:01:00)
  │ [2020 Sep 12 04:00:00, 2020 Sep 12 04:01:00)
  └────

  "I have a bunch of time ranges, but some of them overlap, and they are
  not in the right order. If only there is a way to combine and sort
  them easily."

  ┌────
  │ $ telltime search --time-slots 1000 "2020 . jan . 1, 10, 20 . 13:00 to 14:00 \
  │   || 2019 dec 25 13:00 \
  │   || 2019 dec 25 10am to 17:00 \
  │   || 2020 jan 5 10am to 1:30pm \
  │   || 2020 . jan . 7 to 12 . 9:15am to 2:45pm"
  │ Searching in time zone offset (seconds)            : 36000
  │ Search by default starts from (in above time zone) : 2020 Sep 06 18:01:12
  │ 
  │ Matching time slots (in above time zone):
  │ [2019 Dec 25 10:00:00, 2019 Dec 25 17:00:00)
  │ [2020 Jan 01 13:00:00, 2020 Jan 01 14:00:00)
  │ [2020 Jan 05 10:00:00, 2020 Jan 05 13:30:00)
  │ [2020 Jan 07 09:15:00, 2020 Jan 07 14:45:00)
  │ [2020 Jan 08 09:15:00, 2020 Jan 08 14:45:00)
  │ [2020 Jan 09 09:15:00, 2020 Jan 09 14:45:00)
  │ [2020 Jan 10 09:15:00, 2020 Jan 10 14:45:00)
  │ [2020 Jan 11 09:15:00, 2020 Jan 11 14:45:00)
  │ [2020 Jan 12 09:15:00, 2020 Jan 12 14:45:00)
  │ [2020 Jan 20 13:00:00, 2020 Jan 20 14:00:00)
  └────


Get exact time after some duration from now
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  ┌────
  │ $ telltime from-now "1 hour"
  │ Now                   : 2020-09-03 15:53:29
  │ Duration (original)   : 1 hour
  │ Duration (normalized) : 1 hours 0 mins 0 secs
  │ Now + duration        : 2020-09-03 16:53:29
  └────

  ┌────
  │ $ telltime from-now "1.5 days 2.7 hours 0.5 minutes"
  │ Now                   : 2020-09-03 15:55:43
  │ Duration (original)   : 1.5 days 2.7 hours 0.5 minutes
  │ Duration (normalized) : 1 days 14 hours 42 mins 30 secs
  │ Now + duration        : 2020-09-05 06:38:13
  └────


Difference between ordered select and union
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  `s1 >> s2' is similar to `s1 || s2', but `>>' picks between s1 and s2
  in a round robin fashion, instead of just picking the smallest between
  two.

  One specific differing case would be when the search starts at 4pm
  today, `3pm || 5pm' would return 5pm today and 3pm tomorrow, and so
  on, while `3pm >> 5pm' would return 3pm tomorrow and 5pm tomorrow (a
  5pm is only picked after a 3pm has been picked already).


Ocamlunit emacs minor-mode
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocamlunit-emacs-minor-mode/6373/1>


Manfred Bergmann announced
──────────────────────────

  Here is a first version of this plugin that allows running `dune test'
  with an Emacs key stroke.  It shows the test result in a separate
  buffer and a simple colorized status 'message'.

  <https://github.com/mdbergmann/emacs-ocamlunit>

  While it is possible to run `dune' in 'watch' mode I'd like to
  manually run tests.

  I didn't find a way to specify individual test modules in `dune'. Is
  that possible?


Sihl 0.1.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-sihl-0-1-0/6374/1>


jerben announced
────────────────

  I am happy to announce this milestone release of Sihl, a web framework
  for OCaml.

  Github: <https://github.com/oxidizing/sihl>
  opam: <http://opam.ocaml.org/packages/sihl/>

  Sihl is really just a collection of services that can be plugged into
  each other and a tiny core that knows how to start them. The goal is
  to take care of infrastructure concerns so you can focus on the
  domain.

  After many iterations, the API is in a shape where we dare to show it
  to you :slight_smile: It is still under heavy development so expect
  breakage without a major version bump. However, we just finished
  migrating a project from Reason on NodeJS to OCaml on Sihl, so we use
  it in production.

  We provide service implementations that were useful to us so far. In
  the future we want to provide many more to cover all kinds of
  needs. (PRs are always welcome!)

  Any feedback is greatly appreciated, thanks! :)


jerben then added
─────────────────

  Here is an example of a tiny Sihl app:

  ┌────
  │ module Service = struct
  │   module Random = Sihl.Utils.Random.Service
  │   module Log = Sihl.Log.Service
  │   module Config = Sihl.Config.Service
  │   module Db = Sihl.Data.Db.Service
  │   module MigrationRepo = Sihl.Data.Migration.Service.Repo.MariaDb
  │   module Cmd = Sihl.Cmd.Service
  │   module Migration = Sihl.Data.Migration.Service.Make (Cmd) (Db) (MigrationRepo)
  │   module WebServer = Sihl.Web.Server.Service.Make (Cmd)
  │   module Schedule = Sihl.Schedule.Service.Make (Log)
  │ end
  │ 
  │ let services : (module Sihl.Core.Container.SERVICE) list =
  │   [ (module Service.WebServer) ]
  │ 
  │ let hello_page =
  │   Sihl.Web.Route.get "/hello/" (fun _ ->
  │       Sihl.Web.Res.(html |> set_body "Hello!") |> Lwt.return)
  │ 
  │ let routes = [ ("/page", [ hello_page ], []) ]
  │ 
  │ module App = Sihl.App.Make (Service)
  │ 
  │ let _ = App.(empty |> with_services services |> with_routes routes |> run)
  └────


promise_jsoo 0.1.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-promise-jsoo-0-1-0/6377/1>


Max LANTAS announced
────────────────────

  Hello! I am announcing the first release of `promise_jsoo', a library
  for JS promises in Js_of_ocaml.

  <https://github.com/mnxn/promise_jsoo>
  <https://opam.ocaml.org/packages/promise_jsoo/>

  The library has bindings to the core `Promise' methods as well as
  helper functions that make it easier to deal with a `Promise' of an
  `option' or `result'. It is also possible to use this library with
  [gen_js_api] to make for an easier JavaScript binding experience

  Inspired by [aantron/promise], this library also uses indirection
  internally when handling nested promises in order to ensure that the
  bindings are type safe.

  This project is part of ongoing work to port [vscode-ocaml-platform]
  to Js_of_ocaml.

  Generated documentation can be found [here].


[gen_js_api] <https://github.com/LexiFi/gen_js_api>

[aantron/promise]
<https://github.com/aantron/promise#discussion-how-reason-promise-makes-promises-type-safe>

[vscode-ocaml-platform]
<https://github.com/ocamllabs/vscode-ocaml-platform>

[here]
<https://mnxn.github.io/promise_jsoo/promise_jsoo/Promise/index.html>


Other OCaml News
════════════════

>From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Announcing Signals and Threads, a new podcast from Jane Street]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Announcing Signals and Threads, a new podcast from Jane Street]
<https://blog.janestreet.com/announcing-signals-and-threads-index/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-09-01  7:55 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-09-01  7:55 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of August 25 to
September 01, 2020.

Table of Contents
─────────────────

Writing bindings for Google Apps Script (GAS)
What the Jane Street interns have wrought
a small library for shell/AWK/Perl-like scripting
letters 0.2.0
raylib-ocaml 0.1.0
OCaml Workshop 2020 Online Conference is live now
Other OCaml News
Old CWN


Writing bindings for Google Apps Script (GAS)
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/writing-bindings-for-google-apps-script-gas/6293/1>


Danielo Rodríguez announced
───────────────────────────

  Thanks to the help of this community I successfully completed a crazy
  idea: To write some ocaml functions to use inside [Google Apps Script]
  for a small stupid spreadsheet that I had.

  The way it works now is by having a main index.js file that calls the
  Ocaml functions that are available under a global Lib
  namespace. Everything is bundled using parcel and the Idea was to use
  as few JS code as possible. Because it was easier than I expected I
  decided to go one step further and write some bindings for the GAS
  functions I was using and reduce the glue JS code even more.

  This are the bindings that I wrote so far. They work, but are not
  usable inside Ocaml yet.

  ┌────
  │ type spreadsheet
  │ type sheet
  │ type range
  │ external getActiveSpreadsheet : unit -> spreadsheet = "getActiveSpreadsheet" [@@bs.val][@@bs.scope
  │ "SpreadsheetApp"]
  │ external getSheets : spreadsheet -> sheet array = "getSheets" [@@bs.send]
  │ external getSheetByName : spreadsheet -> string -> sheet = "getSheetByName" [@@bs.send]
  │ external getDataRange : sheet -> range = "getDataRange"  [@@bs.send]
  │ external getValues : range -> 'a array array = "getValues"  [@@bs.send]
  └────

  My doubt are on the edges. When it is just obscure GAS stuff I have no
  doubt, abstract types and functions to interact with them. Is when a
  GAS function returns data where I have doubts. Usually they are just
  arrays of arrays of Numbers or Strings. In the example above, the last
  definition says that you will get an array of arrays of `'a', but that
  is not true because it will be an array of "stuff" (strings, numbers,
  floats).  How should I type it in a way that it's flexible but not
  cumbersome? For example, I don't think using a functor will help
  because you will need to create a functor for every possible return
  type, in my case if you have 3 sheets with 3 different shapes, you
  will need 3 functors.  An alternative that I have used was to provide
  some helper functions to convert from JS to Ocaml types and then
  unwrap the Ocaml types, like the example I'm doing with
  Number_or_string.  This is nothing serious and I will just add the
  bindings that I may need for now, but I want to hear what the
  community (and potential users) thinks.

  If anyone is interested in taking a look on the project, it is here:
  <https://github.com/danielo515/ElectronicProjectsSpreadsheet>


[Google Apps Script] <https://developers.google.com/apps-script>


Matthieu Dubuget said
─────────────────────

  Not answering directly to your question, sorry.

  But here is a binding I have been using for around 4 years:
  <https://dubuget.fr/gitea/matthieu/ocaml-google-app.git>.


Hongbo Zhang also replied
─────────────────────────

  For return type polymorphism, you can use GADT with bs.ignore, the
  rough idea:

  ┌────
  │ type 'a t =  Int : int t | String : string t
  │ external f : ('a t [@bs.ignore]) -> ... -> 'a = "xx"
  └────
  I read discuss.ocaml.org from time to time, but checks
  <https://forum.rescript-lang.org/> daily where you can get a quick
  answer


What the Jane Street interns have wrought
═════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/what-the-jane-street-interns-have-wrought/6294/1>


Yaron Minsky announced
──────────────────────

  I thought folks here might find this interesting:

  <https://blog.janestreet.com/what-the-interns-have-wrought-2020/>

  The post summarizes three of the intern projects that happened this
  summer at Jane Street. It might be interesting if you're looking for
  an internship (or know someone who is), or if you're interested in any
  of the underlying tech. For example, if there's significant interest
  in a library for writing OCaml, we'd be more likely to open-source it.


a small library for shell/AWK/Perl-like scripting
═════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-08/msg00021.html>


Oleg announced
──────────────

  Some time ago Chet Murthy asked about writing shell-like scripts in
  OCaml. Prompted by it, I also want to report on my experience and
  announce a small library that made it pleasant to do
  shell/AWK/Perl-like scripting in OCaml.

  The library is available at
          <http://okmij.org/ftp/ML/myawk/0README.dr>
  and consists of two small ML files, myawk.ml and strings.ml. The
  latter collects general-purpose string operations, more convenient
  than those in Stdlib.String. The rest of that web directory contains
  half a dozen sample scripts with comments.

  Here is the first example: a typical AWK script, but written in OCaml:

  ┌────
  │ #!/bin/env -S ocaml
  │ 
  │ #load "myawk.cma"
  │ open Myawk open Strings
  │ let hash = string_of_int <|> Hashtbl.hash
  │ ;;
  │ (* Sanitize the files originally used by join1.ml and join2.ml
  │    The files are made of space-separated fields; the first field is the
  │    key. It is sensitive; but because it is a key it can't be replaced with
  │    meaningless garbage. We obfuscate it beyond recognition. The third field
  │    is obfuscated as well. The second and fourth can be left as they are,
  │    and the fifth, if present, is replaced with XXX
  │ 
  │    The script is a proper filter: reads from stdin, writes to stdout
  │  *)
  │ 
  │ for_each_line @@ map words @@ function (f1::f2::f3::f4::rest) ->
  │   print [hash f1; f2; hash f3; f4; if rest = [] then "" else "XXX"]
  │ ;;
  └────

  Here <|> is a function composition. I wish it were in Stdlib. The real
  example, used in real life, was performing a database join

  ┌────
  │ SELECT T2.* from Table1 as T1, Table2 as T2 where T1.f1 = T2.f1
  └────

  where Table1 and Table2 are text files with space-separated column
  values. Table1 is supposed to be fed to stdin:

  ┌────
  │ let () =
  │   for_each_line @@ map words @@
  │   map_option (function (x::_) -> Some x | _ -> None) @@
  │   (ignore <|> shell "grep %s table1.txt")
  └────

  It is a typical rough-and-dirty script. Alas, it was too rough: I was
  so excited that it typechecked and worked the first time, that I
  didn't look carefully at the output and overlooked what I was looking
  for (resulting in an unneeded hassle and apology). I should have
  queried exactly for what I wanted:
  ┌────
  │ SELECT T1.f1, T1.f4 FROM Table1 as T1, Table2 as T2
  │ WHERE T1.f1 = T2.f1 AND T1.f3 <> "3"
  └────

  which is actually easy to write in myawk (probably not so in AWK
  though)

  ┌────
  │ let () =
  │   for_each_line ~fname:"table2.txt" @@ map words @@
  │   map_option (function (w::_) -> Some w | _ -> None) @@
  │   fun w ->
  │     for_each_line ~fname:"table1.txt" @@  map words @@
  │     map_option (function
  │      (x::f2::f3::f4::_) when x = w && f4 <> "3" -> Some [x;f4] | _ -> None) @@
  │     print
  └────

  This is the classical nested loop join. Chet Murthy might be pleased
  to see the extensive use of the continuation-passing style. I was
  apprehensive at first, but it turned out not to be a hassle.

  The library has a few other examples, including case-branching and
  rewriting a real AWK script from the OCaml distribution.

  Finally, let's compare with shell scripts. The example below doesn't
  show off the library, but it does show the benefits of OCaml for
  scripting. The original shell script is a sample GIT commit hook,
  quoted in the comments:

  ┌────
  │ (*
  │ From GIT's sample hooks:
  │   ANY-GIT-REPO/.git/hooks/commit-msg.sample
  │ 
  │   # Called by "git commit" with one argument, the name of the file
  │   # that has the commit message.  The hook should exit with non-zero
  │   # status after issuing an appropriate message if it wants to stop the
  │   # commit.  The hook is allowed to edit the commit message file.
  │ 
  │   # This example catches duplicate Signed-off-by lines.
  │ 
  │ test "" = "$(grep '^Signed-off-by: ' "$1" |
  │ 	 sort | uniq -c | sed -e '/^[ 	]*1[ 	]/d')" || {
  │ 	echo >&2 Duplicate Signed-off-by lines.
  │ 	exit 1
  │ }
  │ 
  │ *)
  │ module H = Hashtbl
  │ 
  │ let commit_msg = Sys.argv.(1)
  │ let ht = H.create 5
  │ let () =
  │   for_each_line ~fname:commit_msg @@ fun l ->
  │   if is_prefix "Signed-off-by: " l <> None then begin
  │     if H.find_opt ht l <> None then begin
  │       prerr_endline "Duplicate Signed-off-by lines.";
  │       exit 1
  │     end else
  │       H.add ht l ()
  │   end
  └────

  Although the OCaml script seems to have more characters, one doesn't
  need to type them all. Scripts like that are meant to be entered in an
  editor; even ancient editors have completion facilities.

  Looking at the original shell script brings despair, and drives me
  right towards Unix Haters. Not only the script is algorithmically
  ugly: if a duplicate signed-off line occurs near the beginning, we can
  report it right away and stop. We don't need to read the rest of the
  commit message, filter it, sort it, precisely count all duplicates and
  filter again. Not only the script gratuitously wastes system resources
  (read: the laptop battery) by launching many processes and allocating
  communication buffers. Mainly, the script isn't good at its primary
  purpose: it isn't easy to write and read. Pipeline composition of
  small stream processors is generally a good thing – but not when each
  stream processor is written in its own idiosyncratic
  language. Incidentally, I have doubts about the script: I think that
  quotes around $1 are meant to be embedded; but why they are not
  escaped then? Probably it is some edge case of bash, out of several
  0thousands.

  In contrast, OCaml script does exactly what is required, with no extra
  work. Everything is written in only one language.


letters 0.2.0
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-letters-0-2-0/6307/1>


Miko announced
──────────────

  Getting this release done took a bit longer than expected due to some
  real life factors, but finally here it is.

  This one mainly focuses on the most requested features and
  improvements like simplifying configuration around CA certificates,
  provides some basic documentation and additionally adds support for
  `multipart/alternative' emails with combined HTML and plain text
  content.


jerben then added
─────────────────

  Link to Github: <https://github.com/oxidizing/letters>


raylib-ocaml 0.1.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-raylib-ocaml-0-1-0/6313/1>


Tobias Mock announced
─────────────────────

  I'd like to announce the first version of [raylib-ocaml], a binding to
  the awesome [raylib] game development library. The release can be
  found on opam as ["raylib"].

  The bindings are nearly complete, as far as functions and types go,
  but only a subset was tested so far. I will work on bringing more of
  the numerous examples of the C version to OCaml in the future.

  Currently, raylib-ocaml only works on Linux, but I plan to support
  Windows (and possibly other targets) in the future.

  Feel free to give it a spin and please report any issues you run into.


[raylib-ocaml] <https://github.com/tjammer/raylib-ocaml>

[raylib] <https://www.raylib.com/>

["raylib"] <https://opam.ocaml.org/packages/raylib/>


OCaml Workshop 2020 Online Conference is live now
═════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-workshop-2020-online-conference-is-live-now/6287/30>


Deep in this thread, Didier Wenzek announced
────────────────────────────────────────────

  [OCaml 2020 All Videos]


[OCaml 2020 All Videos]
<https://www.youtube.com/playlist?list=PLKO_ZowsIOu5fHjRj0ua7_QWE_L789K_f>


Other OCaml News
════════════════

>From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [BuckleScript Good and Bad News]
  • [What the interns have wrought, 2020 edition]
  • [Coq 8.12.0 is out]


[OCaml Planet] <http://ocaml.org/community/planet/>

[BuckleScript Good and Bad News]
<http://psellos.com/2020/08/2020.08.east-van-girls.html>

[What the interns have wrought, 2020 edition]
<https://blog.janestreet.com/what-the-interns-have-wrought-2020/>

[Coq 8.12.0 is out] <https://coq.inria.fr/news/coq-8-12-0-is-out.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-08-18  7:25 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-08-18  7:25 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of August 11 to 18,
2020.

Table of Contents
─────────────────

Ppx: omp 2.0.0 and next steps
Old CWN


Ppx: omp 2.0.0 and next steps
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ppx-omp-2-0-0-and-next-steps/6231/1>


Jérémie Dimino announced
────────────────────────

  quick summary:
  • ocaml-migrate-parsetree 2.0.0 release
  • you should add a upper bound in your dev repos
  • ppxlib compatible version coming soon
  • ppxlib is now the official ppx library supported by the OCaml
    platform

  Hi everyone,

  As [previously announced], we are [releasing the version 2.0.0 of
  ocaml-migrate-parsetree]. At the moment nothing is compatible with the
  new version and we will soon release a version of ppxlib that is
  compatible with it. If your project depends on
  ocaml-migrate-parsetree, you should add a upper bound to your
  development repository.

  If you plan to use ocaml-migrate-parsetree 2.0.0 directly, please note
  however that this is a transitory package. The technology implemented
  by ocaml-migrate-parsetree will live on and hopefully find a new home
  in the compiler repository proper. However, ocaml-migrate-parsetree as
  a standalone project will eventually stop being maintained.

  I am also taking the opportunity to announce that *ppxlib is the first
  ppx library officially supported by the OCaml platform*, and the one
  we recommend all ppx authors to use. It is the library that we plan to
  maintain for the long term.

  Other libraries such as `ppx_tools' or `ppx_tools_versioned' may
  continue to be maintained by open source contributors, however they
  will not be maintained by the OCaml platform and will not receive
  updates from the platform when new compilers are released. Only ppxlib
  will receive updates from the platform.

  If you would like to port your project to use ppxlib and are
  experiencing difficulties or have any question, please get in touch by
  replying to this post or opening a ticket on
  <https://github.com/ocaml-ppx/ppxlib>.

  The overall plan described in this post is the result of various
  discussions and/or collaborative effort between the following people:
  @avsm, @ceastlund, @Drup, @gasche, @jeremiedimino, @kit-ty-kate,
  @let-def, @NathanReb and @pitag.


[previously announced]
<https://discuss.ocaml.org/t/ocaml-migrate-parsetree-2-0-0/5991>

[releasing the version 2.0.0 of ocaml-migrate-parsetree]
<https://github.com/ocaml/opam-repository/pull/16999>

Next steps
╌╌╌╌╌╌╌╌╌╌

  As soon as the new version of ppxlib is released, we will work towards
  our next milestone. As a reminder, our current goal is to setup a ppx
  ecosystem that is continously compatible with the trunk of OCaml. To
  achieve that goal, we plan to add a stable API called "Astlib" on top
  of the compiler libraries. To keep things sustainable on the compiler
  side and increase flexibility, Astlib will be minimal and will be
  targeted at ppxlib only rather than be a general API aimed at ppx
  authors.

  The difficulty of this API is that it must expose a stable interface
  to the OCaml AST, which is composed of a large collection of data
  types. To make it work, we plan to use the technology developed in
  ocaml-migrate-parsetree; i.e. whole AST migration functions.

  While we eventually want Astlib to live in the compiler repository, we
  will initially develop it inside the ppxlib repository. Once it is
  ready, we will submit it for inclusion in the compiler. Although, we
  will keep a copy inside ppxlib for older versions of the compiler.

  We also plan to setup a smooth workflow for compiler developers to
  update Astlib when they change the development AST.

  Once this is all done, we will be in a situation where the ppx
  ecosystem is compatible with the trunk of OCaml at all time. And as a
  result, new releases of the compiler will no longer break ppx packages
  as long as they limit themselves to the ppxlib API.


Future
╌╌╌╌╌╌

  While this work will make the ecosystem compatible with the trunk of
  OCaml at all times, it will essentially move the backward
  compatibility issue from the compiler to ppxlib.[1] This will already
  give us a lot more flexibility as for instance a single version of
  ppxlib can be compatible with a wide range of OCaml versions. However,
  we recognise that it is not usual to ask a community to rely on an
  unstable API.

  We made this choice as a trade-off between sustainability and
  complexity. Indeed, we want to maintain Astlib and Ppxlib over the
  long term and the best way to make things sustainable is to use simple
  and clear designs. While we do have solutions in our sleeves that
  would provide a fully stable ppx API, these are much more complicated
  to maintain and work with.

  To mitigate this, we are setting up a Dune based workflow to upgrade
  all ppx rewriters at once. So once the system is rolling and if your
  ppx rewriters are up to date and using Dune, you should expect to
  receive pull requests as we update ppxlib. This last part will take
  some time to be fully rolling, so please bear with us :)

  In any case, about a year after this new world is fully setup, we will
  review the situation and decide whether it is sustainable or whether
  we need to go all the way and mint a fully stable ppx API.


Timeline
╌╌╌╌╌╌╌╌

  • today: ocaml-migrate-parsetree 2.0.0 is being released

  • next week: a ppxlib compatible version is released

  • December 2020: astlib is ready inside the ppxlib repository

  • next OCaml release after that: astlib lives in the compiler

  • September 2021: we review the situation and decide what to do next

  [1]: At any given time the API of ppxlib refer to a single version of
  the OCaml AST. In order to allow OCaml users to enjoy both ppx
  rewriters and new language features, the version of the AST selected
  by ppxlib needs to be bumped after each release of the compiler, which
  is a breaking change that has the potential to break several ppx
  packages.  As a result, ppx packages will still need to be regularly
  updated in order to stay compatible with the latest version of ppxlib.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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@ 2020-07-28 16:57 Alan Schmitt
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From: Alan Schmitt @ 2020-07-28 16:57 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp


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Hello

Here is the latest OCaml Weekly News, for the week of July 21 to 28,
2020.

As I will be away with no internet next week, the next CWN will be on
August 11.

Table of Contents
─────────────────

Embedded ocaml templates
Proposal: Another way to debug memory leaks
Camlp5 (8.00~alpha01) and pa_ppx (0.01)
OCaml 4.11.0, third (and last?) beta release
Other OCaml News
Old CWN


Embedded ocaml templates
════════════════════════

  Archive: [https://discuss.ocaml.org/t/embedded-ocaml-templates/6124/1]


Emile Trotignon announced
─────────────────────────

  I am very happy to announce the release of ocaml-embedded-templates.

  This is a tool similar to camlmix, but camlmix was not updated for 7
  years, and there is no easy way to handle a lot of templates (my
  command takes a directory as an argument and generate an ocaml module
  by going through the directory recursively) I also choosed to use a
  syntax similar to EJS, and there is a ppx for inline EML.

  You can check it out here :
  [https://github.com/EmileTrotignon/embedded_ocaml_templates]

  Here is a more extensive exemple of what can be done with this :
  [https://github.com/EmileTrotignon/resume_of_ocaml] (This project
  generate my resume/website in both latex and html).

  This is my first opam package : feedback is very much welcome.


Proposal: Another way to debug memory leaks
═══════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/proposal-another-way-to-debug-memory-leaks/6134/1]


Jim Fehrle said
───────────────

  `memprof' helps you discover where memory was allocated, which is
  certainly useful.  However, that may not be enough information to
  isolate a leak.  Sometimes you'd like to know what variables refer to
  excessive amounts of memory.

  For this, you'd want to examine all the garbage collection roots and
  report how much memory is used by each.  This is useful information if
  you can map a GC root back to a source file and variable.

  I prototyped code to do that to help with Coq bug
  [https://github.com/coq/coq/issues/12487].  It localized several leaks
  enough across over 500 source files so that we could find and fix
  them.  But my prototype code is a bit crude.  I'd like to clean it up
  and submit it as a PR.  Since this could be done in various ways, I
  wanted to get some design/API feedback up front rather than maybe
  doing some of it twice.  Also I'd like to confident that such a PR
  would be accepted and merged in a reasonable amount of time–otherwise
  why bother.

  [caml_do_roots] shows how to access the GC roots.  There are several
  types of roots:
  • global roots, corresponding to top-level variables in source files
  • dynamic global roots
  • stack and local roots
  • global C roots
  • finalized values
  • memprof
  • hook

  *API (in Gc):*

  ┌────
  │ val print_global_reachable : out_channel -> int -> unit
  └────

  Prints a list to `out_channel' of the global roots that reach more
  than the specified number of words.  Each item shows the number of
  reachable words, the associated index of the root in the `*glob' for
  that file and the name of the source file.

  Something like this (but with only filenames rather than pathnames):

  ┌────
  │   102678 field  17 plugins/ltac/pltac.ml
  │   102730 field  18 plugins/ltac/pltac.ml
  │   164824 field  20 plugins/ltac/tacenv.ml
  │  1542857 field  26 plugins/ltac/tacenv.ml
  │ 35253743 field  65 stm/stm.ml
  │ 35201913 field   8 vernac/vernacstate.ml
  │  8991864 field  24 vernac/library.ml
  │   112035 field   8 vernac/egramml.ml
  │  6145454 field  84 vernac/declaremods.ml
  │  6435878 field  89 vernac/declaremods.ml
  └────

  I would use ELF information in the binary file to map from `*glob'
  back to a filename.  For example, the address symbol of the entry
  `camlTest' corresponds to `test.ml'.  This would only work for binary
  executables compiled with the `-g' option.  It wouldn't work for
  byte-compiled code.  It would print an error message if it's not ELF
  or not `-g'.  Also, being a little lazy, how essential is it to
  support 32-bit binaries?  (Q: What happens if you have 2 source files
  with the same name though in different directories?  Would the symbol
  table distinguish them?)

  ┌────
  │ val get_field_index : Obj.t -> int
  └────

  Returns the `*glob' index number for the top-level variable (passed as
  `Obj.repr var').  I expect there's no way to recover variable names
  from the `*glob' index.  In my experiments, it appeared that the
  entries in `*glob' were in the same order as as the variable and
  function declarations.  This would let a developer do a binary search
  in the code to locate the variable which it probably a necessity for
  large, complex files such as Coq's `stm.ml'–3300 lines, 10+ modules
  defined within the file.  (I noticed that variables defined in modules
  defined within the source file were not in `*glob'.  I expect there is
  a root for the module as a whole and that those variables can be
  readily found within that root.)

  This would need an extended explanation in `gc.mli'.

  ┌────
  │ val print_stack_reachable : out_channel -> int -> unit
  └────

  Prints a backtrace to `out_channel' that also shows which roots for
  each frame reach more than the specified number of words.  (I'd keep
  the "item numbers" since there's no way to translate them to variables
  and they might give some clues.)

  ┌────
  │ Called from file "tactics/redexpr.ml" (inlined), line 207, characters 29-40
  │  356758154 item    0 (stack)
  │ Called from file "plugins/ltac/tacinterp.ml", line 752, characters 6-51
  │   17646719 item    0 (stack)
  │     119041 item    1 (stack)
  │ Called from file "engine/logic_monad.ml", line 195, characters 38-43
  │     119130 item    0 (stack)
  │  373378237 item    1 (stack)
  └────

  As it turns out, 90% of the memory in Coq issue mentioned above is
  reachable only from the stack.

  I didn't consider the other types of roots yet, which I don't fully
  understand, such as local roots.  Just covering global and stack roots
  seems like a good contribution.  Dynamic global roots may be easy to
  add if they are otherwise similar to global roots.  For the others I
  could print the reachable words, but I don't know how to direct the
  developer to look at the relevant part of the code, especially if it's
  in C code.  I suppose `print_global_reachable' and
  `print_stack_reachable' could be a single routine as well.  That's
  probably better.

  Let me know your thoughts.


[caml_do_roots]
https://github.com/ocaml/ocaml/blob/80326033cbedfe59c0664e3912f21017e968a1e5/runtime/roots_nat.c#L399


Camlp5 (8.00~alpha01) and pa_ppx (0.01)
═══════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-camlp5-8-00-alpha01-and-pa-ppx-0-01/6144/1]


Chet Murthy announced
─────────────────────

`Camlp5 (8.00~alpha01)' and `pa_ppx (0.01)'
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  I'm pleased to announce the release of two related projects:

  1. [Camlp5]: version 8.00~alpha01 is an alpha release of Camlp5, with
     full support for OCaml syntax up to version 4.10.0, as well as
     minimal compatibility with version 4.11.0. In particular there is
     full support for PPX attributes and extensions.

  2. [pa_ppx]: version 0.01 is a re-implementation of a large number of
     PPX rewriters (e.g. ppx_deriving (std (show, eq, map, etc), yojson,
     sexp, etc), ppx_import, ppx_assert, others) on top of Camlp5, along
     with an infrastructure for developing new ones.

  This allows projects to combine the existing style of Camlp5 syntax
  extension, with PPX rewriting, without having to jump thru hoops to
  invoke camlp5 on some files, and PPX processors on others.

  Camlp5 alone is not compatible with existing PPX rewriters: Camlp5
  syntax-extensions (e.g. "stream parsers") would be rejected by the
  OCaml parser, and PPX extensions/attributes are ignored by Camlp5
  (again, without `pa_ppx').  `pa_ppx' provides Camlp5-compatible
  versions of many existing PPX rewriters, as well as new ones, so that
  one can use Camlp5 syntax extensions as well as PPX rewriters.  In
  addition, some of the re-implemented rewriters are more-powerful than
  their original namesakes, and there are new ones that add interesting
  functionality.


[Camlp5] https://github.com/camlp5/camlp5

[pa_ppx] https://github.com/chetmurthy/pa_ppx


For democratizing macro-extension-authoring in OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  TL;DR Writing OCaml PPX rewriters is *hard work*.  There is a
  complicated infrastructure that is hard to explain, there are multiple
  such incompatible infrastructures (maybe these are merging?) and it is
  hard enough that most Ocaml programmers do not write macro-extensions
  as a part of their projects.  I believe that using Camlp5 and pa_ppx
  can make it easier to write macro-extensions, via:

  1. providing a simple way of thinking about adding your extension to
     the parsing process.

  2. providing transparent tools (e.g. quotations) for
     pattern-matching/constructing AST fragments

  Explained below in [Macro Extensions with
  Pa_ppx](#macro-extensions-with-pa_ppx).


◊ The original arguments against Camlp4

  The original argument against using Camlp4 as a basis for
  macro-preprocessing in Ocaml, had several points (I can't find the
  original document, but from memory):

  1. *syntax-extension* as the basis of macro-extension leads to brittle
      syntax: multiple syntax extensions often do not combine well.

  2. a different AST type than the Ocaml AST

  3. a different parsing/pretty-printing infrastructure, which must be
     maintained alongside of Ocaml's own parser/pretty-printer.

  4. A new and complicated set of APIs are required to write syntax
     extensions.

  To this, I'll add

  1. Camlp4 was *forked* from Camlp5, things were changed, and hence,
     Camlp4 lost the contribution of its original author.  Hence,
     maintaining Camlp4 was always labor that fell on the Ocaml
     team. [Maybe this doesn't matter, but it counts for something.]


◊ Assessing the arguments, with some hindsight

  1. *syntax-extension* as the basis of macro-extension leads to brittle
      syntax: multiple syntax extensions often do not combine well.

     In retrospect, this is quite valid: even if one prefers and enjoys
     LL(1) grammars and parsing, when multiple authors write
     grammar-extensions which are only combined by third-party projects,
     the conditions are perfect for chaos, and of a sort that
     project-authors simply shouldn't have to sort out.  And this chaos
     is of a different form, than merely having two PPX rewriters use
     the same attribute/extension-names (which is, arguably, easily
     detectable with some straightforward predeclaration).

  2. Camlp4/5 has a different AST type than the Ocaml AST

     Over time, the PPX authors themselves have slowly started to
     conclude that the current reliance on the Ocaml AST is fraught with
     problems.  The "Future of PPX" discussion thread talks about using
     something like s-expressions, and more generally about a
     more-flexible AST type.

  3. a different parsing/pretty-printing infrastructure, which must be
     maintained alongside of Ocaml's own parser/pretty-printer.

     A different AST type necessarily means a different
     parser/pretty-printer.  Of course, one could modify Ocaml's YACC
     parser to produce Camlp5 ASTs, but this is a minor point.

  4. A new and complicated set of APIs are required to write syntax
     extensions.

     With time, it's clear that PPX has produced the same thing.

  5. Maintaining Camlp4 was always labor that fell on the Ocaml team.

     The same argument (that each change to the Ocaml AST requires work
     to update Camlp5) can be made for PPX (specifically, this is the
     raison d'etre of ocaml-migrate-parsetree).  Amusingly, one could
     imagine using ocaml-migrate-parsetree as the basis for making
     Camlp5 OCaml-version-independent, too.  That is, the "backend" of
     Camlp5 could use ocaml-migrate-parsetree to produce ASTs for a
     version of OCaml different from the one on which it was compiled.


Arguments against the current API(s) of PPX rewriting
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The overall argument is that it's too complicated for most OCaml
  programmers to write their own extensions; what we see instead of a
  healthy ecosystem of many authors writing and helping-improve PPX
  rewriters, is a small number of rewriters, mostly written by Jane
  Street and perhaps one or two other shops.  There are a few big
  reasons why this is the case (which correspond to the responses
  above), but one that isn't mentioned is:

  1. When the "extra data" of a PPX extension or attribute is
     easily-expressed with the fixed syntax of PPX payloads, all is
     `~well~' ok, but certainly not in great shape.  Here's an example:

  ┌────
  │ type package_type =
  │ [%import: Parsetree.package_type
  │ 	  [@with core_type    := Parsetree.core_type [@printer Pprintast.core_type];
  │ 		 Asttypes.loc := Asttypes.loc [@polyprinter fun pp fmt x -> pp fmt x.Asttypes.txt];
  │ 		 Longident.t  := Longident.t [@printer pp_longident]]]
  │ [@@deriving show]
  └────

  The expression-syntax of assignment is used to express type-expression
  rewrites.  And this is necesarily limited, because we cannot (for
  example) specify left-hand-sizes that are type-expressions with
  variables.  It's a perversion of the syntax, when what we really want
  to have is something that is precise: "map this type-expression to
  that type-expression".

  Now, with the new Ocaml 4.11.0 syntax, there's a (partial) solution:
  use "raw-string-extensions" like `{%foo|argle|}'.  This is the same as
  `[%foo {|argle|}]'.  This relies on the PPX extension to parse the
  payload.  But there are problems:

  1. Of course, there's no equivalent `{@foo|argle|}' (and "@@", "@@@"
     of course) for attributes.

  2. If the payload in that string doesn't *itself* correspond to some
     parseable Ocaml AST type, then again, we're stuck: we have to
     cobble together a parser instead of being able to merely extend the
     parser of Ocaml to deal with the case.

  Note well that I'm not saying that we should extend the parsing rules
  of the Ocaml language.  Rather, that with an *extensible parser*
  (hence, LL(1)) we can add new nonterminals, add rules that reference
  existing nonterminals, and thereby get an exact syntax (e.g.) for the
  `ppx_import' example above.  That new nonterminal is used *only* in
  parsing the payload – nowhere else – so we haven't introduced examples
  of objection #1 above.

  And it's not even very hard.


Macro Extensions with Pa_ppx
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The basic thesis of `pa_ppx' is "let's not throw the baby out with the
  bathwater".  Camlp5 has a lot of very valuable infrastructure that can
  be used to make writing macro-preprocessors much easier.  `pa_ppx'
  adds a few more.

  1. Quotations for patterns and expressions over all important OCaml
     AST types.

  2. "extensible functions" to make the process of recursing down the
     AST transparent, and the meaning of adding code to that process
     equally transparent.

  3. `pa_ppx' introduces "passes" and allows each extension to register
     which other extensions it must follow, and which may follow it;
     then `pa_ppx' topologically sorts them, so there's no need for
     project-authors to figure out how to order their PPX extension
     invocations.

  As an example of a PPX rewriter based on `pa_ppx', here's
  [pa_ppx.here] from the `pa_ppx' tutorial.  In that example, you'll see
  that Camlp5 infrastructure is used to make things easy:

  1. quotations are used to both build the output AST fragment, and to
     pattern-match on inputs.

  2. the "extensible functions" are used to add our little bit of
     rewriter to the top-down recursion.

  3. and we declare our rewriter to the infrastructure (we don't specify
     what passes it must come before or after, since `pa_ppx.here' is so
     simple).


[pa_ppx.here]
https://pa-ppx.readthedocs.io/en/latest/tutorial.html#an-example-ppx-rewriter-based-on-pa-ppx


Conclusion
╌╌╌╌╌╌╌╌╌╌

  I'm not trying to convince you to switch away from PPX to Camlp5.
  Perhaps, I'm not even merely arguing that you should use `pa_ppx' and
  author new macro-extensions on it.  But I *am* arguing that the
  features of

  1. quotations, with antiquotations in as many places as possible, and
     hence, *in places where Ocaml identifiers are not permitted*.

  2. facilities like "extensible functions", with syntax support for
     them

  3. a new AST type, that is suitable for macro-preprocessing, but isn't
     merely "s-expressions" (after all, there's a reason we all use
     strongly-typed languages)

  4. an extensible parser for the Ocaml language, usable in PPX
     attribute/extension payloads

  are important and valuable, and a PPX rewriter infrastructure that
  makes it possible for the masses to write their own macro-extensions,
  is going to incorporate these things.


OCaml 4.11.0, third (and last?) beta release
════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-4-11-0-third-and-last-beta-release/6149/1]


octachron announced
───────────────────

  The release of OCaml 4.11.0 is near.  As one step further in this
  direction, we have published a third and potentially last beta
  release.

  This new release fixes an infrequent best-fit allocator bug and an
  issue with floating-point software emulation in the ARM EABI port.  On
  the ecosystem side, merlin is now available for this new version of
  OCaml.  The compatibility of the opam ecosystem with OCaml 4.11.0 is
  currently good, and it should be possible to test this beta without
  too much trouble.

  The source code is available at these addresses:

  [https://github.com/ocaml/ocaml/archive/4.11.0+beta3.tar.gz]
  [https://caml.inria.fr/pub/distrib/ocaml-4.11/ocaml-4.11.0+beta3.tar.gz]

  The compiler can also be installed as an OPAM switch with one of the
  following commands:
  ┌────
  │ opam update
  │ opam switch create ocaml-variants.4.11.0+beta3 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam update
  │ opam switch create ocaml-variants.4.11.0+beta3+VARIANT --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where you replace VARIANT with one of these: afl, flambda, fp,
  fp+flambda

  We would love to hear about any bugs. Please report them here:
   [https://github.com/ocaml/ocaml/issues]

  Compared to the previous beta release, the exhaustive list of changes
  is as follows:


Runtime:
╌╌╌╌╌╌╌╌

  • [#9736], [#9749]: Compaction must start in a heap where all free
    blocks are blue, which was not the case with the best-fit
    allocator. (Damien Doligez, report and review by Leo White)

  • + [*new bug fixes*] [#9316], [#9443], [#9463], [#9782]: Use typing
    information from Clambda or mutable Cmm variables. (Stephen Dolan,
    review by Vincent Laviron, Guillaume Bury, Xavier Leroy, and Gabriel
    Scherer; temporary bug report by Richard Jones)


[#9736] https://github.com/ocaml/ocaml/issues/9736

[#9749] https://github.com/ocaml/ocaml/issues/9749

[#9316] https://github.com/ocaml/ocaml/issues/9316

[#9443] https://github.com/ocaml/ocaml/issues/9443

[#9463] https://github.com/ocaml/ocaml/issues/9463

[#9782] https://github.com/ocaml/ocaml/issues/9782


Manual and documentation:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#9541]: Add a documentation page for the instrumented runtime;
    additional changes to option names in the instrumented
    runtime. (Enguerrand Decorne, review by Anil Madhavapeddy, Gabriel
    Scherer, Daniel Bünzli, David Allsopp, Florian Angeletti, and
    Sébastien Hinderer)

  Entries marked with "+" were already present in previous alphas, but
  they have been complemented by new bug fixes.

  If you are interested by the list of new features, and the nearly
  final list of bug fixes the updated change log for OCaml 4.11.0 is
  available at:

  [https://github.com/ocaml/ocaml/blob/4.11/Changes]


[#9541] https://github.com/ocaml/ocaml/issues/9541


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Frama-Clang 0.0.9 is out. Download it here.]


[OCaml Planet] http://ocaml.org/community/planet/

[Frama-Clang 0.0.9 is out. Download it here.]
http://frama-c.com/index.html


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-07-21 14:42 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-07-21 14:42 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of July 14 to 21,
2020.

Table of Contents
─────────────────

Dune-release: version 1.4.0 released
Using AF_XDP sockets for high-performance packet processing in OCaml
Ubase 0.03
clangml 4.2.0: OCaml bindings for Clang API (for C and C++ parsing)
Old CWN


Dune-release: version 1.4.0 released
════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/dune-release-version-1-4-0-released/6103/1]


Sonja Heinze announced
──────────────────────

  This post is about [dune-release], a tool that helps users release
  their packages to Opam in a fast and organized manner. You can install
  it via `opam install dune-release'.

  On behalf of the dune-release team at Tarides, I'm happy to announce
  the new dune-release [1.4.0 release]. The release includes two new
  subcommands described below and a variety of bug fixes and user
  experience improvements. In particular, we've put some work into
  improving the error handling and reporting.

  One of the new subcommands is `dune-release config' , which inspects
  and edits dune-release's global configuration, such as git related,
  opam related and github related data. For example, if you insert a
  typo when being asked for your github id during your first release
  with dune-release, you can correct it comfortably with that new
  subcommand.

  The other new subcommand is `dune-release delegate-info', which helps
  users with an alternative release workflow to integrate dune-release
  into it: imagine you want to use dune-release only for a couple of
  things, such as tagging the distribution and creating the distribution
  tarball and the documentation.  In that case, now you can integrate
  the work done by dune-release into your individual release workflow by
  accessing the path to the created tarball etc via `dune-release
  delegate-info'. It forms part of the broader change in progress
  described in the following post:
  [https://discuss.ocaml.org/t/replacing-dune-release-delegates/4767]


[dune-release] https://github.com/ocamllabs/dune-release/#readme

[1.4.0 release]
https://github.com/ocamllabs/dune-release/releases/tag/1.4.0


Using AF_XDP sockets for high-performance packet processing in OCaml
════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/using-af-xdp-sockets-for-high-performance-packet-processing-in-ocaml/6106/1]


suttonshire announced
─────────────────────

  I just wanted to share a fun result from a project I've been hacking
  on.  [ocaml-xsk] is a binding to AF_XDP interface of libbpf.

  AF_XDP is an address family in Linux for high-performance packet
  processing. With an AF_XDP socket a packet bypasses most of the kernel
  networking stack and is passed directly to userspace program.
  Depending on the configuration packets can be passed from the NIC
  without any data copies on either Rx or Tx. If you're interested in
  this kind of stuff here are a couple very useful resources:

  • [https://github.com/torvalds/linux/blob/master/Documentation/networking/af_xdp.rst]
  • [https://github.com/xdp-project/xdp-tutorial/tree/master/advanced03-AF_XDP]

  The cool part is that without installing large dependencies like DPDK
  you can get packets into your program basically as fast as your NIC
  can provide them! It turns out this is true even if your program is
  written in OCaml. Using ocaml-xsk I could receive or transmit 64 byte
  UDP packets at 14.8M packets per second. This is the limit for a
  10Gb/s NIC.

  I'm still trying to figure out the best interface for AF_XDP. There
  are several resources to manage, and simple receive and transmit
  operations actually require a few steps. But it's encouraging know
  OCaml doesn't get in the way of packet throughput.


[ocaml-xsk] https://github.com/suttonshire/ocaml-xsk


Ubase 0.03
══════════

  Archive: [https://discuss.ocaml.org/t/ann-ubase-0-03/6115/1]


sanette announced
─────────────────

  I'm happy to announce the release of [ubase], a tiny library whose
  only purpose is to remove diacritics (accents, etc.) from utf8-encoded
  strings using the latin alphabet.

  It was created after the discussion:
  [https://discuss.ocaml.org/t/simplify-roman-utf8/4398].

  It's now available from `opam':

  `opam install ubase'

  This also installs an executable that you may use in a shell, for
  instance:

  ┌────
  │ $ ubase "et grønt træ"
  │ et gront trae
  │ 
  │ $ ubase Anh xin lỗi các em bé vì đã đề tặng cuốn sách này cho một ông người lớn.
  │ Anh xin loi cac em be vi da de tang cuon sach nay cho mot ong nguoi lon.
  └────

  More info [here].


[ubase] https://github.com/sanette/ubase

[here] https://sanette.github.io/ubase/


clangml 4.2.0: OCaml bindings for Clang API (for C and C++ parsing)
═══════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-clangml-4-2-0-ocaml-bindings-for-clang-api-for-c-and-c-parsing/6123/1]


Thierry Martinez announced
──────────────────────────

  We are happy to announce the new clangml 4.2.0 release.  Clangml
  provides bindings for all versions of Clang, from 3.4 to the not yet
  released 10.0.1.

  The library can be installed via opam: `opam install clangml' The
  documentation is online:
  [https://memcad.gitlabpages.inria.fr/clangml/]

  This new release improves C++ support, including C++20 specific
  constructs.

  All Clang C/C++ attributes should now be supported.  You may have a
  look to the interface of the new auto-generated module [`Attributes'].

  There is now a lazy version of the AST (`Clang.Lazy.Ast'): this is
  useful to explore large ASTs efficiently (note that Clang parsing
  itself can still be slow; the lazy part only concerns the conversion
  into the `Clang.Lazy.Ast' datatypes).


[`Attributes']
https://memcad.gitlabpages.inria.fr/clangml/doc/clangml/Clang__/Attributes/


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-07-14  9:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-07-14  9:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of July 07 to 14,
2020.

Table of Contents
─────────────────

OCaml 4.11.0, second beta release
letters - simple client abstractions for sending emails over SMTP
A question about Ocaml
Alcotest 1.2.0
Set up OCaml 1.1.0
Old CWN


OCaml 4.11.0, second beta release
═════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-4-11-0-second-beta-release/6063/1]


octachron announced
───────────────────

  The release of OCaml 4.11.0 is approaching.  As one step further in
  this direction, we have published a second beta release. This new
  release fixes an MSVC-specific runtime issue.

  The compatibility of the opam ecosystem with OCaml 4.11.0 is currently
  quite good with only 7 packages not currently available, and it should
  be possible to test this beta without too much trouble.

  The source code is available at these addresses:

  [https://github.com/ocaml/ocaml/archive/4.11.0+beta2.tar.gz]
  [https://caml.inria.fr/pub/distrib/ocaml-4.11/ocaml-4.11.0+beta2.tar.gz]

  The compiler can also be installed as an OPAM switch with one of the
  following commands:
  ┌────
  │ opam switch create ocaml-variants.4.11.0+beta2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.11.0+beta2+<VARIANT> --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────

  where you replace <VARIANT> with one of these: afl, flambda, fp,
  fp+flambda

  We would love to hear about any bugs. Please report them here:
   [https://github.com/ocaml/ocaml/issues]

  If you are interested by the list of new features, and the on-going
  list of bug fixes the updated change log for OCaml 4.11.0 is available
  at:

  [https://github.com/ocaml/ocaml/blob/4.11/Changes]

  Compared to the previous beta release, the exhaustive list of changes
  is as follows:


Runtime
╌╌╌╌╌╌╌

  • [#9714], [#9724]: Use the C++ alignas keyword when compiling in
    C++. Fixes a bug with MSVC C++ 2015/2017. Add a terminator to the
    `caml_domain_state' structure to better ensure that members are
    correctly spaced. (Antonin Décimo, review by David Allsopp and
    Xavier Leroy)


[#9714] https://github.com/ocaml/ocaml/issues/9714

[#9724] https://github.com/ocaml/ocaml/issues/9724


Manual and documentation
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#8644]: fix formatting comment about @raise in stdlib's mli files
    (Élie Brami, review by David Allsopp)

  • [#9712]: Update the version format to allow "`". The new format is
    "major.minor[.patchlevel][(+|')additional-info]", for instance
    "4.12.0~beta1+flambda". This is a documentation-only change for the
    4.11 branch, the new format will be used starting with the 4.12
    branch. (Florian Angeletti, review by Damien Doligez and Xavier
    Leroy)


[#8644] https://github.com/ocaml/ocaml/issues/8644

[#9712] https://github.com/ocaml/ocaml/issues/9712


letters - simple client abstractions for sending emails over SMTP
═════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-letters-simple-client-abstractions-for-sending-emails-over-smtp/6071/1]


Miko announced
──────────────

  Earlier today I've published the first release of [letters]. This
  library aims to provide simple to use client library for sending
  emails over SMTP using _lwt_ for async execution.

  It is build on top of _mrmime_ and _colombe_. While these libraries
  are very capable, they aren't that simple to use, _letters_ is trying
  to fill that gap. Anyway, big thanks for the authors of these projects
  for doing the heavy lifting.

  As this library is still in its early stage, I believe I will break
  the API with first few releases.  Luckily the API is quite simple so
  following these changes should be quite easy.

  To make this library awesome, any feedback or feature request is
  welcome. I'll try to address them as quickly as I can.

  I hope I've managed to scratch someone else's itch too, enjoy.


[letters] https://github.com/oxidizing/letters


A question about Ocaml
══════════════════════

  Archive: [https://discuss.ocaml.org/t/a-question-about-ocaml/6075/21]


Deep in this theard, Yawar Amin said
────────────────────────────────────

  A few ReasonML books:

  • [Web Development With ReasonML]
  • [Exploring ReasonML] (free online)
  • [Learn Type-Driven Development] (co-authored by me)


[Web Development With ReasonML] https://pragprog.com/titles/reasonml/

[Exploring ReasonML] http://reasonmlhub.com/exploring-reasonml/toc.html

[Learn Type-Driven Development]
https://www.packtpub.com/application-development/learn-type-driven-development


Alcotest 1.2.0
══════════════

  Archive: [https://discuss.ocaml.org/t/ann-alcotest-1-2-0/6089/1]


Craig Ferguson announced
────────────────────────

  I'm pleased to announce the release of [Alcotest] 1.2.0, now available
  on Opam.

  This release includes:
  • a new `alcotest-mirage' package for running tests on MirageOS;
  • full UTF-8 support;
  • default coloured output in Dune (without needing to pass
    `--no-buffer');
  • an improved output format.

  The full changelog is available [here].

  [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/ac89cfe4dfeed063560212136c9e2b690a888b6c.png]

  Thanks to our many contributors in this release cycle.


[Alcotest] https://github.com/mirage/alcotest/

[here] https://github.com/mirage/alcotest/blob/1.2.0/CHANGES.md


Set up OCaml 1.1.0
══════════════════

  Archive: [https://discuss.ocaml.org/t/ann-set-up-ocaml-1-1-0/6093/1]


Sora Morimoto announced
───────────────────────

  This release contains these changes:

  • The default opam repository can now be set via input.
  • Linux VMs now use opam 2.0.7.

  [https://github.com/avsm/setup-ocaml/releases/tag/v1.1.0]


Sora Morimoto then added
────────────────────────

  In fact, this release was a long time ago, but I completely forgot to
  post this. By the way, we have made significant improvements to some
  of the documentation. In particular, the action versioning section is
  applicable to other GitHub Actions and definitely worth reading!
  [https://github.com/avsm/setup-ocaml#how-to-specify-the-version]


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-07-07 10:04 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-07-07 10:04 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp


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Hello

Here is the latest OCaml Weekly News, for the week of June 30 to July
07, 2020.

Table of Contents
─────────────────

Releases of ringo
Multicore OCaml: June 2020
Time expression demo
Interactive OCaml development with utop in Emacs
Old CWN


Releases of ringo
═════════════════

  Archive: [https://discuss.ocaml.org/t/ann-releases-of-ringo/5605/5]


Continuing this thread, Raphaël Proust said
───────────────────────────────────────────

  Ringo provides bounded-size key-value stores. More specifically, it
  provides a functor similar to `Hastbl.Make' except that the number of
  bindings held by the tables is limited: inserting additional bindings
  when the limit has been reached causes some previously inserted
  binding to be removed.

  More more specifically, Ringo provides a function `map_maker' that
  takes parameters to customise the policies that determine the
  behaviour of the cache when supernumerary bindings are inserted, and
  returns the functor described above. Once a module `Cache' is
  instantiated using this functor, it can be used as follows:

  ┌────
  │ let cache = Cache.create size
  │ let fetch_data uri =
  │   match Cache.find_opt cache uri with
  │   | Some data -> data
  │   | None ->
  │     let data = really_fetch_data uri in
  │     Cache.replace cache uri data;
  │     data
  └────

  The cache will only hold up to [size] bindings, which avoids leaking
  memory. Additionally, the parameters for `map_maker' allow you to
  customise:

  • The replacement policy: which binding is removed when a
    supernumerary is inserted (currently supports least-recently used
    and first-in first-out).
  • The overflow policy: whether the cache can weakly hold some
    supernumerary elements (if so, the cache may hold more but the GC
    can always collect them if space is lacking).
  • The accounting precision: whether to keep precise track of
    removed/replaced elements.

  In addition, Ringo also provide set-caches: i.e., sets (rather than
  maps) with bounded size and all the same properties as above.

  Also note Ringo-Lwt (`ringo-lwt') provides Lwt wrappers around Ringo
  caches.

  If you have suggestions for a different concise synopsis for `opam',
  feel free to send them this way.

  Use cases are, I guess, caches. In particular those that might receive
  many elements not all of which you can hold in memory. We use it in a
  few places in the Tezos project to hold resources (blocks, operations,
  etc.) that are fetched from the P2p layer: it avoids having to fetch
  them again from the network.

  I think `anycache', `lru', and `lru-cache' are all alternatives
  available on opam.


Raphaël Proust later added
──────────────────────────

  The documentation is now available online at
  [https://nomadic-labs.gitlab.io/ringo/index.html]

  Of particular interest:
  • [The signature for a `ringo' key-value cache]
  • [The entry point for the `ringo' library] (allowing you to
    instantiate modules with the above signature as well as simple value
    caches)
  • [The signature for `ringo-lwt' cache]


[The signature for a `ringo' key-value cache]
https://nomadic-labs.gitlab.io/ringo/ringo/Ringo/module-type-CACHE_MAP/index.html

[The entry point for the `ringo' library]
https://nomadic-labs.gitlab.io/ringo/ringo/Ringo/index.html

[The signature for `ringo-lwt' cache]
https://nomadic-labs.gitlab.io/ringo/ringo-lwt/Ringo_lwt/Sigs/module-type-CACHE_MAP/index.html


Multicore OCaml: June 2020
══════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/multicore-ocaml-june-2020/6047/1]


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the June 2020 [Multicore OCaml] report! As with [previous
  updates], many thanks to @shakthimaan and @kayceesrk for collating the
  updates for the month of June 2020. /This is an incremental update;
  new readers may find it helpful to flick through the previous posts
  first./

  This month has seen a tremendous surge of activity on the upstream
  OCaml project to prepare for multicore integration, as @xavierleroy
  and the core team have driven a number of initiatives to prepare the
  OCaml project for the full multicore featureset.  To reflect this,
  from next month we will have a status page on the ocaml-multicore wiki
  with the current status of both our multicore branch and the upstream
  OCaml project itself.

  Why not from this month? Well, there's good news and bad news.  [Last
  month], I observed that we are a PR away from most of the opam
  ecosystem working with the multicore branch.  The good news is that we
  are still a single PR away from it working, but it's a different one
  :-) The retrofitting of the `Threads' library has brought up [some
  design complexities], and so rather than putting in a "bandaid" fix,
  we are integrating a comprehensive solution that will work with system
  threads, domains and (eventually) fibres.  That work has taken some
  time to get right, and I hope to be able to update you all on an
  opam-friendly OCaml 4.10.0+multicore in a few weeks.

  Aside from this, there have been a number of other improvements going
  into the multicore branches: [mingw Windows support], [callstack
  improvements], [fixing the Unix module] and so on. The full list is in
  the detailed report later in this update.


[Multicore OCaml] https://github.com/ocaml-multicore/ocaml-multicore

[previous updates] https://discuss.ocaml.org/tag/multicore-monthly

[Last month]
https://discuss.ocaml.org/t/multicore-ocaml-may-2020-update/5898

[some design complexities]
https://github.com/ocaml-multicore/ocaml-multicore/pull/342

[mingw Windows support]
https://github.com/ocaml-multicore/ocaml-multicore/pull/351

[callstack improvements]
https://github.com/ocaml-multicore/ocaml-multicore/pull/363

[fixing the Unix module]
https://github.com/ocaml-multicore/ocaml-multicore/pull/346

Sandmark benchmarks
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  A major milestone in this month has been the upgrade to the latest
  dune.2.6.0 to build Multicore OCaml 4.10.0 for the Sandmark
  benchmarking project. A number of new OPAM packages have been added,
  and the existing packages have been upgraded to their latest
  versions. The Multicore OCaml code base has seen continuous
  performance improvements and enhancements which can be observed from
  the various PRs mentioned in the report.

  We would like to thank:

  • @xavierleroy for working on a number of multicore-prequisite PRs to
    make stock OCaml ready for Multicore OCaml.
  • @camlspotter has reviewed and accepted the camlimages changes and
    made a release of camlimages.5.0.3 required for Sandmark.
  • @dinosaure for updating the decompress test benchmarks for Sandmark
    to build and run with dune.2.6.0 for Multicore OCaml 4.10.0.

  A chapter on Parallel Programming in Multicore OCaml with topics on
  task pool, channels section, profiling with code examples is being
  written. We shall provide an early draft version of the document to
  the community for your valuable feedback.


Papers
╌╌╌╌╌╌

  Our "Retrofitting Parallism onto OCaml" paper has been officially
  accepted at [ICFP 2020] which will be held virtually between August
  23-28, 2020. A [preprint] of the paper was made available earlier, and
  will be updated in a few days with the camera-ready version for ICFP.
  Please do feel free to send on comments and queries even after the
  paper is published, of course.

  Excitingly, another multicore-related paper on [Cosmo: A Concurrent
  Separation Logic for Multicore OCaml] will also be presented at the
  same conference.

  The Multicore OCaml updates are first listed in our report, which are
  followed by improvements to the Sandmark benchmarking
  project. Finally, the changes made to upstream OCaml which include
  both the ongoing and completed tasks are mentioned for your reference.


[ICFP 2020]
https://icfp20.sigplan.org/track/icfp-2020-papers#event-overview

[preprint] https://arxiv.org/abs/2004.11663

[Cosmo: A Concurrent Separation Logic for Multicore OCaml]
http://gallium.inria.fr/~fpottier/publis/mevel-jourdan-pottier-cosmo-2020.pdf


Multicore OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

◊ Ongoing

  • [ocaml-multicore/ocaml-multicore#339] Proposal for domain-local
    storage

    An RFC proposal to implement a domain-local storage in Multicore
    OCaml. Kindly review the idea and share your feedback!

  • [ocaml-multicore/ocaml-multicore#342] Implementing the threads
    library with Domains

    An effort to rebase @jhwoodyatt's implementation of the Thread
    library for Domains.

  • [ocaml-multicore/ocaml-multicore#357] Implementation of systhreads
    with pthreads

    Exploring the possibilty of implementing systhreads with pthreads,
    while still maintaining compatibility with the existing solution.

  • [ocaml/dune#3548] Dune fails to pick up secondary compiler

    The `ocaml-secondary-compiler' fails to install with
    dune.2.6.0. This is required as Multicore OCaml cannot build the
    latest dune without systhreads support.


  [ocaml-multicore/ocaml-multicore#339]
  https://github.com/ocaml-multicore/ocaml-multicore/issues/339

  [ocaml-multicore/ocaml-multicore#342]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/342

  [ocaml-multicore/ocaml-multicore#357]
  https://github.com/ocaml-multicore/ocaml-multicore/issues/357

  [ocaml/dune#3548] https://github.com/ocaml/dune/issues/3548


◊ Completed

  • [ocaml-multicore/multicore-opam#22] Update dune to 2.6.0

    The dune version in the Multicore OPAM repository is now updated to
    use the latest 2.6.0.

  • [ocaml-multicore/ocaml-multicore#338] Introduce Lazy.try_force and
    Lazy.try_force_val

    An implementation of `Lazy.try_force' and `Lazy.try_force_val'
    functions to implement concurrent lazy abstractions.

  • [ocaml-multicore/ocaml-multicore#340] Fix Atomic.exchange in
    concurrent_minor_gc

    A patch that introduces `Atomic.exchange' through `Atomic.get' that
    provides the appropriate read barrier for correct exchange semantics
    for `caml_atomic_exchange' in `memory.c'.

  • [ocaml-multicore/ocaml-multicore#343] Fix extcall noalloc DWARF

    The DWARF information emitted for `extcall noalloc' had broken
    backtraces and this PR fixes the same.

  • [ocaml-multicore/ocaml-multicore#345] Absolute exception stack

    The representation of the exception stack is changed from relative
    addressing to absolute addressing and the results are promising. The
    Sandmark serial benchmark results after the change is illustrated in
    the following graph:

    [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/optimized/2X/b/b385409b3f9e44cbfef98de668b0b4d0ed403472_2_1380x436.png]

  • [ocaml-multicore/ocaml-multicore#347] Turn on -Werror by default

    Adds a `--enable-warn-error' option to `configure' to treat C
    compiler warnings as errors.

  • [ocaml-multicore/ocaml-multicore#353] Poll for interrupts in
    cpu_relax without locking

    Use `Caml_check_gc_interrupt' first to poll for interrupts without
    locking, and then proceeding to handle the interrupt with the lock.

  • [ocaml-multicore/ocaml-multicore#354] Add Caml_state_field to
    domain_state.h

    The `Caml_state_field' macro definition in domain_state.h is
    required for base-v0.14.0 to build for Multicore OCaml 4.10.0 with
    dune.2.6.0.

  • [ocaml-multicore/ocaml-multicore#355] One more location to poll for
    interrupts without lock

    Another use of `Caml_check_gc_interrupt' first to poll for
    interrupts without lock, similar to
    [ocaml-multicore/ocaml-multicore#353].

  • [ocaml-multicore/ocaml-multicore#356] Backup threads for domain

    Introduces `backup threads' to perform GC and handle service
    interrupts when the domain is blocked in the kernel.

  • [ocaml-multicore/ocaml-multicore#358] Fix up bad CFI information in
    amd64.S

    Add missing `CFI_ADJUST' directives in `runtime/amd64.S' for
    `caml_call_poll' and `caml_allocN'.

  • [ocaml-multicore/ocaml-multicore#359] Inline caml_domain_alone

    The PR makes `caml_domain_alone' an inline function to improve
    performance for `caml_atomic_cas_field' and other atomics in
    `memory.c'.

  • [ocaml-multicore/ocaml-multicore#360] Parallel minor GC inline mask
    rework

    The inline mask rework for the promotion path to the
    `parallel_minor_gc' branch gives a 3-5% performance improvement for
    `test_decompress' sandmark benchmark, and a decrease in the executed
    instructions for all other benchmarks.

  • [ocaml-multicore/ocaml-multicore#361] Mark stack push work credit

    The PR improves the Multicore mark work accounting to be in line
    with stock OCaml.

  • [ocaml-multicore/ocaml-multicore#362] Iloadmut does not clobber rax
    and rdx when we do not have a read barrier

    A code clean-up to free the registers `rax' and `rdx' for OCaml code
    when `Iloadmut' is used.


  [ocaml-multicore/multicore-opam#22]
  https://github.com/ocaml-multicore/multicore-opam/pull/22

  [ocaml-multicore/ocaml-multicore#338]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/338

  [ocaml-multicore/ocaml-multicore#340]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/340

  [ocaml-multicore/ocaml-multicore#343]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/343

  [ocaml-multicore/ocaml-multicore#345]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/345

  [ocaml-multicore/ocaml-multicore#347]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/347

  [ocaml-multicore/ocaml-multicore#353]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/353

  [ocaml-multicore/ocaml-multicore#354]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/354

  [ocaml-multicore/ocaml-multicore#355]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/355

  [ocaml-multicore/ocaml-multicore#356]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/356

  [ocaml-multicore/ocaml-multicore#358]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/358

  [ocaml-multicore/ocaml-multicore#359]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/359

  [ocaml-multicore/ocaml-multicore#360]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/360

  [ocaml-multicore/ocaml-multicore#361]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/361

  [ocaml-multicore/ocaml-multicore#362]
  https://github.com/ocaml-multicore/ocaml-multicore/pull/362


Benchmarking
╌╌╌╌╌╌╌╌╌╌╌╌

◊ Ongoing

  • [ocaml-bench/sandmark#8] Ability to run compiler variants in
    Sandmark

    A feature to specify configure options when building compiler
    variants such as `flambda' is useful for development and
    testing. This feature is being worked upon.

  • [ocaml-bench/sandmark#107] Add Coq benchmarks

    We are continuing to add more benchmarks to Sandmark for Multicore
    OCaml and investigating adding the [Coq] benchmarks to our
    repertoire!

  • [ocaml-bench/sandmark#124] User configurable paramwrapper added to
    Makefile

    A `PARAMWRAPPER' environment variable can be passed as an argument
    by specifying the `--cpu-list' to be used for parallel benchmark
    runs.

  • [ocaml-bench/sandmark#131] Update decompress benchmarks

    Thanks to @dinosaure for updating the decompress benchmarks in order
    to run them with dune.2.6.0 for Multicore OCaml 4.10.0.

  • [ocaml-bench/sandmark#132] Update dependency packages to use
    dune.2.6.0 and Multicore OCaml 4.10.0

    Sandmark has been running with dune.1.11.4, and we need to move to
    the latest dune.2.6.0 for using Multicore OCaml 4.10.0 and beyond,
    as mentioned in [Promote dune to > 2.0]. The PR updates over 30
    dependency packages and successfully builds both serial and parallel
    benchmarks!


  [ocaml-bench/sandmark#8]
  https://github.com/ocaml-bench/sandmark/issues/8

  [ocaml-bench/sandmark#107]
  https://github.com/ocaml-bench/sandmark/issues/107

  [Coq] https://coq.inria.fr/

  [ocaml-bench/sandmark#124]
  https://github.com/ocaml-bench/sandmark/pull/124

  [ocaml-bench/sandmark#131]
  https://github.com/ocaml-bench/sandmark/pull/131

  [ocaml-bench/sandmark#132]
  https://github.com/ocaml-bench/sandmark/pull/132

  [Promote dune to > 2.0]
  https://github.com/ocaml-bench/sandmark/issues/106


◊ Completed

  • [camlspotter/camlimages#1] Use dune-configurator instead of
    configurator for camlimages

    A new release of `camlimages.5.0.3' was made by @camlspotter after
    accepting the changes to camlimages.opam in order to build with
    dune.2.6.0.

  • [ocaml-bench/sandmark#115] Task API Port: LU-Decomposition, Floyd
    Warshall, Mandelbrot, Nbody

    The changes to use the `Domainslib.Task' API for the listed
    benchmarks have been merged.

  • [ocaml-bench/sandmark#121] Mention sudo access for
    run_all_parallel.sh script

    The README.md file has been updated with the necessary `sudo'
    configuration steps to execute the `run_all_parallel.sh' script for
    nightly builds.

  • [ocaml-bench/sandmark#125] Add cubicle benchmarks

    The `German PFS' and `Szymanski's mutual exclusion algorithm'
    cubicle benchmarks have been included in Sandmark.

  • [ocaml-bench/sandmark#126] Update ocaml-versions README to reflect
    4.10.0+multicore

    The README has now been updated to reflect the latest 4.10.0
    Multicore OCaml compiler and its variants.

  • [ocaml-bench/sandmark#129] Add target to run parallel benchmarks in
    the CI

    The .drone.yml file used by the CI has been updated to run both the
    serial and parallel benchmarks.

  • [ocaml-bench/sandmark#130] Add missing dependencies in
    multicore-numerical

    The `domainslib' library has been added to the dune file for the
    multicore-numerical benchmark.


  [camlspotter/camlimages#1]
  https://gitlab.com/camlspotter/camlimages/-/merge_requests/1

  [ocaml-bench/sandmark#115]
  https://github.com/ocaml-bench/sandmark/pull/115

  [ocaml-bench/sandmark#121]
  https://github.com/ocaml-bench/sandmark/pull/121

  [ocaml-bench/sandmark#125]
  https://github.com/ocaml-bench/sandmark/pull/125

  [ocaml-bench/sandmark#126]
  https://github.com/ocaml-bench/sandmark/pull/126

  [ocaml-bench/sandmark#129]
  https://github.com/ocaml-bench/sandmark/pull/129

  [ocaml-bench/sandmark#130]
  https://github.com/ocaml-bench/sandmark/pull/130


OCaml
╌╌╌╌╌

◊ Ongoing

  • [ocaml/ocaml#9541] Add manual page for the instrumented runtime

    The [instrumented runtime] has been merged to OCaml 4.11.0. A manual
    for the same has been created and is under review.

  • [sadigqj/ocaml#1] GC colours change

    This PR removes the grey colour used in stock OCaml to match the
    scheme used by the Multicore major collector. The performance and
    considerations are included for review.


  [ocaml/ocaml#9541] https://github.com/ocaml/ocaml/pull/9541

  [instrumented runtime] https://github.com/ocaml/ocaml/pull/9082

  [sadigqj/ocaml#1] https://github.com/sadiqj/ocaml/pull/1


◊ Completed

  • [ocaml/ocaml#9619] A self-describing representation for function
    closures

    The PR provides a way to record the position of the environment for
    each entry point for function closures.

  • [ocaml/ocaml#9649] Marshaling for the new closure representation

    The `output_value' marshaler has been updated to use the new closure
    representation. There is no change required for the `input_value'
    unmarshaler.

  • [ocaml/ocaml#9655] Introduce type Obj.raw_data and functions
    Obj.raw_field, Obj.set_raw_field to manipulate out-of-heap pointers

    The PR introduces a type `Obj.bits', and functions `Obj.field_bits'
    and `Obj.set_field_bits' to read and write bit representation of
    block fields to support the no-naked-pointer operation.

  • [ocaml/ocaml#9678] Reimplement Obj.reachable_word using a hash table
    to detect sharing

    The `caml_obj_reachable_words' now uses a hash table instead of
    modifying the mark bits of block headers to detect sharing. This is
    required for compatibility with Multicore OCaml.

  • [ocaml/ocaml#9680] Naked pointers and the bytecode interpreter

    The bytecode interpreter implementation is updated to support the
    no-naked-pointers mode operation as required by Multicore OCaml.

  • [ocaml/ocaml#9682] Signal handling in native code without the page
    table

    The patch uses the code fragment table instead of a page table
    lookup for signal handlers to know whether the signal came from
    ocamlopt-generated code.

  • [ocaml/ocaml#9683] globroots.c: adapt to no-naked-pointers mode

    The patch considers out-of-heap pointers as major-heap pointers in
    no-naked-pointers mode for global roots management.

  • [ocaml/ocaml#9689] Generic hashing for the new closure
    representation

    The hashing functions have been updated to use the latest closure
    representation from [ocaml/ocaml#9619] for the no-naked-pointers
    mode.

  • [ocaml/ocaml#9698] The end of the page table is near

    The PR eliminates some of the use of the page tables in the runtime
    system when built with no-naked-pointers mode.

  Our thanks to all the OCaml developers and users in the community for
  their continued support and contribution to the project. Stay safe!


  [ocaml/ocaml#9619] https://github.com/ocaml/ocaml/pull/9619

  [ocaml/ocaml#9649] https://github.com/ocaml/ocaml/pull/9649

  [ocaml/ocaml#9655] https://github.com/ocaml/ocaml/pull/9655

  [ocaml/ocaml#9678] https://github.com/ocaml/ocaml/pull/9678

  [ocaml/ocaml#9680] https://github.com/ocaml/ocaml/pull/9680

  [ocaml/ocaml#9682] https://github.com/ocaml/ocaml/pull/9682

  [ocaml/ocaml#9683] https://github.com/ocaml/ocaml/pull/9683

  [ocaml/ocaml#9689] https://github.com/ocaml/ocaml/pull/9689

  [ocaml/ocaml#9698] https://github.com/ocaml/ocaml/pull/9698


Acronyms
╌╌╌╌╌╌╌╌

  • API: Application Programming Interface
  • CFI: Call Frame Information
  • CI: Continuous Integration
  • DWARF: Debugging With Attributed Record Formats
  • GC: Garbage Collector
  • ICFP: International Conference on Functional Programming
  • OPAM: OCaml Package Manager
  • PR: Pull Request
  • RFC: Request for Comments


Time expression demo
════════════════════

  Archive: [https://discuss.ocaml.org/t/time-expression-demo/6052/1]


Darren announced
────────────────

  An interactive demo for a small part of our time stuff and schedule
  handling library is available here:
  [https://daypack-dev.github.io/time-expr-demo/]

  Time expression is in essence a language for specifying time points or
  time slots precisely and concisely, while trying to mimic natural
  language.

  The implementation of the demo core itself can be seen here:
  [https://github.com/daypack-dev/time-expr-demo/blob/master/src/demo.ml]
  , where the usage of Daypack-lib is shown.

  Lastly, the library is still a prototype, so expect some faults in the
  outputs of the demo here and there.


Interactive OCaml development with utop in Emacs
════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/interactive-ocaml-development-with-utop-in-emacs/6058/1]


Samarth Kishor announced
────────────────────────

  I made a [blog post] about REPL driven development with utop in Emacs
  a few months ago. Please let me know if you found it useful or have
  anything to add!  I'm a bit new to OCaml so any feedback helps.

  There was a [similar post about REPL driven development] last year and
  my post addresses a lot of those points. I wish I'd seen that post
  before I wrote this since there's a ton of useful information in the
  comments.


[blog post]
https://samarthkishor.github.io/posts/interactive_ocaml_development/

[similar post about REPL driven development]
https://discuss.ocaml.org/t/ocaml-repl-driven-development/4068


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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Hello

Here is the latest OCaml Weekly News, for the week of June 23 to 30,
2020.

Table of Contents
─────────────────

finch - static site generator
ANN: Releases of ringo
OCaml 4.11, first beta release
FlexDLL 0.38 released
Other OCaml News
Old CWN


finch - static site generator
═════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-finch-static-site-generator/6026/1]


roddy announced
───────────────

  Announcing [finch], a simple static site generator. It uses content
  written as Markdown plus YAML frontmatter like Jekyll/Hugo etc. and
  produces output with [Jingoo] templates. It also has some integrations
  with React (as in the JS library) in the form of Jingoo filters: the
  motivation behind it was to make it easier to develop sites that use
  React just for some in some parts rather than structuring the whole
  site as a single page application.


[finch] https://github.com/roddyyaga/finch

[Jingoo] https://github.com/tategakibunko/jingoo


ANN: Releases of ringo
══════════════════════

  Archive: [https://discuss.ocaml.org/t/ann-releases-of-ringo/5605/3]


Raphaël Proust announced
────────────────────────

  Version 0.5 of `ringo' and `ringo-lwt' are now available in
  `opam'. Although this version changes `ringo-lwt' only, both packages
  are released anew to keep the version numbers in sync. This version
  includes:

  • Improvement in documentation.
  • Simplifications and reduction in the memory footprint of lwt-wrapped
    caches.
  • Fix for a race condition in the automatic cleanup (previously, on
    weak caches only, a promise being rejected could cause a different
    promise to be removed from the cache)
  • Fix a leak
  • More test, including a test for leakiness.


OCaml 4.11, first beta release
══════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-4-11-first-beta-release/6042/1]


octachron announced
───────────────────

  The release of OCaml 4.11.0 is approaching.

  After three alpha releases, we have created a first beta version to
  help you adapt your software to the new features ahead of the release.

  The compatibility of the opam ecosystem with OCaml 4.11.0 is currently
  quite good, and it should be possible to test this beta without too
  much trouble.

  The source code is available at these addresses:

  [https://github.com/ocaml/ocaml/archive/4.11.0+beta1.tar.gz]
  [https://caml.inria.fr/pub/distrib/ocaml-4.11/ocaml-4.11.0+beta1.tar.gz]

  The compiler can also be installed as an OPAM switch with one of the
  following commands.
  ┌────
  │ opam switch create ocaml-variants.4.11.0+beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.11.0+beta1+VARIANT --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where you replace VARIANT with one of these: afl, flambda, fp,
  fp+flambda

  We want to know about all bugs. Please report them here:
   [https://github.com/ocaml/ocaml/issues]

  If you are interested by the list of new features, and the on-going
  list of bug fixes the updated change log for OCaml 4.11.0 is available
  at:

  [https://github.com/ocaml/ocaml/blob/4.11/Changes]

  Compared to the last alpha release, this first beta release contains
  the following new bug fixes:


Driver
╌╌╌╌╌╌

  • [#9011]: Allow linking .cmxa files with no units on MSVC by not
    requiring the .lib file to be present. (David Allsopp, report by
    Dimitry Bely, review by Xavier Leroy)


[#9011] https://github.com/ocaml/ocaml/issues/9011


Typechecker
╌╌╌╌╌╌╌╌╌╌╌

  • [#9384], [#9385]: Fix copy scope bugs in substitutions (Leo White,
    review by Thomas Refis, report by Nick Roberts)

  • [#9695], [#9702]: no error when opening an alias to a missing module
    (Jacques Garrigue, report and review by Gabriel Scherer)


[#9384] https://github.com/ocaml/ocaml/issues/9384

[#9385] https://github.com/ocaml/ocaml/issues/9385

[#9695] https://github.com/ocaml/ocaml/issues/9695

[#9702] https://github.com/ocaml/ocaml/issues/9702


Warnings
╌╌╌╌╌╌╌╌

  • [#7897], [#9537]: Fix warning 38 for rebound extension constructors
    (Leo White, review by Florian Angeletti)

  • [#9244]: Fix some missing usage warnings (Leo White, review by
    Florian Angeletti)


[#7897] https://github.com/ocaml/ocaml/issues/7897

[#9537] https://github.com/ocaml/ocaml/issues/9537

[#9244] https://github.com/ocaml/ocaml/issues/9244


Toplevel
╌╌╌╌╌╌╌╌

  • [#9415]: Treat `open struct' as `include struct' in toplevel (Leo
    White, review by Thomas Refis)

  • [#9416]: Avoid warning 58 in flambda ocamlnat (Leo White, review by
    Florian Angeletti)


[#9415] https://github.com/ocaml/ocaml/issues/9415

[#9416] https://github.com/ocaml/ocaml/issues/9416


Flambda backend
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#9163]: Treat loops properly in un_anf (Leo White, review by Mark
    Shinwell, Pierre Chambart and Vincent Laviron)


[#9163] https://github.com/ocaml/ocaml/issues/9163


FlexDLL 0.38 released
═════════════════════

  Archive: [https://discuss.ocaml.org/t/flexdll-0-38-released/6043/1]


David Allsopp announced
───────────────────────

  We are pleased to announce the release of FlexDLL 0.38!

  FlexDLL provides a dlopen-like interface for Windows and is used to
  simplify the linking process for the native Windows ports of OCaml and
  to allow dynamic loading of C code (bytecode stub libraries and native
  Dynlink). It is also used for the same purpose in the Cygwin ports of
  OCaml, except that they can be configured without shared library
  support.

  The release includes various bugfixes as well as proper support for
  C++ linking on mingw and linking against data symbols in import
  libraries.

  Please see the [release page] for more information.


[release page] https://github.com/alainfrisch/flexdll/releases/tag/0.38


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Frama-C 21.1 (Scandium) is out. Download it here.]


[OCaml Planet] http://ocaml.org/community/planet/

[Frama-C 21.1 (Scandium) is out. Download it here.]
http://frama-c.com/index.html


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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@ 2020-06-16  8:36 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-06-16  8:36 UTC (permalink / raw)
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Hello

Here is the latest OCaml Weekly News, for the week of June 09 to 16,
2020.

Table of Contents
─────────────────

First release of monolith
Sylvain Conchon joined OCamlPro's team
First release of streaming
Senior software engineer at Asemio in Tulsa, OK
Other OCaml News
Old CWN


First release of monolith
═════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-first-release-of-monolith/5946/1]


François Pottier announced
──────────────────────────

  It is my pleasure to announce the first release of Monolith.

  Monolith offers facilities for testing an OCaml library (for instance,
  a data structure implementation) by comparing it against a reference
  implementation.  It uses a form of black-box testing, and relies on
  `afl-fuzz' for efficiency.

  The user must describe what types and operations the library
  provides. Under the best circumstances, this requires 2-3 lines of
  code per type or operation.  The user must also provide a reference
  implementation of the library.

  Then, like a monkey typing on a keyboard, Monolith attempts to
  exercise the library in every possible way, in the hope of discovering
  a scenario where the library behaves incorrectly. If such a scenario
  is discovered, it is printed in the form of an OCaml program, so as to
  help the user reproduce the problem.

  At this time, a tutorial is not yet available. There is however an API
  documentation and a number of demos.

  Repository: [https://gitlab.inria.fr/fpottier/monolith]

  API Documentation:
    [http://cambium.inria.fr/~fpottier/monolith/doc/monolith/Monolith/index.html]

  Installation:
  ┌────
  │ opam update
  │ opam install monolith
  └────


Sylvain Conchon joined OCamlPro's team
══════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/sylvain-conchon-joined-ocamlpros-team/5956/1]


OCamlPro announced
──────────────────

  Sylvain Conchon joined OCamlPro's team as Formal Methods CSO. He
  created Alt-Ergo and has been teaching OCaml in universities for about
  20 years. He shares thoughts on interactions between industry and
  research labs, and his vision of Formal methods and OCaml as language
  for the industry. Read his interview on our blog:
  [https://www.ocamlpro.com/2020/06/05/interview-sylvain-conchon-cso-on-formal-methods/]


First release of streaming
══════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-first-release-of-streaming/5961/1]


Rizo announced
──────────────

  It is my pleasure to announce the first public release of `streaming'
  – a library for building efficient, incremental data processing
  pipelines that compose and don't leak resources.

  I built streaming as a result of many experiments with different
  streaming and iteration models for OCaml. There are multiple packages
  on OPAM that share some of the goals of `streaming' (we even have
  `Stdlib.Seq' now!), but none of them combine (1) excellent
  performance, (2) safe resource handling and (3) pure functional style
  for combinators.  Streaming solves these problems by implementing
  three basic and independent models: _sources_, _sinks_ and _flows_ –
  they represents different parts of the pipeline that correspond to
  producing, consuming and transforming elements.  These models can be
  defined and composed independently to produce reusable "streaming
  blocks".

  The library defines a central `Stream' model that relies on sources,
  sinks and flows. This model is a push-based iterator with performance
  characteristics similar to the `iter' iterator, which has type `('a ->
  unit) -> unit', and is known for being very efficient. But unlike
  `iter', it has a pure functional core (no need to use mutable state
  and exceptions for flow control!) and can handle resource allocation
  and clean up in a lazy and deterministic way. All of this while having
  a slightly better performance for common stream operations.

  For those who are curious about the performance characteristics of
  `streaming' and other models, I created a dedicated repository for
  stream benchmarks: [https://github.com/rizo/streams-bench]. In
  particular, it includes a few simple benchmarks for `Gen',
  `Base.Sequence', `Stdlib.Seq', `Iter', `Streaming.Stream' and
  `Streaming.Source'.

  The library should soon be published on opam. In the meantime, I
  invite you to read the docs and explore the code:

  • Library documentation: [https://odis-labs.github.io/streaming]
  • Github project: [https://github.com/odis-labs/streaming]


Guillaume Bury askec
────────────────────

  That's great ! From the benchmarks, it looks like you hit a really
  good implementation !

  I've looked (maybe a bit fast) at the API documentation, and it is
  admittedly a bit outside the scope of streams/iterators, but I was
  wondering if there was some proper way to:
  • connect a sink to a source to create some loop
  • have some kind of fixpoint on streams

  I guess it would always be possible to use some references and/or some
  complex functions to encode these into the provided API, but I was
  wondering if there was a clean way to do it.

  For a bit of context and explanation, what I have in mind is the case
  of a program (let's say a type-checker or something close to the idea)
  with a *persistent state*, that should operate over a stream of
  inputs, which are top-level phrases, and produce some outputs, for
  instance print some result for each correctly type-checked statement
  (and an error otherwise).  The type-checker would basically be a
  function of type `(`input * `state) -> (`output * `state)', and
  starting from an initial state, it would process an input element
  (giving the output to some sink), and then the next input element
  would be processed with the state that was reached after processing
  the previous element: the state would reach the sink of the flow, and
  then be inserted back into the source.  Separately, imagine the
  language being type-checked has a notion of include, then one of the
  step of the flow would be to expand each include into a stream of
  inputs/phrases, but each of the phrases in this stream would need to
  be expanded, so a simple `flat_map~/~flatten' is not enough.

  I already have a custom implementation that handle these features, but
  I was wondering whether I could use `streaming' to handle most of the
  code linking all of the steps, ^^


Rizo replied
────────────

        if there was some proper way to:
        • connect a sink to a source to create some loop
        • have some kind of fixpoint on streams

  Regarding the first point: yes! That's exactly the point of the
  `Stream' module. You see, sources are pull-based abstractions, while
  sinks are push-based. Source's type essentially says something like
  _"I might give you some data, if you ask"_, while sink's type is the
  opposite _"I might take some data, if you give it to me"_. They are
  completely and intentionally decoupled; it is Stream's role to drive
  the computation by pulling data from sources and pushing it into
  sinks. So the easiest way to connect them is:

  ┌────
  │ Stream.(from srouce |> into sink)
  └────

  Of course, that's not very useful per se, but it illustrates my
  point. Take a look at the [`Stream.from'] code to see the
  implementation of the loop you're asking for. It does some extra work
  to ensure that resources are correctly handled, but it should be clear
  what the loop is doing.

  The stream types in the library are currently abstract because I
  didn't want to commit to a particular representation just yet. If this
  is a problem for your use case, let me know, I'll expose them in a
  `Private' module.

  Regarding the second point: I'm not sure what you mean in practice by
  "fixpoint on streams". I guess the one thing that could help implement
  something like that is the [`Stream.run'] function. It allows you to
  continue reading elements from a source even after a sink is filled by
  returning a leftover stream.  This stream can be used with
  `Stream.run' repeatedly.

  Alternatively there's also [`Flow.through'], which consumes input
  trying to fill sinks repeatedly and produces their aggregated values
  as a stream. Super useful for things like streaming parsing. Might
  even help with your use-case for top-level phrases.

  On a more general note though, the type `('input * 'state) -> ('output
  * 'state)' looks a lot like a [mealy machine]. `Streaming.Sink' is a
  [moore machine], which is slightly less general because the output
  values do not depend on input values, only on the state.

  I thought about exposing different kinds of sinks in streaming, but
  wanted to make sure that the common use cases are covered first. I'll
  keep your case in mind for future versions of the library.


[`Stream.from']
https://github.com/odis-labs/streaming/blob/0.8.0/lib/Stream.ml#L42

[`Stream.run']
https://odis-labs.github.io/streaming/streaming/Streaming/Stream/index.html#val-run

[`Flow.through']
https://odis-labs.github.io/streaming/streaming/Streaming/Flow/index.html#val-through

[mealy machine] https://en.wikipedia.org/wiki/Mealy_machine

[moore machine] https://en.wikipedia.org/wiki/Moore_machine


Senior software engineer at Asemio in Tulsa, OK
═══════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/senior-software-engineer-at-asemio-in-tulsa-ok/5979/1]


Simon Grondin announced
───────────────────────

  We are Asemio and our team of data scientists, software engineers,
  architects, and management consultants are working together to achieve
  a nationwide data ecosystem for social good.

  You’ll be working on the Asemio Community Integration Platform. It
  features state-of-the-art privacy-preserving, pre-processing and
  pipeline management, as well as record linkage technology.

  The back end is written in OCaml. The front end is compiled from OCaml
  to JavaScript and uses a modern MVC framework.  The work you’ll be
  doing will touch numerous technical disciplines, including
  cryptography, distributed systems, language design and implementation,
  data analytics, and data visualizations.

  We prefer candidates willing to relocate, but we could make an
  exception for an exceptional candidate.

  For more information or to apply, please refer to our SE listing:
  [https://stackoverflow.com/jobs/401383/ocaml-senior-software-engineer-asemio]


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Frama-C 21.0 (Scandium) is out. Download it here.]
  • [Every proof assistant: Epigram 2 - Autopsy, Obituary, Apology]


[OCaml Planet] http://ocaml.org/community/planet/

[Frama-C 21.0 (Scandium) is out. Download it here.]
http://frama-c.com/index.html

[Every proof assistant: Epigram 2 - Autopsy, Obituary, Apology]
http://math.andrej.com/2020/06/09/epigram-2-autopsy-obituary-apology/


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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@ 2020-06-09  8:28 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-06-09  8:28 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of June 02 to 09,
2020.

Table of Contents
─────────────────

Multicore Update: April 2020, with a preprint paper
BAP 2.1.0 Release
Migrating an Async project to Lwt, a short primer
jose 0.4.0
OCaml 4.11.0, second alpha release
OCaml Workshop 2020: Call for Volunteers
Introduction to Lwt
Other OCaml News
Old CWN


Multicore Update: April 2020, with a preprint paper
═══════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/multicore-update-april-2020-with-a-preprint-paper/5630/26]


Continuing this thread, Daniel Bünzli asked and KC Sivaramakrishnan replied
───────────────────────────────────────────────────────────────────────────

        One thing that I didn’t get from the paper is how exactly
        `ConcurMinor' breaks the current FFI and the impact it
        would have on the existing eco-system, on a scale from “it
        affect all projects” to “only people doing *that* fancy
        thing” :–) ?

  All the projects that use the C API. The details are here:
  [https://github.com/ocaml-multicore/ocaml-multicore/wiki/C-API-changes]

        At the end of the paper it seems you make the point that
        `ParMinor' is the solution to go with for the time
        being. Does this means you are going to leave behind the
        work done on `ConcurMinor' or do you intend to continue to
        maintain it ?

  We don't intend to maintain it. It is quite a bit of work to maintain
  and port the changes across two different GCs.  `ParMinor' GC is now
  at 4.11 branch point (the default multicore compiler is 4.10 +
  ParMinor now). The `ConcMinor' is at 4.06.1.

  Given that `ConcMinor' breaks the C API, the ecosystem would have to
  be fixed for `ConcMinor' to be useful. The code changes are indeed
  intricate; the differences are not just in the minor GC, but the
  compilers internal use of the C API. It will be quite a bit of work to
  keep both GCs in the same source distribution.


Guillaume Munch-Maccagnoni then said
────────────────────────────────────

        Given that `ConcMinor' breaks the C API, the ecosystem
        would have to be fixed for `ConcMinor' to be useful.

  I do not think this is necessarily true.

  Here is why I think so, but be warned that this is preliminary as I do
  not have time to explore this idea further on my own at the moment.


State in Rust
╌╌╌╌╌╌╌╌╌╌╌╌╌

  Breaking the C API is a consequence of deciding that all
  single-threaded shared mutable state must assume they are also shared
  between threads. So a new read barrier is used to promote values when
  read from another thread. But for data types that were correct up to
  now, users must also be careful to avoid races from now on… for
  instance by avoiding sharing values of such types between domains.

  One lesson of Rust is that there are different kinds of mutable state,
  for different usages, with different means to achieve thread-safety.

  The closest there is to current OCaml's `mutable' is the notion of
  single-threaded multiple-writers mutable state (_`Cell'_). It is made
  thread-safe in Rust by statically preventing values containing `Cell'
  from crossing thread boundaries (by virtue of not having the _`Send'
  trait_). The same restriction is used to make some data structures
  more efficient by avoiding the cost of synchronisation (cf. the
  reference-counting pointer `Rc' vs. the atomic reference-counting
  pointer `Arc').

  This is not enough by itself, and Rust offers other kinds of state for
  communicating and sharing values between threads.

  _`UnsafeCell'_ like Ocaml multicore's `mutable' (though yours is safe
  thanks to the work on the memory model): it has almost no restriction
  and can be sent across domains, but the user is likewise told to
  “avoid data races”. It is rarely used alone, but together with type
  abstraction it can be used to program safe concurrent data structures.

  Lastly, the default notion of state in Rust is linear state, which can
  be sent freely across threads. Thread-safety is ensured by restricting
  aliasing using the ownership and borrowing discipline.


A backwards-compatible concurrent collector?
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  If I had to imagine a backwards-compatible OCaml with static control
  of interference à la Rust based on `ConcMinor', it would distinguish
  the three kinds of state (concretely with other keywords in addition
  to `mutable'). `mutable' would keep its current meaning of
  single-domain, multiple-writers state and not require a read barrier,
  and in particular preserve the API. (I count systhreads as
  single-threaded for this purpose, since here it means "sharing the
  same minor heap".)

  Programs could progressively transition to other kinds of state when
  parallelising the program. Concretely, a data structure like
  `Stack.t', instead of becoming racy, would keep its current meaning,
  but users could replace it with a linear stack or a concurrent stack,
  two data structures distinct from the first one, when parallelizing
  their programs.

  So how could this fit with the current plans? It is not entirely clear
  to me. If people start to rely on parallelism in an unstructured way
  (e.g. no clear distinction between different kinds of data types
  arising from different ways of ensuring thread-safety) then one will
  also lose the ability to retrofit `ConcMinor' in a
  backwards-compatible manner (by losing the information that the
  current `mutable' API is single-threaded). The API breakage of
  `ConcMinor' which might only be virtual right now (if I trust this
  preliminary, not fully-explored idea) will become real.  (Further
  difficulties arise with the emulation of the `Thread' library with
  domains, but this could be changed later.)

  But if users are provided in advance with a general direction for a
  model of control of interference this might happen differently. And
  eventually having such a model is desirable in any case, as it helps
  parallelizing programs (for instance the Firefox people reported that
  they had attempted and failed twice to parallelise the CSS engine in
  C++ before succeeding with Rust). Furthermore, in an imaginary
  retrofitting of `ConcMinor', one could imagine enforcing something
  like the `Send' trait at the level of the read barrier until there is
  a better way (there would be two kinds of barriers, one of which would
  raise an exception if a state happened to be incorrectly shared across
  domains, and not be required in the FFI).

  I find `ConcMinor' interesting from a systems programming perspective
  compared to the stop-the-world collector because it could (I hope)
  offer possibilities such as having a low-latency domain communicating
  with a higher-latency domain. Moreover the performance cost of the
  read barrier might be lower in this scheme if it could be removed for
  all but the concurrent data structures.


BAP 2.1.0 Release
═════════════════

  Archive: [https://discuss.ocaml.org/t/ann-bap-2-1-0-release/5906/1]


Ivan Gotovchits announced
─────────────────────────

  The Carnegie Mellon University Binary Analysis Platform ([CMU BAP]) is
  a suite of utilities and libraries that enables analysis of programs
  that are represented as machine code (aka binaries). CMU BAP is
  written in OCaml and uses plugin-based architecture to enable
  extensibility. We also have a domain-specific language, called Primus
  Lisp, that we use to write analysis, specify verification conditions,
  interact with the built-in SMT solver, and model the semantics of
  machine instructions and functions.

  The 2.1.0 Release is very rich in [new features] but the most
  prominent addition is the new [symbolic executor] mode for the Primus
  framework. We also significantly updated the Primus framework,
  integrated it with our new Knowledge Base, which was introduced in the
  BAP 2.0 release; we made our interpreter much faster; we added the
  systems and components facilities, inspired by Common Lisp; and we
  implemented a gradual type checker for Primus Lisp with type
  inference. We also added an ability to represent machine instructions
  as intrinsic functions so now it is possible to express their
  semantics using Primus Lisp since we added IEEE754 primitives to the
  Lisp interpreter.

  As usual, we upgraded BAP to the newer versions of the Core library
  and OCaml (we now support OCaml versions from 4.07 to 4.09). We also
  significantly improved our build times and added an optional omake
  backend, which we are using in-house.

  From the user perspective, one of the key features of BAP as an
  analysis platform is that you can run BAP on binaries that you can't
  run otherwise, either because they need special hardware or software,
  or need to interact with the outside world. In the past couple of
  months, we have run BAP on various firmware and found numerous
  zero-day vulnerabilities, particular, we were able to find critical
  vulnerabilities in the VxWorks operating system that runs on,
  potentially, billions of devices including mission-critical and
  military appliances.

  As always, questions, suggestions, and opinions are very welcome!


[CMU BAP] https://github.com/BinaryAnalysisPlatform/bap

[new features]
https://github.com/BinaryAnalysisPlatform/bap/releases/tag/v2.1.0

[symbolic executor]
https://github.com/BinaryAnalysisPlatform/bap/pull/1105


Migrating an Async project to Lwt, a short primer
═════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/migrating-an-async-project-to-lwt-a-short-primer/5908/1]


Michael Bacarella announced
───────────────────────────

  Consider this a post where I think aloud about my experience migrating
  an Async project to Lwt.  I've spent about a weekend doing such a
  thing, and if, in the process of talking about it here I can save a
  few people an hour or two (or perhaps inspire confidence to take such
  a project on in the first place) then it will have been worthwhile.

  This wouldn't be a complete post if I didn't also mention @dkim's
  [translation of Real World OCaml's Async examples to Lwt]

  This was born out of a previous effort where I [tried to mix Lwt and
  Async in the same project].  This didn't go so well, so I tried
  converting the whole thing to Lwt, and it turns out adapting to Lwt if
  you're an Async person is actually much easier than I thought it would
  be.


[translation of Real World OCaml's Async examples to Lwt]
https://github.com/dkim/rwo-lwt

[tried to mix Lwt and Async in the same project]
https://discuss.ocaml.org/t/best-practices-on-mixing-lwt-and-async/5372

Basics
╌╌╌╌╌╌

  Both libraries involve promises/futures.  Async calls its promises
  `Deferred.t', whereas in Lwt they're called `Lwt.t'.

  In Async you start your program by saying `never_returns (Scheduler.go
  ())' or `Command.async_spec' after you set up your initial
  `Deferred.t'.

  In Lwt you say `Lwt_main.run' on a top-level `Lwt.t' argument.  Note
  you can re-run `Lwt_main.run' in a single program as many times as you
  want, but perhaps you shouldn't run multiple `Lwt_main.run' in
  parallel.

  There's an easy correspondence between basic operators.

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   Async                      Lwt                     
  ────────────────────────────────────────────────────
   `Deferred.bind'            `Lwt.bind'              
   `Deferred.return'          `Lwt.return'            
   `>>='                      `>>='                   
   `Deferred.map'             `Lwt.map'               
   `>>|'                      `>|='                   
   `Deferred.don't_wait_for'  `Lwt.async'             
   `In_thread.run'            `Lwt_preemptive.detach' 
  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━


Starvation worries
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The most important difference between Async and Lwt is that *fulfilled
  promises are acted on immediately*, whereas Async kinda punts them to
  the end of a work queue and runs their thunks later.

  A return loop like this starves the rest of Lwt:

  ┌────
  │ open Lwt.Infix
  │ 
  │ let main () =
  │   let rec loop () =
  │     Lwt.return ()
  │     >>= fun () ->
  │     loop ()
  │   in
  │   Lwt.async (loop ());
  │   Lwt_io.printlf "this line never prints!"
  │ ;;
  │ 
  │ let () = Lwt_main.run main ;;
  └────

  whereas the corresponding Async loop does not starve:

  ┌────
  │ open! Async
  │ 
  │ let main () =
  │   let rec loop () =
  │     Deferred.return ()
  │     >>= fun () ->
  │     loop ()
  │   in
  │   don't_wait_for (loop ());
  │   printf "this line does print!\n";
  │   return ()
  │ ;;
  │ 
  │ let () =
  │   let cmd = Command.async_spec ~summary:"" Command.Spec.empty main in
  │   Command.run cmd
  │ ;;
  └────

  Fortunately there's a workaround. You can get something closer to the
  Async-style behavior in Lwt by using `Lwt.yield ()' instead of
  `Lwt.return ()'.


Spawning threads
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  From time to time you may need to run something in a system thread.
  In Async you say `In_thread.run', whereas in Lwt you say
  `Lwt_preemptive.detach'.  For simple things they're pretty much
  interchangeable, but one stumbling point for me was that in Async you
  can create a named thread and always use that for the `In_thread.run',
  with multiple simultaneous dispatches to that thread becoming
  sequenced.

  This is really useful for interacting with libraries that aren't so
  thread friendly.

  Lwt's detach doesn't provide an easy way to do this out of the box,
  but I think you can still deal with thread unfriendly libraries by
  using the `Lwt_preemptive.run_in_main' call.

  Basically, never exit the detach thread you started to interact with
  your library, and instead have it block on promise that gets filled
  through run_in_main.  In this way you can sequence your detached Lwt
  thread similarly to Async.

  Happy to explain further if this is unclear.


Other libraries
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  `Async.Unix' has a somewhat built-up conception of the UNIX API,
  whereas `Lwt_main' is more a direct mapping of ocaml's `Unix' module
  to promises.

  Async `Clock.every' and `Clock.after' don't have exact analogs, but
  you can make new versions pretty simply.

  Example of a shallow imitation of Async `Clock.every'
  ┌────
  │ let every span f =
  │   Lwt.async (fun () ->
  │     let span = Time.Span.to_sec span in
  │     let rec loop () =
  │       f ();
  │       Lwt_unix.sleep span
  │       >>= fun () ->
  │       loop ()
  │     in
  │     loop ())
  │ ;;
  └────

  *Open questions*

  I haven't sorted out a good Lwt substitute that's as comfortable as
  Async Pipe yet.  Though some combination of Lwt_stream, Lwt_sequence
  and `lwt-pipe' might fit the bill.  If you just happen to know already
  feel free to cluephone.


Closing remarks
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This is basically everything?  I'm almost suspicious that I'm not
  having more problems, but will happily accept grace when it arises.


Raphaël Proust then said
────────────────────────

        I haven’t sorted out a good Lwt substitute that’s as
        comfortable as Async Pipe yet. Though some combination of
        Lwt_stream, Lwt_sequence and `lwt-pipe' might fit the
        bill. If you just happen to know already feel free to
        cluephone.

  The Tezos project has a pipe-like module:
  [https://gitlab.com/tezos/tezos/-/blob/master/src/lib_stdlib/lwt_pipe.mli]
  It hasn't been released as a standalone library (yet) but it is
  released as part of the `tezos-stdlib' package.

  I haven't used Async's pipe, so I don't know how close of a match it
  is.


jose 0.4.0
══════════

  Archive: [https://discuss.ocaml.org/t/ann-jose-0-4-0/5909/1]


Ulrik Strid announced
─────────────────────

  A new release of JOSE has been published to opam

  The following changes has been made
  • RFC7638: Implement thumbprints @undu
  • Make kid optional in the header and jwk to align better with the
    spec, this is a breaking change

  I have started dog fooding the library for a OpenID Connect client
  which hopefully will help with the design going forward.


OCaml 4.11.0, second alpha release
══════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-4-11-0-second-alpha-release/5910/1]


octachron announced
───────────────────

  A new alpha version of OCaml 4.11.0 has been published.  Compared to
  the first alpha version, this version contains the following new bug
  fixes:

  • *additional fixes* [6673], [1132], [+9617]: Relax the handling of
     explicit polymorphic types (Leo White, review by Jacques Garrigue
     and Gabriel Scherer)

  • *additional fixes* [7364], [2188], [+9592], [+9609]: improvement of
     the unboxability check for types with a single
     constructor. Mutually-recursive type declarations can now contain
     unboxed types. This is based on the paper
     [https://arxiv.org/abs/1811.02300]

  • [7817], [9546]: Unsound inclusion check for polymorphic variant
    (Jacques Garrigue, report by Mikhail Mandrykin, review by Gabriel
    Scherer)

  • [9549], [9557]: Make -flarge-toc the default for PowerPC and
    introduce -fsmall-toc to enable the previous behaviour. (David
    Allsopp, report by Nathaniel Wesley Filardo, review by Xavier Leroy)

  • [9320], [9550]: under Windows, make sure that the Unix.exec*
    functions properly quote their argument lists. (Xavier Leroy, report
    by André Maroneze, review by Nicolás Ojeda Bär and David Allsopp)

  • [9490], [9505]: ensure proper rounding of file times returned by
    Unix.stat, Unix.lstat, Unix.fstat. (Xavier Leroy and Guillaume
    Melquiond, report by David Brown, review by Gabriel Scherer and
    David Allsopp)

  • [8676], [9594]: turn debugger off in programs launched by the
    program being debugged (Xavier Leroy, report by Michael Soegtrop,
    review by Gabriel Scherer)

  • [9552]: restore ocamloptp build and installation (Florian Angeletti,
    review by David Allsopp and Xavier Leroy)

  • [7708], [9580]: Ensure Stdlib documentation index refers to
    Stdlib. (Stephen Dolan, review by Florian Angeletti, report by
    Hannes Mehnert)

  • [9189], [9281]: fix a conflict with Gentoo build system by removing
    an one-letter Makefile variable. (Florian Angeletti, report by Ralph
    Seichter, review by David Allsopp and Damien Doligez)

  The compiler can be installed as an OPAM switch with one of the
  following commands
  ┌────
  │ opam switch create ocaml-variants.4.11.0+alpha2 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.11.0+alpha2+<VARIANT> --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where <VARIANT> is replaced with one of these: afl, flambda, fp,
  fp+flambda

  The source code for the alpha is also available at these addresses:

  • [https://github.com/ocaml/ocaml/archive/4.11.0+alpha2.tar.gz]
  • [https://caml.inria.fr/pub/distrib/ocaml-4.11/ocaml-4.11.0+alpha2.tar.gz]

  If you find any bugs, please report them here:
   [https://github.com/ocaml/ocaml/issues]


[6673] https://github.com/ocaml/ocaml/issues/6673

[1132] https://github.com/ocaml/ocaml/issues/1132

[+9617] https://github.com/ocaml/ocaml/issues/9617

[7364] https://github.com/ocaml/ocaml/issues/7364

[2188] https://github.com/ocaml/ocaml/issues/2188

[+9592] https://github.com/ocaml/ocaml/issues/9592

[+9609] https://github.com/ocaml/ocaml/issues/9609

[7817] https://github.com/ocaml/ocaml/issues/7817

[9546] https://github.com/ocaml/ocaml/issues/9546

[9549] https://github.com/ocaml/ocaml/issues/9549

[9557] https://github.com/ocaml/ocaml/issues/9557

[9320] https://github.com/ocaml/ocaml/issues/9320

[9550] https://github.com/ocaml/ocaml/issues/9550

[9490] https://github.com/ocaml/ocaml/issues/9490

[9505] https://github.com/ocaml/ocaml/issues/9505

[8676] https://github.com/ocaml/ocaml/issues/8676

[9594] https://github.com/ocaml/ocaml/issues/9594

[9552] https://github.com/ocaml/ocaml/issues/9552

[7708] https://github.com/ocaml/ocaml/issues/7708

[9580] https://github.com/ocaml/ocaml/issues/9580

[9189] https://github.com/ocaml/ocaml/issues/9189

[9281] https://github.com/ocaml/ocaml/issues/9281


OCaml Workshop 2020: Call for Volunteers
════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-workshop-2020-call-for-volunteers/5913/1]


Ivan Gotovchits announced
─────────────────────────

  The OCaml Workshop will be held in the virtual format this year, which
  poses new challenges and requires people with special talents and
  training. The Organizing Committee is seeking for members who will
  volunteer to fill one (or more) of the following roles:

  1. AV Editor
  2. Session Host
  3. Transcribers/Interpreter
  4. Content Manager
  5. Accessibility Chair

  The roles are described in details below. We are asking prospective
  Organizing Committee members to contact the Organizing Committee chair
  ([ivg@ieee.org]([mailto:ivg@ieee.org])), indicating which role(s) they
  are ready to take.


[AV Editor]
╌╌╌╌╌╌╌╌╌╌╌

  AV (Audio/Video) editors are responsible for previewing the
  presentations and providing help and feedback to the authors. Ideally
  we target for one editor per talk.


[AV Editor] https://icfp20.sigplan.org/home/ocaml-2020#av-editor

◊ [Duties]

  • Preview and (if necessary) post-process or (ask the author to shoot
    again) the pre-recorded videos.
  • Advise authors and help in choice of software and hardware, teach
    how to set up the camera, light, make sure that the audio is of good
    quality and, in general, channel our quality guidelines.
  • Ensure that all videos are of the same quality, the audio levels are
    the same, and that everything is loud and clear.


  [Duties] https://icfp20.sigplan.org/home/ocaml-2020#duties


[Session Hosts]
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Session hosts will assist session chairs in streaming the pre-recorded
  videos as well as helping and moderating the Q&A sessions and the
  panel session. They will also be responsible for security and be ready
  to react to potential threats and wrongdoers. Since we will broadcast
  sessions in several time zones we need several hosts for each session.


[Session Hosts] https://icfp20.sigplan.org/home/ocaml-2020#session-hosts

◊ [Duties]

  • Moderating the text chats
  • Controlling microphones in the video-conferencing
  • Watching for the time
  • Performing sound checks
  • Welcoming and otherwise guiding participants


  [Duties] https://icfp20.sigplan.org/home/ocaml-2020#duties


[Transcribers / Interpreters]
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  We would like to have at least English transcriptions for each talk
  and translations to other languages are very welcome. Transcriptions
  enable accessibility as well as potentially increase the audience and
  publicity as they could be indexed by the search engines.


[Transcribers / Interpreters]
https://icfp20.sigplan.org/home/ocaml-2020#transcribers-interpreters

◊ [Duties]

  • Create transcriptions for videos, potentially in other languages.


  [Duties] https://icfp20.sigplan.org/home/ocaml-2020#duties


[Content Manager]
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The content manager will be responsible for maintaining the web
  presence of the conference on [https://ocaml.org/]. We plan to have
  all videos available, as well as maintain a page for each submitted
  work.


[Content Manager]
https://icfp20.sigplan.org/home/ocaml-2020#content-manager


[Accessibility Chair]
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  We are striving to make the conference accessible to everyone and we
  are looking for volunteers who have experience in online
  accessibility.


[Accessibility Chair]
https://icfp20.sigplan.org/home/ocaml-2020#accessibility-chair

◊ [Duties]

  • Helping with the selection of accessible platforms and tools.
  • Working with attendees to ensure the necessary access services are
    included.
  • Establishing best practices for preparing and running accessible
    sessions.


  [Duties] https://icfp20.sigplan.org/home/ocaml-2020#duties


Introduction to Lwt
═══════════════════

  Archive: [https://discuss.ocaml.org/t/introduction-to-lwt/5940/1]


Raphaël Proust announced
────────────────────────

  I've published
  [https://raphael-proust.github.io/code/lwt-part-1.html], a 2-part
  introduction to Lwt.

  The main aim of the introduction is to give a good mental model of
  what promises are, how they behave and how to use them. It assumes
  basic familiarity with OCaml.

  Don't hesitate to ask questions or share feedback.


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Using ASCII waveforms to test hardware designs]


[OCaml Planet] http://ocaml.org/community/planet/

[Using ASCII waveforms to test hardware designs]
https://blog.janestreet.com/using-ascii-waveforms-to-test-hardware-designs/


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-05-19  9:52 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-05-19  9:52 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of May 12 to 19,
2020.

Table of Contents
─────────────────

ocamlformat 0.14.2
ML Family Workshop 2020: Call for presentations
memprof-limits preview (and a guide to handle asynchronous exceptions)
Tezos 7.0 is now available on opam
Official OCaml bindings for verified Everest cryptography
nmea and sail-gadgets
Is there specialized math library for statistics?
New OCaml books?
Other OCaml News
Old CWN


ocamlformat 0.14.2
══════════════════

  Archive: [https://discuss.ocaml.org/t/ann-ocamlformat-0-14-2/5754/1]


Guillaume Petiot announced
──────────────────────────

  We are pleased to announce the release of `ocamlformat' 0.14.2.  This
  minor release improves the recent 0.14.0 and 0.14.1 releases regarding
  the `doc-comments' option.


How to migrate from 0.13.0
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Here are the changes of the `doc-comments' options compared to
  ocamlformat 0.13.0:
  • `after' has been renamed to `after-when-possible' to take into
    account the technical limitations of ocamlformat;
  • a new value `before-except-val' has been added, placing doc-comments
    before the corresponding code, but placing doc-comments of val and
    external declarations after the corresponding declaration;
  • `before' is unchanged.

  Here is the full list of changes made by the 0.14.0 release:
  [https://discuss.ocaml.org/t/ann-ocamlformat-0-14-0/5435]


How to migrate from 0.14.0
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The 0.14.0 release lead to some regression of the `doc-comments'
  behavior that (although intended for us) lead to some surprise from a
  lot of users.  The behavior of `doc-comments' has thus been reverted
  to it's 0.13.0 state with the following changes:

  The `doc-comments-val' option has been removed and merged with
  `doc-comments'. The placement of documentation comments on `val' and
  `external' items is now controlled by `doc-comments' .

  • `doc-comments=after' becomes `doc-comments=after-when-possible' to
    take into account the technical limitations of ocamlformat;
  • `doc-comments=before' is unchanged;
  • `doc-comments-val' is now replaced with `doc-comments'

  To reproduce the former behaviors
  • `doc-comments=before' + `doc-comments-val=before' : now use
    `doc-comments=before' ;
  • `doc-comments=before' + `doc-comments-val=after' : now use
    `doc-comments=before-except-val' ;
  • `doc-comments=after' + `doc-comments-val=before' : this behavior did
    not make much sense and is not available anymore;
  • `doc-comments=after' + `doc-comments-val=after' : now use
    `doc-comments=after-when-possible'.


How to migrate from 0.14.1
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The 0.14.1 release was preserving the behavior of 0.13.0 regarding
  `doc-comments', it added a `unset' value to the `doc-comments-val'
  option.  This option has been removed with the following changes:

  The `doc-comments-val' option has been removed and merged with
  `doc-comments'. The placement of documentation comments on `val' and
  `external' items is now controlled by `doc-comments' .

  • `doc-comments=after' becomes `doc-comments=after-when-possible' to
    take into account the technical limitations of ocamlformat;
  • `doc-comments=before' is unchanged;
  • `doc-comments-val' is now replaced with `doc-comments'

  To reproduce the former behaviors
  • `doc-comments=before' + `doc-comments-val=before' : now use
    `doc-comments=before' ;
  • `doc-comments=before' + `doc-comments-val=after' : now use
    `doc-comments=before-except-val' ;
  • `doc-comments=after' + `doc-comments-val=before' : this behavior did
    not make much sense and is not available anymore;
  • `doc-comments=after' + `doc-comments-val=after' : now use
    `doc-comments=after-when-possible'.


Thank you
╌╌╌╌╌╌╌╌╌

  We would like to thank our early users to help us on the road of a
  stable 1.0.0 release of ocamlformat.


ML Family Workshop 2020: Call for presentations
═══════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ml-family-workshop-2020-call-for-presentations/5441/4]


Leo White announced
───────────────────

  ICFP, and by extension the ML workshop, will be now officially be held
  online with a significantly reduced fee. Due to the change in official
  status we decided to extend the submission deadline to the end of May.


Important Dates (updated)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Friday 29th May (any time zone): Abstract submission deadline
  • Friday 17th July: Author notification
  • Thursday 27th August: ML Family Workshop


memprof-limits preview (and a guide to handle asynchronous exceptions)
══════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-memprof-limits-preview-and-a-guide-to-handle-asynchronous-exceptions/5756/1]


Guillaume Munch-Maccagnoni announced
────────────────────────────────────

  Dear OCamlers, I am happy to pre-announce [memprof-limits], an
  implementation of per-thread global memory limits, and per-thread
  allocation limits à la Haskell, compatible with systhreads.

  Memprof-limits interrupts the execution by raising an _asynchronous
  exception_, an exception that can arise at almost any location in the
  code. I also announce [a guide on how to recover from asynchronous
  exceptions and other unexpected exceptions] that you find in the
  documentation. It summarises knowledge acquired in OCaml by the Coq
  proof assistant as well as in other programming languages. To my
  knowledge, this has never been told in OCaml textbooks, so I thought
  it might be of general interest to you. This research is part of a
  wider work aiming to regulate the use of asynchronous exceptions in
  OCaml in coordination with multicore language designers.

  _Global memory limits_ let you bound the memory consumption inside
  specific parts of your program, in terms of memory used by the whole
  program. It is inspired by [this other post], but in a form readily
  available for use with systhreads.

  _Allocation limits_ let you bound the execution of parts of the
  program measured in number of allocations, analogous to the same
  feature in Haskell advocated in [a nice post by Simon
  Marlow]. Allocation limits count allocations but _not_ deallocations,
  and is therefore a measure of the work done, which can be more
  suitable than execution time.

  Memprof-limits, as the name tells, uses the upcoming Memprof engine
  from OCaml 4.11, with a low sampling rate that does not affect
  performance. A reimplementation of the Memprof interface compatible
  with memprof-limits running at the same time is provided for profiling
  needs.

  Memprof-limits is available on the public opam repository, but depends
  on OCaml 4.11 which at the moment is available from the beta opam
  repository only. It is _experimental_ for reasons explained in the
  manual.


[memprof-limits] https://gitlab.com/gadmm/memprof-limits

[a guide on how to recover from asynchronous exceptions and other
unexpected exceptions] https://gitlab.com/gadmm/memprof-limits#recover

[this other post]
https://discuss.ocaml.org/t/todays-trick-memory-limits-with-gc-alarms/4431

[a nice post by Simon Marlow]
https://simonmar.github.io/posts/2017-01-24-asynchronous-exceptions.html

FAQ
╌╌╌

◊ “Is it wise to rely on the statistical nature of Memprof? If I set an allocation limit of 100 KB, and run a function that allocates exactly 50 KB, then the function might fail, due to the random nature of Memprof.”

  Memprof-limits is provided with a [statistical analysis] meant to help
  you chose appropriate values for the limit depending on a target safe
  allocation value. (Nice pictures omitted because this discuss does not
  support svg.)

  Long story short, memprof-limits starts being accurate-enough starting
  around a safe allocation value of 100 KB with the default sampling
  rate (meaning a limit of 1 to 3 MB depending on chosen precision),
  with the ratio between the maximal safe allocation and the limit
  dropping very quickly for higher values. Correctly, the analysis shows
  that limits under 500 KB are unreliable.

  I have found that the statistical nature of Memprof makes it very easy
  to reason about its application and not have to factor in runtime
  implementation details. In addition, Memprof is nevertheless
  deterministic, which is (essential and) useful for reproducing runs in
  test scenarios.


  [statistical analysis]
  https://gitlab.com/gadmm/memprof-limits#statistical


◊ “But can we really program with memprof-limits, that is, not only write programs but also reason about them, given the probabilistic nature of the guarantees?”

  Yes, if we make two additional hypotheses:

  1. Allocation limits (as used in Haskell) are used by determining peak
     reasonable allocation usage empirically and picking a limit at a
     comfortable margin over it, rather than computing a precise memory
     bound to be used as a limit. In very controlled environments where
     the latter would be possible, there probably would be better
     solutions, and the language this is inspired from makes it very
     hard to make predictions on memory use.
  2. The programmer is fine with a very unlikely possibility of a false
     positive; indeed the program is already designed to let true
     positives fail without bringing down mission-critical parts of the
     program. For instance they can prefer to see a legitimate client
     having a connexion closed once every 10ⁿ year for *n* of their
     choosing, if that is the price to pay for avoiding being subject to
     DOS on maliciously-crafted requests.

  Under these hypotheses, the statistical limit is just as reliable as
  the precise limits à la Haskell.


◊ “Is it possible to also implement _local memory limits_, to bound the memory consumption of a particular function?”

  Yes but read on.

  [Yang & Mazières (2014)] advocates in favour of an _allocator-pays_
  model of cost attribution, and note its similarity with memory
  profiling. In this model, it is possible for instance to process
  untrusted user input under some memory limit, before the result is
  distributed to the rest of the program.

  Implementing memory limits based on the allocator-pays model, by
  adapting allocation limits to take into account deallocations, would
  be very easy thanks to the facilities provided by Memprof. Moreover,
  the statistical analysis of allocation limits can be transposed, and
  guarantees similarly accuracy at a low runtime cost for limits greater
  than 100KB.

  There is one surprising difficulty, though, which has to do with the
  way the GC works. The GC has a space overhead: memory that is wasted
  because unreachable values are not collected immediately. This
  overhead has to be taken into account when choosing the
  limit. However, this overhead is non-local and dependent on the
  _total_ major heap size: one cannot just say “take the double of the
  desired limit”. Indeed, active threads will pay for memory that has
  been allocated in the past and kept alive. More experimentation is
  needed to provide guidance on how to take the space overhead into
  account.


  [Yang & Mazières (2014)]
  https://dl.acm.org/doi/10.1145/2594291.2594341


◊ “Can this be used to bound the consumption of lightweight threads in Lwt and Async?”

  It is straightforward to make memprof-limits parametric in the notion
  of _thread id_ used to track per-thread limits.  However, to the best
  of my knowledge, Lwt and Async are not meant to play well when the
  computation is interrupted by asynchronous exceptions. If you have
  more information about this limitation or are interested in
  experimenting, please get in touch.


Thanks
╌╌╌╌╌╌

  Thank you to Jacques-Henri Jourdan for his explanations about Memprof
  and Stephen Dolan for his feedback.


Tezos 7.0 is now available on opam
══════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-tezos-7-0-is-now-available-on-opam/5764/1]


Pierre Boutillier announced
───────────────────────────

  Tezos executables and libraries have just been released on `opam'. You
  can thus build them from source with a simple `opam install tezos' and
  build your own projects upon them.


What is Tezos
╌╌╌╌╌╌╌╌╌╌╌╌╌

  Tezos is a distributed consensus platform with meta-consensus
  capability. Tezos not only comes to consensus about the state of its
  ledger, like Bitcoin or Ethereum. It also comes to consensus about how
  the protocol and the nodes should adapt and upgrade. For more
  information about the project, see [https://tezos.com].

  Our implementation of Tezos is written in OCaml. It is split into
  several libraries (command-line interface `tezos-clic', peer-to-peer
  library `tezos-p2p', cryptographic primitives `tezos-crypto~…) and
  executables (node ~tezos-node', client ~tezos-client~…).


Useful Links
╌╌╌╌╌╌╌╌╌╌╌╌

  Source code for this particular implementation can be found at
  [https://gitlab.com/tezos/tezos/]. Developer documentation is
  available at [https://tezos.gitlab.io/]. In particular, documentation
  for this specific release (version 7.0) is available at
  [http://tezos.gitlab.io/releases/version-7.html].


Installation Instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Tezos (internal compiler in order to self amend itself) requires a
  specific version of the compiler (OCaml 4.09.1):

  ┌────
  │ opam switch 4.09.1
  └────

  Tezos also requires some external libraries:

  ┌────
  │ opam depext tezos
  └────

  Finally, to install all binaries:

  ┌────
  │ opam install tezos
  └────


Replying to Nick Betteridge, Raphaël Proust said
────────────────────────────────────────────────

  Tezos has a soft-updating mechanism that works (roughly) as follows:

  The network starts with a genesis protocol (“protocol” here means
  “economic protocol”: the rules according to which smart contracts are
  initiated and acted upon, transactions take place, etc.) in which a
  single public key is specified.

  The genesis protocol has no notion of coin, currency, smart-contract,
  etc. Instead, the genesis protocol knows a single operation: a
  protocol injection.

  The protocol injection for genesis requires the operation to be signed
  by the private key that matches the public key of the genesis
  block. And the protocol injection changes, irreversibly, the genesis
  protocol to a new protocol. This new protocol specifies what
  constitutes a valid block to add to the chain.

  In the Tezos blockchain, the protocol injected on top of genesis
  included a notion of coins and an in-protocol voting system to inject
  new protocols based on consensus amongst coin-holders. There is even a
  system to obtain the protocol sources over the blockchain network so
  they can be compiled by each node and dynlinked directly in: you don't
  need to update/restart your node to get the protocol updates. However,
  this is arbitrary: you can start a new block-chain with a different
  protocol.

  For example, you could re-implement Bitcoin (proof-of-work,
  coins+transfer, etc.) as a protocol that you inject on top of
  genesis. Your block chain would have a tezos genesis block, then a
  block that activate your own version of bitcoin, and then the blocks
  would be similar to what you would find on the bitcoin block-chain.

  Of particular interest to you, the protocol you inject can have
  entirely different on-chain notions (e.g., a TCG/CCG with no coins at
  all but a notion of ownership over cards) and different soft-updating
  mechanism (e.g., the new protocol can accept genesis-style updates (a
  “dictatorship” where a single person controls the protocol) or even no
  soft-updating mechanism at all (a “stale” protocol where you need to
  hard-fork if you want to make significant changes)).

  For this use case (of starting your own chain with a different
  protocol), you might be better off cloning the git repository, doing
  some minimal clean up, etc. This is because the tezos binaries include
  the sources for all protocols that have been used on the chain (so you
  don't *need* to get them over the network even if you can).

  You might be interested in the following blog post about how to write
  your own protocol:
  [https://blog.nomadic-labs.com/how-to-write-a-tezos-protocol.html]


Official OCaml bindings for verified Everest cryptography
═════════════════════════════════════════════════════════

  Archive:
  [https://sympa.inria.fr/sympa/arc/caml-list/2020-05/msg00017.html]


Jonathan Protzenko announced
────────────────────────────

  The Everest team is pleased to announce the release of official OCaml
  bindings for all of our verified cryptographic algorithms, now
  available through OPAM as packages hacl-star and hacl-star-raw.

  We provide bindings for the following:
  • HACL*, a library of pure C algorithms
  • Vale, a collection of optimized core assembly routines for maximum
    performance
  • EverCrypt, an agile, multiplexing API with CPU auto-detection that
    brings together HACL* and Vale.

  Our code is compiled from the F* programming language to C via the
  KReMLin compiler ("K&R meets ML"). We offer two OPAM packages:
  • hacl-star-raw consists of low-level ocaml-ctypes bindings generated
    by KReMLin
  • hacl-star is a hand-written OCaml idiomatic API that uses much more
    pleasant signatures, types and abstractions and is also safer, as it
    checks all static preconditions at run-time

  We support AES{128,256}-GCM, Chacha20-Poly1305, Curve25519 / Ed25519,
  P256, MD5, SHA-{1,2,3} (all variants), Blake2 (s&b), HMAC/HKDF, and
  the HPKE and SecretBox high-level APIs. Some algorithms are optimized
  for Intel chips, notably AES-GCM – see
  [https://hacl-star.github.io/Supported.html] for full details.

  General documentation about the project is available at
  [https://hacl-star.github.io/index.html] – sample code for the OCaml
  API is provided as part of the test suite
  [https://github.com/project-everest/hacl-star/tree/master/bindings/ocaml/tests]

  This work was performed by Victor Dumitrescu from Nomadic Labs, one of
  the teams responsible for the core development of the Tezos
  blockchain.


nmea and sail-gadgets
═════════════════════

  Archive: [https://discuss.ocaml.org/t/ann-nmea-sail-gadgets/5773/1]


Davide Gessa announced
──────────────────────

  Ahoy developers, few days ago I published a new ocaml library called
  *nmea*, which is essentially a parser for NMEA0183 sentences, a format
  for encoding instruments data in boats. There are many sentences,
  regarding GPS, compass data, wind, air pressure, water temperature,
  waypoints handling, ais, autopilot and more; at the moment the library
  is able to decode GPS sentences and compass data, but I'll implement
  more sentences in the spare time. I tested it with my boat GPS and
  with a gps usb dongle.

  After that, I started a new tiny experiment called *sail-gadgets*,
  which is a Gtk program that elaborates and displays NMEA data received
  from various boat instruments (wind vane, autopilot, gps, radar, ais,
  etc). Sail-gadgets can be extended with "gadgets" modules, each one
  providing new functionalities and new tabs to the main interface.

  Data from sensors are handled using /React/ signals, so in every
  gadget we can compose data from various sensor to obtain new reactive
  values.

  The gadgets I'm planning to write:
  • dashboard: shows current position, speed, heading, tripdist, compass
  • satview: shows current connected gps satellites (partially done)
  • wind: shows wind indicator with true / apparent speed and direction
  • radar: shows AIS and Radar targets in range
  • mob: allows to drop a marker in the current position, and drive you
    to that point
  • startline: helper for regatta start
  • track: shows current track in a vector map

  The hard thing in my opinion is writing new custom widget with cairo
  (compass, radar, and things like that).

  Finally, the project is intended to run over *gtk-broadway*, so every
  html5 enabled device can access the application.

  [https://raw.githubusercontent.com/dakk/sail-gadgets/master/media/broadway.jpg]

  Hope there are some sailor here that want to join writing some gadgets
  :) Repos are:

  • [https://github.com/dakk/nmea]
  • [https://github.com/dakk/sail-gadgets]


Is there specialized math library for statistics?
═════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/is-there-specialized-math-library-for-statistics/5778/1]


hss asked
─────────

  I searched to find math library which is written in OCaml, but there
  are only few repositories.

  I'd like to use some function like coefficient correlation,
  covariance, etc.

  I found Lacaml but it seems not to support them.

  Could you give some link if you know?


bnguyenvanyen replied
─────────────────────

  Hi, you can take a look at Owl : [https://ocaml.xyz/]

  There are stat functions and also a lot more


UnixJunkie also replied
───────────────────────

  There is also this one:
  [https://github.com/superbobry/pareto]
  GSL powered OCaml statistics library
  [http://superbobry.github.io/pareto/0.2]

  And probably even some more:
  ┌────
  │ opam search statistic
  │ # Packages matching: match(*statistic*)
  │ # Name            # Installed # Synopsis
  │ [...]
  │ gsl               --          GSL - Bindings to the GNU Scientific Library
  │ oml               --          Math Library
  │ owl               --          OCaml Scientific and Engineering Computing
  │ owl-plplot        --          OCaml Scientific and Engineering Computing
  │ pareto            --          GSL powered OCaml statistics library.
  │ statsd-client     --          StatsD client library
  │ [...]
  └────


New OCaml books?
════════════════

  Archive: [https://discuss.ocaml.org/t/new-ocaml-books/5789/1]


Axel Wintermann asked
─────────────────────

  I wonder, why there are no new OCaml books since 2014 year? Many books
  are published on Haskell, Scala, F# themes, but no OCaml. I think we
  need new books for learning and for rising interest in our beautiful
  language.


Takuma Ishikawa replied
───────────────────────

  • There is an ongoing work for 2nd edition of Real World OCaml:
    [http://dev.realworldocaml.org/].
  • OCaml Scientific Computing is also ongoing:
    [https://ocaml.xyz/book/].
  • A Japanese book "コンピュータを操る", published in Feb. 2020 for
    beginners of programming, uses OCaml Blockly:
    [https://www.saiensu.co.jp/search/?isbn=978-4-7819-1470-1&y=2020#detail].


Weng Shiwei also replied
────────────────────────

  A Chinese book [OCaml语言编程基础教程] ([an introduction to OCaml
  language programming]) is published in 2018.


[OCaml语言编程基础教程] https://e.jd.com/30417662.html

[an introduction to OCaml language programming]
https://caml.inria.fr/about/books.en.html#idm277


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Every proof assistant: MMT]


[OCaml Planet] http://ocaml.org/community/planet/

[Every proof assistant: MMT]
http://math.andrej.com/2020/05/15/mmt-a-foundation-independent-logical-system/


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-05-12  7:45 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-05-12  7:45 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of May 05 to 12,
2020.

Table of Contents
─────────────────

Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
Are there learning materials for OCaml for those with no programming experience?
Dune meeting notes
OCaml 4.11.0, first alpha release
OCaml Users and Developers Meeting 2020
VSCode Platform Plugin 0.5.0
Other OCaml News
Old CWN


Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
═══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/looking-for-lovely-idiomatic-examples-of-ocaml-used-for-shell-scripting-in-the-manner-of-perl-python-but-esp-perl/5703/13]


Continuing this thread, Chet Murthy said and Aaron L. Zeng replied
──────────────────────────────────────────────────────────────────

        • needs to be Ocaml code, not an interpreter. I mean, if
          I’m not going to write it in Ocaml, I might as well
          write in Perl, yes?

  I think shexp might deserve another look.  It's not an interpreter for
  a sexp-based shell language, as its name might unfortunately
  deceivingly suggest.  It's really a DSL for constructing shell
  pipelines using a `'a Process.t' monad.  The s-expression part is
  advertising that you can debug and trace the actions performed using
  s-expressions.

        The second-most-important part of Perl/Bash scripting is
        string-handling. And it’s certainly the part of Ocaml
        that’s most painful when writing scripts. Let’s stipulate
        that there are nice libraries to make this easy. I’m an
        Ocaml bigot, I have to believe this anyway *grin* . This
        library doesn’t seem to use 'em, nor choose/promote a
        particular set of such libraries.

  I've found [Base] plus [Re] to be sufficient for most of my
  string-manipulation needs.  It's never going to be as concise as
  Perl's built-in "magic" support for regexps, but you gain explicitness
  and clarity, which is part of the benefit of OCaml anyway.


[Base] https://github.com/janestreet/base/

[Re] https://github.com/ocaml/ocaml-re


Chet Murthy said and Donn Cave replied
──────────────────────────────────────

        It’s not as trivial in Ocaml, for many complicated reasons
        that boil down to “gee, string-handling is a PITA”.

  Really?  hadn't noticed.  Ha ha.

  I could never really get urge for Perl, but I use its ancestor awk a
  lot, and I'm trying out some awk-like simple string functions, like

  ┌────
  │ let strlen = String.length
  │ let sub s i n = let b = strlen s
  │      in if i < b
  │ 	 then let n = min n (b - i)
  │ 	 in String.sub s i n
  │     else ""
  │ (* substring to end of line *)
  │ let substr a i = if i < strlen a
  │      then String.sub a i ((strlen a) - i)
  │      else ""
  │ let matchre t s = try
  │      Str.search_forward t s 0
  │      with | Not_found -> -1
  └────

  etc.

  So "open Awk" gets me a handful of more basic variations on common
  string functions, with less elaborate parameters, no normal
  exceptions, etc.  Including a line by line file processing function.
  I have just newly started on this and haven't used it extensively, but
  it seems fairly promising.  No wacky syntax or hyper intelligent
  string processing, no packages, just a few dozen lines of cheater
  functions.

  "Awk" is a misnomer, in that there's little correspondence between
  this and awk, it was just what inspired me to try it.


Raphaël Proust said
───────────────────

  I don't think it's lovely and I have no idea if it is idiomatic, but I
  made a few scripts of my own in OCaml using the same library that
  other mentioned: `bos'

  • [typepass] uses `xdotool' to type passwords from the `password'
    password manager
  • [conn] wraps `wpa_supplicant', `dhcpcd', `ip', and other network
    management CLI
  • [laptop-status] fetches status information for laptops (e.g.,
    battery level) and prints it in a nicely formatted form
  • [bakelite] increases or decreases screen brightness


[typepass] https://gitlab.com/raphael-proust/typepass

[conn] https://gitlab.com/raphael-proust/conn

[laptop-status] https://gitlab.com/raphael-proust/laptop-status

[bakelite] https://gitlab.com/raphael-proust/bakelite


Vasile Rotaru also said
───────────────────────

  [https://github.com/hammerlab/genspio]


Gabriel Radanne also said
─────────────────────────

  I have no particular opinion about the rest, but at least on the regex
  side, this might be of interest:
  [https://github.com/paurkedal/ppx_regexp]

  If that's still not good enough, I would be very interested by
  suggestions on how to make it more convenient. :)


OCamlUser proposed
──────────────────

  I'm not sure about idiomatic, but I do have a utop config that I use
  to do some one-off scripting in OCaml that uses `shexp'

  ┌────
  │ #use "topfind"
  │ #warnings "+a"
  │ #thread
  │ #require "ppx_jane,core"
  │ #require "shexp.process"
  │ #require "lambdasoup"
  │ module List' = List
  │ open Shexp_process
  │ open Shexp_process.Infix
  │ open Core
  │ 
  │ module Html = struct
  │     include Soup
  │ 
  │     let of_string = parse
  │ end
  │ 
  │ let read_lines cmd =
  │     eval (call cmd |- read_all)
  │ ;;
  │ 
  │ let wget url =
  │     read_lines ["wget"; "-O"; "-"; url]
  │ ;;
  │ 
  │ let chrome_curl url =
  │     read_lines ["curl"; "-k"; "-sA"; "Chrome"; "-L"; url; "-o"; "-"]
  │ ;;
  │ 
  │ let split_lines = String.split ~on:'\n'
  │ let filter_lines substring = List.filter ~f:String.(is_substring ~substring)
  │ let to_html = Html.of_string
  │ let find_html pat html = Html.(html $$ pat)
  │ 
  │ let (%) = Fn.compose
  └────

  Then a simple script called `shexp' in my path:
  ┌────
  │ utop -init ~/bin/ocaml-shexp-config
  └────

  I add little helper functions as I come upon them. I find it's much
  easier to transition to a file, or full program when I need
  it. Example program:

  ┌────
  │ utop # read_lines ["sensors"] |> split_lines |> filter_lines "Core 0";;
  │ - : string list =
  │ ["Core 0:        +63.0°C  (high = +84.0°C, crit = +100.0°C)"]
  └────


Anton Kochkov said
──────────────────

  Not exactly OCaml, but can be made with the OCaml syntax as well - see
  [BATSH].


[BATSH] https://github.com/batsh-dev-team/Batsh


Bikal Lem also said
───────────────────

  I just found this - [https://github.com/ShamoX/cash]. @Chet_Murthy
  This may be the closest to ocaml shell scripting experience re perl.


Are there learning materials for OCaml for those with no programming experience?
════════════════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/are-there-learning-materials-for-ocaml-for-those-with-no-programming-experience/5684/9]


Continuing this threaad, Luc_ML said
────────────────────────────────────

  Before studying more complex books, it's a good idea to first get an
  overview.

  [OCaml for the Skeptical / OCaml in a Nutshell] : the title is funny;
  its main advantage is that it covers most OCaml concepts in *21 short
  sections* where you can experiment by yourself on simple but essential
  things.

  The books/courses already mentioned are nice. You can also consider
  this one that offers many examples/exercises and also a good overview:
  [Developing Applications With Objective Caml].

  LE LANGAGE CAML mentioned by @nojb is an excellent book. Written in
  Caml Light, it's easy to turn it by yourself into OCaml. It offers a
  great chance to learn how to do a lot of things in *pure* Caml with
  only stdlib and a simple syntax extension system (use camlp5 (i.e. the
  "genuine camlp4") that is fine for that. It works out of the box to
  deal with streams and it's a chance to understand what is a
  LL(1)/recursive descent parser).


[OCaml for the Skeptical / OCaml in a Nutshell]
https://www2.lib.uchicago.edu/keith/ocaml-class/class-01.html

[Developing Applications With Objective Caml]
https://caml.inria.fr/pub/docs/oreilly-book/


Dune meeting notes
══════════════════

  Archive: [https://discuss.ocaml.org/t/dune-meeting-notes/5710/1]


Jérémie Dimino announced
────────────────────────

  I just wanted to publicise that we are now publishing the notes from
  our Dune meetings on the wiki:

  [https://github.com/ocaml/dune/wiki]

  These meetings happen via video-conference every two weeks. If you are
  interested in following the development of Dune more closely, this is
  good place to look at.


OCaml 4.11.0, first alpha release
═════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-4-11-0-first-alpha-release/5716/1]


octachron announced
───────────────────

  The set of new features for the future version 4.11.0 of OCaml has
  been frozen.  In the next few months, the OCaml compiler team is
  focusing on bug hunting and fixing.

  For this release cycle, we have decided to test publishing regularly
  alpha versions of OCaml 4.11.0 in order to help fellow hackers join us
  early in our bug hunting and opam ecosystem fixing fun.  Once the opam
  ecosystem is in shape, these alpha releases will morph into the usual
  beta and release candidate releases.

  If you find any bugs, please report them here:
   [https://github.com/ocaml/ocaml/issues]

  The compiler can be installed as an OPAM switch with one of the
  following commands
  ┌────
  │ opam switch create ocaml-variants.4.11.0+alpha1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.11.0+alpha1+VARIANT --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where you replace VARIANT with one of these: afl, flambda, fp,
  fp+flambda

  The source code for the alpha is also available at these addresses:

  [https://github.com/ocaml/ocaml/archive/4.11.0+alpha1.tar.gz]
  [https://caml.inria.fr/pub/distrib/ocaml-4.11/ocaml-4.11.0+alpha1.tar.gz]

  If you are interested by the ongoing list of new features and fixed
  bugs, the updated change log for OCaml 4.11.0 is available at:

  [https://github.com/ocaml/ocaml/blob/4.11/Changes]


OCaml Users and Developers Meeting 2020
═══════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ocaml-users-and-developers-meeting-2020/5454/2]


Ivan Gotovchits announced
─────────────────────────

  Due to the multiple requests and since ICFP will be now officially
  held online with a significantly reduced fee, we decided to extend the
  submission deadline till the end of this month. We are hoping to
  attract a larger and more diverse audience this year, given that the
  new format is more accessible both travel-wise and financially.

  Please, share the news widely!


Important Dates (updated)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Talk proposal submission deadline: May 29th, 2020, AoE
  • Author Notification: July 17th, 2020
  • OCaml Workshop: August 28th, 2020


VSCode Platform Plugin 0.5.0
════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-vscode-platform-plugin-0-5-0/5752/1]


Rudi Grinberg announced
───────────────────────

  This release contains a couple of major improvements:

  • Syntax highlighting is vastly improved. There's now highlighting for
    many more filetypes, and the core highlighting for OCaml is far more
    accurate.
  • There's integration with package managers such as opam and esy. One
    may now explicitly use them to explicitly select the sandbox that
    contains the lsp server and related tools.

  Under the hood, the entire plugin was rewritten from typescript to
  OCaml (bucklescript). This should hopefully make contribution more
  accessible to OCaml hackers.

  I'd like to thank @rustykey, @mnxn, @prometheansacrifice, and @imbsky
  for their contributions to this release. Their help is the reason for
  this vastly improved version of the plugin.

  As usual, the plugin is available directly using vscode's extension
  market place. I'll leave a link to the plugin [here] to avoid
  confusion with the many other OCaml plugins available.

  Please report any issues on the [bug tracker]


[here]
https://marketplace.visualstudio.com/items?itemName=ocamllabs.ocaml-platform

[bug tracker] https://github.com/ocamllabs/vscode-ocaml-platform/issues


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Ocsigen Start 2.18 released]
  • [Ocsigen Toolkit 2.7 with new widget Ot_tongue]


[OCaml Planet] http://ocaml.org/community/planet/

[Ocsigen Start 2.18 released]
https://ocsigen.github.io/blog/2020/05/05/os/

[Ocsigen Toolkit 2.7 with new widget Ot_tongue]
https://ocsigen.github.io/blog/2020/05/04/ot/


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-05-05  7:45 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-05-05  7:45 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of April 28 to May
05, 2020.

Table of Contents
─────────────────

Lwt now has let* syntax
JOSE 0.3.0 - Now with 100% more encryption
Are there learning materials for OCaml for those with no programming experience?
The recent evolution of utop, lambda-term, zed and underneath projects
Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
Old CWN


Lwt now has let* syntax
═══════════════════════

  Archive: [https://discuss.ocaml.org/t/lwt-now-has-let-syntax/5651/1]


Anton Bachin announced
──────────────────────

  [Lwt] now has `let*' and `let+' syntax, which can be used like this:

  ┌────
  │ open Lwt.Syntax
  │ 
  │ let () =
  │   let request =
  │     let* addresses = Lwt_unix.getaddrinfo "google.com" "80" [] in
  │     let google = Lwt_unix.((List.hd addresses).ai_addr) in
  │ 
  │     Lwt_io.(with_connection google (fun (incoming, outgoing) ->
  │       let* () = write outgoing "GET / HTTP/1.1\r\n" in
  │       let* () = write outgoing "Connection: close\r\n\r\n" in
  │       let* response = read incoming in
  │       Lwt.return (Some response)))
  │   in
  │ 
  │   let timeout =
  │     let* () = Lwt_unix.sleep 5. in
  │     Lwt.return None
  │   in
  │ 
  │   match Lwt_main.run (Lwt.pick [request; timeout]) with
  │   | Some response -> print_string response
  │   | None -> prerr_endline "Request timed out"; exit 1
  └────

  This is now released in Lwt [5.3.0]. Thanks to Rahul Kumar for adding
  `let*', and @CraigFe for adding `let+'!


[Lwt] https://github.com/ocsigen/lwt

[5.3.0] https://github.com/ocsigen/lwt/releases/tag/5.3.0


Thomas Coopman asked
────────────────────

  Awesome this looks great.

  2 quick questions:

  1. I don't see this new version documented on ocsigen yet? Is that a
     build that needs to be done manually?
  2. Is `ppx_lwt' still recommend for some usecases like `try%'? For
     what cases is one preferred over the other?


Anton Bachin replied
────────────────────

  Good questions :slight_smile:

  1. The docs generation is blocked on an Ocsigen "internal" package
     `wikidoc', which has not been updated to support 4.08. So,
     effectively, `let*' is exactly what is preventing docs generation
     for the time being. I'll post the docs as soon as that is fixed.
  2. `ppx_lwt' is probably still the recommended way, because of better
     backtraces, and things like `try%lwt'. `let*' is nice for people
     that don't want to use the PPX. They can still benefit from a
     monadic syntax.


JOSE 0.3.0 - Now with 100% more encryption
══════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/ann-jose-0-3-0-now-with-100-more-encryption/5667/1]


Ulrik Strid announced
─────────────────────

  I recently released a version 0.3.0 of JOSE.

  [https://github.com/ulrikstrid/reason-jose]
  [https://ulrikstrid.github.io/reason-jose]

  It now includes some of the JWE (JSON Web Encryption) spec. A huge
  thank you goes out to @hannes for helping me implementing one of the
  gnarlier combinations of decryption that I could then use as a base
  for encryption and more `alg' and `enc'.

  I also refactored the JWK (JSON Web Keys) implementation to unify and
  simplify the representation. It is now possible to use a private key
  for anything a public key can do since it's a superset.

  A special thanks to @anmonteiro for helping me with the design and
  reviewing my code.


Are there learning materials for OCaml for those with no programming experience?
════════════════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/are-there-learning-materials-for-ocaml-for-those-with-no-programming-experience/5684/1]


Aaron Christianson asked
────────────────────────

  OCaml is a language with some advanced features, but a very gentle
  learning curve. It seems like it would be well-suited to teaching
  beginners to program (a few tricky error messages notwithstanding),
  but I haven't seen many resources targeted at teaching programming
  from scratch. Does anyone here know any?


Daniel Bünzli replied
─────────────────────

  There is [*OCaml from the Very Beginning*] written by @JohnWhitington.


[*OCaml from the Very Beginning*] http://ocaml-book.com/


Nicolás Ojeda Bär also replied
──────────────────────────────

  An excellent (free) book is "LE LANGAGE CAML"
  [https://caml.inria.fr/pub/distrib/books/llc.pdf].


Pierre also replied
───────────────────

  There's also [CS3110] from Cornell University. Here's [the
  textbook]. It's pretty great!


[CS3110] https://www.cs.cornell.edu/courses/cs3110/2020sp/

[the textbook]
https://www.cs.cornell.edu/courses/cs3110/2019sp/textbook/


The recent evolution of utop, lambda-term, zed and underneath projects
══════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/the-recent-evolution-of-utop-lambda-term-zed-and-underneath-projects/5687/1]


ZAN DoYe announced
──────────────────

  Hi, dear OCaml guys! We've been keeping quiet for more than one year
  though utop, lambda-term, zed and some related projects were still
  evolving during the period of time. This is because of two reasons:

  1. The new feature had nothing to do with the fields where most OCaml
     developers are working on:

     [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/a30d5fb6fc075a50801b387299cc820965d48ca0.png]

     [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/9/91b88f0c492702212f00f17af1bf0e18ee1a463b.png]

     Recognizing, editing, fuzzy searching for Character
     Variation(mainly for ancient CJK characters).

     Nevertheless, the new feature brought us a good side effect – the
     long-existing [Issue with asian charset] was resolved. UTop users
     will notice the refinement naturally, so no announcement was
     needed.

  2. I didn't deem the first few new editions of zed 2 and lambda-term 2
     stable enough.


[Issue with asian charset]
https://github.com/ocaml-community/lambda-term/issues/2

3.0 era
╌╌╌╌╌╌╌

  This time, we are entering zed 3, lambda-term 3 era. The features
  introduced since zed 2, lambda-term 2 are quite stable now and the new
  feature coming to us will have a bit more impact, especially to vim
  users. So it's worthwhile to draft an announcement:


◊ VI Editing Mode

  [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/c/ca11924046977d89d4345ad135977c6960470edc.gif]

  OCaml guys, hope you enjoy this.


List of notable changes:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • zed 2:
    • wide, combined glyph(Character Variation, IPA, CJK …)
    • add wanted_column support for wide width character

  • lambda-term 2:
    • wide, combined glyph(Character Variation, IPA, CJK …)
    • add horizontal scrolling support for wide width character

  • zed 3:
    • add new actions for convenience

  • lambda-term 3:
    • `LTerm_read_line': add initial support for vi editing mode:
    • motions:
      • h l 0 ^ $
      • j k gg G
      • w W e E b B ge gE
      • f F t T
      • aw iw aW iW
      • include or inner ( ), [ ], { }, < >, ' and "
      • generic quote: aq? iq? where ? could be any character
      • bracket matching: jump back and forth between matched brackets
    • delete, change, yank with motions
    • paste: p P
    • line joining: J

  for a full list of the changes, please visit the homepages of each
  project.


Projects underneath:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [charInfo_width]: Determine column width for a character
  • [mew] & [mew_vi]: Modal editing witch & Its VI interpreter
    complement. In a word, modal editing engine generators.


[charInfo_width] https://bitbucket.org/zandoye/charinfo_width/

[mew] https://github.com/kandu/mew

[mew_vi] https://github.com/kandu/mew_vi


What's next
╌╌╌╌╌╌╌╌╌╌╌

◊ VI Editing Mode

  1. Visual mode

     [https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/7/7cc45010710ad28d8d1e859e9b28806469ef8080.gif]
  2. register support and more vi compatible


◊ CJKV

  We've recorded more then 100 thousand entries about the structure of
  CJK characters, what is a character consists of, how are the
  sub-assemblies glue together etc. And as a complement to
  charInfo_width, we may release a new project called charInfo_structure
  ;)


Looking for "lovely, idiomatic" examples of Ocaml used for shell-scripting in the manner of Perl/Python (but esp. Perl)
═══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  [https://discuss.ocaml.org/t/looking-for-lovely-idiomatic-examples-of-ocaml-used-for-shell-scripting-in-the-manner-of-perl-python-but-esp-perl/5703/1]


Chet Murthy announced
─────────────────────

  I wonder if there are people who have written nontrivial Ocaml code
  for shell-scripting, that they think exemplifies the right way to do
  it.  I've been a Perl hacker for 25yr, and so when I reach for Ocaml
  to write stuff that should be Perl shell-scripts, I always find it a
  bit painful, and there's a significant overhead to getting the job
  done.  Some of that is applying ocaml to a new domain, but some of it
  is that I'm just not using the right idioms and tools (and there are
  so many to choose from).

  So if anybody has good pointers, I'd appreciate learning about them.


Bikal Lem
─────────

  Haven't tried it myself, but this looks promising …
  [https://github.com/janestreet/shexp].

  At least it has the great Sean Connery in its README so possibly worth
  delving a bit. :)


Hezekiah Carty
──────────────

  [bos] seems like it can do a lot of what you're looking for. It's at
  least worth taking a look, though it may not be at Perl levels of
  concise for this kind of task.


[bos] https://erratique.ch/software/bos


Martin Jambon
─────────────

  I tried to summarize my take on the subject into this gist:
  [https://gist.github.com/mjambon/bb07b24f89fa60c973735307ce9c6cb9]

  I'm not aware of the existence of such tool, but this is how I might
  design it. This should be reminiscent of camlp4's quotation and
  anti-quotation system, which allows alternating between two syntaxes
  within a source file.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] mailto:alan.schmitt@polytechnique.org

[the archive] http://alan.petitepomme.net/cwn/

[RSS feed of the archives] http://alan.petitepomme.net/cwn/cwn.rss

[online] http://lists.idyll.org/listinfo/caml-news-weekly/

[Alan Schmitt] http://alan.petitepomme.net/


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-04-28 12:44 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-04-28 12:44 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 29726 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of April 21 to 28,
2020.

Table of Contents
─────────────────

opam 2.0.7 and 2.1.0 alpha
OCaml 4.11, release plan
ocamlformat pre-commit hook
New release of naboris 0.1.2
ANN: Releases of ringo
resto 0.2 released
Retrofitting Parallelism onto OCaml (research paper)
Multicore Update: April 2020, with a preprint paper
Why did Core remove polymorphic comparison operators in OCaml 4.10.0?
New release of js_of_ocaml 3.6.0
Other OCaml News
Old CWN


opam 2.0.7 and 2.1.0 alpha
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-opam-2-0-7-and-2-1-0-alpha/5583/1>


R. Boujbel announced
────────────────────

  We are pleased to announce the release of [opam 2.0.7] and an [2.1.0
  alpha].

  This 2.0.7 version contains backported fixes, you can find more
  information in this [blog post].

  The 2.1.0~alpha contains many new features (cf. [blog post] or
  [release note]). If you want to take a look, a few glitches or
  regressions are expected, please report them to [the bug-tracker].

  *opam is a source-based package manager for OCaml. It supports
   multiple simultaneous compiler installations, flexible package
   constraints, and a Git-friendly development workflow.*


[opam 2.0.7] <https://github.com/ocaml/opam/releases/tag/2.0.7>

[2.1.0 alpha] <https://github.com/ocaml/opam/releases/tag/2.1.0-alpha>

[blog post] <https://opam.ocaml.org/blog/opam-2-0-7>

[blog post] <https://opam.ocaml.org/blog/opam-2-1-0-alpha/>

[release note] <https://github.com/ocaml/opam/releases/tag/2.1.0-alpha>

[the bug-tracker] <https://github.com/ocaml/opam/issues>


Anil Madhavapeddy then added
────────────────────────────

  Thanks for all the hard work that's gone into this release, @rjbou
  @AltGr and @dra27!

  To set expectations, this alpha release is for our users to smoke test
  the new features and let us know if they work for your usecases.

  In particular, the opam external dependency management and support for
  recursive pins are both commonly requested features. Please do take
  this alpha for a spin, and report feedback here on this thread.

  After this alpha is cut, there will be a sequence of beta releases
  (the number of which depend on the reported bug tail), and then the
  final opam 2.1.0 release. Your testing _now_ will greatly help us put
  a quality release out of the door.


OCaml 4.11, release plan
════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-11-release-plan/5600/1>


octachron announced
───────────────────

  The new version of OCaml, OCaml 4.11.0, has started its bugfix period:
  the set of new features is now mostly frozen, and in the three
  upcoming months, we will focus mostly on fixing bugs.

  For this release cycle, we will experiment releasing an alpha version
  of the compiler.

  This new alpha version is expected to work as a synchronization point
  for people working on updating the opam ecosystem for the new
  release. Once the opam ecosystem is in shape for some wider audience
  testings, we will publish a beta version as usual. This should be
  happen around June.

  One of the most notable change in this release is `Statmemprof', a new
  statistical memory profiler directly integrated into the GC.

  The provisional Changes list is [here].

  At this point of time, it is better to take this list with a grain of
  salt: there are a handful of new features that are still under
  integration, problematic features might be removed, and of course the
  list of bug fixes is incomplete.

  But one of the most notable feature in this change log, `Statmemprof'
  which a new statistical memory profiler API, is most probably here to
  stay.


[here] <https://github.com/ocaml/ocaml/blob/4.11/Changes>


Guillaume Munch-Maccagnoni then added
─────────────────────────────────────

  It should be mentioned that Memprof is documented as “~EXPERIMENTAL~”,
  and at least one breaking change is being considered in 4.12. This
  also mean that suggestion for improvement will be welcome (AFAIU).


ocamlformat pre-commit hook
═══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocamlformat-pre-commit-hook/5602/1>


Brendan Long announced
──────────────────────

  This is kind of trivial but I figured it might be useful for other
  people. We created a hook config for using [ocamlformat] with
  [pre-commit]:

  <https://github.com/arenadotio/pre-commit-ocamlformat>

  pre-commit is a tool that makes it easier to run checks on changed
  files before commiting them, and this makes it so you can auto-run
  ocamlformat and ensure no unformatted code gets into your repo.

  1. [Install pre-commit] like `pip install pre-commit'
  2. In your repo, add a .pre-commit-config.yaml like:
     ┌────
     │ ---
     │ repos:
     │   - repo: https://github.com/arenadotio/pre-commit-ocamlformat
     │     rev: master # or pick a commit sha I guess
     │     hooks:
     │      - id: ocamlformat
     └────
  1. Run `pre-commit install'
  2. Now every time you run `git commit' (or `pre-commit run'), it will
     run every staged OCaml file through ocamlformat and complain if
     there are any changes:
     ┌────
     │ $ pre-commit run ocamlformat
     │ ocamlformat.....Failed
     │ - hook id: ocamlformat
     │ - files were modified by this hook
     │ $ git add .
     │ $ pre-commit run ocamlformat
     │ ocamlformat.....Passed
     └────


[ocamlformat] <https://github.com/ocaml-ppx/ocamlformat#ocamlformat>

[pre-commit] <https://pre-commit.com/>

[Install pre-commit] <https://pre-commit.com/#install>


New release of naboris 0.1.2
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-naboris-0-1-2/5604/1>


Shawn McGinty announced
───────────────────────

  Simple http server for OCaml/ReasonML.

  [naboris] has been updated to 0.1.2

  This release comes with a few improvements to the API but most notably
  it has much better documentation at [naboris.dev]


[naboris] <https://naboris.dev>

[naboris.dev] <https://naboris.dev>


ANN: Releases of ringo
══════════════════════

  Archive: <https://discuss.ocaml.org/t/ann-releases-of-ringo/5605/1>


Raphaël Proust announced
────────────────────────

  On behalf of Nomadic Labs, I am please to announce the first few
  releases of Ringo: a library for caches. Ringo offers two kinds of
  caches: Maps for caches of key-value pairs and Sets for caches of
  simple elements. In addition, each kind of cache can be tweaked to
  handle their bounds differently.

  Ringo versions 0.1, 0.2 and 0.3 are available on `opam'. As the
  version number and the bundled announce suggests, this library is
  still in early phases of release: additional replacement policies will
  be added, the interface will probably change somewhat,
  etc. Suggestions welcome!

  Even though the interface is still in early phases of release, the
  implementation is covered by a lot of tests and is already in use in
  the Tezos project.

  The code is available at <https://gitlab.com/nomadic-labs/ringo>


resto 0.2 released
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-resto-0-2-released/5028/3>


Raphaël Proust announced
────────────────────────

Release of `resto 0.5'
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  On behalf of Nomadic Labs, I'm happy to announce the release of
  version 0.5 of `resto'.

  The main change brought in this release are:
  • relaxing of dependency bounds,
  • documentation!


Retrofitting Parallelism onto OCaml (research paper)
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/retrofitting-parallelism-onto-ocaml-research-paper/5628/1>


Guillaume Munch-Maccagnoni announced
────────────────────────────────────

  The following paper on the multicore GC design by @kayceesrk and his
  coauthors has been posted on arXiv today and might interest the
  community: <https://arxiv.org/abs/2004.11663>


Multicore Update: April 2020, with a preprint paper
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-update-april-2020-with-a-preprint-paper/5630/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the April 2020 update from the Multicore OCaml team, across
  the UK, India, France and Switzerland!  Although most of us are in
  lockdown, we continue to march forward.  As with [previous updates],
  thanks to @shakthimaan and @kayceesrk for help assembling it all.


[previous updates] <https://discuss.ocaml.org/tag/multicore-monthly>

◊ Preprint: Retrofitting Parallelism onto OCaml

  We've put up a preprint of a paper titled ["Retrofitting Parallelism
  onto OCaml" ] for which we would be grateful to receive feedback.  The
  paper lays out the problem space for the multicore extension of OCaml
  and presents the design choices, implementation and evaluation of the
  concurrent garbage collector (GC).

  Note that this is *not a final paper* as it is currently under peer
  review, so any feedback given now can still be incorporated.  Please
  use the e-mail contact details in the [pdf paper] for @kayceesrk and
  myself so we can aggregate (and acknowledge!) any such comments.


  ["Retrofitting Parallelism onto OCaml" ]
  <https://arxiv.org/abs/2004.11663>

  [pdf paper] <https://arxiv.org/pdf/2004.11663.pdf>


◊ Rebasing Progress

  The Multicore OCaml rebase from 4.06.1 has gained momentum.  We have
  successfully rebased the parallel-minor-GC all the way onto the [4.09
  OCaml trees].  We will publish updated opam packages when we get to
  the recently branched 4.11 in the next couple of weeks.

  Rebasing complex features like this is a "slow and steady" process due
  to the number of intermediate conflicts and bootstrapping, so we will
  not be publishing opam packages for every intermediate version –
  instead, the 4.11 trees will form the new "stable base" for any PRs.


  [4.09 OCaml trees]
  <https://github.com/ocaml-multicore/ocaml-multicore/tree/parallel_minor_gc_4_09>


◊ Higher-level Domainslib API

  A thread from [last month's update] on building a parallel raytracer
  led to some useful advancements in the [domainslib] library to provide
  async/await-style task support. See the updates below for more
  details.

  There is also an interesting discussion on
  [ocaml-multicore/ocaml-multicore#324] about how to go about profiling
  and optimising your own small programs.  More experiments with
  parallel algorithms with different scheduling properties would be most
  useful at this time.


  [last month's update]
  <https://discuss.ocaml.org/t/multicore-ocaml-march-2020-update/5406/8>

  [domainslib] <https://github.com/ocaml-multicore/domainslib>

  [ocaml-multicore/ocaml-multicore#324]
  <https://github.com/ocaml-multicore/ocaml-multicore/issues/324>


◊ Upstreamed features in 4.11

  The [4.11 release has recently branched] and has the following
  multicore-relevant changes in it:

  • A concurrency-safe marshalling implementation (originally in
    [ocaml#9293], then implemented again in [ocaml#9353]). This will
    have a slight speed hit to marshalling-heavy programs, so feedback
    on trying this in your projects with 4.11 will be appreciated to the
    upstream OCaml issue tracker.
  • A runtime eventlog tracing system using the CTF format is on the
    verge of being merged in 4.11 over in [ocaml#9082].  This will also
    be of interest to those who need sequential program profiling, and
    is a generalisation of the infrastructure that was essential to our
    development of the multicore GC.  If anyone is interested in helping
    with hacking on the OCaml side of CTF support to build clients,
    please get in touch with me or @kayceesrk.

  In addition to the above highlights, we have also been making
  continuous improvements and additions to the Sandmark benchmarking
  test infrastructure. The various ongoing and completed tasks are
  provided below for your reference.


  [4.11 release has recently branched]
  <https://discuss.ocaml.org/t/ocaml-4-11-release-plan/5600>

  [ocaml#9293] <https://github.com/ocaml/ocaml/pull/9293>

  [ocaml#9353] <https://github.com/ocaml/ocaml/pull/9353>

  [ocaml#9082] <https://github.com/ocaml/ocaml/pull/9082>


Multicore OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

◊ Ongoing

  • [ocaml-multicore/ocaml-multicore] Promote Multicore OCaml to trunk

    The rebasing of Multicore OCaml from 4.06 to 4.10 is being worked,
    and we are now at 4.09! In a few weeks, we expect to complete the
    rebase to the latest trunk release.
  • [ocaml-multicore/eventlog-tools]: OCaml Eventlog Tools

    A project that provides a set of tools for runtime tracing for OCaml
    4.11.0 and higher has been created. This includes a simple OCaml
    decoder for eventlog's trace and a built-in chrome converter tool.
  • [ocaml-multicore/domainslib#5] Add parallel_scan to domainslib

    A [parallel_scan] implementation that uses the Task API with
    prefix_sum and summed_area_table has now been added to the
    Domain-level Parallel Programming library for Multicore OCaml
    (domainslib) library.


  [ocaml-multicore/ocaml-multicore]
  <https://github.com/ocaml-multicore/ocaml-multicore/tree/parallel_minor_gc_4_09>

  [ocaml-multicore/eventlog-tools]
  <https://github.com/ocaml-multicore/eventlog-tools>

  [ocaml-multicore/domainslib#5]
  <https://github.com/ocaml-multicore/domainslib/pull/5>

  [parallel_scan]
  <https://en.wikipedia.org/wiki/Prefix_sum#Shared_memory:_Two-level_algorithm>


◊ Completed

  The following PRs have been merged into Multicore OCaml and its
  ecosystem projects:

  • [ocaml-multicore/ocaml-multicore#328] Multicore compiler with
    Flambda

    Support for Flambda has been merged into the Multicore OCaml project
    repository. The translation is now performed at cmmgen instead of
    lambda for clambda conversion.
  • [ocaml-multicore/ocaml-multicore#324] Optimizing a Multicore program

    The following [documentation] provides a detailed example on how to
    do performance debugging for a Multicore program to improve the
    runtime performance.
  • [ocaml-multicore/ocaml-multicore#325] Added eventlog_to_latencies.py
    script

    A script to generate a latency report from an eventlog has now been
    included in the ocaml-multicore repository.
  • [ocaml-multicore/domainslib#4] Add support for task_pools

    The domainslib library now has support for work-stealing task pools
    with async/await parallelism. You are encouraged to try the
    [examples].


  [ocaml-multicore/ocaml-multicore#328]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/328>

  [ocaml-multicore/ocaml-multicore#324]
  <https://github.com/ocaml-multicore/ocaml-multicore/issues/324>

  [documentation]
  <https://github.com/ocaml-multicore/ocaml-multicore/issues/324#issuecomment-610183856>

  [ocaml-multicore/ocaml-multicore#325]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/325>

  [ocaml-multicore/domainslib#4]
  <https://github.com/ocaml-multicore/domainslib/pull/4>

  [examples]
  <https://github.com/ocaml-multicore/domainslib/tree/task_pool/test>


Benchmarking
╌╌╌╌╌╌╌╌╌╌╌╌

  A number of new benchmarks are being ported to the [Sandmark]
  performance benchmarking test suite.

  • [ocaml-bench/sandmark#104] Added python pip3 dependency

    A check_dependency function has now been defined in the Makefile
    along with a list of dependencies and pip packages for Ubuntu. You
    can now run `make depend' prior to building the benchmark suite to
    ensure that you have the required software. The `python3-pip'
    package has been added to the list of dependencies.
  • [ocaml-bench/sandmark#96] Sandmark Analyze notebooks

    The setup, builds and execution scripts for developer branches on
    bench2.ocamllabs.io have been migrated to winter.ocamllabs.io.

    A UI and automated script driven notebooks for analyzing sequential
    bench results is being worked upon.
  • [ocaml-bench/sandmark#108] Porting mergesort and matrix
    multiplication using Task Pool API library

    This is an on-going PR to implement merge sort and
    matrix_multiplication using `parallel_for'.
  • [cubicle]

    `Cubicle' is a model checker and an automatic SMT theorem prover. At
    present, it is being ported to Multicore OCaml, and this is a work
    in progress.
  • [raytracers]

    Raytracers is a repository that contains ray tracer implementation
    for different parallel functional programming languages. The OCaml
    implementation has now been updated to use the new `Domainslib.Task'
    API.

    Also, a few [experiments] were performed on flambda parameters for
    the Multicore raytracer which gives around 25% speedup, but it does
    not yet remove the boxing of floats. The experiments are to be
    repeated with a merge against the wip flambda2 trees on 4.11, that
    removes float boxing.


[Sandmark] <https://github.com/ocaml-bench/sandmark>

[ocaml-bench/sandmark#104]
<https://github.com/ocaml-bench/sandmark/pull/104>

[ocaml-bench/sandmark#96]
<https://github.com/ocaml-bench/sandmark/issues/96>

[ocaml-bench/sandmark#108]
<https://github.com/ocaml-bench/sandmark/pull/108>

[cubicle] <https://github.com/Sudha247/cubicle/tree/add-multicore>

[raytracers] <https://github.com/athas/raytracers/pull/6>

[experiments]
<https://github.com/kayceesrk/raytracers/blob/flambda/ocaml/myocamlbuild.ml>


OCaml
╌╌╌╌╌

◊ Ongoing

  • [ocaml/ocaml#9082] Eventlog tracing system

    A substantial number of commits have gone into this PR based on
    reviews and feedback. These include updates to the configure script,
    handling warnings and exceptions, adding build support for Windows,
    removing unused code and coding style changes. This patch will be
    cherry-picked for the 4.11 release.


  [ocaml/ocaml#9082] <https://github.com/ocaml/ocaml/pull/9082>


◊ Completed

  • [ocaml/ocaml#9353] Reimplement `output_value' using a hash table to
    detect sharing

    This PR which implements a hash table and bit vector as required for
    Multicore OCaml has been merged to 4.11.

  Our thanks as always go to all the OCaml developers and users in the
  community for their continued support, and contribution to the
  project!


  [ocaml/ocaml#9353] <https://github.com/ocaml/ocaml/pull/9353>


Acronyms
╌╌╌╌╌╌╌╌

  • API: Application Programming Interface
  • GC: Garbage Collector
  • PIP: Pip Installs Python
  • PR: Pull Request
  • SMT: Satisfiability Modulo Theories
  • UI: User Interface


Why did Core remove polymorphic comparison operators in OCaml 4.10.0?
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/why-did-core-remove-polymorphic-comparison-operators-in-ocaml-4-10-0/5633/1>


Trung Ta asked
──────────────

  I'm using the Core library in a project, and recently when I upgraded
  my OCaml from 4.08.1 to 4.10.0, plenty of compilation errors suddenly
  appears for comparison expressions like:

  `if (xs = []) then ...'  or `if (x = true) then ...'

  I saw that this change was discussed in this [thread] about
  monomorphic comparison operators in Base, but did not expect that Core
  would make it a default behavior.

  So I'd like to ask since which version that Core removed such
  polymorphic comparison operators?  (I couldn't find it in release
  notes of Core)

  Also, if I defined a sum type like `type ternary = True | False |
  Unkn', what will be a correct way to write `if (x = True) then ...'
  (which is allowed in the new Core)?

  I can temporarily fix by writing `if (x == True) then ...', but using
  `==' doesn't seem correct, since `==' is about comparing physical
  objects…

  Thanks for spending your time to check my question.


[thread]
<https://discuss.ocaml.org/t/monomorphic-comparison-operator-of-janestreet-base-library/1585>


Aaron L. Zeng replied
─────────────────────

  The change was announced in
  <https://discuss.ocaml.org/t/ann-v0-13-release-of-jane-street-packages/4735>,
  although unfortunately it doesn't look like the CHANGES.md file was
  updated in the repo.  I would consider the thread to be the canonical
  announcement.

        Also, if I defined a sum type like `type ternary = True |
        False | Unkn' , what will be a correct way to write `if (x
        = True) then ...' (which is allowed in the new Core)?

  Here's a few suggestions:

  1. Define equality/compare functions using [`ppx_compare']
     ┌────
     │ type ternary = True | False | Unkn [@@deriving equal]
     │ 
     │ let f x = if (equal_ternary x True) then ...
     └────
  2. Define equality/compare functions manually
     ┌────
     │ let equal_ternary t1 t2 =
     │   match t1, t2 with
     │   | True, True | False, False | Unkn, Unkn -> true
     │   | _ -> false
     └────
  3. Explicitly request polymorphic comparison operators using the
     `Poly' module:
     ┌────
     │ let f x = if (Poly.(=) x True) then ...
     └────


[`ppx_compare'] <https://github.com/janestreet/ppx_compare>


Trung said and Aaron L. Zeng replied
────────────────────────────────────

        btw,

        ┌────
        │ type ternary = True | False | Unkn [@@deriving equal]
        └────

        should be: `[@@deriving eq]'

  That depends on which preprocessor you are using.  `[@@deriving
  equal]' comes from ppx_compare, whereas `[@@deriving eq]' comes from
  [ppx_deriving].  Base/Core and the like have better support for the
  former, which is a Jane Street project, although you can feel free to
  use the latter—the naming conventions are different, so it may not be
  as convenient.


[ppx_deriving] <https://github.com/ocaml-ppx/ppx_deriving>


New release of js_of_ocaml 3.6.0
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-new-release-of-js-of-ocaml-3-6-0/5634/1>


Hhugo announced
───────────────

  I'm pleased to announce the release [Js_of_ocaml] 3.6.0.

  Js_of_ocaml is a compiler from OCaml bytecode to JavaScript. It makes
  it possible to run pure OCaml programs in JavaScript environment like
  browsers and Node.js.

  Try it [online].

  Notable changes:
  • The `js_of_ocaml' compiler now accepts sub-commands (link,
    build-runtime, build-fs, ..). The plan for future versions is to
    remove other binary (e.g. jsoo_link) and consolidate everything
    inside the `js_of_ocaml' binary itself.
  • The standard JavaScript runtime is now embedded in the compiler
    (findlib is no longer needed to locate it)
  • Add support for the Str library (Regular expressions and high-level
    string processing) shipped with the OCaml compiler
  • Change memory representation of `Int64.t' (you might need to update
    your JavaScript stubs)
  • Many bug fixes (thanks to many more tests)


[Js_of_ocaml] <https://github.com/ocsigen/js_of_ocaml>

[online]
<https://ocsigen.org/js_of_ocaml/3.6.0/manual/files/toplevel/index.html>


Kirill Alexander Khalitov asked and Hhugo replied
─────────────────────────────────────────────────

        1 Does the project have roadmap?

  There is no official roadmap, the project evolves based on issues,
  requests and contributions.  You can take a look at some of the
  [Github issues]

        2 Is the project generally exists only for Ocsigen needs?

  js_of_ocaml is used by various projects, not only Ocsigen. See
  [Bonsai], [sketch-sh] or [jscoq] for instance.

        3 Will it be adopted for modern front-end development
        (commonjs/esmodules compatibility for working with
        existing building tools ex. webpack, etc).

  Being more friendly with the JavaScript ecosystem as been discussed
  here and there in the past but little has been done, possibly by lack
  of interest or use cases.

        4 Does the project competing with bucklescript?

  I don't think so. The two projects have different goals and different
  audience. One of Js_of_ocaml main goal is to stay as close as possible
  to the official OCaml semantic, allowing to leverage existing OCaml
  libraries without any modification.

        5 Why not to do ocaml to js compiler tools (based on
        js_of_ocaml and bucklescript experience) that combine
        possibility of using native ocaml and js libraries across
        back-end and front-end like implemented in Scala.js/Fable
        F#?

  I don't understand this question. I would expect both js_of_ocaml and
  bucklescript to be like Scala.js/Fable F# in their own way.


[Github issues]
<https://github.com/ocsigen/js_of_ocaml/issues?q=is:open+is:issue+label:enhancement>

[Bonsai] <https://github.com/janestreet/bonsai>

[sketch-sh] <https://github.com/Sketch-sh/sketch-sh>

[jscoq] <https://github.com/jscoq/jscoq>


Kirill Alexander Khalitov then said
───────────────────────────────────

  I mean what Scala.js/Fable F# allows to use the most native libraries
  (not all) and JS ones (from npm registry or from custom JS module) in
  one project (ex. front-end). But in case of js_of_ocaml we limited to
  native OCaml libs and "HTML scripts" (not JS compatible modules). For
  bucklescript case we have whole JS ecosystem but have no access to
  useful native libs from opam registry.


Xavier Van de Woestyne replied
──────────────────────────────

  In Js_of_OCaml, you can deal with JavaScript's module (and npm/yarn),
  using for example:

  ┌────
  │ (* val require : string -> 'a *)
  │ let require module_name =
  │   let open Js.Unsafe in
  │   fun_call
  │     (js_expr "require")
  │     [|inject (Js.string module_name)|]
  └────


Other OCaml News
════════════════

>From the ocamlcore planet blog
──────────────────────────────

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [Every proof assistant]
  • [opam 2.0.7 release]
  • [opam 2.1.0 alpha is here!]


[OCaml Planet] <http://ocaml.org/community/planet/>

[Every proof assistant]
<http://math.andrej.com/2020/04/28/every-theorem-prover/>

[opam 2.0.7 release]
<http://www.ocamlpro.com/2020/04/21/opam-2-0-7-release/>

[opam 2.1.0 alpha is here!]
<http://www.ocamlpro.com/2020/04/21/opam-2-1-0-alpha-is-here/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-04-21  8:58 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-04-21  8:58 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of April 14 to 21,
2020.

Table of Contents
─────────────────

Current_incr: a small incremental library with no dependencies
Scikit-learn for OCaml
OCaml and opam container images updated: new Fedora/Alpine/Ubuntu images
OCamlformat 0.14.0
Hashconsing an AST via PPX
Genprint v0.4
Other OCaml News
Old CWN


Current_incr: a small incremental library with no dependencies
══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-current-incr-a-small-incremental-library-with-no-dependencies/5531/1>


Thomas Leonard announced
────────────────────────

  The recent [OCurrent 0.2] release included a little incremental
  library which might be interesting to some people. It is useful for
  writing programs that need to keep some computation up-to-date
  efficiently as the inputs change.

  It is similar to the existing [incremental] and [react] libraries
  already in opam. Unlike `incremental' (which pulls in the whole of
  `core_kernel'), `current_incr' has no runtime dependencies (and build
  dependencies only on `ocaml' and `dune'). Unlike `react',
  `current_incr' immediately stops computations when they are no longer
  needed (rather than relying on weak references and the garbage
  collector).

  It is a fairly direct implementation of the [Adaptive Functional
  Programming] paper, and might be a good starting point for people
  wanting to learn about that.

  You can get the library using `opam':

  ┌────
  │ opam install current_incr
  └────

  Here's a simple example (in utop):

  ┌────
  │ #require "current_incr";;
  │
  │ let total = Current_incr.var 10
  │ let complete = Current_incr.var 5
  │
  │ let status =
  │   Current_incr.of_cc begin
  │     Current_incr.read (Current_incr.of_var total) @@ function
  │     | 0 -> Current_incr.write "No jobs"
  │     | total ->
  │       Current_incr.read (Current_incr.of_var complete) @@ fun complete ->
  │       let frac = float_of_int complete /. float_of_int total in
  │       Printf.sprintf "%d/%d jobs complete (%.1f%%)"
  │ 		     complete total (100. *. frac)
  │       |> Current_incr.write
  │   end
  └────

  This defines two input variables (`total' and `complete') and a
  "changeable computation" (`status') whose output depends on them. At
  the top-level, we can observe the initial state using `observe':

  ┌────
  │ # print_endline @@ Current_incr.observe status;;
  │ 5/10 jobs complete (50.0%)
  └────

  Unlike a plain `ref' cell, a `Current_incr.var' keeps track of which
  computations depend on it. After changing them, you must call
  `propagate' to update the results:

  ┌────
  │ # Current_incr.change total 12;;
  │ # Current_incr.change complete 4;;
  │ # print_endline @@ Current_incr.observe status;;
  │ 5/10 jobs complete (50.0%)	(* Not yet updated *)
  │
  │ # Current_incr.propagate ();
  │ # print_endline @@ Current_incr.observe status;;
  │ 4/12 jobs complete (33.3%)
  └────

  Computations can have side-effects, and you can use `on_release' to
  run some compensating action if the computation needs to be undone
  later. Here's a function that publishes a result, and also registers a
  compensation for it:

  ┌────
  │ let publish msg =
  │   Printf.printf "PUBLISH: %s\n%!" msg;
  │   Current_incr.on_release @@ fun () ->
  │   Printf.printf "RETRACT: %s\n%!" msg
  └────

  It can be used like this:

  ┌────
  │ # let display = Current_incr.map publish status;;
  │ PUBLISH: 4/12 jobs complete (33.3%)
  │
  │ # Current_incr.change total 0;
  │ # Current_incr.propagate ()
  │ RETRACT: 4/12 jobs complete (33.3%)
  │ PUBLISH: No jobs
  └────

  A major difference between this and the react library (which I've used
  in previously in [0install's progress reporting] and [CueKeeper]) is
  that `Current_incr' does not depend on the garbage collector to decide
  when to stop a computation. In react, you'd have to be careful to make
  sure that `display' didn't get GC'd (even though you don't need to
  refer to it again) because if it did then the output would stop
  getting updated. Also, setting `total' to `0' in react might cause the
  program to crash with a division-by-zero exception, because the `frac'
  computation will continue running until it gets GC'd, even though it
  isn't needed for anything now.

  [`Current_incr''s API] is pretty small. You might want to wrap it to
  provide extra features, e.g.

  • Use of a `result' type to propagate errors.
  • Integration with `Lwt' to allow asynchronous computations.
  • Static analysis to render your computation with graphviz.
  • Persistence of state to disk.

  If you need that, consider using the main [OCurrent] library, which
  extends `current_incr' with these features.


[OCurrent 0.2] <https://github.com/ocurrent/ocurrent/releases/tag/v0.2>

[incremental] <https://github.com/janestreet/incremental>

[react] <https://erratique.ch/software/react>

[Adaptive Functional Programming]
<https://www.cs.cmu.edu/~guyb/papers/popl02.pdf>

[0install's progress reporting]
<https://stackoverflow.com/questions/19975140/how-to-stop-ocaml-garbage-collecting-my-reactive-event-handler>

[CueKeeper]
<https://roscidus.com/blog/blog/2015/06/22/cuekeeper-internals-irmin/>

[`Current_incr''s API]
<https://ocurrent.github.io/ocurrent/current_incr/Current_incr/index.html>

[OCurrent] <https://github.com/ocurrent/ocurrent>


Scikit-learn for OCaml
══════════════════════

  Archive: <https://discuss.ocaml.org/t/scikit-learn-for-ocaml/5536/1>


UnixJunkie announced
────────────────────

  Ronan Lehy just hacked this:

  <https://github.com/lehy/ocaml-sklearn>

  This might interest a significant number of people out there.  We are
  no more condemned to live in a world full of snakes that will bite us
  at run-time. :smiley:


Ronan Le Hy then said
─────────────────────

  So I came here to announce ocaml-sklearn as it just got published on
  Opam, but I see @UnixJunkie did it for me (arigato gozai
  masu). Anyway:
  • this ambitions to cover the complete scikit-learn API
  • this ambition is currently not totally realized, but I wanted to
    release something initial that one can play with
  • it's all @UnixJunkie's fault with his funny R wrappers.

  So:
  • opam install sklearn
  • go check out [scikit-learn and its awesome documentation] to know
    what it does
  • look at [ocaml-sklearn's documentation] to see what the current
    OCaml API looks like
  • have fun with it and tell me what you think of it.


[scikit-learn and its awesome documentation] <https://scikit-learn.org>

[ocaml-sklearn's documentation] <https://lehy.github.io/ocaml-sklearn/>


Anton Kochkov then added
────────────────────────

  Probably worth to add here:
  • <https://github.com/ocaml-community/awesome-ocaml#machine-learning>


OCaml and opam container images updated: new Fedora/Alpine/Ubuntu images
════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-and-opam-container-images-updated-new-fedora-alpine-ubuntu-images/5539/1>


Anil Madhavapeddy announced
───────────────────────────

  The Docker [ocaml and opam container images] have been updated:

  • Alpine 3.11, Fedora 31 and Ubuntu 20.04 (beta) are now included.
  • Ubuntu 19.04 and Fedora 29 and 30 are now deprecated.
  • OCaml 4.09.1 and 4.11.0~dev have been refreshed.

  You can find the full details of the container images available [on
  the OCaml infrastructure wiki].

  The containers are generated from a set of scripts using
  [ocaml-dockerfile], and will be migrating over the next six months to
  use an [ocurrent]-based infrastructure. There will be an announcement
  on this forum about any user-facing changes that involves, with plenty
  of time to transition your own CIs over.  Thanks go to @talex5 and
  @XVilka for contributions to this round of updates.


[ocaml and opam container images] <https://hub.docker.com/r/ocaml/opam2>

[on the OCaml infrastructure wiki]
<https://github.com/ocaml/infrastructure/wiki/Containers>

[ocaml-dockerfile] <https://github.com/avsm/ocaml-dockerfile>

[ocurrent] <https://ocurrent.org>


OCamlformat 0.14.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocamlformat-0-14-0/5435/24>


Jules announced
───────────────

  As Etienne mentioned, we have released OCamlformat 0.14.1, reverting
  the change to the defaults and our plans to deprecate the
  `doc-comments' option.

  For projects that already upgraded to 0.14.0 (eg. Coq), the
  `doc-comments' option will change its meaning again. It is necessary
  to add `doc-comments=before' to have the documentation comments placed
  before.  Moreover, the new option `doc-comments-val' added in 0.14.0
  has a higher precedence than `doc-comments', even when it's not
  set. It is thus necessary to set them both to `before' to have the old
  "before" behavior.  This will be improved in the next release (see
  <https://github.com/ocaml-ppx/ocamlformat/pull/1340>).

  Thank you to our early adopters to bear us. We are improving our
  release process to reduce confusion for the next updates. As usual, if
  you have any feedback, please open an issue on
  <https://github.com/ocaml-ppx/ocamlformat> to discuss it with us.


Hashconsing an AST via PPX
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/hashconsing-an-ast-via-ppx/5558/1>


Chet Murthy announced
─────────────────────

  [up-front (so nobody gets the wrong idea): I'm not pushing Camlp5.
  Rather, I'm just noting that this sort of thing is really easy to do,
  and I encourage someone to do something similar using the PPX
  infrastructure.]

  I didn't want to derail the "Future of PPX" thread, so I thought I'd
  post separately to answer ivg@ 's issue about hashconsing of ASTs
  using PPX.  It's actually [uh, I think] really, really easy to
  implement hashconsing of ADTs, using a PPX extension.  On a lark, I
  decided to do it *today*, and while the code I've got isn't sufficient
  to use, I think it's not very far away, and I have the perfect
  use-case already in-mind.  It took me two hours to implement the
  rewriter and the testcase, on top of the other infrastructure, which
  has no support for hashconsing of any sort.

  Here are some examples of data-types and functions that are
  automaticaly hash-consed.  The idea is that in the pattern-match the
  pattern is annotated with a variable (in this example, "z"); the
  expression that is supposed to be hash-consed against that pattern is
  annotated with that same variable.  [The code that descends to the
  expression is a little weak right now, but I think that's easily
  fixable.]  The algorithm goes as follows:

  (1) "decorate" the pattern with "as z_<integer>" variables everywhere
  in constructors.  This allows us to refer to parts of the original
  value.

  (2) then find each expression that is marked with that same varable.
  Structurally descend the pattern and the expression in parallel and
  generate code to compare sub-structure and hashcons where appropriate.

  And that's really it.  I'm sure this can be implemented using the PPX
  tools.

  Some comments: (1) what's nice, is that we can just take
  already-written code like `List.map' and annotate it; that generates a
  hash-consed version.  And since the generated code never uses deep
  structural equality (only pointer-equality) it should be only
  marginally slower than the original implementation.

  (2) The variable in the annotation ("z") is used as the base for
  generating a whole slew of fresh variables, and I don't bother (yet)
  to check for clashes; this (again) is straightforward, but hey, I
  started two hours ago.

  ┌────
  │ type t = Leaf of int | Node of t * int * t
  │
  │ module HCList = struct
  │
  │ let rec map f = function
  │     [][@hashrecons z] -> [][@hashrecons z]
  │   | (a::l)[@hashrecons z] -> let r = f a in ((r :: map f l)[@hashrecons z])
  │
  │ end
  │
  │ let deep =
  │ let rec deep = (function
  │   Leaf n[@hashrecons z] -> Leaf n[@hashrecons z]
  │ | Node (l, n, r) [@hashrecons z] ->
  │   Node (deep l, n, deep r) [@hashrecons z]
  │   )
  │ [@@ocaml.warning "-26"]
  │ in deep
  │
  │ type sexp =
  │   | Atom of string
  │   | List of sexp list
  │
  │ let sexp_deep =
  │   let rec deep = function
  │       Atom s[@hashrecons z] -> Atom s[@hashrecons z]
  │     | List l[@hashrecons z] -> List (HCList.map deep l)[@hashrecons z]
  │   in deep
  └────

  Links: First, at the commit, so they won't change

  the testcase file:
  <https://github.com/chetmurthy/pa_ppx/commit/5dd6b2ef3ca3677e11a0ad696074200101bd661f#diff-e6dffe78fc6c27bdffa41970c4a7f1ca>

  the "ppx rewriter":
  <https://github.com/chetmurthy/pa_ppx/commit/5dd6b2ef3ca3677e11a0ad696074200101bd661f#diff-24aeaf51366017948f5735727f001c85>

  Second, the files with human-readable names, etc.:

  the testcase:
  <https://github.com/chetmurthy/pa_ppx/blob/master/tests/test_hashrecons.ml>

  the "ppx rewriter":
  <https://github.com/chetmurthy/pa_ppx/blob/master/pa_hashrecons/pa_hashrecons.ml>

  The projects:

  chetmurthy/pa_ppx: A reimplementation of ppx_deriving, all its
  plugins, ppx_import, and a few others.

  <https://github.com/chetmurthy/pa_ppx>

  chetmurthy/camlp5: Camlp5, version pre-8.00 on which the above is
  based.  This is on the branch 26.attempt-pa-deriving .


Kakadu said
───────────

  I experimented with this some time ago for ML workshop.  The idea was
  to provide function: `t -> htbl -> htbl * t' which rewrites value of
  type `t' by removing equal subtrees. Essentially it is just a fold
  over data type.

  <https://github.com/kakadu/GT/blob/master/regression/test816hash.ml#L74>


Chet Murthy asked and Josh Berdine replied
──────────────────────────────────────────

        If you wanna use a hashtable (and, I presume, Obj.magic)
        you can write a single function that does the trick for
        all immutable data-types, right?

  Yes, we have some magic @mbouaziz [code] in Infer that does this to
  create as much sharing as possible as values are Marshaled out.


[code]
<https://github.com/facebook/infer/blob/master/infer/src/istd/MaximumSharing.ml>


Genprint v0.4
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-genprint-v0-4/5575/1>


progman announced
─────────────────

  A re-announcement of Genprint, a general value printing library, that
  addresses prior limitations that made it none too useful!

  1. It didn't work correctly for 4.08.0, the latest compiler release as
     of first announcement (though fine for 4.02 .. 4.07.1)
  2. There was an awkward need to specify a search path for .cmt files
     when working with the likes of Dune (which uses separate
     directories for source, .cmi and (for opt) .cmt files)
  3. More often than not values of interest would display simply as
     `<abstr>' owing to the presence of signature abstraction of the
     module's type of interest.

  These issues have been addressed:
  1. Works with versions 4.04 .. 4.10.0 (earlier versions became invalid
     after a dependency change to ppxlib)
  2. The location of .cmt files is captured automatically by the PPX
     preprocessor.
  3. Signatures at the implementation level (.mli files) and internally
     (functor application constraints) are removed to reveal the inner
     structure of otherwise abstract values.  For instance, the
     Ephemeron module:
     ┌────
     │ module EM=Ephemeron.K1.Make(struct type t=int let equal=(=) let hash=Hashtbl.hash end)
     │ open EM
     │ let _=
     │   let v=EM.create 0 in
     │   EM.add v 12345678 'X';
     │   let emprint ppf (v: Obj.Ephemeron.t) =
     │     Format.fprintf ppf "<C wrapper of key/data>" in
     │   [%install_printer emprint];
     │   [%pr ephem v];
     └────

     Which prints:
     ┌────
     │ ephem => {size = 1;
     │           data =
     │            [|Empty; Empty; Empty; Empty; Empty; Empty; Empty; Empty; Empty;
     │              Empty; Empty; Cons (922381915, <C wrapper of key/data>, Empty);
     │              Empty; Empty; Empty; Empty|];
     │           seed = 0; initial_size = 16}
     └────
     This also demos the [%install_printer] facility which mirrors the
     REPL's.

  Installation is via the Opam main repository.

  Additionally, the project repository [contains] two compiler versions
  of _ocamldebug_ integrated with the Genprint library which thereby
  becomes its default printer.

  All of which makes this library much more useful than previously.  See
  the [project page] for the details.


[contains]
<https://github.com/progman1/genprintlib/tree/master/debugger>

[project page] <https://github.com/progman1/genprintlib>


Other OCaml News
════════════════

From the ocamlcore planet blog
──────────────────────────────

  Editor note: Thanks to [ezcurl], I can restore this section. I'm
  putting all the links this week, I will prune to only put the new ones
  next week.

  Here are links from many OCaml blogs aggregated at [OCaml Planet].

  • [An in-depth Look at OCaml’s new “Best-fit” Garbage Collector
    Strategy]
  • [Sliding Tile Puzzle, Self-Contained OCaml Webapp]
  • [New version of Try OCaml in beta!]
  • [Frama-Clang 0.0.8 is out. Download it here.]
  • [A reasonable TyXML release | Drup's thingies]
  • [Alt-Ergo Users’ Club Annual Meeting]
  • [OCaml iOS Apps Ported to Browser]
  • [Watch all of Jane Street's tech talks]
  • [Mercurial: prettyconfig extension]
  • [Mercurial extensions (update)]
  • [2019 at OCamlPro]
  • [Bitbucket repository migration]
  • [Troubleshooting systemd with SystemTap]
  • [Ocsigen Start updated]
  • [Ocsigen Start updated]
  • [opam 2.0.6 release]
  • [opam 2.0.6 release]
  • [Hackers and climate activists join forces in Leipzig]
  • [Deploying authoritative OCaml-DNS servers as MirageOS unikernels]
  • [Reproducible MirageOS unikernel builds]
  • [Using Python and OCaml in the same Jupyter notebook]
  • [Coq 8.11+beta1 is out]
  • [Deep-Learning the Hardest Go Problem in the World]
  • [Frama-C 20.0 (Calcium) is out. Download it here.]
  • [Testing OCaml releases with opamcheck]
  • [Coq 8.10.2 is out]
  • [Announcing Irmin 2.0.0]
  • [BAP 2.0 is released]
  • [CI/CD pipelines: Monad, Arrow or Dart?]
  • [On fixed-point theorems in synthetic computability]
  • [Runners in action]
  • [Coq 8.10.1 is out]
  • [Announcing MirageOS 3.6.0]
  • [Commas in big numbers everywhere: An OpenType adventure]
  • [Coq 8.10.0 is out]
  • [OCaml expert and beginner training by OCamlPro (in French):
    Nov. 5-6 & 7-8]
  • [Mr. MIME - Parse and generate emails]
  • [A look back on OCaml since 2011]
  • [Frama-C 19.1 (Potassium) is out. Download ithere.]
  • [Coq 8.10+beta3 is out]
  • [Updated Cheat Sheets: OCaml Language and OCaml Standard Library]
  • [Frama-Clang 0.0.7 is out. Download ithere.]
  • [Decompress: Experiences with OCaml optimization]
  • [On complete ordered fields]
  • [An introduction to fuzzing OCaml with AFL, Crowbar and Bun]
  • [What is algebraic about algebraic effects?]
  • [The blog moved from Wordpress to Jekyll]
  • [OCamlPro’s compiler team work update]
  • [What the interns have wrought, 2019 edition]
  • [Decompress: The New Decompress API]


[ezcurl] <https://github.com/c-cube/ezcurl>

[OCaml Planet] <http://ocaml.org/community/planet/>

[An in-depth Look at OCaml’s new “Best-fit” Garbage Collector Strategy]
<http://www.ocamlpro.com/2020/03/23/ocaml-new-best-fit-garbage-collector/>

[Sliding Tile Puzzle, Self-Contained OCaml Webapp]
<http://psellos.com/2020/03/2020.03.how-i-wrote-elastic-man.html>

[New version of Try OCaml in beta!]
<http://www.ocamlpro.com/2020/03/16/new-version-of-try-ocaml-in-beta/>

[Frama-Clang 0.0.8 is out. Download it here.]
<http://frama-c.com/index.html>

[A reasonable TyXML release | Drup's thingies]
<https://drup.github.io/2020/03/06/tyxml440/>

[Alt-Ergo Users’ Club Annual Meeting]
<http://www.ocamlpro.com/2020/03/03/alt-ergo-userss-club-annual-meeting/>

[OCaml iOS Apps Ported to Browser]
<http://psellos.com/2020/02/2020.02.kid-charlemagne.html>

[Watch all of Jane Street's tech talks]
<https://blog.janestreet.com/watch-all-of-jane-streets-tech-talks/>

[Mercurial: prettyconfig extension]
<http://blog.0branch.com/posts/2020-02-15-prettyconfig-extension.html>

[Mercurial extensions (update)]
<http://blog.0branch.com/posts/2020-02-05-hg-extensions.html>

[2019 at OCamlPro]
<http://www.ocamlpro.com/2020/02/04/2019-at-ocamlpro/>

[Bitbucket repository migration]
<http://blog.0branch.com/posts/2020-02-03-bitbucket-migration.html>

[Troubleshooting systemd with SystemTap]
<https://blog.janestreet.com/troubleshooting-systemd-with-systemtap/>

[Ocsigen Start updated]
<https://ocsigen.github.io/blog/2020/01/20/release/>

[opam 2.0.6 release]
<http://www.ocamlpro.com/2020/01/16/opam-2-0-6-release/>

[opam 2.0.6 release] <https://opam.ocaml.org/blog/opam-2-0-6/>

[Hackers and climate activists join forces in Leipzig]
<https://mirage.io/blog/ccc-2019-leipzig>

[Deploying authoritative OCaml-DNS servers as MirageOS unikernels]
<https://hannes.nqsb.io/Posts/DnsServer>

[Reproducible MirageOS unikernel builds]
<https://hannes.nqsb.io/Posts/ReproducibleOPAM>

[Using Python and OCaml in the same Jupyter notebook]
<https://blog.janestreet.com/using-python-and-ocaml-in-the-same-jupyter-notebook/>

[Coq 8.11+beta1 is out]
<https://coq.inria.fr/news/coq-8-11beta1-is-out.html>

[Deep-Learning the Hardest Go Problem in the World]
<https://blog.janestreet.com/deep-learning-the-hardest-go-problem-in-the-world/>

[Frama-C 20.0 (Calcium) is out. Download it here.]
<http://frama-c.com/index.html>

[Testing OCaml releases with opamcheck]
<http://gallium.inria.fr/blog/an-ocaml-release-story-1>

[Coq 8.10.2 is out] <https://coq.inria.fr/news/coq-8-10-2-is-out.html>

[Announcing Irmin 2.0.0] <https://mirage.io/blog/introducing-irmin-v2>

[BAP 2.0 is released]
<http://binaryanalysisplatform.github.io/bap-2-release>

[CI/CD pipelines: Monad, Arrow or Dart?]
<https://roscidus.com/blog/blog/2019/11/14/cicd-pipelines/>

[On fixed-point theorems in synthetic computability]
<http://math.andrej.com/2019/11/07/on-fixed-point-theorems-in-synthetic-computability/>

[Runners in action]
<http://math.andrej.com/2019/10/28/runners-in-action/>

[Coq 8.10.1 is out] <https://coq.inria.fr/news/coq-8-10-1-is-out.html>

[Announcing MirageOS 3.6.0]
<https://mirage.io/blog/announcing-mirage-36-release>

[Commas in big numbers everywhere: An OpenType adventure]
<https://blog.janestreet.com/commas-in-big-numbers-everywhere/>

[Coq 8.10.0 is out] <https://coq.inria.fr/news/coq-8-10-0-is-out.html>

[OCaml expert and beginner training by OCamlPro (in French): Nov. 5-6 &
7-8]
<http://www.ocamlpro.com/2019/09/25/ocaml-expert-and-beginner-training-by-ocamlpro-in-french-nov-5-6-7-8/>

[Mr. MIME - Parse and generate emails]
<https://tarides.com/blog/2019-09-25-mr-mime-parse-and-generate-emails.html>

[A look back on OCaml since 2011]
<http://www.ocamlpro.com/2019/09/20/a-look-back-on-ocaml/>

[Frama-C 19.1 (Potassium) is out. Download ithere.]
<http://frama-c.com/index.html>

[Coq 8.10+beta3 is out]
<https://coq.inria.fr/news/coq-8-10beta3-is-out.html>

[Updated Cheat Sheets: OCaml Language and OCaml Standard Library]
<http://www.ocamlpro.com/2019/09/13/updated-cheat-sheets-ocaml-language-and-ocaml-standard-library/>

[Frama-Clang 0.0.7 is out. Download ithere.]
<http://frama-c.com/index.html>

[Decompress: Experiences with OCaml optimization]
<https://tarides.com/blog/2019-09-13-decompress-experiences-with-ocaml-optimization.html>

[On complete ordered fields]
<http://math.andrej.com/2019/09/09/on-complete-ordered-fields/>

[An introduction to fuzzing OCaml with AFL, Crowbar and Bun]
<https://tarides.com/blog/2019-09-04-an-introduction-to-fuzzing-ocaml-with-afl-crowbar-and-bun.html>

[What is algebraic about algebraic effects?]
<http://math.andrej.com/2019/09/03/what-is-algebraic-about-algebraic-effects/>

[The blog moved from Wordpress to Jekyll]
<http://math.andrej.com/2019/09/03/the-blog-moved-from-wordpress-to-jekyll/>

[OCamlPro’s compiler team work update]
<http://www.ocamlpro.com/2019/08/30/ocamlpros-compiler-team-work-update/>

[What the interns have wrought, 2019 edition]
<https://blog.janestreet.com/what-the-interns-have-wrought-2019/>

[Decompress: The New Decompress API]
<https://tarides.com/blog/2019-08-26-decompress-the-new-decompress-api.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-04-14  7:28 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-04-14  7:28 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of April 07 to 14,
2020.

Table of Contents
─────────────────

Announcing dune-deps: produces a project-centric dependency graph
OCamlformat 0.14.0
Dune 2.5.0
Old CWN


Announcing dune-deps: produces a project-centric dependency graph
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announcing-dune-deps-produces-a-project-centric-dependency-graph/5451/3>


Martin Jambon announced
───────────────────────

  Since the original announcement, I received some good feedback from
  users working on large projects. Thank you!

  The latest version released today is 1.2.0. It is already available on
  opam-repository (thank you @kit-ty-kate). The changes since the
  original release, besides bug fixes, include:

  • Ability to select or ignore dune files and folders to scan. For
    example, `dune-deps foo bar -x bar/test' uses all the dune files
    found in folders `foo' and `bar' but will ignore `bar/test'. This is
    useful for ignoring uninteresting parts of the project and for
    ignoring parse errors (see bug [#4]).
  • Executable name disambiguation. For example, private executables of
    the same name like `foo/main' and `bar/baz/main' are now rendered as
    `main<foo>' and `main<baz>' respectively instead of just `main'.
  • Optional exclusion of all executables or all external libraries with
    `--no-exe' and `--no-ext'.
  • Ability to show only the dependencies and/or the reverse
    dependencies of selected libraries. See below.

  Whole-project graphs for large projects tend to be unreadable. To deal
  with that, I added support for an "hourglass view" (⌛) option for
  showing only the dependencies and reverse dependencies of a component
  of interest.

  The following is obtained with `-h opam-client' on the opam project:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/6/66098faac9fd6681e3c0f4fe357aef8ff34bcaf2.png>

  Please [let us know] if this works for your favorite projects! The
  source code of dune-deps makes it somewhat easier now to experiment
  with new strategies for eliminating nodes. See the `Filter' and
  `Filterable' modules.

  Check out `dune-deps --help' for detailed documentation on the
  options.


[#4] <https://github.com/mjambon/dune-deps/issues/4>

[let us know] <https://github.com/mjambon/dune-deps/issues>


Sean Grove said and Martin Jambon replied
─────────────────────────────────────────

        That’s a nice idea - it’d be great to have this available
        as a GitHub action so anyone could do this with just a
        click or two!

  So, I made a [generic yaml workflow] that people can stick into their
  git/github project. This will automatically maintain the dependency
  graph `.deps/deps.png' which can be included in a readme.


[generic yaml workflow] <https://github.com/mjambon/dune-deps-action>


OCamlformat 0.14.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocamlformat-0-14-0/5435/21>


Etienne Millon announced
────────────────────────

  As described in this thread, ocamlformat 0.14.0 introduced a new
  algorithm to determine how documentation comments are placed. We
  underestimated the impact of making this the default, and this means
  that many unwanted diffs were present for 0.13.0 -> 0.14.0 upgrades.

  We are going to prepare a 0.14.1 release next week reverting this
  behavior back to the 0.13.0 defaults. Users still on 0.13.0 are
  encouraged to wait for this and upgrade directly to 0.14.1.

  Sorry for the inconvenience, and thanks for the feedback!


Dune 2.5.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-5-0/5494/1>


Rudi Grinberg announced
───────────────────────

  The dune team is pleased to announce the release of dune 2.5.0. This
  release has been brewing for a while and contains a few interesting
  features. I'll highlight some of the bigger ones:

  • The coq support has been thoroughly extended. There's now support
    for both composition of coq libraries in the same workspace and
    extraction of coq code to OCaml.

  • There's a new `$ dune upgrade' subcommand to help you upgrade dune
    files from 1.x to 2.x

  • `$ dune utop' will now load ppx preprocessors to the toplevel. Ppx
    authors might enjoy this style of interactive development.

  • There's a new `(subdir ..)' stanza that can be used to evaluate
    stanzas in sub directories. This makes it possible to have a single
    dune file for an entire project (generated or not).

  I'd like to thank everyone who contributed to dune 2.5.0. Your help is
  greatly appreciated.

  Here's the full change log:


2.5.0 (09/04/2020)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Add a `--release' option meaning the same as `-p' but without the
    package filtering. This is useful for custom `dune' invocation in
    opam files where we don't want `-p' (#3260, @diml)

  • Fix a bug introduced in 2.4.0 causing `.bc' programs to be built
    with `-custom' by default (#3269, fixes #3262, @diml)

  • Allow contexts to be defined with local switches in workspace files
    (#3265, fix #3264, @rgrinberg)

  • Delay expansion errors until the rule is used to build something
    (#3261, fix #3252, @rgrinberg, @diml)

  • [coq] Support for theory dependencies and compositional builds using
    new field `(theories ...)' (#2053, @ejgallego, @rgrinberg)

  • From now on, each version of a syntax extension must be explicitely
    tied to a minimum version of the dune language. Inconsistent
    versions in a `dune-project' will trigger a warning for version
    <=2.4 and an error for versions >2.4 of the dune language. (#3270,
    fixes #2957, @voodoos)

  • [coq] Bump coq lang version to 0.2. New coq features presented this
    release require this version of the coq lang. (#3283, @ejgallego)

  • Prevent installation of public executables disabled using the
    `enabled_if' field.  Installation will now simply skip such
    executables instead of raising an error. (#3195, @voodoos)

  • `dune upgrade' will now try to upgrade projects using versions <2.0
    to version 2.0 of the dune language. (#3174, @voodoos)

  • Add a `top' command to integrate dune with any toplevel, not just
    utop. It is meant to be used with the new `#use_output' directive of
    OCaml 4.11 (#2952, @mbernat, @diml)

  • Allow per-package `version' in generated `opam' files (#3287,
    @toots)

  • [coq] Introduce the `coq.extraction' stanza. It can be used to
    extract OCaml sources (#3299, fixes #2178, @rgrinberg)

  • Load ppx rewriters in dune utop and add pps field to toplevel
    stanza. Ppx extensions will now be usable in the toplevel (#3266,
    fixes #346, @stephanieyou)

  • Add a `(subdir ..)' stanza to allow evaluating stanzas in sub
    directories.  (#3268, @rgrinberg)

  • Fix a bug preventing one from running inline tests in multiple modes
    (#3352, @diml)

  • Allow the use of the `%{profile}' variable in the `enabled_if' field
    of the library stanza. (#3344, @mrmr1993)

  • Allow the use of `%{ocaml_version}' variable in `enabled_if' field
    of the library stanza. (#3339, @voodoos)

  • Fix dune build freezing on MacOS when cache is enabled. (#3249,
    fixes ##2973, @artempyanykh)


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-04-07  7:51 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-04-07  7:51 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of March 31 to April
07, 2020.

Table of Contents
─────────────────

Making a music player in OCaml
The end of Camlp4
OCamlformat 0.14.0
ML Family Workshop 2020: Call for presentations
Announcing Sek, an efficient implementation of sequences
Announcing dune-deps: produces a project-centric dependency graph
OCaml Users and Developers Meeting 2020
Old CWN


Making a music player in OCaml
══════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/making-a-music-player-in-ocaml/5413/1>


Dracose asked
─────────────

  I'm interested in making my own music player in OCaml so I wanted to
  know whether there were any existing ones and/or examples of how to
  make one. Bear in mind, I am interested in the actual logic of how to
  read a music file (or a playlist) and listening to it, rather than the
  front-end part of a music player.  (My knowledge of OCaml is
  intermediate)


Thomas Blanc suggested
──────────────────────

  You want to check <https://github.com/savonet/liquidsoap>


Yotam Barnoy then said
──────────────────────

  Wow @PatJ I didn't know about liquidsoap. I added it to
  ocamlverse. This is what we have for the audio page now, in case it's
  helpful to the OP: <https://ocamlverse.github.io/content/audio.html>


gndl also replied
─────────────────

  I experimented with several solutions in the [playo] project.  One of
  the possible solutions is to use [ocaml-gstreamer].  If you find that
  the gstreamer framework is too annoying (which I can understand :-),
  you can use [ocaml-ffmpeg]. note however that, in the latest version
  of ocaml-ffmpeg, the audio device output [no longer works]. To
  overcome this drawback, you can use [ocaml-portaudio].


[playo] <https://github.com/gndl/playo>

[ocaml-gstreamer] <https://github.com/savonet/ocaml-gstreamer>

[ocaml-ffmpeg] <https://github.com/savonet/ocaml-ffmpeg>

[no longer works] <https://github.com/savonet/ocaml-ffmpeg/issues/32>

[ocaml-portaudio] <https://github.com/savonet/ocaml-portaudio>


The end of Camlp4
═════════════════

  Archive: <https://discuss.ocaml.org/t/the-end-of-camlp4/4216/96>


Continuing this old thread, Chet Murthy announced
─────────────────────────────────────────────────

  Perhaps worth mentioning briefly that for anybody who -wants- to
  continue using camlp4, I'm (a) maintaining camlp5 and bringing it
  up-to-date with everything in ocaml 4.10.0 that I can think of, and
  (b) I'd be happy to help them port their dependency over to camlp5.

  This is not to be construed as an argument for using camlp4/5.


OCamlformat 0.14.0
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocamlformat-0-14-0/5435/1>


Etienne Millon announced
────────────────────────

  On behalf of the development team, I'd like to announce the release of
  ocamlformat version 0.14.0 :tada:.

  Here are the main highlights of this release:


Support for OCaml 4.10
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  This means both that it compiles and runs using this version, but also
  that it can format 4.10-specific language features (`module _' and
  multi-indices operators).


Preliminary support for invalid files
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  As OCamlformat operates on ASTs, it normally requires a valid input
  file. This release adds a `--format-invalid-files' option to detect
  invalid parts and print them verbatim. This feature is still
  experimental.


Preserving more concrete syntax
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Starting with this release, OCamlformat is going to preserve more
  concrete syntax. For example, `module M = functor (K : S) -> struct
  end' and `module M (K : S) = struct end' are equivalent. In the past,
  both variants would be formatted as the latter. Now, the original
  syntax is preserved. In some cases, preserving was possible through
  the means of an option: for example, to choice between `let%name x = e
  in body' and `[%name let x = e in body]', was controlled by the
  `extension-sugar' option. This option is now deprecated and
  OCamlformat will now always preserve what was in the source file (this
  was the default behaviour).

  Similarly, it was possible to control how special characters are
  escaped in string and character literals through the `escape-strings'
  and `escape-chars' options. They are being deprecated and the only
  possible behavior will be preserving the concrete syntax (as done by
  default).

  The reason for this change is that we feel that ocamlformat should be
  just about formatting. The fact that this behavior was configurable is
  in part due to the fact that it operates on OCaml ASTs, but end users
  should not have to be surprised by their code being transformed on
  reformatting.

  In the future, we plan to extend that to other similar constructs,
  such as using `(~/')~ or `begin~/~end', or spacing between module
  items.


Placement of doc comments
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Placing doc comments `(** ... *)' is controlled by the `doc-comments'
  configuration option. It is always possible to put them before the
  item they refer to, and this is what the `doc-comments=before' option
  does. The alternative `doc-comments=after' will try to do its best to
  put them after, but in some cases it is not possible. For example, in
  a variant type declaration, a doc-comment put immediately after will
  be attached to the last constructor by documentation
  tools. Ocamlformat needs to preserve the meaning of programs, so in
  these cases, it will instead put the comment before. In the case of
  `module' declarations, putting the comment after might not be very
  useful if the corresponding module is very large.

  This requires a complex rule to determine which comments will be put
  before and which comments will be put after. So in this version, we
  are deprecating this mechanism and replacing it with a simpler one
  controlled by `doc-comments-val' that applies only to `val' and
  `external' items. For these items, it is always possible to attach
  documents before or after them. For all other items, like type or
  module declarations, the doc comments will consistenly be put before.


Many bugs found by fuzzing
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  We hooked ocamlformat to AFL, looking for programs that parse
  correctly but trigger errors during formatting. This approach worked
  very well and more than 20 logical bugs were found with this
  technique.


Upgrading
╌╌╌╌╌╌╌╌╌

  To upgrade from ocamlformat 0.13.0, one needs to upgrade the
  ocamlformat binary and replace the `version' field in `.ocamlformat'
  files by `0.14.0' and then:

  • if you used `doc-comments=after', you can replace it by
    `doc-comments-val=after'.  This will move doc-comments on module
    items except `val' and `external' ones.
  • if you used `doc-comments=before', you can remove it as it is now
    the default.
  • if you set `escape-chars=preserve', `escape-strings=preserve', or
    `extension-sugar=preserve' explicitly, you can
  remove them safely (they were the default)
  • if you used another value for one of these options (such as
    `escape-strings=hexadecimal'), you will need to remove them as
    well. This will not trigger a diff, but ocamlformat will not enforce
    a particular concrete syntax for new code.


A note for new users
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  We encourage you to try ocamlformat, that can be installed from opam
  directly (`opam install ocamlformat'), but please remember that it is
  still beta software. We added a [FAQ for new users] that should help
  you decide if ocamlformat is the right choice for you.


[FAQ for new users]
<https://github.com/ocaml-ppx/ocamlformat#faq-for-new-users>


Etienne Millon later added
──────────────────────────

  This upgrade is likely to generate a huge diff on projects that use
  the default profile, so I would like to expand a bit on the reason.

  According to [the syntax rules used by the ocaml tools] (the ocaml
  compilers, ocamldoc, odoc), it is always possible to put the
  doc-comment before an item.

  Some teams prefer to put the documentation after. But that is not
  always possible. For example, `type t = A | B (** doc *)' will attach
  the doc-comment to `B', not to `t'. The only way to attach the comment
  to `t' is by putting the comment before.

  Enter ocamlformat: doc-comment placement is controlled by an option
  with two values, `before' or `after'. `before' will always place the
  comment before. `after' determines if it is possible to put the
  comment after, and if it is not, will put it before.

  Some items cannot have comments after, like variant types (as
  described above). But there is another reason not to put comments
  after. In some cases, that can put the comment far from the thing it
  is documenting. Considering modules, the following is nice:

  ┌────
  │ module M = L.M
  │ (** doc *)
  └────

  But this is not great is the structure is large:

  ┌────
  │ module M = struct
  │   ...
  │   ...
  │ end
  │ (** doc *)
  └────

  To summarize, when ocamlformat is configured to put comments after, it
  has to follow a complex heuristic to determine whether it has to
  fallback to before. In the case of a module, it depends on its shape,
  how many functor arguments are there, this kind of things (for various
  reasons, we don't know how large something is going to be in advance,
  so we have to look at its shape). The point is that it is complicated
  to understand and explain, and that fixing it always makes it more
  complex. Another aspect is that in the end, we want ocamlformat to be
  pretty stable when it reaches 1.0.0, and complex rules are at odds
  with this goal.

  So, we have decided to simplify the rule: instead of looking deep in
  the AST, we just look at the kind of item this is. For `val' and
  `external' items, it is always possible to put the doc-comment after,
  so we follow exactly what the configuration option says.

  As a user of the default profile, what this means for you: for items
  that are not `val' or `external', and considered "simple" by the
  0.13.0 heuristic, doc-comments are going to move from after to before.

  Based on these reasons, you will understand that `before' is always
  simpler. You can opt into this by setting
  `doc-comments-val=before'. This will cause an even larger diff as all
  items are going to move before (that is: all items described just
  above, plus `val' and `external' items), but the rule gets extremely
  simple (everything is put before). It is possible that this option
  will become the default in the future, but we have not decided this
  yet (in this case, if you did not opt into it, you will see comments
  on `val' and `external' items move at that time).


[the syntax rules used by the ocaml tools]
<https://caml.inria.fr/pub/docs/manual-ocaml/ocamldoc.html#ss:ocamldoc-placement>


ML Family Workshop 2020: Call for presentations
═══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ml-family-workshop-2020-call-for-presentations/5441/1>


Leo White announced
───────────────────

  We are happy to invite submissions to the ML Family Workshop 2020, to
  be held during the ICFP conference week on Thursday, August 27th.

  The ML family workshop warmly welcomes submission touching on the
  programming languages traditionally seen as part of the "ML family"
  (Standard ML, OCaml, F#, CakeML, SML#, Manticore, MetaOCaml,
  etc.). The scope of the workshop includes all aspects of the design,
  semantics, theory, application, implementation, and teaching of the
  members of the ML family. We also encourage presentations from related
  languages (such as Haskell, Scala, Rust, Nemerle, Links, Koka, F*,
  Eff, ATS, etc), to exchange experience of further developing ML ideas.

  Currently, the workshop is still scheduled to go ahead as planned in
  Jersey City, however it is likely that the ML workshop will end up
  being a virtual workshop this year. Either way provisions will be made
  to allow speakers to present their work remotely.

  See our detailed CFP online on the ICFP website:

  <https://icfp20.sigplan.org/home/mlfamilyworkshop-2020>


Important dates
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Friday 15th May (any time zone): Abstract submission deadline
  • Friday 26th June: Author notification
  • Thursday 27th August: ML Family Workshop


Program committee
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Youyou Cong (Tokyo Institute of Technology)
  • Gowtham Kaki (Purdue University)
  • Neel Krishnaswami (University of Cambridge)
  • Daan Leijen (Microsoft Research)
  • Koko Muroya (Kyoto University)
  • Atsushi Ohori (Tohoku University)
  • Jonathan Protzenko (Microsoft Research)
  • Gabriel Radanne (INRIA)
  • Claudio Russo (Dfinity)
  • Leo White (Jane Street) (Chair)
  • Jeremy Yallop (University of Cambridge)


Submission details
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  See the online CFP for the details on the expected submission format.

  Submissions must be uploaded to the workshop submission website

  <https://ml2020.hotcrp.com/>

  before the submission deadline.


Announcing Sek, an efficient implementation of sequences
════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announcing-sek-an-efficient-implementation-of-sequences/5442/1>


François Pottier announced
──────────────────────────

  We are pleased to announce the first release of Sek, an OCaml library
  that offers an efficient implementation of sequences.

  The library offers both ephemeral (mutable) sequences and persistent
  (immutable) sequences, and offers constant-time conversions between
  these flavors.

  It supports all of the standard operations on stacks, queues, deques
  (e.g.  push, pop at either end), catenable sequences (concat, split),
  and random access sequences (get, set).

  Data is stored internally in chunks (fixed-capacity arrays), which is
  why this data structure is known as a chunK SEquence.

  It is intended to achieve excellent time complexity and memory usage.

  This is an initial release. The library has not been tested in
  production, but has received extensive unit testing, via afl-fuzz and
  ocaml+afl – which are remarkably effective tools, by the way!

  This is work in progress; more features, such as iterators, will be
  added in the future.

  To install Sek, just type

  ┌────
  │ opam update && opam install sek
  └────

  Documentation is [online].

  Feedback is welcome!

  Arthur Charguéraud
  François Pottier
  with contributions by Émilie Guermeur


[online] <http://cambium.inria.fr/~fpottier/sek/doc/sek/Sek/index.html>


Yaron Minsky asked and Fabian replied
─────────────────────────────────────

        I’m particularly interested in how it compares to
        Base.Sequence and Seq in the OCaml distribution, but
        surely there are others as well.

  This actually looks like an array/vector structure (supporting, among
  other things, fast access to the nth element), so a comparison with
  `CCVector', `CCFun_vec', `BatVect', `Clarity.Vector' etc. would be
  more appropriate. The name is a bit unfortunate considering the naming
  used in the general ecosystem.

  Some time ago, I added some crude benchmarks to [containers'
  benchsuite].  I'll see if I can add Sek when I find time.


[containers' benchsuite]
<https://github.com/c-cube/ocaml-containers/blob/d34b7588b028f3618cc44d3f4c6417295db586c8/benchs/run_benchs.ml#L112>


gasche said
───────────

  I think it really is a sequence library in the sense that in maintains
  an in-order sequence of items, and sequences can be joined/split
  efficiently. It also provides logarithmic random access, but this is
  probably not competitive with fixed-size arrays. It would be
  comparable to "persistent vector" libraries, ropes, finger trees,
  etc. The fact that the authors expose a Stack/Queue interface suggests
  that it has also been tuned to perform reasonably well in this case.

  It does not provide any delayed computation of items, so in that
  regard it is not comparable to Sequence/Seq.

  @charguer has designed similar datastructures in the past to represent
  the work-queues of concurrent workers (you want at least a fast "push"
  to add a new task and, when doing work-stealing, having a fast "split"
  is convenient). See [Theory and Practice of Chunked Sequences], Umut
  Acar, Arthur Charguéraud, Mike Rainey, 2014, and [A Work-Efficient
  Algorithm for Parallel Unordered Depth-First Search].

  As far as I know, the OCaml implementation just released has not been
  tested/benchmarked for parallel algorithms. I would be curious to see
  an experiment of parallel graph traversal with this structure and
  Multicore-OCaml.


[Theory and Practice of Chunked Sequences]
<https://www.chargueraud.org/research/2014/chunkedseq/chunkedseq.pdf>

[A Work-Efficient Algorithm for Parallel Unordered Depth-First Search]
<https://www.chargueraud.org/research/2015/pdfs/pdfs_sc15.pdf>


Announcing dune-deps: produces a project-centric dependency graph
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announcing-dune-deps-produces-a-project-centric-dependency-graph/5451/1>


Martin Jambon announced
───────────────────────

  I'm happy to announce the availability of [dune-deps], a command-line
  tool that scans a dune project and gathers the dependencies into a
  graph. The output is in the dot format, supported by the `dot' command
  from [graphviz].

  It shows the dependencies between the following:

  • libraries defined by the project,
  • executables defined by the project,
  • direct dependencies on external libraries.

  Dependencies are extracted by parsing `dune' files. As an example,
  here's what we obtain for the [sources of opam], which has over 50K
  lines of code:

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/f/f6213fa7fda52521c6782988155ab23b997dafb8.png>

  The commands for this are:
  ┌────
  │ # obtain the project's sources
  │ $ git clone --depth=1 https://github.com/ocaml/opam.git
  │
  │ # extract dependencies and eliminate superfluous graph edges
  │ $ dune-deps opam | tred > deps.dot
  │
  │ # render the graph
  │ $ dot -Tpng deps.dot -o deps.png
  └────

  A suggestion is to include such graph in your project's `README.md'.


[dune-deps] <https://github.com/mjambon/dune-deps>

[graphviz] <https://www.graphviz.org/>

[sources of opam] <https://github.com/ocaml/opam>


OCaml Users and Developers Meeting 2020
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-users-and-developers-meeting-2020/5454/1>


Ivan Gotovchits announced
─────────────────────────

  It is my pleasure to invite submissions to the OCaml Users and
  Developers Workshop 2020, which is again co-located with ICFP and will
  be held on Friday 28th August 2020 in Jersey City, NJ, USA.

  The OCaml Users and Developers Workshop brings together the OCaml
  community, including users of OCaml in industry, academia, hobbyists
  and the free software community. Previous editions have been
  co-located with ICFP since 2012 in Copenhagen, Boston, Gothenburg,
  Nara, Oxford, St Louis and last year in Berlin, following OCaml
  Meetings in Paris in 2010 and 2011.


Important Links
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • <https://ocaml.org/meetings/ocaml/2020/>
  • <https://icfp20.sigplan.org/home/ocaml-2020>
  • <https://ocaml2020.hotcrp.com/>


Important Dates
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Talk proposal submission deadline: May 8th, 2020, AoE
  • Author Notification: June 26th, 2020
  • OCaml Workshop: August 28th, 2020


Scope
╌╌╌╌╌

  Presentations and discussions focus on the OCaml programming language
  and its community. We aim to solicit talks on all aspects related to
  improving the use or development of the language and its programming
  environment, including, for example (but not limited to):

  • compiler developments, new backends, runtime and architectures

  • practical type system improvements, such as GADTs, first-class
    modules, generic programming, or dependent types

  • new library or application releases, and their design rationales

  • tools and infrastructure services, and their enhancements

  • prominent industrial or experimental uses of OCaml, or deployments
    in unusual situations.


Presentations
╌╌╌╌╌╌╌╌╌╌╌╌╌

  The workshop is an informal meeting with no formal proceedings. The
  presentation material will be available online from the workshop
  homepage. The presentations may be recorded and made available at a
  later date.

  The main presentation format is a workshop talk, traditionally around
  20 minutes in length, plus question time, but we also have a poster
  session during the workshop – this allows to present more diverse
  work, and gives time for discussion. The program committee will decide
  which presentations should be delivered as posters or talks.


Submission
╌╌╌╌╌╌╌╌╌╌

  To submit a presentation, please register a description of the talk
  (about 2 pages long) at

  <https://ocaml2020.hotcrp.com/>

  providing a clear statement of what will be provided by the
  presentation: the problems that are addressed, the solutions or
  methods that are proposed.

  LaTeX-produced PDFs are a common and welcome submission format. For
  accessibility purposes, we ask PDF submitters to also provide the
  sources of their submission in a textual format, such as .tex
  sources. Reviewers may read either the submitted PDF or the text
  version.


ML family workshop
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The ML family workshop, held on the previous day, deals with general
  issues of the ML-style programming and type systems, focuses on more
  research-oriented work that is less specific to a language in
  particular. There is an overlap between the two workshops, and we have
  occasionally transferred presentations from one to the other in the
  past. Authors who feel their submission fits both workshops are
  encouraged to mention it at submission time and/or contact the Program
  Chairs.


Program Committee
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Ivan Gotovchits, CMU, USA
  • Florian Angeletti, INRIA, France
  • Chris Casinghino, Draper Laboratory, USA
  • Catherine Gasnier, Facebook, USA
  • Rudi Grinberg, OCaml Labs, UK
  • Oleg Kiselyov, Tohoku University, Japan
  • Andreas Rossberg, Dfinity Stiftung, Germany
  • Marcello Seri, University of Groningen, Netherlands
  • Edwin Torok, Citrix, UK
  • Leo White, Jane Street, USA
  • Greta Yorsh, Jane Street, USA
  • Sarah Zennou, Airbus, France


COVID-19 Notice
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  While ICFP-20 [is still scheduled to be held as planned], chances are
  high that it will be turned into a virtual conference. Which means a
  wider audience and reduced (hopefully) fees. We will keep you posted.


[is still scheduled to be held as planned]
<https://icfp20.sigplan.org/home/icfp-2020>


Questions and contact
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Please send any questions to the chair: Ivan Gotovchits (ivg@ieee.org)


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-03-31  9:54 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-03-31  9:54 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of March 24 to 31,
2020.

Table of Contents
─────────────────

An In-Depth Look at OCaml’s New “Best-Fit” Garbage Collector Strategy
First release of Pp, a pretty-printing library
soupault: a static website generator based on HTML rewriting
routes: path based routing for web applications
Compiler Engineer at Mixtional Code in Darmstadt or anywhere else in Germany
tiny-httpd 0.5
Visual Studio Code plugin for OCaml
Dismas: a tool for automatically making cross-versions of opam packages
Multicore OCaml: March 2020 update
Old CWN


An In-Depth Look at OCaml’s New “Best-Fit” Garbage Collector Strategy
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/an-in-depth-look-at-ocaml-s-new-best-fit-garbage-collector-strategy/5370/1>


OCamlPro announced
──────────────────

  The Garbage Collector is probably OCaml’s greatest unsung hero. Its
  pragmatic approach allows us to allocate without much fear of
  efficiency loss. We looked into its new "Best-fit" strategy and here
  is what we learned!
  [http://www.ocamlpro.com/2020/03/23/ocaml-new-best-fit-garbage-collector/]


[http://www.ocamlpro.com/2020/03/23/ocaml-new-best-fit-garbage-collector/]
<http://www.ocamlpro.com/2020/03/23/ocaml-new-best-fit-garbage-collector/>


First release of Pp, a pretty-printing library
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-pp-a-pretty-printing-library/5371/1>


Jérémie Dimino announced
────────────────────────

  I'm happy to announce the first release of the [pp library]! This
  library provides a lean alternative to the [Format module] of the
  standard library. It uses the same comcepts of boxes and break hints,
  however it defines its own algebra which some might find easier to
  work with and reason about.  I personally do :) The final rendering is
  still done via a formatter which makes it easy to integrate `Pp' in
  existing programs using `Format'.

  We introduced this module in [Dune] to help improve the formatting of
  messages printed in the terminal and it has been a success. The new
  API is smaller, simpler and makes it easy for developers to do the
  right thing. Once the `Pp' module of Dune was mature enough, we
  decided to extract it into a separate library so that it could benefit
  others.

  The library itself is composed of a single `Pp' module and has no
  dependencies.  Its documentation is self-contained and no previous
  knowledge is required to start using it, however the various guides
  for the `Format' module such as [this one] should be applicable to
  `Pp' as well.

  If you have used `Format' before and like me found its API complicated
  and difficult to use, I hope that you will find `Pp' nicer to work
  with!


[pp library] <https://github.com/diml/pp>

[Format module]
<https://caml.inria.fr/pub/docs/manual-ocaml/libref/Format.html>

[Dune] <https://dune.build>

[this one] <http://caml.inria.fr/resources/doc/guides/format.en.html>


Josh Berdine then said
──────────────────────

  Another great resource for understanding the core mental model of
  Format is [Format Unraveled], although if I understand pp correctly
  the discussion about Format not being document-based won't apply to
  pp.


[Format Unraveled]
<https://hal.archives-ouvertes.fr/hal-01503081/file/format-unraveled.pdf>


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/13>


Daniil Baturin announced
────────────────────────

  [1.10.0] release is available.

  Bug fixes:
  • Files without extensions are handled correctly.

  New features:
  • Plugin discovery: if you save a plugin to `plugins/my-plugin.lua',
    it's automatically loaded as a widget named
  `my-plugin'. List of plugin directories is configurable.
  • New plugin API functions: `HTMLget_tag_name', `HTML.select_any_of',
    `HTML.select_all_of'.
  • The `HTML' module is now "monadic": giving a nil to a function that
    expects an element gives you a nil back, rather than cause a runtime
    error.


[1.10.0] <https://soupault.neocities.org/blog/soupault-1.10-release>


routes: path based routing for web applications
═══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-routes-path-based-routing-for-web-applications/3624/6>


Anurag Soni announced
─────────────────────

  [0.7.2] release is now available on opam. There have been quite a few
  changes since the previous versions.

  • Routes doesn't deal with HTTP methods anymore
  • The internal implementation is now based around a trie like data
    structure
  • Routes have pretty printers
  • sprintf style route printing is supported again
  • Minimum supported OCaml version is now 4.05 (it used to be 4.06)
  • There is a release available for bucklescript as well and it is
    available to install via [npm].


[0.7.2] <http://opam.ocaml.org/packages/routes/>

[npm] <https://www.npmjs.com/package/@anuragsoni/routes>


Compiler Engineer at Mixtional Code in Darmstadt or anywhere else in Germany
════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/compiler-engineer-at-mixtional-code-in-darmstadt-or-anywhere-else-in-germany/5377/1>


Gerd Stolpmann announced
────────────────────────

  Type of position:

  • regular hire (no freelancers)
  • full time
  • work from home anywhere in Germany, or in the office in Darmstadt
  • work for a small and highly skilled international team, located in
    the US and Europe
  • the team language is English

  We are developing a compiler for a no-code platform that translates
  our DSL to bytecode and/or WebAssembly. The language is largely of
  functional type but is also able to manage state with a spreadsheet
  model, allowing reactive programming without having to resort to
  libraries. The language is statically typed using a Hindley-Milner
  type checker. The compiler is primarily written in OCaml. Other
  languages of our platform are Go, Elm, and Javascript.

  We are looking for a compiler engineer with strong skills in all
  relevant areas:

  • fluent in OCaml or a similar language such as Haskell
  • Understanding of the structure of the DSL, including syntax and
    semantics
  • Translation of FP languages to executable code
  • Code optimization
  • Graph algorithms
  • Type checking

  We are open to both juniors and seniors, and payment will be
  accordingly. We are not so much interested in formal certifications
  but rather in real practice, either from previous jobs, research
  projects, or contributions to open source projects.

  The no-code platform is being developed by engineers in Europe and the
  US at various places, and we usually do not meet physically but in
  video conferences. Working from home is very usual. We also get you a
  desk in your home town if you prefer this. The compiler development is
  lead by Gerd Stolpmann from Darmstadt.

  Due to the strong connections to the US, video conferences will often
  have to take place in evening hours, until around 7pm or 8pm.

  Applications: please follow the "Apply" link at the official web page
  describing the position: <https://rmx.mixtional.de/static/54657cda/>

  Gerd Stolpmann
  CEO of Mixtional Code GmbH (and OCaml hacker of the first hour)
  Contact and company details: <https://www.mixtional.de/contact.html>


Sébastien Besnier asked
───────────────────────

  I'm living in France, can I apply to the position (we are neighbors!)?


Gerd Stolpmann replied
──────────────────────

  Well, I can (at the moment) only make contracts using German law and
  for the social security system here. So, if you need a doctor you'd
  have to travel… If my company was a bit bigger there would be the
  option of opening a second site in France (even a very minimal one),
  but the setup costs are so far too high (lawyers and accountants), and
  it is too distracting for me to keep up with the fine points of the
  system in France. Unfortunately, the EU is not that far that it is
  super simple for an employer to hire anywhere in Europe. - Thanks for
  asking.


tiny-httpd 0.5
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-tiny-httpd-0-5/5381/1>


Simon Cruanes announced
───────────────────────

  I just released tiny-httpd 0.5 and the new tiny-httpd-camlzip, which
  makes it possible to use `deflate' transparently for queries and
  responses. The server has evolved quietly and is getting somewhat more
  robust: I'm using it for an internal tool with big html pages (up to
  several MB) and it's reasonably fast and doesn't seem to
  memleak. There's also an improved `http_of_dir' to quickly and simply
  serve a directory on an arbitrary port.

  Previous announcement [here]


[here] <https://discuss.ocaml.org/t/ann-tiny-httpd-0-1/4727>


Visual Studio Code plugin for OCaml
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-preview-visual-studio-code-plugin-for-ocaml/5395/1>


Rudi Grinberg announced
───────────────────────

  I'm proud to announce a preview release of an [VSC extension for
  OCaml]. You can fetch and install this plugin directly from the
  extension marketplace if you search for "OCaml Labs". The extension
  isn't yet mature, but I believe that it offers a user experience
  comparable to other VSC extensions for OCaml already. The plugin
  should be used in conjunction with [ocaml-lsp]

  The extension is for the OCaml "platform", which means that its scope
  includes support for various tools used in OCaml development such as
  dune, opam.

  Bug reports & contributions are welcome. Happy hacking.


[VSC extension for OCaml]
<https://github.com/ocamllabs/vscode-ocaml-platform>

[ocaml-lsp] <https://github.com/ocaml/ocaml-lsp>


Dismas: a tool for automatically making cross-versions of opam packages
═══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-prototype-dismas-a-tool-for-automatically-making-cross-versions-of-opam-packages/5404/1>


Daniil Baturin announced
────────────────────────

  opam-cross-* are seriously lagging behind the official opam repository
  and fdopen's opam-windows, not least because importing packages by
  hand is a lot of work.  I suppose at least a semi-automated process
  could help those repos grow and stay in sync with the upstream much
  faster.

  I've made a prototype of a tool for "stealing" packages into
  cross-repos. For obvious reasons it's called Dismas.  You can find it
  here: <https://github.com/dmbaturin/scripts/blob/master/dismas.ml>

  Limitations:

  • the code is a real mess for now
  • only dune is supported by automatic build command adjustment
  • it cannot handle cases when both native and cross-version of a
    dependency are needed

  However:

  • For simple packages that use dune exclusively, it's completely
    automated. I've ported bigstreamaf and angstrom to test it, and
    cross-versions built just fine from its output, no editing was
    needed.
  • It automatically converts dependencies from foo to too-$toolchain
    and removes dependencies and build steps only
  needed for `with-test' and `with-doc'.

  ┌────
  │ $ ./dismas.ml windows containers ~/devel/opam-repository/packages/containers/containers.2.8.1/opam
  │ opam-version: "2.0"
  │ maintainer: "simon.cruanes.2007@m4x.org"
  │ synopsis:
  │   "A modular, clean and powerful extension of the OCaml standard library"
  │ build: [
  │   ["dune" "build" "-p" "containers" "-j" jobs "-x" "windows"]
  │ ]
  │ depends: [
  │   "ocaml-windows" {>= "4.03.0"}
  │   "dune" {>= "1.1"}
  │   "dune-configurator"
  │   "seq-windows"
  │ ]
  │ depopts: ["base-unix" "base-threads"]
  │ tags: ["stdlib" "containers" "iterators" "list" "heap" "queue"]
  │ homepage: "https://github.com/c-cube/ocaml-containers/"
  │ doc: "https://c-cube.github.io/ocaml-containers"
  │ dev-repo: "git+https://github.com/c-cube/ocaml-containers.git"
  │ bug-reports: "https://github.com/c-cube/ocaml-containers/issues/"
  │ authors: "Simon Cruanes"
  │ url {
  │   src: "https://github.com/c-cube/ocaml-containers/archive/v2.8.1.tar.gz"
  │   checksum: [
  │     "md5=d84e09c5d0abc501aa17cd502e31a038"
  │     "sha512=8b832f4ada6035e80d81be0cfb7bdffb695ec67d465ed6097a144019e2b8a8f909095e78019c3da2d8181cc3cd730cd48f7519e87d3162442562103b7f36aabb"
  │   ]
  │ }
  │
  │ $ ./dismas.ml windows containers ~/devel/opam-repository/packages/containers/containers.2.8.1/opam | diff
  │ ~/devel/opam-repository/packages/containers/containers.2.8.1/opam -
  │ 3c3,4
  │ < synopsis: "A modular, clean and powerful extension of the OCaml standard library"
  │ ---
  │ > synopsis:
  │ >   "A modular, clean and powerful extension of the OCaml standard library"
  │ 5,7c6
  │ <   ["dune" "build" "-p" name "-j" jobs]
  │ <   ["dune" "build" "@doc" "-p" name ] {with-doc}
  │ <   ["dune" "runtest" "-p" name "-j" jobs] {with-test}
  │ ---
  │ >   ["dune" "build" "-p" "containers" "-j" jobs "-x" "windows"]
  │ 10,11c9,10
  │ <   "ocaml" { >= "4.03.0" }
  │ <   "dune" { >= "1.1" }
  │ ---
  │ >   "ocaml-windows" {>= "4.03.0"}
  │ >   "dune" {>= "1.1"}
  │ 13,21c12
  │ <   "seq"
  │ <   "qtest" { with-test }
  │ <   "qcheck" { with-test }
  │ <   "ounit" { with-test }
  │ <   "iter" { with-test }
  │ <   "gen" { with-test }
  │ <   "uutf" { with-test }
  │ <   "mdx" { with-test & >= "1.5.0" & < "2.0.0" }
  │ <   "odoc" { with-doc }
  │ ---
  │ >   "seq-windows"
  │ 23,27c14,15
  │ < depopts: [
  │ <   "base-unix"
  │ <   "base-threads"
  │ < ]
  │ < tags: [ "stdlib" "containers" "iterators" "list" "heap" "queue" ]
  │ ---
  │ > depopts: ["base-unix" "base-threads"]
  │ > tags: ["stdlib" "containers" "iterators" "list" "heap" "queue"]
  └────

  Things to do:

  • identify all packages that don't need cross-versions. Is cppo one of
    them, for example?
  • add support for cases when both native and cross versions are
    needed. If menhir the only one?
  • add support for other build systems. Do all of them work well with
    `OCAMLFIND_TOOLCHAIN=windows` if the build setup is written
    correctly?

  Input from @toots and @pirbo is welcome.


Romain Beauxis then said
────────────────────────

  That's a great initiative! Here are a couple of thoughts:
  • For dune-based packages, things are indeed pretty
    straight-forward. Finding out which dependencies need to be ported
    as cross-dependency is indeed the part that's hard to automatize
  • For other build systems, it's less clear to me how to
    automatize. Maybe others have some thoughts about it.
  • The CI system on opam-cross-windows is pretty good at building from
    scratch and failing if some deps are missing so trial and error
    there can be a great tool.
  • Once solved for one cross situation, the problem of
    cross-dependencies should be exactly the same for all other cross
    environment (android, iOS)

  I haven't looked at the tool very closely yet but I'd say a first
  improvement would be to be able to track cross-dependencies resolution
  and generate new version of the package using them and/or generate
  other cross-compiled packages using them.


Anton Kochkov said
──────────────────

  For automated pull requests, you might be interested in
  <https://discuss.ocaml.org/t/dependabot-and-ocaml/4282>


Daniil Baturin then asked
─────────────────────────

  I'm not sure if I understand the premise of dependabot. Why would
  anyone hardcode specific dependency versions? Maybe it makes sense in
  certain ecosystems that suffer from never-ending ecological disasters…
  ;)

  In any case, most opam packages don't have a constraint on the upper
  versions of their dependencies. Can dependabot use custom tracking
  rules to check for presense of a newer version in the repo?  My
  thought was much simpler actually: track the commits in
  opam-repository, run recently changed files through Dismas and send
  pull requests to opam-cross-*


Yawar Amin replied
──────────────────

  It's common practice nowadays to use semantic versioning and have
  lockfiles for reproducible builds. Dependabot updates semantic version
  ranges and lockfiles. See e.g.

  • <https://github.com/thoughtbot/velveteen/pull/31/files>
  • <https://github.com/mozilla/adr/pull/77/files>


Multicore OCaml: March 2020 update
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-march-2020-update/5406/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the March 2020 news update from the Multicore OCaml team!
  This update has been assembled with @shakthimaan and @kayceesrk, as
  with the [February] and [January] ones.

  Our work this month was primarily focused on performance improvements
  to the Multicore OCaml compiler and runtime, as part of a
  comprehensive evaluation exercise. We continue to add additional
  benchmarks to the Sandmark test suite. The eventlog tracing system and
  the use of hash tables for marshaling in upstream OCaml are in
  progress, and more PRs are being queued up for OCaml 4.11.0-dev as
  well.

  The biggest observable change for users trying the branch is that a
  new GC (the "parallel minor gc") has been merged in preference to the
  previous one ("the concurrent minor gc").  We will have the details in
  longer form at a later stage, but the essential gist is that *the
  parallel minor GC no longer requires a read barrier or changes to the
  C API*.  It may have slightly worse scalability properties at a very
  high number of cores, but is roughly equivalent at up to 24 cores in
  our evaluations.  Given the vast usability improvement from not having
  to port existing C FFI uses, we have decided to make the parallel
  minor GC the default one for our first upstream runtime patches. The
  concurrent minor GC follow at a later stage when we ramp up testing to
  64-core+ machines.  The [multicore opam remote] has been updated to
  reflect these changes, for those who wish to try it out at home.

  We are now at a stage where we are porting larger applications to
  multicore.  Thanks go to:
  • @UnixJunkie who helped us integrate the Gram Matrix benchmark in
    <https://github.com/ocaml-bench/sandmark/issues/99>
  • @jhw has done extensive work towards supporting Systhreads in
    <https://github.com/ocaml-multicore/ocaml-multicore/pull/240>. Systhreads
    is currently disabled in multicore, leading to some popular packages
    not compiling.
  • @antron has been advising us on how best to port `Lwt_preemptive`
    and the `Lwt_unix` modules to multicore, giving us a widely used IO
    stack to test more applications against.

  If you do have other suggestions for application that you think might
  provide useful benchmarks, then please do get in touch with myself or
  @kayceesrk.

  Onto the details! The various ongoing and completed tasks for
  Multicore OCaml are listed first, which is followed by the changes to
  the Sandmark benchmarking infrastructure and ongoing PRs to upstream
  OCaml.


[February]
<https://discuss.ocaml.org/t/multicore-ocaml-feb-2020-update/5227>

[January]
<https://discuss.ocaml.org/t/multicore-ocaml-january-2020-update/5090>

[multicore opam remote]
<https://github.com/ocaml-multicore/multicore-opam>

Multicore OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

◊ Ongoing

  • [ocaml-multicore/ocaml-multicore#240] Proposed implementation of
    threads in terms of Domain and Atomic

    A new implementation of the `Threads` library for use with the new
    `Domain` and `Atomic` modules in Multicore OCaml has been
    proposed. This builds Dune 2.4.0 which in turn makes it useful to
    build other packages. This PR is open for review.

  • [ocaml-multicore/safepoints-cmm-mach] Better safe points for OCaml

    A newer implementation to insert safe points at the Cmm level is
    being worked upon in this branch.


  [ocaml-multicore/ocaml-multicore#240]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/240>

  [ocaml-multicore/safepoints-cmm-mach]
  <https://github.com/anmolsahoo25/ocaml-multicore/tree/safepoints-cmm-mach>


◊ Completed

  The following PRs have been merged into Multicore OCaml:

  • [ocaml-multicore/ocaml-multicore#303] Account correctly for
    incremental mark budget

    The patch correctly measures the incremental mark budget value, and
    improves the maximum latency for the `menhir.ocamly` benchmark.

  • [ocaml-multicore/ocaml-multicore#307] Put the phase change event in
    the actual phase change code. The PR includes the
    `major_gc/phase_change` event in the appropriate context.

  • [ocaml-multicore/ocaml-multicore#309] Don't take all the full pools
    in one go.

    The code change selects one of the `global_full_pools` to try
    sweeping it later, instead of adopting all of the full ones.

  • [ocaml-multicore/ocaml-multicore#310] Statistics for the current
    domain are more recent than other domains

    The statistics (`minor_words`, `promoted_words`, `major_words`,
    `minor_collections`) for the current domain are more recent, and are
    used in the right context.

  • [ocaml-multicore/ocaml-multicore#315] Writes in `caml_blit_fields`
    should always use `caml_modify_field` to record `young_to_young`
    pointers

    The PR enforces that `caml_modify_field()` is always used to store
    `young_to_young` pointers.

  • [ocaml-multicore/ocaml-multicore#316] Fix bug with `Weak.blit`.

    The ephemerons are allocated as marked, but, the keys or data can be
    unmarked. The blit operations copy weak references from one
    ephemeron to another without marking them. The patch marks the keys
    that are blitted in order to keep the unreachable keys alive for
    another major cycle.

  • [ocaml-multicore/ocaml-multicore#317] Return early for 0 length blit

    The PR forces a `CAMLreturn()` call if the blit length is zero in
    `byterun/weak.c`.

  • [ocaml-multicore/ocaml-multicore#320] Move `num_domains_running`
    decrement

    The `caml_domain_alone()` invocation needs to be used in the shared
    heap teardown, and hence the `num_domains_running` decrement is
    moved as the last operation for at least the `shared_heap` lockfree
    fast paths.


  [ocaml-multicore/ocaml-multicore#303]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/303>

  [ocaml-multicore/ocaml-multicore#307]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/307>

  [ocaml-multicore/ocaml-multicore#309]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/309>

  [ocaml-multicore/ocaml-multicore#310]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/310>

  [ocaml-multicore/ocaml-multicore#315]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/315>

  [ocaml-multicore/ocaml-multicore#316]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/316>

  [ocaml-multicore/ocaml-multicore#317]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/317>

  [ocaml-multicore/ocaml-multicore#320]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/320>


Benchmarking
╌╌╌╌╌╌╌╌╌╌╌╌

  The [Sandmark] performance benchmarking test suite has had newer
  benchmarks added, and work is underway to enhance its functionality.

  • [ocaml-bench/sandmark#88] Add PingPong Multicore benchmark

    The PingPong benchmark that uses producer and consumer queues has
    now been included into Sandmark.

  • [ocaml-bench/sandmark#98] Add the read/write Irmin benchmark

    A basic read/write file performance benchmark for Irmin has been
    added to Sandmark. You can vary the following input parameters:
    number of branches, number of keys, percentage of reads and writes,
    number of iterations, and the number of write operations.

  • [ocaml-bench/sandmark#100] Add Gram Matrix benchmark

     A request [ocaml-bench/sandmark#99] to include the Gram Matrix
    initialization numerical benchmark was created. This is useful for
    machine learning applications and is now available in the Sandmark
    performance benchmark suite. The speedup
    (sequential_time/multi_threaded_time) versus number of cores for
    Multicore (Concurrent Minor Collector), Parmap and Parany is quite
    significant and illustrated in the graph:
    <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/2/20dc869a8dda1c815714a97e6a84f6f81c914cf4.png>

  • [ocaml-bench/sandmark#103] Add depend target in Makefile

    Sandmark now includes a `depend` target defined in the Makefile to
    check that both `libgmp-dev` and `libdw-dev` packages are installed
    and available on Ubuntu.

  • [ocaml-bench/sandmark#90] More parallel benchmarks

    An issue has been created to add more parallel benchmarks. We will
    use this to keep track of the requests. Please feel free to add your
    wish list of benchmarks!


[Sandmark] <https://github.com/ocaml-bench/sandmark>

[ocaml-bench/sandmark#88]
<https://github.com/ocaml-bench/sandmark/pull/88>

[ocaml-bench/sandmark#98]
<https://github.com/ocaml-bench/sandmark/pull/98>

[ocaml-bench/sandmark#100]
<https://github.com/ocaml-bench/sandmark/issues/100>

[ocaml-bench/sandmark#99]
<https://github.com/ocaml-bench/sandmark/issues/99>

[ocaml-bench/sandmark#103]
<https://github.com/ocaml-bench/sandmark/pull/103>

[ocaml-bench/sandmark#90]
<https://github.com/ocaml-bench/sandmark/issues/90>


OCaml
╌╌╌╌╌

◊ Ongoing

  • [ocaml/ocaml#9082] Eventlog tracing system

    The configure script has now been be updated so that it can build on
    Windows. Apart from this major change, a number of minor commits
    have been made for the build and sanity checks. This PR is currently
    under review.

  • [ocaml/ocaml#9353] Reimplement output_value using a hash table to
    detect sharing.

    The [ocaml/ocaml#9293] "Use addrmap hash table for marshaling" PR
    has been re-implemented using a hash table and bit vector, thanks to
    @xavierleroy. This is a pre-requisite for Multicore OCaml that uses
    a concurrent garbage collector.

  As always, we thank the OCaml developers and users in the community
  for their code reviews, support, and contribution to the project. From
  OCaml Labs, stay safe and healthy out there!


  [ocaml/ocaml#9082] <https://github.com/ocaml/ocaml/pull/9082>

  [ocaml/ocaml#9353] <https://github.com/ocaml/ocaml/pull/9353>

  [ocaml/ocaml#9293] <https://github.com/ocaml/ocaml/pull/9293>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-03-24  9:31 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-03-24  9:31 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 13108 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 17 to 24,
2020.

Table of Contents
─────────────────

Luv 0.5.1 — a libuv binding — Windows support
resto 0.2 released
Bisect_ppx 2.0.0 — code coverage for OCaml with nice HTML reports
OCaml 4.09.1 released
Cookie 0.1.6
First release of lwt-pipeline
Using Ocaml as scripting language - piping sh commands
Old CWN


Luv 0.5.1 — a libuv binding — Windows support
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/luv-0-5-1-a-libuv-binding-windows-support/5334/1>


Anton Bachin announced
──────────────────────

  I am pleased to announce release [0.5.1] of [**Luv**]. The main change
  is the addition of Windows support, which makes Luv fully
  cross-platform.

  Accordingly, Luv 0.5.1 is now installable from both the main opam
  repo, and from opam-repository-mingw.

  <https://github.com/aantron/luv>

  Also, as a side effect of the build system refactoring that was needed
  to support Windows, Luv's build system no longer requires Python, and
  supports cross-compilation.

  The other noteworthy change in release 0.5.1 is a routine upgrade of
  the vendored libuv to its latest version, [1.35.0].


[0.5.1] <https://github.com/aantron/luv/releases/tag/0.5.1>

[**Luv**] <https://github.com/aantron/luv>

[1.35.0] <https://github.com/libuv/libuv/releases/tag/v1.35.0>


resto 0.2 released
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-resto-0-2-released/5028/2>


Raphaël Proust announced
────────────────────────

Releases of `resto' 0.3 and 0.4
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  On behalf of Nomadic Labs, I'm happy to announce the release of
  versions 0.3 and 0.4 of `resto'. Both versions are available through
  `opam' and available on <https://gitlab.com/nomadic-labs/resto>.

  The main change in 0.3 is to depend on `json-data-encoding', the fork
  of the unmaintained `ocplib-json-typed'.

  The changes of 0.4 are more invasive and require users changes:
  • handle the new ``Gone' response code, and
  • pass `gettimeofday' manually.

  This last feature removes a dependency from `resto-cohttp' to `Unix',
  and thus helps with use within a `js_of_ocaml' environment.


Bisect_ppx 2.0.0 — code coverage for OCaml with nice HTML reports
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/bisect-ppx-2-0-0-code-coverage-for-ocaml-with-nice-html-reports/5338/1>


Anton Bachin announced
──────────────────────

  I am pleased to announce [release 2.0.0] of [**Bisect_ppx**], the
  OCaml coverage tool, which helps you see which parts of your code are
  not being tested.

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/1/1911adc6af898b6f4efd7dc69d2c1f90699031ba.gif>

  This release is a major upgrade. The highlights are:

  • Support for BuckleScript, js_of_ocaml, and esy. In other words,
    Bisect_ppx now compiles to both native code and JS, and is published
    in both opam and npm.
  • The ability to [send reports automatically] from Travis and CircleCI
    to Coveralls and Codecov. More integrations can be added over time.
  • The awkward `(*BISECT-IGNORE*)' comments for excluding code from
    instrumentation have been replaced by AST attributes like
    `[@coverage off]'
    (<https://github.com/aantron/bisect_ppx#Exclusion>).
  • A new, more principled instrumentation algorithm.
  • A new reporter command line based on [Cmdliner]. Run
    `bisect-ppx-report --help' to get started with it.
  • Syntax highlighting.

  You are invited to peruse the all-new [README] for details :)

  Several features have been deprecated; mostly command-line flags. You
  can see the list in the *Deprecations* section of the
  [changelog]. However, it may be easier to simply try using Bisect_ppx
  as before – it will warn you if you use a deprecated flag. The
  deprecated flags will be removed in Bisect_ppx 2.1.0, expected around
  July 2020.

  Happy testing!

  <https://github.com/aantron/bisect_ppx>


[release 2.0.0]
<https://github.com/aantron/bisect_ppx/releases/tag/2.0.0>

[**Bisect_ppx**] <https://github.com/aantron/bisect_ppx>

[send reports automatically]
<https://github.com/aantron/bisect_ppx#Coveralls>

[Cmdliner] <https://erratique.ch/software/cmdliner/doc/Cmdliner>

[README] <https://github.com/aantron/bisect_ppx#readme>

[changelog] <https://github.com/aantron/bisect_ppx/releases/tag/2.0.0>


OCaml 4.09.1 released
═════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-09-1-released/5341/1>


octachron announced
───────────────────

  We have the pleasure of celebrating the anniversary of the first
  spacewalk, conducted by Alexei Leonov, by announcing the release of
  OCaml version 4.09.1.  This is mainly a bug-fix release, with a
  handful of configuration fixes and a GC fix backported from 4.10.0
  . See the list of changes below for more details.

  It is (or soon will be) available as a set of OPAM switches, and as a
  source download here:

  <https://github.com/ocaml/ocaml/archive/4.09.1.tar.gz>


Changes in 4.09.1:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#9073], [#9120]: fix incorrect GC ratio multiplier when allocating
    custom blocks with caml_alloc_custom_mem in runtime/custom.c (Markus
    Mottl, review by Gabriel Scherer and Damien Doligez)

  • [#8855], [#8858]: Links for tools not created when installing with
    –disable-installing-byecode-programs (e.g. ocamldep.opt installed,
    but ocamldep link not created) (David Allsopp, report by Thomas
    Leonard)

  • [#8947], [#9134], [#9302]: fix/improve support for the BFD library
    (Sébastien Hinderer, review by Damien Doligez and David Allsopp)

  • [#8953], [#8954]: Fix error submessages in the toplevel: do not
    display dummy locations (Armaël Guéneau, review by Gabriel Scherer)

  • [#8965], [#8979]: Alpine build failure caused by
    check-parser-uptodate-or-warn.sh (Gabriel Scherer and David Allsopp,
    report by Anton Kochkov)

  • [#8985], [#8986]: fix generation of the primitives when the locale
    collation is incompatible with C. (David Allsopp, review by Nicolás
    Ojeda Bär, report by Sebastian Rasmussen)

  • [#9050], [#9076]: install missing compilerlibs/ocamlmiddleend
    archives (Gabriel Scherer, review by Florian Angeletti, report by
    Olaf Hering)

  • [#9144], [#9180]: multiple definitions of global variables in the C
    runtime, causing problems with GCC 10.0 and possibly with other C
    compilers (Xavier Leroy, report by Jürgen Reuter, review by Mark
    Shinwell)

  • [#9180]: pass -fno-common option to C compiler when available, so as
    to detect problematic multiple definitions of global variables in
    the C runtime (Xavier Leroy, review by Mark Shinwell)

  • [#9128]: Fix a bug in bytecode mode which could lead to a
    segmentation fault. The bug was caused by the fact that the atom
    table shared a page with some bytecode. The fix makes sure both the
    atom table and the minor heap have their own pages. (Jacques-Henri
    Jourdan, review by Stephen Dolan, Xavier Leroy and Gabriel Scherer)


[#9073] <https://github.com/ocaml/ocaml/issues/9073>

[#9120] <https://github.com/ocaml/ocaml/issues/9120>

[#8855] <https://github.com/ocaml/ocaml/issues/8855>

[#8858] <https://github.com/ocaml/ocaml/issues/8858>

[#8947] <https://github.com/ocaml/ocaml/issues/8947>

[#9134] <https://github.com/ocaml/ocaml/issues/9134>

[#9302] <https://github.com/ocaml/ocaml/issues/9302>

[#8953] <https://github.com/ocaml/ocaml/issues/8953>

[#8954] <https://github.com/ocaml/ocaml/issues/8954>

[#8965] <https://github.com/ocaml/ocaml/issues/8965>

[#8979] <https://github.com/ocaml/ocaml/issues/8979>

[#8985] <https://github.com/ocaml/ocaml/issues/8985>

[#8986] <https://github.com/ocaml/ocaml/issues/8986>

[#9050] <https://github.com/ocaml/ocaml/issues/9050>

[#9076] <https://github.com/ocaml/ocaml/issues/9076>

[#9144] <https://github.com/ocaml/ocaml/issues/9144>

[#9180] <https://github.com/ocaml/ocaml/issues/9180>

[#9128] <https://github.com/ocaml/ocaml/issues/9128>


Cookie 0.1.6
════════════

  Archive: <https://discuss.ocaml.org/t/ann-cookie-0-1-6/5346/1>


Ulrik Strid announced
─────────────────────

  I recently released a cookie library. It can parse and create cookie
  headers (`list((string, string)' which both Cohttp and Httpaf uses),
  both `Set-Cookie' and `Cookie' so it works on both client and
  server. It should be compliant with
  <https://tools.ietf.org/html/rfc6265> and I have a pretty good test
  suite for the parsing of cookies at least.

  I couldn’t find a standalone library before this so I decided to
  create one since I need it for my web framework, `Morph'.

  The next step is to create and publish integrations with
  [`ocaml-session'] which I have started.

  • Repo: <https://github.com/ulrikstrid/ocaml-cookie>
  • Docs: <https://ulrikstrid.github.io/ocaml-cookie>


[`ocaml-session'] <https://github.com/inhabitedtype/ocaml-session>


First release of lwt-pipeline
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-lwt-pipeline/4220/2>


Raphaël Proust announced
────────────────────────

  A second release of `lwt-pipeline' (v0.2) is available through
  `opam'. This new release makes no change to the code and only affects
  the following:

  • looser constraints on versions of `dune' dependency,
  • tests,
  • tests are executed in CI,
  • minor documentation improvements.


Using Ocaml as scripting language - piping sh commands
══════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/using-ocaml-as-scripting-language-piping-sh-commands/5366/1>


Nicolas Tollenaere announced
────────────────────────────

  I am trying to use ocaml to pipe the result of a command to another (I
  would also be interested in feeding a string or a io stream into a sh
  command). For example, I would like to do the equivalent of cat
  foo.txt | grep thing, or pipe the result of one of my ocaml function
  into grep.

  Quite surprinsingly, neither the Stdlib or Batteries Sys modules
  expose any way to handle the output of Sys.command directly (I would
  have thought there would be optional input and output arguments
  defaulting to stdin and stdout, or something along that). Batteries IO
  module does expose a pipe function but it's not clear for me how it
  would interact with the Sys module. Any ideas or other modules/package
  I could use ?


Nicolás Ojeda Bär suggested
───────────────────────────

  I think you may be interested by
  <https://github.com/janestreet/shexp>.


Nicolas Tollenaere then said
────────────────────────────

  @grayswandyr @nojb Thanks for the suggestion. I just found shcaml
  <http://tov.github.io/shcaml/doc/> and I was going to give it a try,
  do you know how it compares to shexp ?


David Chemouil replied
──────────────────────

  AFAIK shcaml is unmaintained, but the approach is very nice indeed.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-03-17 11:04 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-03-17 11:04 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 12110 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 10 to 17,
2020.

Table of Contents
─────────────────

Unicode 13.0.0 update for Uucd, Uucp, Uunf and Uuseg
Introducing dune describe
Introducing Model_quickcheck. Quickcheck for stateful, imperative code
Odig 0.0.5
Suggestions for ocaml documentation
Introducing Gopcaml mode - structural OCaml editing
Try OCaml 2.0 (beta)
jose 0.2.0
Old CWN


Unicode 13.0.0 update for Uucd, Uucp, Uunf and Uuseg
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/unicode-13-0-0-update-for-uucd-uucp-uunf-and-uuseg/5298/1>


Daniel Bünzli announced
───────────────────────

  Unicode 13.0.0 was released on the 10th of march.

  It adds 5390 characters to the standard including graphic symbols for
  legacy computing. If you were looking for characters representing
  seven-segment decimal digits, now you [have them]. For the curious,
  the [encoding proposal] has the motivation and source of these new
  symbols. For more information about all the other additions, see [this
  page].

  Accordingly the libraries mentioned at the end of this message had to
  be updated, consult the individual release notes for details. Both
  Uucd and Uucp are incompatible releases sinces new script and block
  enumerants had to be added.

  Uucp has a new Emoji module with the new emoji properties introduced
  in 13.0.0 which are now used by Uuseg to improve emoji
  segmentation. The overall compiled size of Uucp shrinked a bit; here
  uucp.cmxs went from 7.8Mo to 4.6Mo. Further reduction can likely be
  achieved with more work. Thanks to David Kaloper Meršinjak for helping
  on this.

  A periodic reminder, if Unicode still puzzles you, read an absolute
  minimal Unicode introduction and OCaml Unicode tips on [this page]
  (also available via `odig doc uucp').

  Happy retro computing,

  Daniel

  P.S. The OCaml compiler [detected] an obsolete rule in the 13.0.0
  update of the Unicode line breaking algorithm.

  —

  Uucd 13.0.0 Unicode character database decoder for OCaml.

  <http://erratique.ch/software/uucd>

  Uucp 13.0.0 Unicode character properties for OCaml.

  <http://erratique.ch/software/uucp>

  Uunf 13.0.0 Unicode text normalization for OCaml.

  <http://erratique.ch/software/uunf>

  Uuseg 13.0.0 Unicode text segmentation for OCaml.

  <http://erratique.ch/software/uuseg>


[have them] <https://www.unicode.org/charts/PDF/U1FB00.pdf>

[encoding proposal]
<https://www.unicode.org/L2/L2019/19025-terminals-prop.pdf>

[this page]
<http://blog.unicode.org/2020/03/announcing-unicode-standard-version-130.html>

[this page] <https://erratique.ch/software/uucp/doc/unicode.html>

[detected]
<https://www.unicode.org/mail-arch/unicode-ml/y2020-m03/0000.html>


Introducing dune describe
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/introducing-dune-describe/5300/1>


Jérémie Dimino announced
────────────────────────

  Just a quick post to introduce the new `dune describe' command in Dune
  2.4.0. If you'd like to write a tool that needs to understand the
  structure of a dune project, figure out where the cmt files are
  located, etc…, this is the command to look at.

  The command is not production ready yet, but the infrastructure is in
  place. If you are interested in releasing tools that rely on it,
  please let us know so that we can discuss what information you need
  out of dune and also so that we can stabilise it.

  <https://dune.build/blog/dune-describe/>


Introducing Model_quickcheck. Quickcheck for stateful, imperative code
══════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/introducing-model-quickcheck-quickcheck-for-stateful-imperative-code/5301/1>


suttonshire announced
─────────────────────

  I'm sharing a small project I've been working on that I hope will be
  interesting or useful to the community. [Model_quickcheck] is a
  model-based testing system that allows you to validate the
  "properties" of stateful, imperative OCaml programs. It's built on
  Jane Street's Base_quickcheck.

  I just started learning OCaml and one of the first projects I've been
  working on is a user-space reliable transport protocol. Writing tests
  for this system became unwieldy because I was trying to validate
  certain properties of the protocol by thinking up very specific
  sequences of actions that would invoke behaviors that relied on that
  property. I got tired of it and got curious if there was a way to
  generate these interesting sequences. My research turned up frameworks
  like [QCSTM] and [PropEr] for state machine property-based
  testing. This seemed to be exactly what I needed so I started building
  something similar.

  To use Model_quickcheck you specify a set of actions to apply to your
  program, a model that describes the state of you program and a set of
  predicates that define the properties of you system. The model is
  hopefully a simpler representation of your system e.g. a map instead
  of a key-value database, or a queue instead of a reliable network
  protocol. Model_quickcheck then generates a random sequences of
  actions applies them to your system and verifies the properties.

  This has been an exciting and useful project. I've learned a bunch
  about the Base library, Quickcheck, first class modules, and inline
  tests. I'm just getting started, but I just wanted to share the
  project with the community since I've learned a lot by lurking here.


[Model_quickcheck] <https://github.com/suttonshire/model_quickcheck>

[QCSTM] <https://github.com/jmid/qcstm>

[PropEr] <https://propertesting.com/book_state_machine_properties.html>


Odig 0.0.5
══════════

  Archive: <https://discuss.ocaml.org/t/ann-odig-0-0-5/5304/1>


Daniel Bünzli announced
───────────────────────

  `odig' has a new release. See the [release notes] for details.

  Installation: `opam install ocaml-manual odig'

  Tutorial: <https://erratique.ch/software/odig/doc/manual.html>

  odig is a command line tool to lookup documentation of installed OCaml
  packages. It shows package metadata, readmes, change logs, licenses,
  cross-referenced `odoc' API documentation and manuals.


[release notes]
<https://github.com/b0-system/odig/blob/v0.0.5/CHANGES.md#v005-2019-03-11-la-forclaz-vs>


Suggestions for ocaml documentation
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/suggestions-for-ocaml-documentation/4504/50>


sanette announced
─────────────────

  The "OCaml API", which is the documentation for the standard library,
  is now complete for all versions 4.00–4.10, with a quick search field,
  on the demo site:

  <https://sanette.github.io/ocaml-api/>


Introducing Gopcaml mode - structural OCaml editing
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/introducing-gopcaml-mode-structural-ocaml-editing/5310/1>


Kiran Gopinathan announced
──────────────────────────

  Hi all, I am pleased to announce the first release of Gopcaml-mode, a
  new emacs library that aims to extend the existing OCaml editing
  experience with structural editing capabilities.

  A picture is worth a thousand words, so I'll cut to the chase, and
  start with a few demonstrations:


Examples
╌╌╌╌╌╌╌╌

  • AST-based code navigation - `C-M-n, C-M-p, C-M-u, C-M-d, C-M-f,
    C-M-b'

  <https://gitlab.com/gopiandcode/gopcaml-mode/-/raw/master/images/gopcaml_move_expression_example.gif>

  • AST-based code transformation -`C-M-N, C-M-P, C-M-F, C-M-B'

  <https://gitlab.com/gopiandcode/gopcaml-mode/-/raw/master/images/gopcaml_move_function_example.gif>

  • Mark exp - `C-M-SPC'

  <https://gitlab.com/gopiandcode/gopcaml-mode/-/raw/master/images/gopcaml_mark_sexp.gif>

  • Extract expression into letdef - `C-c C-e'

  <https://gitlab.com/gopiandcode/gopcaml-mode/-/raw/master/images/gopcaml_extraction_expressions.gif>

  This is just a small sample of the features - a full listing is
  provided at the project readme, which can be found at the [project
  page].


[project page] <https://gitlab.com/gopiandcode/gopcaml-mode>


Notes
╌╌╌╌╌

  This plugin is quite faithful to the OCaml specification and doesn't
  reimplement a separate OCaml parser as some other plugins do - instead
  I use the Ecaml package (which allows interfacing with Emacs from
  OCaml code) to allow delegating to the OCaml parser (from
  Ocaml-compiler-libs) directly.

  It's in the process of being published to opam, and should be
  available to download soon.


Try OCaml 2.0 (beta)
════════════════════

  Archive: <https://discuss.ocaml.org/t/ann-try-ocaml-2-0-beta/5325/1>


Louis Gesbert announced
───────────────────────

  OCamlPro is happy to announce the release of a new version of the
  venerable [Try OCaml tool].

  This tool allows you to quickly test OCaml snippets from anywhere,
  directly from your browser. It's still in beta, so any issues or
  comments are welcome below.

  The new version is a complete refactor and redesign, based on the
  backend of Learn-OCaml.

  Original announcement:
  <http://www.ocamlpro.com/2020/03/16/new-version-of-try-ocaml-in-beta/>


[Try OCaml tool] <https://try.ocamlpro.com>


jose 0.2.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-jose-0-2-0/5328/1>


Ulrik Strid announced
─────────────────────

  I recently released a JavaScript Object Signing and Encryption library
  to opam.

  The main usecase for JOSE is JWT and JWK and is a comprehensive
  library for both unlike some other libraries that currently exist in
  the ecosystem. It uses mirage-crypto and supports RSA and OCT keys
  currently and will support EC when mirage-crypto does.

  I have not really implemented the encryption part yet but if anyone
  needs JWE I'll gladly do the work or accept PRs.

  The project was initially developed in Reason but I changed over to
  OCaml at some point because of limitations in Reason at the time but
  the repo still has the old name.

  The docs can be found here:
  <https://ulrikstrid.github.io/reason-jose/>

  The repo can be found here:
  <https://github.com/ulrikstrid/reason-jose/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-03-10 14:28 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-03-10 14:28 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 23566 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of March 03 to 10,
2020.

Table of Contents
─────────────────

Non opam workflows
First release of metapp
OCaml 4.10 released
Transept 0.1.0: Generalised Parser Combinators
Multicore OCaml: Feb 2020 update
owl 0.8.0 and 0.9.0 released
Parser combinators vs. parser preprocessors?
Dune 2.4.0
Tyxml 4.4.0
first release of oplsr: an OCaml wrapper to the pls R package - Partial Least Squares (PLS) regression
Old CWN


Non opam workflows
══════════════════

  Archive: <https://discuss.ocaml.org/t/non-opam-workflows/5232/1>


Manas asked
───────────

  Very recently, I learnt that there is a significant chunk of users in
  the OCaml community that does not use opam to install packages. As a
  small initiative to contribute to tooling, I want to ensure what I
  build is compatible with these workflows - workflows I'm not familiar
  with myself.

  I'd love to learn more - what does it look like? How do you setup your
  compiler, dune and merlin (and/or soon ocamllsp)? How do you configure
  your editor to find them and what would make it easier to do so?

  I'm told of Duniverse as one tool that being used in these non-opam
  workflows. Are there any more popular ones out there?


Théo Zimmermann replied
───────────────────────

  I am one of these people. I mostly rely on Nix, whose package
  repository nixpkgs provides package sets for all (relatively recent)
  versions of OCaml. These package sets are not generally as complete as
  what you can find on opam, so it sometimes happens that I open a PR on
  the nixpkgs repository to add a new package (and in the meantime I use
  my local updated copy of the nixpkgs repo).

  You can see the list of available OCaml packages at:
  <https://nixos.org/nixos/packages.html?channel=nixpkgs-unstable&query=ocamlPackages>
  (This is for the default OCaml version, currently 4.07 in
  nixpkgs-unstable. Other package sets are called
  `ocaml-ng.ocamlPackages_4_0X' but are not shown in this web search.)

  Most OCaml packages are available at a single version in nixpkgs (even
  though you can choose your version of OCaml). To gain more flexibility
  on the exact version I use in one of my project, I am planning to test
  Duniverse. At that point, I would rely on Duniverse for library
  dependencies, but I would still rely on Nix to install OCaml, findlib,
  Dune, Duniverse (I'll have to take care of packaging it), utop,
  merlin, or ocamlformat.

  Nix is pretty straightforward to use. You generally provide a
  `default.nix' at the root of your repository, and it will list the
  dependencies that you use.  When you want to go develop your project,
  you just enter a special shell (with the `nix-shell' command) and you
  are in an environment where the tools you need are in `PATH' and the
  libraries you need are in `OCAMLPATH'.

  There's just one tool that I needed special configuration for:
  `ocamlformat' (especially because some projects use it and some do
  not). When I use it, my `default.nix' contains:

  ┌────
  │ shellHook = ''
  │   export OCAMLFORMAT_LOCATION=${ocamlformat}
  │ '';
  └────

  which will export an environment variable when I enter the shell.

  And my `.emacs' contains:

  ┌────
  │ (setq ocamlformat-location (getenv "OCAMLFORMAT_LOCATION"))
  │ (when (> (length ocamlformat-location) 0)
  │  (add-to-list 'load-path (concat ocamlformat-location "/share/emacs/site-lisp"))
  │  (require 'ocamlformat)
  │  (add-hook 'tuareg-mode-hook
  │ 	   (lambda () (add-hook 'before-save-hook 'ocamlformat-before-save))))
  └────

        I want to ensure what I build is compatible with these
        workflows

  If you mean as a library author, then all you have to ensure is that
  you use Dune as the build system (makes the Duniverse workflow better,
  and makes it easier to package your library in nixpkgs,
  cf. `buildDunePackage' documented at
  <https://nixos.org/nixpkgs/manual/#sec-language-ocaml>).


Rwmjones also replied
─────────────────────

  You might want to check out the Fedora OCaml packages.

  Unfortunately I don't have a convenient way to link to the whole list,
  but if you look at all the OCaml packages here:
  <https://koji.fedoraproject.org/koji/search?match=glob&type=package&terms=ocaml>*
  and then if you substitute the `ocaml-<packagename>' in two places in
  this URL:
  <https://src.fedoraproject.org/rpms/ocaml-re/blob/master/f/ocaml-re.spec>
  (example showing `ocaml-re' package), you can see how we build and
  package them in the `%prep', `%build' and `%install' sections.

  And yes, please make sure your software doesn't depend on opam.
  Building everything in your home directory is not suitable for
  enterprise software distribution.


First release of metapp
═══════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-metapp/5250/1>


Thierry Martinez announced
──────────────────────────

  I am happy to announce the first release of `metapp', yet another
  preprocessor for OCaml.  Similarly to [`ppx_optcomp'], `metapp' is a
  PPX rewriter.  But instead of introducing a specific DSL for
  preprocessor directives, `metapp' provides a `[%meta ...]' extension,
  where the dots `...' are arbitrary OCaml expressions that are
  substituted at compile-time by the AST nodes they evaluate into. These
  expressions build AST nodes either by (anti-)quoting some code
  directly, or by using `compiler-libs' ([`Parsetree'], [`Ast_helper'],
  …).

  In particular, this preprocessor is easy to use for conditional
  compilation, and is an alternative to [`cppo'] and [`ppx_optcomp'].

  ┌────
  │ let option_get o =
  │   [%meta if Sys.ocaml_version >= "4.08.0" then
  │      [%e Option.get o]
  │   else
  │      [%e match o with
  │      | None -> invalid_arg "option_get"
  │      | Some x -> x]]
  └────

  In this example, the code between `[%e ... ]' is "anti-quoted": it is
  the code that is inserted (conditionally) in the rewritten module.  Of
  course, the anti-quoted code can contain itself some `[%meta ...]'
  code. `[%meta ...]' can even itself contain other levels of `[%meta
  ...]' code for multi-stage programming.

  An example of usage of `metapp' is the [`metaquot'] package, which
  implements the same quoters as `ppx_tools.metaquot': `[%expr ...]',
  `[%type: ...]', etc.  These quoters are implemented by
  meta-programming: the meta-code introspects `Parsetree.cmi' from
  `compiler-libs' to generate the code matching the current OCaml
  version.


[`ppx_optcomp'] <https://github.com/janestreet/ppx_optcomp>

[`Parsetree']
<https://caml.inria.fr/pub/docs/manual-ocaml/compilerlibref/Parsetree.html>

[`Ast_helper']
<https://caml.inria.fr/pub/docs/manual-ocaml/compilerlibref/Ast_helper.html>

[`cppo'] <https://github.com/ocaml-community/cppo>

[`metaquot'] <https://github.com/thierry-martinez/metaquot>


Raphaël Proust added
────────────────────

  To potentially save a few second to the next readers:
  <https://github.com/thierry-martinez/metapp> seems to be the repo
  where it is hosted.


Thierry Martinez then said
──────────────────────────

  Thanks, @raphael-proust! The package is also available via opam: `opam
  install metapp' (and `metaquot' is available via opam as well).


OCaml 4.10 released
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-10-released/5194/5>


octachron continued this thread
───────────────────────────────

  The Merlin team has just released a preview version of Merlin which is
  compatible with 4.10.0 (Merlin is an editor service that provides
  modern IDE features for OCaml) .

  This is a preview version:

  • the support for short-path is disabled
  • only OCaml 4.10.0 is supported in this preview

  It can be installed via opam with the usual
  ┌────
  │ opam install merlin
  └────


Transept 0.1.0: Generalised Parser Combinators
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-transept-0-1-0-generalised-parser-combinators/5262/1>


Didier Plaindoux announced
──────────────────────────

  I’m happy to announce the first release of Transept an OCaml
  implementation of generalized parsers combinators.

  This implementation has been inspired by a 19 years old paper -
  written by Daan Leijen and Erik Meijer - titled “Parsec: Direct Style
  Monadic Parser Combinators For The Real World” [1]. The current
  implementation provides basic combinators dedicated to char, chars
  recognition but also conjunction, sequence, repetition and more. Since
  the current design relies on the abstract definition of manipulated
  element most of the parsers are generic and can be used with streams
  of chars or something else.

  Finally, with this library, I wanted to share my love of OCaml modules
  🤗

  Opam: <https://opam.ocaml.org/packages/transept/transept.0.1.0/>

  [1]
  <https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/parsec-paper-letter.pdf>


Didier Wenzek then said
───────────────────────

  It good to see yet another parser combinator for OCaml, even if this
  makes more difficult the choice of one of them. I believe this
  highlights how well OCaml shines for this kind of applications where
  both high-level expressiveness and performance matter.

  [`angstrom'] is one the alternatives and provides a comparison with
  others. It would be good to position `transept' here.

  There is also a more recent article with a radically new approach: [A
  Typed, Algebraic Approach to Parsing] by Neelakantan R. Krishnaswami
  and Jeremy Yallop - PLDI 2019. This paper proposes a [library of
  parser combinators] for context-free expressions, an algebraic
  presentation of the context-free languages. The key points are
  • the use of types to statically reject any language which cannot be
    parsed unambiguously and linearly;
  • the use of staging, with OcamlBER, to produce parsers which
    performance are close to those of hand-written code.


[`angstrom'] <https://github.com/inhabitedtype/angstrom>

[A Typed, Algebraic Approach to Parsing]
<https://www.cl.cam.ac.uk/~nk480/parsing.pdf>

[library of parser combinators] <https://github.com/yallop/ocaml-asp/>


Multicore OCaml: Feb 2020 update
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-feb-2020-update/5227/3>


Continuing this thread, Rwmjones asked
──────────────────────────────────────

  Hi Anil (or anyone!).  Is there a place I can find more about breaking
  changes that might be made to C extensions?  As you may know we have a
  lot of C code which interfaces with OCaml, both as ordinary extensions
  written in C, but also embedding OCaml in C programs (although that's
  much more rare), and I'd like a heads up about what's likely to
  change.


Anil Madhavapeddy replied
─────────────────────────

  Hi @rwmjones! In a nutshell: no breaking C changes. The longer version
  is that we implemented two different minor collectors in order to
  evaluate various tradeoffs systematically:

  • a concurrent minor collector that requires a read barrier and some C
    API changes in order to create more safe points
  • a stop-the-world minor collector that doesn't require a read barrier
    and no extra C API changes, but would probably cause longer pauses

  The good news is that our STW collector scales up much better than we
  expected (tested to 24 cores), and so our first domains patchset will
  almost certainly use that version now.  We expect to shift to a
  concurrent (and possibly pauseless) collection algorithm at some
  future point, but in terms of upstreaming it looks like we should be
  able to delay any C API changes until after the first version of
  multicore has landed.

  Do you have any nice standalone candidate programs using the C FFI we
  could add to Sandmark?


owl 0.8.0 and 0.9.0 released
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-owl-0-8-0-and-0-9-0-released/5281/1>


Marcello Seri announced
───────────────────────

  We are happy to announce *two* new releases of `owl': a dedicated
  system for scientific and engineering computing in OCaml.

  Since our previous announcement in July last year, there has been an
  [enormous amount of work] going on to cleanup and extend owl's
  internals and its interfaces.

  In this period we have been trying to release often and keep
  disruption to a minimum. Owl 0.8.0 and 0.9.0 are exceptional in this
  respect:

  • `owl.0.8.0':
    • the discrepancy between `owl-base' (pure ocaml) and `owl' (links
      cblas/lapacke) interfaces started becoming a problem in few
      places. In this release many interfaces have been unified and
      reused. The algodiff module has undergone a similar
      refactoring. Although most users should be shielded from these
      changes, they may break existing code, requiring an upper bound on
      owl and some localized updates. This should mostly boil down to
      changes like
      ┌────
      │ -module CGraph_D = Owl_computation_engine.Make_Graph (Owl_computation_cpu_device.Make (Dense.Ndarray.D))
      │ +module CGraph_D = Owl_computation_engine.Make_Graph (Owl_computation_cpu_device.Make (Owl_algodiff_primal_ops.D))
      └────
    • this is the last edition supporting OCaml compiler versions <
      4.10.0 (more on this later).
  • `owl.0.9.0': the main difference between `0.8.0' and `0.9.0' is that
    owl now requires OCaml 4.10.0. This release of OCaml introduces
    *extended indexing operators*. With them we can now write things
    like `x.%{0;3}' (for indexing) and `x.${[0:2];[2;4]}' (for slicing)
    instead of the more cumbersome `x.%{[|0;3|]}' and
    `x.${[[0:2];[2;4]]}'.

  The project is thoroughly documented at [ocaml.xyz ] where you can
  find multiple examples of use.

  A lot of work has (and is) been going into improving the
  documentation, you can find the results in the new [owl book]:
  <https://ocaml.xyz/book/toc.html>. This is currently targeting the
  development version of owl, so using `master' or `0.9.0' is the best
  bet if you want to try the examples out.

  One of the issue of the old documentation was that it was getting
  stale very fast: the book is reusing some of the infrastructure of
  RWO, so all examples get recompiled and retested continuously to
  ensure their correctness.

  As a final note, we would like to send a huge thank to the [OCaml
  Software Foundation], see also the [announcement made on this forum],
  which has given us some funding that will support a retreat of the
  maintainers and a development sprint that will take place at the end
  of March.

  We meant to announce the retreat and sprint for some time now, but the
  size and publicity of the event may depend on updates to the various
  governmental and institutional recommendation in regards to COVID-19
  spreading.  If a public event will be possible, we will make a
  separate announce on this forum.

  We want to also thank all the contributors for the increasing number
  of comments, fixes and discussions that are helping us shape the next
  releases of owl.

  The Owl Dev Team


[enormous amount of work]
<https://github.com/owlbarn/owl/blob/master/CHANGES.md>

[ocaml.xyz ] <http://ocaml.xyz>

[owl book] <https://ocaml.xyz/book/toc.html>

[OCaml Software Foundation] <http://ocaml-sf.org/>

[announcement made on this forum]
<https://discuss.ocaml.org/t/ann-the-ocaml-software-foundation/4476>


Parser combinators vs. parser preprocessors?
════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/parser-combinators-vs-parser-preprocessors/5263/4>


Continuing this thread, yallop said
───────────────────────────────────

  Gasche said:
        Combinators also describe a grammar; they can build a
        representation that is then processed. I think it would be
        perfectly reasonable to provide combinators to describe a
        L(AL)R grammar, and then a function from such a grammar to
        a parsing automaton, along with the result of various
        analyses. This would solve the “additional tooling”
        problem of typical parser generators, and also the “lack
        of conflict analysis” problem of typical parser combinator
        libraries. But it may require support for staging for
        performance reasons.

  Readers of this thread may be interested in the [asp] (*algebraic
  staged parsing*) library (also described in the [Transept post] linked
  above), which is built on an approach along the lines @gasche
  describes:
  • combinators that describe a grammar (using context-free expressions)
  • an analysis (formulated as a type system) that ensures deterministic
    parsing
  • staging to eliminate performance overhead

  The interface is pretty standard, with combinators for alternation,
  sequencing, etc., and performance is quite good (better than
  `ocamlyacc' on our benchmarks).

  There's a paper, [A typed algebraic approach to parsing], that
  describes the design in more detail.

  Chet_Murthy said:
        Also, I’m personally a massive LL(1) (over LALR) bigot

  Grammars built using `asp' are essentially LL(1).  (The weasel word
  "essentially" isn't hiding much here, but the paper has the details.)


[asp] <https://github.com/yallop/ocaml-asp/>

[Transept post]
<https://discuss.ocaml.org/t/ann-transept-0-1-0-generalised-parser-combinators/5262>

[A typed algebraic approach to parsing]
<https://www.cl.cam.ac.uk/~jdy22/papers/a-typed-algebraic-approach-to-parsing.pdf>


Dune 2.4.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-4-0/5288/1>


Rudi Grinberg announced
───────────────────────

  On behalf of the dune team, I'm pleased to announce the release of
  dune 2.4.0. This releases features support for [mdx], an interesting
  take on the notebook paradigm by the RWO team. This release also
  includes a crucial fix to polling mode which makes it usable in
  environments with finite memory :slight_smile:.

  Happy hacking!


[mdx] <https://github.com/realworldocaml/mdx>

2.4.0 (06/03/2020)
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Add `mdx' extension and stanza version 0.1 (#3094, @NathanReb)

  • Allow to make Odoc warnings fatal. This is configured from the `(env
    ...)'  stanza. (#3029, @Julow)

  • Fix separate compilation of JS when findlib is not
    installed. (#3177, @nojb)

  • Add a `dune describe' command to obtain the topology of a dune
    workspace, for projects such as ROTOR. (#3128, @diml)

  • Add `plugin' linking mode for executables and the
      `(embed_in_plugin_libraries ...)' field. (#3141, @nojb)

  • Add an `%{ext_plugin}' variable (#3141, @nojb)

  • Dune will no longer build shared objects for stubs if
    `supports_shared_libraries' is false (#3225, fixes #3222,
    @rgrinberg)

  • Fix a memory leak in the file-watching mode (`dune build -w')
    (#3220, @snowleopard and @aalekseyev)


Tyxml 4.4.0
═══════════

  Archive: <https://discuss.ocaml.org/t/ann-tyxml-4-4-0/5290/1>


Gabriel Radanne announced
─────────────────────────

  I have the pleasure to announce the release of [TyXML 4.4.0], with
  special Reason support!

  [TyXML] is a library for building statically correct HTML and SVG
  documents. TyXML provides a set of combinators which use the OCaml
  type system to ensure the validity of the HTML. TyXML is now a stable
  library and this release comes with a few newly supported elements and
  attributes (such as ARIA elements) and associated bug fixes. However,
  the main novelty of this release is a long awaited feature: the
  support for [Reason’s JSX syntax] in the brand new `tyxml-jsx'
  package.

  See the complete announcement for code examples and details:
  <https://drup.github.io/2020/03/06/tyxml440/>


[TyXML 4.4.0] <https://github.com/ocsigen/tyxml/releases/tag/4.4.0>

[TyXML] <https://github.com/ocsigen/tyxml>

[Reason’s JSX syntax] <https://reasonml.github.io/docs/en/jsx.html>


first release of oplsr: an OCaml wrapper to the pls R package - Partial Least Squares (PLS) regression
══════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-oplsr-an-ocaml-wrapper-to-the-pls-r-package-partial-least-squares-pls-regression/5293/1>


UnixJunkie announced
────────────────────

  It is my great pleasure to release one more hackish wrapper to use
  some R package from within OCaml:

  <https://github.com/UnixJunkie/oplsr>

  For some background:
  <https://en.wikipedia.org/wiki/Partial_least_squares_regression>

  Cf. test.ml in the sources for a usage example.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-03-03  8:00 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-03-03  8:00 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Here is the latest OCaml Weekly News, for the week of February 25 to
March 03, 2020.

Table of Contents
─────────────────

OCaml 4.10 released
Summary of the Dune retreat 2020
Multicore OCaml: Feb 2020 update
Oplot 0.50
soupault: a static website generator based on HTML rewriting
Old CWN


OCaml 4.10 released
═══════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-10-released/5194/4>


Contnuing this thread, Anil Madhavapeddy said
─────────────────────────────────────────────

  Indeed, many thanks to everyone who leapt in to make 4.10 ready in
  opam in such record time!  Just a note that the CI Docker images are
  now also rebuilt for x86_64, arm32/64 and ppc64le to reflect the 4.10
  release, so feel free to start using
  them. <https://hub.docker.com/r/ocaml/opam2/tags>


Summary of the Dune retreat 2020
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/summary-of-the-dune-retreat-2020/5224/1>


Jérémie Dimino announced
────────────────────────

  We recently organised the second Dune retreat. If you'd like to see
  what is happening in the Dune world at the moment, please find a
  summary of what we discussed and work on in this blog post!

  <https://dune.build/blog/dune-retreat-2020/>


Multicore OCaml: Feb 2020 update
════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-feb-2020-update/5227/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the February 2020 news update from the Multicore OCaml
  team, spread across the UK, India, France and Switzerland! This
  follows on from [last month's] update, and has been put together by
  @shakthimaan and @kayceesrk.

  The [release of OCaml 4.10.0] has successfully pushed out some
  prerequisite features into the upstream compiler.  Our work in
  February has focussed on getting the multicore OCaml branch "feature
  complete" with respect to the complete OCaml language, and doing
  extensive benchmarking and stress testing to test our two minor heap
  implementations.

  To this end, a number of significant patches have been merged into the
  [Multicore OCaml trees] that essentially provide complete coverage of
  the language features. We encourage you to test the same for
  regressions and provide any improvements or report shortcomings to
  us. There are ongoing OCaml PRs and issues that are also under review,
  and we hope to complete those for the 4.11 release cycle. A new set of
  parallel benchmarks have been added to our [Sandmark benchmarking
  suite] (live instance [here]), including enhancements to the build
  setup.


[last month's]
<https://discuss.ocaml.org/t/multicore-ocaml-january-2020-update/5090>

[release of OCaml 4.10.0]
<https://discuss.ocaml.org/t/ocaml-4-10-released/5194>

[Multicore OCaml trees]
<https://github.com/ocaml-multicore/ocaml-multicore>

[Sandmark benchmarking suite] <https://github.com/ocaml-bench/sandmark>

[here] <http://bench2.ocamllabs.io>

Multicore OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

◊ Completed

  The following PRs have been merged into Multicore OCaml:

  • [ocaml-multicore/ocaml-multicore#281] Introduce `Forcing_tag' to fix
    concurrency bug with lazy values

    A `Forcing_tag' is used to implement lazy values to handle a
    concurrency bug. It behaves like a locked bit, and any concurrent
    access by a mutator will raise an exception on that domain.

  • [ocaml-multicore/ocaml-multicore#282] Safepoints

    A preliminary version of safe points has been merged into the
    Multicore OCaml trees. [ocaml-multicore/ocaml-multicore#187] also
    contains more discussion and background about how coverage can be
    improved in future PRs.

  • [ocaml-multicore/ocaml-multicore#285] Introduce an 'opportunistic'
    major collection slice

    An "opportunistic work credit" is implemented in this PR which forms
    a basis for doing mark and sweep work while waiting to synchronise
    with other domains.

  • [ocaml-multicore/ocaml-multicore#286] Do fflush and variable args in
    caml_gc_log

    The caml_gc_log() function has been updated to ensure that `fflush'
    is invoked only when GC logging is enabled.

  • [ocaml-multicore/ocaml-multicore#287] Increase EVENT_BUF_SIZE

    During debugging with event trace data it is useful to reduce the
    buffer flush times, and hence the `EVENT_BUF_SIZE' has now been
    increased.

  • [ocaml-multicore/ocaml-multicore#288] Write barrier optimization

    This PR closes the regression for the `chameneos_redux_lwt'
    benchmarking in Sandmark by using `intnat' to avoid sign extensions
    and cleans up `write_barrier' to improve overall performance.

  • [ocaml-multicore/ocaml-multicore#290] Unify sweep budget to be in
    word size

    The PR updates the sweep work units to all be in word size. This is
    to handle the differences between the budget for setup, sweep and
    for large allocations in blocks.


  [ocaml-multicore/ocaml-multicore#281]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/281>

  [ocaml-multicore/ocaml-multicore#282]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/282>

  [ocaml-multicore/ocaml-multicore#187]
  <https://github.com/ocaml-multicore/ocaml-multicore/issues/187>

  [ocaml-multicore/ocaml-multicore#285]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/285>

  [ocaml-multicore/ocaml-multicore#286]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/286>

  [ocaml-multicore/ocaml-multicore#287]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/287>

  [ocaml-multicore/ocaml-multicore#288]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/288>

  [ocaml-multicore/ocaml-multicore#290]
  <https://github.com/ocaml-multicore/ocaml-multicore/pull/290>


◊ Ongoing

  • A lot of work is ongoing for the implementation of a synchronised
    minor garbage collector for Multicore OCaml, including benchmarking
    for the stop-the-world (stw) branch.  We will publish the results of
    this in a future update, as we are assembling a currently
    comprehensive evaluation of the runtime against the mainstream
    runtime.


Benchmarking
╌╌╌╌╌╌╌╌╌╌╌╌

  [Sandmark] now has support to run parallel benchmarks. We can also now
  about GC latency measurements for both stock OCaml and Multicore OCaml
  compiler.

  • [ocaml-bench/sandmark#73] More parallel benchmarks

    A number of parallel benchmarks such as N-body, Quick Sort and
    matrix multiplication have now been added to Sandmark!

  • [ocaml-bench/sandmark#76] Promote packages. Unbreak CI.

    The Continuous Integration build can now execute after updating and
    promoting packages in Sandmark.

  • [ocaml-bench/sandmark#78] Add support for collecting information
    about GC pausetimes on trunk

    The PR now helps process the runtime log and produces a `.bench'
    file that captures the GC pause times. This works on both stock
    OCaml and in Multicore OCaml.

  • [ocaml-bench/sandmark#86] Read and write Irmin benchmark

    A test for measuring Irmin's merge capabilities with Git as its
    filesystem is being tested with different read and write rates.

  • A number of other parallel benchmarks like Merge sort,
    Floyd-Warshall matrix, prime number generation, parallel map, filter
    et. al. have been added to Sandmark.


[Sandmark] <http://bench2.ocamllabs.io/>

[ocaml-bench/sandmark#73]
<https://github.com/ocaml-bench/sandmark/pull/73>

[ocaml-bench/sandmark#76]
<https://github.com/ocaml-bench/sandmark/pull/76>

[ocaml-bench/sandmark#78]
<https://github.com/ocaml-bench/sandmark/pull/78>

[ocaml-bench/sandmark#86]
<https://github.com/ocaml-bench/sandmark/pull/86>


Documentation
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Examples using domainslib and modifying Domains are currently being
    worked upon for a chapter on Parallel Programming for Multicore
    OCaml. We will release an early draft to the community for your
    feedback.


OCaml
╌╌╌╌╌

  One PR opened to OCaml this month, which fixes up the marshalling
  scheme to be multicore compatible. The complete set of [upstream
  multicore prerequisites] are labelled in the compiler issue tracker.

  • [ocaml/ocaml#9293] Use addrmap hash table for marshaling

    The hash table (addrmap) implementation from Multicore OCaml has
    been ported to upstream OCaml to avoid using GC mark bits to
    represent visitedness.


[upstream multicore prerequisites]
<https://github.com/ocaml/ocaml/labels/multicore-prerequisite>

[ocaml/ocaml#9293] <https://github.com/ocaml/ocaml/pull/9293>


Acronyms
╌╌╌╌╌╌╌╌

  • CTF: Common Trace Format
  • CI: Continuous Integration
  • GC: Garbage Collector
  • PR: Pull Request

  As always, many thanks to our fellow OCaml developers and users who
  have reviewed our code, reported bugs or otherwise assisted this
  month.


Oplot 0.50
══════════

  Archive: <https://discuss.ocaml.org/t/ann-oplot-0-50/5235/1>


sanette announced
─────────────────

  I'm happy to annouce the revival of the `oplot' library.

  If you ever wanted to quickly draw the graph of an intriguing
  mathematical function, animate it by varying a parameter, or explore a
  3D surface, without leaving your favorite programming language, then
  `oplot' is for you.

  If you're familiar with LaTeX and want to produce nice mathematical
  graphics decorated with LaTeX formulas, that you can view onscreen,
  export to images or vector graphics (pdf, eps) then `oplot' is even
  more for you!

  • Installation: `opam install oplot'
  • documentation:
    <https://sanette.github.io/oplot/oplot/Oplot/index.html>
  • source code, issues, etc: <https://github.com/sanette/oplot>

  Drawing is hardware accelerated (opengl) thanks to the venerable
  `ocamlsdl' and `lablgl' libraries. I'm glad they still work perfectly.

  Happy plotting.


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/12>


Daniil Baturin announced
────────────────────────

  [1.9.0] release is now available.

  • `--index-only' option that makes soupault dump the site metadata to
    JSON and stop at that
  • Metadata extraction and index generation can now be limited to
    specific pages/section/path regexes, just like widgets
  • The `preprocess_element' widget now supports a list of selectors,
    e.g. `selector = ["code", "pre code"]'.
  • Plugin API now has functions for running external programs, and some
    more element tree access functions.
  • CSS selector parse errors are now handled gracefully ([lambdasoup
    PR#31]).
  • The `title' widget now correctly removes HTML tags from the supposed
    title string and doesn't add extra whitespace (fixes by [Thomas
    Letan]).


[1.9.0] <https://soupault.neocities.org/blog/soupault-1.9.0-release/>

[lambdasoup PR#31] <https://github.com/aantron/lambdasoup/pull/31>

[Thomas Letan] <https://soap.coffee/~lthms/>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-02-18  8:18 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-02-18  8:18 UTC (permalink / raw)
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[-- Attachment #1: Type: text/plain, Size: 14952 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of February 11 to 18,
2020.

Table of Contents
─────────────────

Logical 0.3.0
OCaml 4.10.0, first release candidate
New release of Menhir, including bug fixes
First release of data-encoding, JSON and binary serialisation
Opam package popularity?
What's the OCaml equivalent for HLint?
New release of naboris 0.1.1
Category theory for Programmers book - OCaml flavor
Call for Speakers: Build Meetup New York April 2020
Old CWN


Logical 0.3.0
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-logical-0-3-0/5150/1>


Tóth Róbert announced
─────────────────────

  I proud to announce that I published Logical 0.3.0 and it's available
  in opam. I'm also not to proud to announce that I did a bunch of
  breaking changes in this release. :D

  During development of this release, I realized that I made the biggest
  mistake I could do as a library maintainer, which is that I didn't use
  my own library, so I made a bunch of stupid design mistakes, which I
  hopefully fixed in this release.

  Changelog:
  • Added both_multi goal
  • Removed set from the type system
  • Moved type system to separate module
  • Re-factored state to be a map instead of an association list
  • Added bunch of examples to the bin folder

  One of my main goal with Logical was to solve the puzzles that I found
  in this entertaining article:
  <https://xmonader.github.io/prolog/2018/12/21/solving-murder-prolog.html>
  and it became a reality so hurray.  Another important thing to mention
  is that I can proudly say that Logical is capable of solving a mystery
  murder, so it's at least a mystery murder complete
  language/framework. :D

  Future plans(0.4.0 release):
  • I want to introduce conditions or validations (I need to find a good
    name for it) on the variables, which would basically be a function,
    which is run when the variable gets it's value, so it's possible to
    assess if the value is a good one or not. I think this feature is
    extremely general, flexible and powerful, so I have to be careful
    how I implement it(if I will). :D It also means that implementing
    negation in Logical will become a breeze, so that's it for being
    negation free.
  • I'm thinking of creating a Variable module, which will by more like
    a syntactic sugar for creating variables. I'm not sure about this,
    because this would make Goal.equal "obsolete".
  • I will hide Base's datatypes behind ours, so the user don't have to
    depend on base to use the library.

  Let me know if you have any suggestion or comment about Logical.

  Github: <https://github.com/StrykerKKD/Logical>
  Docs: <https://strykerkkd.github.io/Logical>


OCaml 4.10.0, first release candidate
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-4-10-0-first-release-candidate/5137/2>


octachron announced
───────────────────

  We have released a second release candidate to integrate a bug fix for
  32-bit users of the new best-fit allocator:

  <https://github.com/ocaml/ocaml/pull/9292>

  The fix should be transparent for other users, the release is mostly
  here to try to minimize the difference between the candidate and final
  binaries.


New release of Menhir, including bug fixes
══════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-02/msg00023.html>


François Pottier announced
──────────────────────────

  Dear users of OCaml & Menhir,

  It is my pleasure to announce a new release of Menhir.

  ┌────
  │ opam update
  │ opam upgrade menhir
  └────

  This release fixes two bugs in our implementation of Pager's
  algorithm.  Menhir relies on this algorithm to build an LR automaton
  and to decide which states can safely be merged, where "safely" means
  "without creating unexplainable conflicts". One bug (which had been
  known for a long time, but not fixed) would cause Menhir to sometimes
  make an unsafe merge decision, thereby creating an unexplainable
  conflict. The other bug (which had never been discovered until now)
  would cause Menhir to sometimes miss a safe merge decision, thereby
  creating an automaton with needlessly many states.

  In summary, after upgrading to this version, you may find (in some
  cases) that the parser produced by Menhir for your grammar has
  changed. It may have slightly more or slightly fewer states than the
  parser produced by previous versions of Menhir. Even in cases where
  the parser hasn't changed, the numbering of the states can be
  different.

  Feedback is welcome.

  Happy parsing,

  François Pottier
  francois.pottier@inria.fr
  <http://cambium.inria.fr/~fpottier/>


2020/02/11
╌╌╌╌╌╌╌╌╌╌

  • Re-implement Menhir's default algorithm for constructing LR(1)
    automata, namely Pager's algorithm. This closes issue #21 (reported
    by Andrej Bauer), a bug that would sometimes cause unexplainable
    conflicts to appear, because states were merged too
    aggressively. This also removes an unreported bug that would cause
    the automaton to have too many states, because states were *not*
    merged aggressively enough. In summary, the old and new construction
    algorithms differ: in many cases, the resulting automaton is
    unchanged, but in some cases, the automaton produced by the new
    algorithm may have slightly more or slightly fewer states.

  • Re-implement Menhir's algorithm for constructing automata in
    `--no-pager' mode. In this (undocumented) mode, Menhir does not
    merge any states, but allows itself to redirect a transition from a
    state `s' to a *larger* state `s''. This method yields an automaton
    whose states form a subset of the states of the canonical LR(1)
    automaton. It usually has significantly fewer states than the
    canonical automaton, and significantly more states than the
    automaton produced by Pager's algorithm. The new construction method
    removes an unreported bug that would cause the automaton to have too
    many states. The automaton produced by the new algorithm will
    usually have significantly fewer states than the automaton produced
    by the previous algorithm.

  • Re-implement Menhir's algorithms for constructing automata in
    `--lalr' and `--canonical' modes. The previous algorithms were
    correct, as far as we know, so the output of the new algorithms is
    the same, up to a possible renumbering of the states. The new
    algorithms are slightly faster.

  • Increase the maximum length of a production, which used to be 127,
    up to 1023. Display a polite error message if this length is
    exceeded. (Problem reported by Andreas Abel.)

  • The new switch `--timings-to <filename>' causes internal timing
    information to be written to the file `<filename>'.

  • A version of the library `fix' is now vendored (included) inside
    Menhir. This should have no impact for end users, but implies that
    `dune' 2.2.0 or later is required.


First release of data-encoding, JSON and binary serialisation
═════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-first-release-of-data-encoding-json-and-binary-serialisation/4444/8>


Raphaël Proust announced
────────────────────────

  The newly released version (0.2) addresses this. All the binary
  reading/writing primitives use `result' by default and have `_opt' and
  `_exn' variants.

  The JSON primitives are not yet changed because they rely on an
  external library that has more idiosyncratic error management. (This
  will eventually be fixed in a future version.)


Opam package popularity?
════════════════════════

  Archive: <https://discuss.ocaml.org/t/opam-package-popularity/5159/1>


Chet Murthy asked
─────────────────

  Is there someplace a database of opam packages and their popularity?
  Obviously it'd be inaccurate, but it'd still be interesting to see
  which packages are most-often downloaded via opam …..


Levi Roth replied
─────────────────

  The listing at <https://opam.ocaml.org/packages/index-popularity.html>
  has the download counts (I think for the latest month, not sure if
  that means past 30 days or since the start of the current calendar
  month) as title attributes on the table rows.


What's the OCaml equivalent for HLint?
══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/whats-the-ocaml-equivalent-for-hlint/5167/1>


Fangyi Zhou asked
─────────────────

  I've been using OCaml for quite a while and one thing I've been
  looking for is a good linter, ideally something like the Haskell
  [HLint].

  I found [this] which seems quite old - latest release in 2012.

  Sorry if this has been raised previously.


[HLint] <https://github.com/ndmitchell/hlint>

[this] <http://mascot.x9c.fr/index.html>


"Aaron L. Zeng
──────────────

  Something similar, but not as featureful, is [ppx_js_style].  It's
  somewhat opinionated, but the checks aren't Jane Street-specific.


[ppx_js_style] <https://github.com/janestreet/ppx_js_style>


New release of naboris 0.1.1
════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announce-new-release-of-naboris-0-1-1/5173/1>


Shawn McGinty announced
───────────────────────

  <https://github.com/shawn-mcginty/naboris>

  • *(much)* Better performance
  • API improvements


Category theory for Programmers book - OCaml flavor
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/category-theory-for-programmers-book-ocaml-flavor/3905/4>


Anton Kochkov announced
───────────────────────

  Thanks to @Arul the book was finished, and now is available for
  download here -
  <https://github.com/hmemcpy/milewski-ctfp-pdf/releases/tag/v1.4.0-rc1>

  Please, enjoy and report a feedback.


Call for Speakers: Build Meetup New York April 2020
═══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/call-for-speakers-build-meetup-new-york-april-2020/5174/1>


Jérémie Dimino announced
────────────────────────

  On April 7th and 8th, [Jane Street], [Bloomberg] and [Google] will be
  hosting a Build Meetup at the [Jane Street offices] in New York City.

  As we begin shaping our schedule, we are reaching out to a number of
  communities to find people who would like to participate in the
  event. Speaker sign-ups are now live [here].

  We are excited to announce that the keynote will be presented by the
  authors of the research paper “[From Laptop to Lambda: Outsourcing
  Everyday Jobs to Thousands of Transient Functional Containers]” which
  examines the exciting possibilities for build through the use of cloud
  functions.

  The entire event will be themed around all things build and test:
  Bazel, Buck, BuildStream, CMake, Dune, Goma, Pants, Recc and Remote
  Execution. In addition to this, we are interested in the growing
  surrounding ecosystems, such as editor integration and developer build
  experience as a whole.

  The meetup will run as follows: on day one, a series of talks will be
  presented along with breakfast, lunch and refreshments. This will be
  followed by an evening social at a nearby venue to continue the
  discussions from throughout the day.

  On the second day there will be an opportunity for broader community
  collaboration and discussion during our all day code sprint.

  We are looking for insightful and engaging talks and presentations on
  topics focused around build systems. Have you worked tirelessly for
  the past 6 months on a new feature for project foo you would like to
  showcase? Have you and your team spent the last year integrating the
  tool bar at your workplace? Do you have some comparisons to make
  between qux and quux that the community could benefit from?

  If so, we would love to [hear from you]!

  We welcome proposals for talks across the entire ecosystem. Each talk
  should ideally last 30 minutes, followed by time for questions.

  Keep your eyes out for meetup registration information, which will be
  sent separately over the next few weeks!


[Jane Street] <https://www.janestreet.com/>

[Bloomberg] <https://www.techatbloomberg.com/>

[Google] <http://www.google.com/>

[Jane Street offices] <https://www.janestreet.com/contact-us/nyc/>

[here]
<https://docs.google.com/forms/d/e/1FAIpQLSdtOR-oAcxmxxYpkSpTPSbsrR_eLwza6plhyAkBGA6UrLK5xw/viewform?usp=sf_link>

[From Laptop to Lambda: Outsourcing Everyday Jobs to Thousands of
Transient Functional Containers]
<http://stanford.edu/~sadjad/gg-paper.pdf>

[hear from you]
<https://docs.google.com/forms/d/e/1FAIpQLSdtOR-oAcxmxxYpkSpTPSbsrR_eLwza6plhyAkBGA6UrLK5xw/viewform?usp=sf_link>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-02-04  8:47 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-02-04  8:47 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

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Hello

Here is the latest OCaml Weekly News, for the week of January 28 to
February 04, 2020.

Table of Contents
─────────────────

Multicore OCaml: January 2020 update
Use Case for Ephemerons?
`json-data-encoding' version 0.8 (was `ocplib-json-typed')
Developer position at Abacus Medicine, Copenhagen
Camlp5 version 7.11 release (4.10 compatibility)
Old CWN


Multicore OCaml: January 2020 update
════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/multicore-ocaml-january-2020-update/5090/1>


Anil Madhavapeddy announced
───────────────────────────

  Welcome to the January 2020 news update from the Multicore OCaml team!
  We're going to summarise our activites monthly to highlight what we're
  working on throughout this year. This update has kindly been assembled
  by @shakthimaan and @kayceesrk.

  The most common question we get is how to contribute to the overall
  multicore effort. As I [noted last year], we are now in the process of
  steadily upstreaming our efforts to mainline OCaml. Therefore, the
  best way by far to contribute is to test for regressions or
  opportunities for improvements in the patches that are outstanding in
  the main OCaml repository.

  A secondary benefit would be to review the PRs in the [multicore
  repository], but those tend to be more difficult to evaluate
  externally as they are being spotted as a result of stress testing at
  the moment. A negative contribution would be to raise discussion of
  orthogonal features or new project management mechanisms – this takes
  time and effort to reply to, and the team has a very full plate
  already now that the upstreaming has begun. We don't want to prevent
  those discussions from happening of course, but would appreciate if
  they were directed to the general OCaml bugtracker or another thread
  on this forum.

  We'll first go over the OCaml PRs and issues, then cover the multicore
  repository and our Sandmark benchmarking infrastructure. A new
  initiative to implement and test new parallel algorithms for Multicore
  OCaml is also underway.


[noted last year]
<https://discuss.ocaml.org/t/multicore-prerequisite-patches-appearing-in-released-ocaml-compilers-now/4408>

[multicore repository]
<https://github.com/ocaml-multicore/ocaml-multicore/pulls>

OCaml
╌╌╌╌╌

◊ Ongoing

  • [ocaml/ocaml#9082] Eventlog tracing system

    Eventlog is a proposal for a new tracing facility for OCaml runtime
    that provides metrics and counters, and uses the Binary Trace Format
    (CTF). The next step to get this merged is to incubate the tracing
    features in separate runtime variant, so it can be selected at
    application link time.

  • [ocaml/ocaml#8984] Towards a new closure representation

    A new layout for closures has been proposed for traversal by the
    garbage collector without the use of a page table. This is very much
    useful for Multicore OCaml and for performance improvements. The PR
    is awaiting review from other developers, and can then be rebased
    against trunk for testing and merge.

  • [ocaml-multicore/ocaml-multicore#187] Better Safe Points

    A patch to regularly poll for inter-domain interrupts to provide
    better safe points is actively being reviewed. This is to ensure
    that any pending interrupts are notified by the runtime system.

  • Work is underway on improving the marshaling (runtime/extern.c) in
    upstream OCaml to avoid using GC mark bits to represent visitedness,
    and to use a hash table (addrmap) implementation.


  [ocaml/ocaml#9082] <https://github.com/ocaml/ocaml/pull/9082>

  [ocaml/ocaml#8984] <https://github.com/ocaml/ocaml/pull/8984>

  [ocaml-multicore/ocaml-multicore#187]
  <https://github.com/ocaml-multicore/ocaml-multicore/issues/187>


◊ Completed

  The following PRs have been merged to upstream OCaml trunk:

  • [ocaml/ocaml#8713] Move C global variables to a dedicated structure

    This PR moves the C global variables to a "domain state"
    table. Every domain requires its own table of domain local
    variables, and hence this is required for Multicore runtime.

    This uncovered a number of [compatability issues] with the C header
    files, which were all included in the recent OCaml 4.10.0+beta2
    release via the next item.

  • [ocaml/ocaml#9253] Move back `caml_*' to thematic headers

    The `caml_*' definitions from runtime/caml/compatibility.h have been
    moved to provide a compatible API for OCaml versions 4.04 to
    4.10. This change is also useful for Multicore domains that have
    their own state.


  [ocaml/ocaml#8713] <https://github.com/ocaml/ocaml/pull/8713>

  [compatability issues] <https://github.com/ocaml/ocaml/issues/9205>

  [ocaml/ocaml#9253] <https://github.com/ocaml/ocaml/pull/9253>


Multicore OCaml
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The following PRs have been merged into the Multicore OCaml trees:

  • [ocaml-multicore/ocaml-multicore#275] Fix lazy behaviour for
    Multicore

    A `caml_obj_forward_lazy()' function is implemented to handle lazy
    values in Multicore Ocaml.

  • [ocaml-multicore/ocaml-multicore#269] Move from a global
    `pools_to_rescan' to a domain-local one

    During stress testing, a segmentation fault occurred when a pool was
    being rescanned while a domain was allocating in to it. The rescan
    has now been moved to the domain local, and hence this situation
    will not occur again.

  • [ocaml-multicore/ocaml-multicore#268] Fix for a few space leaks

    The space leaks that occurred during domain spawning and termination
    when performing the stress tests have been fixed in this PR.

  • [ocaml-multicore/ocaml-multicore#272] Fix for DWARF CFI for
    non-allocating external calls

    The entry to `caml_classify_float_unboxed' caused a corrupted
    backtrace, and a fix that clearly specifies the boundary between
    OCaml and C has been provided.

  • An effort to implement a synchronized minor garbage collector for
    Multicore OCaml is actively being researched and worked
    upon. Benchmarking for a work-sharing parallel stop-the-world branch
    against multicore trunk has been performed along with clearing
    technical debt, handling race conditions, and fixing segmentation
    faults. The C-API reversion changes have been tested and merged into
    the stop-the-world minor GC branch for Multicore OCaml.


[ocaml-multicore/ocaml-multicore#275]
<https://github.com/ocaml-multicore/ocaml-multicore/pull/275>

[ocaml-multicore/ocaml-multicore#269]
<https://github.com/ocaml-multicore/ocaml-multicore/pull/269>

[ocaml-multicore/ocaml-multicore#268]
<https://github.com/ocaml-multicore/ocaml-multicore/pull/268>

[ocaml-multicore/ocaml-multicore#272]
<https://github.com/ocaml-multicore/ocaml-multicore/pull/272>


Benchmarking
╌╌╌╌╌╌╌╌╌╌╌╌

  • The [Sandmark] performance benchmarking infrastructure has been
    improved for backfilling data, tracking branches and naming
    benchmarks.

  • Numerical parallel benchmarks have been added to the Multicore
    compiler.

  • An [Irmin] macro benchmark has been included in Sandmark. A test for
    measuring Irmin's merge capabilities with Git as its filesystem is
    being tested with different read and write rates.

  • Work is also underway to implement parallel algorithms for N-body,
    reverse-complement, k-nucleotide, binary-trees, fasta,
    fannkuch-redux, regex-redux, Game of Life, RayTracing, Barnes Hut,
    Count Graphs, SSSP and from the MultiMLton benchmarks to test on
    Multicore OCaml.


[Sandmark] <http://bench2.ocamllabs.io/>

[Irmin] <https://irmin.org>


Documentation
╌╌╌╌╌╌╌╌╌╌╌╌╌

  • A chapter on Parallel Programming in Multicore OCaml is being
    written and an early draft will be made available to the community
    for their feedback. It is based on Domains, with examples to
    implement array sums, Pi approximation, and trapezoidal rules for
    definite integrals.


Acronyms
╌╌╌╌╌╌╌╌

  • API: Application Programming Interface
  • CTF: Common Trace Format
  • CFI: Call Frame Information
  • DWARF: Debugging With Attributed Record Formats
  • GC: Garbage Collector
  • PR: Pull Request
  • SSSP: Single Source Shortest Path


Nicolas Tollenaere asked
────────────────────────

  If I may ask a question, I am curious about the status of integration
  of effects into the type system. According to this page
  <https://ocamlverse.github.io/content/future_ocaml.html#typed-algebraic-effects>,
  original plan was to merge an untyped version of effect, before it was
  decided to integrate them into the system. I have seen this
  presentation of leo white on this matter
  <https://www.janestreet.com/tech-talks/effective-programming/> along
  with this one <https://www.youtube.com/watch?v=ibpUJmlEWi4> (from
  2016). My understanding was that, at the time of the last
  presentation, there was still some theoretical issues to be solved
  (although the speaker did not seem too worried about finding some way
  around eventually). I have no idea about the current status of the
  project. Reading your post it seems that you are now in an integration
  phase (PR reviews and all) that would imply that you're done with
  (most) theoretical questions. But that could either mean that you are
  integrating an untyped version of effects (and the type system is let
  for future development) or that you have indeed settled on a
  design. Which one is it ? Anyway, thanks for the post and the work in
  general, this project seems awesome (even if I did not dive into it
  too much until now)


Anil Madhavapeddy replied
─────────────────────────

  Good question; our current focus in getting the runtime components
  upstreamed (the "Domains" API) and some of the mechanisms that could
  be used by an effect system.  We haven't yet settled on a final design
  for an effect extension to OCaml, but the general preference is to
  skip integrating an untyped effect system if a typed version lands in
  the right timescales. This will happen after all the runtime pieces
  are upstreamed, which will allow everyone to use multicore parallelism
  via the lower-level Domains API.


Use Case for Ephemerons?
════════════════════════

  Archive: <https://discuss.ocaml.org/t/use-case-for-ephemerons/2838/3>


Continuing this old thread, Yawar Amin said
───────────────────────────────────────────

  [Here's another use] (disclaimer: this is my project).

  What's happening here is that I'm using an 'ephemeral cache' (i.e. a
  cache backed by an ephemeron hash table, [here]) to store subscribers
  to a 'topic', i.e. a pub-sub bus. You get a subscription token when
  you subscribe to a topic, and part of that token is the cache key. The
  cache is 'ephemeral' so as soon as the subscription token goes out of
  scope, it and its corresponding subscription (concretely, the stream
  and its push function) are automatically deleted from the cache.

  Hence, there's no 'unsubscribe' or 'close topic' functionality–it's
  assumed that you want to unsubscribe if you let the subscription token
  go out of scope.


[Here's another use]
<https://github.com/yawaramin/re-web/blob/766da0c0e06652824e34416bc518ee37197a90fb/ReWeb/Topic.ml>

[here]
<https://github.com/yawaramin/re-web/blob/766da0c0e06652824e34416bc518ee37197a90fb/ReWeb/Cache.ml#L41>


`json-data-encoding' version 0.8 (was `ocplib-json-typed')
══════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-json-data-encoding-version-0-8-was-ocplib-json-typed/5095/1>


Raphaël Proust announced
────────────────────────

  I'm happy to announce that Nomadic Labs is now in charge of the
  development, maintenance and release of `json-data-encoding' – the
  library previously known as `ocplib-json-typed'. Even though we are
  changing to a more descriptive name, we are maintaining continuity of
  version numbers. As a result, this is an announce for the version
  `0.8'.

  The library `json-data-encoding' lets you define encodings for a given
  OCaml type, and use that encoding to encode values of that type into
  JSON or decode JSON into values of that type. The library supports
  multiple JSON backends: `Ezjsonm', `Yojson', native browser
  representation (for `js_of_ocaml', via the package
  `json-data-encoding-browser') and `BSON' (via the package
  `json-data-encoding-bson').

  It is available via `opam' (`opam install json-data-encoding') and
  hosted on <https://gitlab.com/nomadic-labs/json-data-encoding/>

  Changes from the version v0.7 include:
  • extensive tests using `Crowbar' (adapted from similar tests on
    `data-encoding' originally by @gasche)
  • minor documentation improvements
  • improved self documentation capabilities for unions' cases (work by
    @smondet)
  • improved schema equality (work by @rbardou)


Developer position at Abacus Medicine, Copenhagen
═════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/developer-position-at-abacus-medicine-copenhagen/5119/1>


mokn announced
──────────────

  Abacus Medicine has an open developer position. We do parallel
  distribution of medicine in EU and for that we have developed a system
  to handle the trading. A part of this system is developed in OCaml.

  Unfortunately the job description is only in danish, but we do accept
  applications in english: [Job description]


[Job description]
<https://www.jobindex.dk/jobannonce/351439/software-developer>


Camlp5 version 7.11 release (4.10 compatibility)
════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-camlp5-version-7-11-release-4-10-compatibility/5121/1>


Chet Murthy announced
─────────────────────

  New release 7.11 of Camlp5. Compatible with all OCaml versions >=
  4.00.0, latest OCaml version 4.10+beta2 included.

  Main improvement: compatible with 4.10's blank module names and
  generative functors.

  Home page, including downloading and documentation at:
  <https://camlp5.github.io/>

  Enjoy!

  N.B. I'm new to helping out with camlp5, so might have made some
  mistakes; any users who find problems should contact me either
  directly, or (better) thru issues on
  <https://github.com/camlp5/camlp5/releases> and I'll be sure to get
  right on it.

  N.B.#2: There are still lots of gaps between current Ocaml, and
  Camlp5's support; I'm working on fixing that, and there'll soon be a
  release that brings camlp5 as up-to-date as possible with Ocaml.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-01-28 10:53 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-01-28 10:53 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 8910 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 21 to 28,
2020.

Table of Contents
─────────────────

New release of Menhir (20200123)
Ocaml cross compiler?
Two master internship proposals to explore social and technical aspects of the creation of the OCaml and Coq platforms
Proper way to allocate an OCaml string from C code in OCaml 4.10?
OCaml 4.10.0, second beta
Old CWN


New release of Menhir (20200123)
════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-01/msg00040.html>


François Pottier announced
──────────────────────────

  It is my pleasure to announce a new release of Menhir, the LR(1)
  parser generator.

  ┌────
  │ opam update
  │ opam install menhir
  │ opam install coq-menhirlib # if you wish to use menhir --coq
  └────

  There are no new features, only a significant change in the manner in
  which Menhir is built:

  • Menhir is now built and installed by dune. This should make life
    easier for Menhir's developers: in particular, `make test' and `make
    speed' can be run straight away and do not requiring installing
    Menhir first. This should also make compilation much faster on
    multi-core machines. (Contributed by Nicolás Ojeda Bär, to whom many
    thanks are due.)

  • There used to be a distinction between two slightly different ways
    of installing Menhir, namely with and without `ocamlfind'. This
    distinction disappears. The command line switch
    `--suggest-ocamlfind' is deprecated and causes Menhir to print
    `false'.

  We hope that these changes do not break any of the code that relies on
  Menhir today. Please report any problems that you might
  encounter. Happy hacking!


Ocaml cross compiler?
═════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-cross-compiler/1494/7>


Deep in this thread, Dmitry Ponyatov asked
──────────────────────────────────────────

  What about embedded targets like Cortex-M (STM32F3/F4)?  How much
  memory should it have to have to run OCaml-compiled programs?


Ivan Gotovchits replied
───────────────────────

  You may find this [page] interesting. To summarize, with _a lot of
  work_ you can make a subset of OCaml programs runnable on a
  microcontroller. You will also need to rewrite OCaml's runtime and
  develop a new GC for it.

  In real life, no, you can't run OCaml on a microcontroller. You need
  at least a couple of megabytes of normal RAM with MMU.


[page] <http://www.algo-prog.info/ocapic/web/index.php?id=ocapic>


Ivan Gotovchits then added
──────────────────────────

  Hmm, found this [project], that is also quite relevant to you, it is
  quite alive, so maybe you have chances :)


[project] <https://github.com/stevenvar/OMicroB>


Two master internship proposals to explore social and technical aspects of the creation of the OCaml and Coq platforms
══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/two-master-internship-proposals-to-explore-social-and-technical-aspects-of-the-creation-of-the-ocaml-and-coq-platforms/5073/1>


Théo Zimmermann announced
─────────────────────────

  We are looking for candidates for the following two internships
  intended to prefigure the creation of the OCaml and Coq platforms:
  • a first internship is focused on exploring technical aspects:
    <https://www.irif.fr/_media/users/theo/internship_proposal_platform_tech.pdf>
  • a second internship is focused on exploring social and policy
    aspects:
    <https://www.irif.fr/_media/users/theo/internship_proposal_platform_social.pdf>

  Please feel free to forward this announcement.  Interested students
  should send their resume and cover letter at
  [yrg@irif.fr](<mailto:yrg@irif.fr>) and
  [theo@irif.fr](<mailto:theo@irif.fr>).

  Yann Régis-Gianas (Inria, IRIF, OCaml Foundation) and Théo Zimmermann
  (Inria, IRIF, Coq development team)


Proper way to allocate an OCaml string from C code in OCaml 4.10?
═════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/proper-way-to-allocate-an-ocaml-string-from-c-code-in-ocaml-4-10/5075/1>


Rwmjones asked
──────────────

  Previously to allocate a string with explicit length (ie.  one which
  may contain \0 characters) in C code we have used:

  ┌────
  │ strv = caml_alloc_string (count);
  │ memcpy (String_val (strv), str, count);
  └────

  In OCaml 4.10 this doesn't compile because String_val returns a `const
  char *'.

  I could change String_val to Bytes_val, but that feels wrong.  The
  runtime seems to use `&Byte_u (strv, 0)'.

  It's a shame there's not a caml_copy_string_len function, but what is
  the proper way to do this for OCaml 4.10+, especially a way that won't
  break in future and will be compatible with multicore?


yallop suggested
────────────────

  You can use [`caml_alloc_initialized_string']:

  ┌────
  │ CAMLextern value caml_alloc_initialized_string (mlsize_t len, const char *);
  └────


[`caml_alloc_initialized_string']
<https://github.com/ocaml/ocaml/blob/d408e58ea15ec890a2c6d98441d261db51a6735d/runtime/caml/alloc.h#L38~>


OCaml 4.10.0, second beta
═════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-10-0-second-beta/5083/1>


octachron announced
───────────────────

  The release of OCaml 4.10.0 is near. We have released a second beta
  version to help you adapt your softwares and libraries to the new
  features ahead of the release.

  This new beta contains an update to the internal runtime API that
  should make it easier to maintain compatibility across version for
  expert users; and a small fix for the analysis of recursive values.

  The source code is available at these addresses:

  <https://github.com/ocaml/ocaml/archive/4.10.0+beta2.tar.gz>
  <https://caml.inria.fr/pub/distrib/ocaml-4.10/ocaml-4.10.0+beta2.tar.gz>

  The compiler can also be installed as an OPAM switch with one of the
  following commands.
  ┌────
  │ opam switch create ocaml-variants.4.10.0+beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.10.0+beta1+<VARIANT> --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where you replace <VARIANT> with one of these:
  • afl
  • flambda
  • fp
  • fp+flambda

  For a better experience, you can use the opam alpha repository
  provided by:
  ┌────
  │ opam repository add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────
  This repository contains a handful of temporary patched packages, that
  you can use while waiting for the packages to be properly patched.
  This repository should not be used in production and you probably want
  to install it only for the beta switch.

  We want to know about all bugs. Please report them here:

  <https://github.com/ocaml/ocaml/issues>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-01-21 14:08 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-01-21 14:08 UTC (permalink / raw)
  To: lwn, cwn, caml-list, comp

[-- Attachment #1: Type: text/plain, Size: 6423 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 14 to 21,
2020.

Table of Contents
─────────────────

How does the compiler check for exhaustive pattern matching?
resto 0.2 released
opam 2.0.6 release
soupault: a static website generator based on HTML rewriting
Spin: Project scaffolding tool and set of templates for Reason and OCaml
Old CWN


How does the compiler check for exhaustive pattern matching?
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/how-does-the-compiler-check-for-exhaustive-pattern-matching/5013/1>


Dylan Irlbeck asked
───────────────────

  Hi all. I'm relatively new to OCaml, and I was curious on how the
  compiler is able to give a warning when a case list is non-exhaustive
  - both from a high-level and, if possible, the implementation of this
  check. I have some ideas about how one could do this, but none of my
  ideas seem like they'd be nearly as efficient as the OCaml compiler
  is.


gasche replied
──────────────

  The canonical reference for exhaustivity-checking in OCaml is the
  scientific publication

        [Warnings for pattern matching] Luc Maranget 2007

  The general idea is to consider all the patterns of a given
  pattern-matching at once, generalize this structure to a "matrix" of
  patterns (matching on several values in parallel), and devise an
  algorithm to "explore" these pattern matrices in such a way that you
  eventually tell if a given pattern-matrix is exhaustive, or can
  propose a counter-example.

  (I guess we should write a high-level/accessible blog post about
  this.)


[Warnings for pattern matching]
<http://moscova.inria.fr/~maranget/papers/warn/index.html>


resto 0.2 released
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-resto-0-2-released/5028/1>


Raphaël Proust announced
────────────────────────

  On behalf on Nomadic Labs, I'm happy to announce the release of
  version 0.2 of `resto', a library to create type-safe HTTP/JSON
  services.

  The library is available through opam (`opam install resto'),
  distributed under LGPL, and hosted on
  <https://gitlab.com/nomadic-labs/resto>.

  `resto' was previously released as `ocplib-resto' maintained by
  OCamlPro. The project is now maintained by Nomadic Labs.

  Along with many bugfixes and a few added features, the main change of
  this release is that the library is split into multiple packages with
  fine-grained dependencies.


opam 2.0.6 release
══════════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam-2-0-6-release/5038/1>


R. Boujbel announced
────────────────────

  We are pleased to announce the minor release of [opam 2.0.6].

  This new version contains mainly build update & fixes. You can find
  more information in this [blog post].

  _opam is a source-based package manager for OCaml. It supports
  multiple simultaneous compiler installations, flexible package
  constraints, and a Git-friendly development workflow._


[opam 2.0.6] <https://github.com/ocaml/opam/releases/tag/2.0.6>

[blog post] <https://opam.ocaml.org/blog/opam-2-0-6>


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/11>


Daniil Baturin announced
────────────────────────

  soupault 1.8.0 is [released] along with Lua-ML 0.9.1.

  Lua-ML now raises `Failure' when Lua code execution fails. There's
  much room for improvement in that area, for now I've just done
  something that is better than just displaying errors on stderr but
  otherwise allowing syntax and runtime errors pass silently.

  If you have any ideas how perfect interpreter error reporting _should_
  work, please share!

  As of improvements in soupault itself, there's now:
  • A way for plugins to specify their minimum supported soupault
    version like `Plugin.require_version("1.8.0")'
  • `TARGET_DIR' environment variable and `target_dir' Lua global that
    contains the directory where the rendered page will be written, to
    make it easier for plugins/scripts to place processed assets
    together with pages.
  • "Build profiles": if you add `profile = "production"' or similar to
    widget config, that widget will be ignored unless you run `soupault
    --profile production'.
  • A bunch of new utility functions for plugins.


[released] <https://soupault.neocities.org/blog/soupault-1.8.0-release/>


Spin: Project scaffolding tool and set of templates for Reason and OCaml
════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/spin-project-scaffolding-tool-and-set-of-templates-for-reason-and-ocaml/5047/1>


Mohamed Elsharnouby announced
─────────────────────────────

  <https://github.com/tmattio/spin>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-01-14 14:16 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-01-14 14:16 UTC (permalink / raw)
  To: lwn, cwn, caml-list

[-- Attachment #1: Type: text/plain, Size: 24944 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of January 07 to 14,
2020.

Table of Contents
─────────────────

Calling a single function on every member of a GADT?
OCamlPro's opam cheat sheet, with a new theme!
OCaml 4.10.0, first beta
Data engineer positions at Elastic, US/Canada/Western Europe (proximate to NA timezones)
Release of naboris 0.1.0 a simple http server
esy@0.6.0 release
Old CWN


Calling a single function on every member of a GADT?
════════════════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2020-01/msg00007.html>


Ivan Gotovchits asked
─────────────────────

  I'm basically trying to do the equivalent of this simple `fold'
  function:

  ┌────
  │ module Simple =
  │ struct
  │   type term =
  │      | Int of int
  │      | Add
  │      | App of term * term
  │ 
  │   let rec fold i f = function
  │     | Int _ as t -> f i t
  │     | Add -> f i Add
  │     | App (x, y) as t -> f (fold (fold i f x) f y) t
  │ end
  └────

  … but using a GADT:

  ┌────
  │ module Gadt =
  │ struct
  │   type _ term =
  │      | Int : int -> int term
  │      | Add : (int -> int -> int) term
  │      | App : ('b -> 'a) term * 'b term -> 'a term
  │ 
  │   let rec fold : type a. 'r -> ('r -> _ term -> 'r) -> 'r = fun i f -> function
  │     | Int _ as t -> f i t
  │     | Add -> f i Add
  │ (*
  │      ^ Error: This pattern matches values of type (int -> int -> int) term
  │ 	but a pattern was expected which matches values of type int term
  │ 	Type int -> int -> int is not compatible with type int
  │ *)
  │     | App (x, y) as t -> f (fold (fold i f x) f y) t
  │ end
  └────

  I've tried other variants of the syntax and got many encouragements
  but no green flag from the type-checker.  Why is the compiler
  expecting an int term in there? I though the whole point of the `type
  a. ...' syntax was to allow the matched type to vary from one pattern
  to the next?  Is there a way to do this?


Ivan Gotovchits replied
───────────────────────

  It is the limitation of the let-bound polymorphism. A parameter of a
  function is monomorphic in its body. The classical example doesn't
  even reference any GADT,

  ┌────
  │ let example f  = f "hello", f 42
  └────

  It won't compile even though we can provide a polymorphic function
  that can applied both to integers and to strings, e.g., `exampe (fun x
  -> x)' should be possible, but not, because of the let-bounded
  polymorphism. There are a few solutions available in OCaml, the
  simplest is to use records, e.g.,

  ┌────
  │ type app = {apply : 'a. 'a -> 'a}
  │ 
  │ let example {apply} = apply "hello", apply 42;;
  │ 
  │ val example : app -> string * int = <fun>
  └────

  Now we have `app' that is polymorphic.  In your case, I would define a
  visitor type, e.g.,

  ┌────
  │ type 'r visitor = {visit : 'a. 'a term -> 'r -> 'r}
  │ 
  │ let rec fold : type a. 'r -> 'r visitor -> a term -> 'r =
  │   fun i f t -> match t with
  │     | Int _ as t -> f.visit i t
  │     | Add as t -> f.visit i t
  │     | App (x,y) as t ->
  │ 	let i = fold i f x in
  │ 	let i = fold i f y in
  │ 	f.visit i t
  └────


Jacques Garrigue also replied
─────────────────────────────

  Actually, this is a rare case where using a polymorphic method may be
  handy too:

  ┌────
  │ let rec fold : type a r. r -> <v : 'b. r -> 'b term -> r> -> a term -> r =
  │      fun i f -> function
  │      | Int _ as t -> f#v i t
  │      | Add -> f#v i Add
  │      | App (x, y) as t -> f#v (fold (fold i f x) f y) t
  │ 
  │ let v =
  │    object method v : type a. _ -> a Gadt.term -> _ =
  │      fun x -> function
  │        | Int n -> x+n
  │        | Add -> x+1
  │        | App _ -> x+2
  │    end
  │ 
  │ let r = Gadt.fold 0 v (App (App (Add, Int 3), Int 5))
  └────

  The point being that to match on a Gadt you will anyway need to use
  the (type a) construct to allow refinement.


rixed asked and Ivan Gotovchits replied
───────────────────────────────────────

        So there is no lighter syntax to specify that `f' should
        accept any member of a GADT than the syntax to specify
        that `f' should accept any type at all?

  Only three methods of introducing rank-2 polymorphism are known to me:
  1. records
  2. objects
  3. first-class modules

  Jacques has demonstrated the solution with objects, which might be a
  little bit more lightweight, at least as you don't need to define a
  new data type beforehand. But the invocation is more verbose and
  requires an annotation from the caller side, which could be
  confusing. The third solution relies on first-class modules and is
  even more verbose, at least on the definition side. Just for the sake
  of completeness,

  ┌────
  │   module type Visitor = sig
  │     type t
  │     val term : t -> 'a term -> t
  │   end
  │ 
  │   let rec fold : type a r. r -> (module Visitor with type t = r) -> a term
  │ -> r =
  │     fun i ((module Visit) as f) t -> match t with
  │       | Int _ as t -> Visit.term i t
  │       | Add as t -> Visit.term i t
  │       | App (x,y) as t ->
  │ 	  let i = fold i f x in
  │ 	  let i = fold i f y in
  │ 	  Visit.term i t
  │ 
  │   let s = fold 0 (module struct
  │       type t = int
  │       let term x _ = x + 1
  │     end)
  └────

  And again, it is not about GADT. GADT act as a red herring here. As
  I've demonstrated earlier, using a simple pair will suffice to display
  the limitation of the prenex polymorphism. Even no ADT is required,
  just apply one term to another two and you will get them unified,
  e.g.,

  ┌────
  │ let f g x y : unit = g x; g y
  └────

  will have type

  ┌────
  │ val f : ('a -> unit) -> 'a -> 'a -> unit
  └────

  because 'a is quantified on the scope of `f' not `g', in other words,
  it has type (not an OCaml syntax)

  ┌────
  │ val f : forall 'a. ('a -> unit) -> 'a -> 'a -> unit
  └────

  while we would like to have a type

  ┌────
  │ val f : forall 'b, 'c. (forall 'a. 'a -> unit) -> 'b -> 'c -> unit
  └────

  OCaml doesn't allow us to define types like `('a. 'a -> 'a)' and the
  reason is not that it is hard to extend the parser it is…

        I wonder, is this just a limitation of the OCaml parser or
        is there some deep reason for these work-around (like is
        the case, from my understanding, for the value
        restriction)?

  Yep, good catch! It is because of the impurity. Indeed, Haskell has
  the Rank2Types extension that lets us write types like `(forall a. a
  -> ()) -> b -> c -> ()', with no extra syntactic burden (modulo having
  to provide the type annotation). But functions in Haskell are pure,
  therefore it is possible. To make the story short and obvious, let me
  do a simple demonstration of how things can go wrong in a language
  with side-effects.  Let's go back to the simple example of pairs and
  the identity function.  Consider the following nasty identity
  function,

  ┌────
  │ let bad_id () =
  │   let cache = ref None in
  │   fun x -> match cache.contents with
  │     | None -> cache := Some x; x
  │     | Some cache -> cache
  └────

  It has type `unit -> 'a -> 'a' therefore, if we would have the rank-1
  polymorphism enabled for functions, we could apply it to the function

  ┌────
  │ let map2 : fun ('a. 'a -> 'a) -> 'b -> 'c -> 'b * 'c = fun f (x,y) -> f x, f y
  └────

  as

  ┌────
  │ let x,y : string * int = map2 (bad_id ()) "hello", 42
  └────

  and will get a segmentation fault, as `y' will now have type int but
  hold a string.

  And here comes the syntax as a savior as it lets us specify functions
  that are guaranteed to be syntactic values. Indeed, all three
  solutions syntactically guarantee that the provided argument is a
  function, not a closure. Indeed, let's introduce the universal
  identity via a record,

  ┌────
  │ type id = { f : 'a. 'a -> 'a}
  └────

  and we can see that our `bad_id' is not accepted due to the value
  restriction, while good_id, defined as,

  ┌────
  │ let good_id x = x
  └────

  is perfectly fine, e.g.,

  ┌────
  │ let id1 = {f = good_id} (*accepted *)
  │ let id2 = {f = bad_id}   (* rejected *)
  └────

  moreover, even a fine, but not syntactic, identity is also rejected

  ┌────
  │ let fine_id () x = x
  │ let id3 = {f = fine_id ()} (* rejected *)
  └────

  with the message

  ┌────
  │ This field value has type 'b -> 'b which is less general than 'a. 'a -> 'a
  └────

  The same is true with modules,

  ┌────
  │ module type Id = sig
  │   val f : 'a -> 'a
  │ end
  │ module Id1 : Id = struct let f = good_id end   (* accepted *)
  │ module Id2 : Id = struct let f = bad_id () end (* rejected *)
  │ module Id3 : Id = struct let f = fine_id () end (* rejected *)
  └────

  and with objects (left as an exercise).

  To summarize, in order to enable rank2 polymorphism we need a special
  kind of values to bear universal functions, as we can't rely on
  ordinary functions, which could be constructed using partial
  application. OCaml already had objects and records, which serve as a
  fine media for universally quantified functions. Later first class
  modules were introduced, which could also be used for the same
  purpose. Probably, one could devise a special syntax (or rely on the
  new attributes and extensions syntax, e.g., `map2 [%rank2 : fun x ->
  x] ("hello",42)' but probably this will lead to an unnecessary
  bloating of the language and the implementation, especially since we
  already have three solutions with a more or less tolerable syntax (and
  are in the base language, not an extension).  Besides, if we will use
  the `[@@unboxed]' annotation, or visitor will have the same
  representation as a function, e.g.,

  ┌────
  │ type 'r visitor = {visit : 'a. 'r -> 'a term -> 'r} [@@unboxed]
  │ let count x _ = x + 1
  │ let counter = {visit=count}
  └────

  and

  ┌────
  │ # Core_kernel.phys_same count counter;;
  │ - : bool = true
  └────

  Concerning rank-n polymorphism, in OCaml is is achieved using
  functors.  Yes, they are a little bit syntactically heavy and force us
  to write signatures, but this is necessary anyway as rank-n is
  undecidable (non-inferrable). Finally, as a real-world example [1] of
  rank-2 polymorphism consider the universal WAVL tree that is a binary
  tree with each element having a different type (aka heterogeneous
  map). We use it in BAP as a backing store. You might find a few tricks
  there, especially using continuation-passing in the recursive cases.

  Cheers, Ivan

  [1]:
  <https://github.com/BinaryAnalysisPlatform/bap/blob/b40689e636607b977758af048b79d65684ce48c3/lib/knowledge/bap_knowledge.ml#L847-L1693>


Malcolm Matalka asked and Ivan Gotovchits replied
─────────────────────────────────────────────────

        Why is type checking creating a record different than type
        checking a function argument?

        If we had the syntax (or something like it):

        let map2 : ('a. 'a -> 'a) -> ('b * 'c) -> ('b * 'c)

        Why would the type checker not be able to see that

        map2 good_id ("hi", 42)

        is valid but

        map2 (fine_id ()) ("hi", 32)

        is not, using the same logic that is verifying creating
        the "id" record is not valid?

  I believe it is possible, as it is possible in Haskell (with
  RankNTypes and ScopedTypeVariables). The main (theoretical) difference
  is that in OCaml we need to check whether an expression is expansive
  and use a specialized generalization in case if it is (for the relaxed
  value restriction). It will, however, complicate the type inference
  engine a lot, but most importantly, changing the typing rule of
  functions will have a tremendous impact on the language. So this would
  be a very impractical solution.  Especially, since we don't have the
  mechanism of language extensions, enabling RankNTypes will make a lot
  of programs untypeable, as they will now require type annotations
  (recall that RankN is undecidable in general).  It could probably be
  implemented as a compiler command line parameter, like `-rectypes' but
  this will be still quite impractical since more often code like `fun f
  -> f 1, f true' is a programmer error, rather than a true request for
  universal polymorphism (the same as with rectypes, recursive types a
  more often an error rather than a deliberate attempt). Therefore,
  enabling RankN(^1) polymorphism will type too many programs (not that
  it is unsound, just many programs won't have sense) at the cost of
  even more obscure type errors. On the other hand, we have three
  syntactic constructs that let us express non-prenex polymorphism of
  the necessary rank(^2) without breaking anything else. So it looks
  like a good deal - we can have rankN polymorphism and decidable type
  checker at the same time. Just think of polymorphic records/methods as
  an embedded DSL for rankN polymorphism.

  `==========' Footnotes:

  1) An important point, that I forgot to notice, is that enabling
     scoped
  type variables, will inevitably enable rankN polymorphism, e.g., since
  now any type could be a polytype, then suppose we have type
  `'a. ('b.'b -> 'a) -> 'a' could be instantiated to 'a = 'd. ('c. ->
  'd) -> 'd, so that our type is now `'d. ('b. 'b -> ('c. 'c -> 'd) ->
  'd) -> ('c. 'c -> 'd) -> 'd' which is now rank3. Therefore, enabling
  arbitrary quantification in the arrow type will lead to rankN and
  immediately make undecidable most of the type checker.

  1) We can craft arbitrary rank using records with universally
     quantified
  type variables, e.g., here is an example of rank3 polymorphism:

  ┌────
  │ type 'a rank1 = {f1 : 's. 's -> 'a}
  │ type 'a rank2 = {f2 : 'r. 'r -> 'a rank1}
  └────

  Indeed, `f2' has type `'a.('r. 'r -> ('s. 's -> 'a)'


OCamlPro's opam cheat sheet, with a new theme!
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/rfc-ocamlpros-opam-cheat-sheet-with-a-new-theme/4689/3>


Thomas Blanc announced
──────────────────────

  The opam cheat-sheet is now published in its final form.

  You can get the [colored] and [black-and-white] versions from our
  website.

  Happy hacking!


[colored]
<http://www.ocamlpro.com/wp-content/uploads/2019/11/ocaml-opam.pdf>

[black-and-white]
<http://www.ocamlpro.com/wp-content/uploads/2020/01/ocaml-opam-bw.pdf>


OCaml 4.10.0, first beta
════════════════════════

  Archive: <https://discuss.ocaml.org/t/ocaml-4-10-0-first-beta/4989/1>


octachron announced
───────────────────

  The release of OCaml 4.10.0 is approaching. We have published a first
  beta version to help you adapt your software to the new features ahead
  of the release.

  During our preliminary tests for this new beta, we discovered that the
  recent work towards a multicore-ready OCaml runtime introduced
  compatibility issues within some opam packages, that were tweaking the
  runtime internals.  Most of those opam packages have been fixed, or
  will be soon.  Nevertheless, if you are affected by such compatibility
  issue, please speak up.

  The source code is available at these addresses:

  <https://github.com/ocaml/ocaml/archive/4.10.0+beta1.tar.gz>
  <https://caml.inria.fr/pub/distrib/ocaml-4.10/ocaml-4.10.0+beta1.tar.gz>

  The compiler can also be installed as an OPAM switch with one of the
  following commands.
  ┌────
  │ opam switch create ocaml-variants.4.10.0+beta1 --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  or
  ┌────
  │ opam switch create ocaml-variants.4.10.0+beta1+<VARIANT> --repositories=default,beta=git+https://github.com/ocaml/ocaml-beta-repository.git
  └────
  where you replace <VARIANT> with one of these:
  • afl
  • flambda
  • fp
  • fp+flambda

  We want to know about all bugs. Please report them here:

  <https://github.com/ocaml/ocaml/issues>

  Happy hacking.


Kate added
──────────

  For the people wanting to give OCaml 4.10.0beta1 a shot, here is an
  opam overlay which adds fixes to major packages for them to work with
  this beta: <https://github.com/kit-ty-kate/opam-alpha-repository>

  To use it, simple call:
  ┌────
  │ $ opam switch 4.10
  │ $ opam repository add alpha git://github.com/kit-ty-kate/opam-alpha-repository.git
  └────

  Obviously, this repository should not be used in production and
  probably contains a few bugs, but at least it allows everyone to have
  almost as many packages available as with OCaml 4.09. Only 60ish
  packages are still not available, but apart from the notable exception
  of `merlin' all the essential packages and dependencies are there.

  This work has been part of the release-readyness effort founded by the
  OCaml Software Foundation as announced here:
  <https://discuss.ocaml.org/t/ann-the-ocaml-software-foundation/4476/13>

  The rest of the effort is going to be put towards having `merlin'
  available for OCaml 4.10 and upstreaming all the fixes from
  opam-alpha-repository (most of them have PRs associated already). I'm
  hopeful for them be all upstreamed and available before the stable
  release of OCaml 4.10.


Data engineer positions at Elastic, US/Canada/Western Europe (proximate to NA timezones)
════════════════════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/job-data-engineer-positions-at-elastic-us-canada-western-europe-proximate-to-na-timezones/4991/1>


Hezekiah Carty announced
────────────────────────

  Our team here at [Elastic] has positions open for a few security data
  engineers (aka wranglers of data and all the systems involved).  We
  are a distributed company so you don't have to be close to an office
  to be considered.  Infosec industry experience is _not_ required,
  though of course welcome.  We're surrounded by experts in the field so
  you'll have lots of opportunities to learn as you go!

  The official postings are available here (both have the same text and
  only differ in title/seniority):
  • Security data engineer -
    <https://jobs.elastic.co/jobs/security-solutions/amer-distributed-/security-data-engineer/2005140#/>
  • Senior security data engineer -
    <https://jobs.elastic.co/jobs/security-solutions/amer-distributed-/security-senior-data-engineer/2005152#/>

  Language-wise, OCaml/Reason makes up most of the code you’ll be
  working on. Python makes up most of the rest, in particular taking
  advantage of the machine learning and natural language processing
  goodies that ecosystem provides. Most of the tools and service we
  develop are internally focused, supporting security research and
  improvements to security protections for our users. For those
  so-inclined, there are lots of opportunities to present at and attend
  conferences, present work in blog posts, contribute to open source
  software projects and otherwise engage the community.

  The positions are very similar to our [last hiring announcement],
  though we had a different name at that point!

  Please reach out to me if you have any questions. I’m available on the
  OCaml or Reason Discord servers or by email at
  hezekiah.carty@elastic.co.


[Elastic] <https://www.elastic.co/>

[last hiring announcement]
<https://discuss.ocaml.org/t/filled-posting-is-no-longer-open-threat-research-engineer-job-endgame-us/1937>


Release of naboris 0.1.0 a simple http server
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/release-of-naboris-0-1-0-a-simple-http-server/4994/1>


Shawn McGinty announced
───────────────────────

  <https://github.com/shawn-mcginty/naboris>

  I could use input on the API and the documentation.  Working on trying
  to improve both at the moment.

  The goal was to create a very simple library for building RESTful type
  of web servers.  Make it _very_ easy to manage handle request/response
  lifecycle and sessions.

  In my opinion this type of web server is a great entry point for new
  developers looking to explore the OCaml/Reason world.

  Recently I have fallen in love with OCaml and Reason, and as a mostly
  web centered developer I've found this area quite lacking.  I'm still
  new to the language and eco system so any guidance would be highly
  appreciated!


Yawar Amin replied
──────────────────

  Wow! It seems we had much the same idea–OCaml/Reason more accessible
  to web developers new to the ecosystem :-D I've been working on
  something very similar: <https://github.com/yawaramin/re-web/>


Ulrik Strid said
────────────────

  There is also opium <https://github.com/rgrinberg/opium>

  And morph <https://github.com/reason-native-web/morph> that has
  similar goals.

  It would be nice if we could either create a shared core that all
  could build from or collaborate on one.


esy@0.6.0 release
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-esy-0-6-0-release/5010/1>


Andrey Popp announced
─────────────────────

  We've just released a new version of esy. You can install it with npm:
  ┌────
  │ $ npm install -g esy@0.6.0
  └────

  [esy] is a package.json driven workflow for native development with
  Reason/OCaml (and even C/C++). It provides per-project build
  environments which are isolated from each other but share underlying
  build caches so creating new environments is cheap.

  While 0.6.0 is mainly about "quality-of-life" improvements it also got
  few new features including a basic support for garbage collection of
  unused build artifacts.

  For more info see a [blog post] by @prometheansacrifice which
  highlights important updates in 0.6.0.


[esy] <https://esy.sh>

[blog post] <https://esy.sh/blog/2020/01/12/0.6.0.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2020-01-07 13:43 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2020-01-07 13:43 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of December 31, 2019
to January 07, 2020.

Table of Contents
─────────────────

ocaml-lsp preview
Mkocaml Release - Project generator
Garbage Collection, Side-effects and Purity
A Lightweight OCaml Webapp Tutorial (Using Opium, Caqti, and Tyxml)
Release of owl-symbolic 0.1.0
Static lifetime
Old CWN


ocaml-lsp preview
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocaml-lsp-preview/4876/15>


Continuing this thread, Edwin Török said
────────────────────────────────────────

  Here is an example with ALE and Neovim (tested with v0.3.8):
  • Install the [Ale] plugin. If your Vim has support for packages (Vim
    8+ or Neovim) you can simply clone it in the correct subdir, no need
    for a plugin manager: `git clone https://github.com/w0rp/ale.git
    .vim/pack/my-plugins/start/ale'
  • Add this to your .vimrc:

  ┌────
  │ " only invoke merlin to check for errors when
  │ " exiting insert mode, not on each keystroke.
  │ let g:ale_lint_on_text_changed="never"
  │ let g:ale_lint_on_insert_leave=1
  │ 
  │ " enable ALE's internal completion if deoplete is not used
  │ let g:ale_completion_enabled=1
  │ 
  │ " only pop up completion when stopped typing for ~0.5s,
  │ " to avoid distracting when completion is not needed
  │ let g:ale_completion_delay=500
  │ 
  │ " see ale-completion-completeopt-bug
  │ set completeopt=menu,menuone,preview,noselect,noinsert
  │ 
  │ if has('packages')
  │     packloadall
  │ 
  │     " This should be part of ALE itself, like ols.vim
  │     call ale#linter#Define('ocaml',{
  │                 \ 'name':'ocaml-lsp',
  │                 \ 'lsp': 'stdio',
  │                 \ 'executable': 'ocamllsp',
  │                 \ 'command': '%e',
  │                 \ 'project_root': function('ale#handlers#ols#GetProjectRoot')
  │                 \})
  │ 
  │     " remap 'gd' like Merlin would
  │     nmap <silent><buffer> gd  <Plug>(ale_go_to_definition_in_split)<CR>
  │ 
  │     " go back
  │     nnoremap <silent> <LocalLeader>gb <C-O>
  │ 
  │     " show list of file:line:col of references for symbol under cursor
  │     nmap <silent><buffer> <LocalLeader>go :ALEFindReferences -relative<CR>
  │ 
  │     " Show documentation if available, and type
  │     nmap <silent><buffer> <LocalLeader>hh <Plug>(ale_hover)<CR>
  │ 
  │     " So I can type ,hh. More convenient than \hh.
  │     nmap , <LocalLeader>
  │     vmap , <LocalLeader>
  │ endif
  └────


[Ale] <https://github.com/dense-analysis/ale>


Mkocaml Release - Project generator
═══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/mkocaml-release-project-generator/4949/1>


Chris Nevers announced
──────────────────────

  I recently created a tool to generate OCaml projects. I constantly
  have difficulties with dune commands and setting up opam files,
  etc. Mkocaml generates a dune project with inline tests, opam file,
  git repository, git ignore, and a Makefile with easy commands. This
  tool can be of great help to newcomers, allowing them to get up and
  running faster!

  <https://github.com/chrisnevers/mkocaml>


Garbage Collection, Side-effects and Purity
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/garbage-collection-side-effects-and-purity/4737/1>


Gerard asked
────────────

  GC = Garbage Collection

  GC, in a pure program, is a point that's always confused me. I always
  understood that freeing memory from a program was impure and would
  create side-effects but it seems it doesn't matter if the program is
  remove from all consequences of those impure acts and side-effects.

  Basically, if any memory block has no remaining references in the
  program, then freeing that block will have no consequences on the
  running program so its allowed to happen behind the scenes..

  Is this correct reasoning?


Guillaume Munch-Maccagnoni replied
──────────────────────────────────

  To answer your question “does de-allocation creates a side-effect?”:

  To state the obvious: if you care about the memory consumption of your
  program, then you care about the side-effect of de-allocation, and
  this indeed voids purity.

  A language like OCaml lets you reason about de-allocation. Memory is
  collected when values are no longer reachable. Like in other
  languages, 1) a value that does not escape and goes out of scope will
  get collected, and 2) you can reason about when a value escapes and
  goes out of scope thanks to OCaml respecting the strict evaluation
  order of value types. OCaml (like other compiled languages) is in fact
  more precise: it ties the dynamic notion of reachability to the
  lexical notion of variable occurrence. For instance, in the following:

  ┌────
  │ let x = get_huge_data () in
  │ let z = long_running_function x in
  │ f z
  └────

  OCaml will be able to collect the value in `x' before `x' goes out of
  scope, and thus if possible before `long_running_function'
  returns. Indeed, OCaml performs liveness analysis during compilation,
  and records the information about variable occurrences in frame
  descriptors, for consumption by the GC when it scans for roots. In
  fact, you can rely on call-by-value operational semantics to (loosely)
  reason that a value no longer appears in a program, and therefore that
  the corresponding memory will be collected by the GC¹ ([Morrisett,
  Felleisen and Harper, "Abstract Models of Memory Management"]). Of
  course, using lazy or higher-order interfaces (when closures escape;
  with many idioms they do not) will make it harder to reason about the
  lifetime of values.

  (¹: For OCaml, this is a conjecture I make, for subsets which could be
  given such operational semantics, and only for native
  compilation. Morrisett, Felleisen and Harper's semantics obviously
  assumes that the results of liveness analysis are made available to
  the GC, but this is not written, nor is there any mention of the link
  between liveness analysis and accuracy of garbage collection in
  Appel's "Modern Compiler Implementation in C". I assume that it was
  part of folklore at the time, though recently I mentioned it to some
  functional PL researcher and they seemed surprised. I only found it
  explicitly mentioned in later papers from the OOP community. I checked
  that everything seems in place for OCaml to allow such reasoning, but
  only the authors of the original code, @xavierleroy and
  @damiendoligez, can tell us if this is intended to be part of the
  language semantics.)

  Furthermore, memory is not collected immediately when a value becomes
  unreachable. Instead:

  • Short-lived values are allocated contiguously and deallocated in a
    batch, so that allocating and deallocating short-lived values is
    very cheap, with additional benefits in terms of cache
    locality. This replaces stack allocation from languages with
    explicit memory management.

  • Longer-lived values are moved to a heap that is scanned
    incrementally, to ensure a bounded latency. In contrast, naive
    reference-counting and unique pointers from C++/Rust make you pay
    the cost of deallocation up-front.

  While this is essential for understanding the performance of OCaml
  programs, from the point of view of deallocation-as-an-effect, the
  delaying of the collection of unreachable memory can be seen as a
  runtime optimisation, that does not change the effectful status of
  deallocation (the memory still gets freed). [The intuition is that an
  effect can support some degree of reordering without requiring purity,
  as illustrated by strong monads which can be commutative without being
  idempotent, one possible definition of purity for semanticists.]

  But is de-allocation an effect _in practice_? Faced with the
  scepticism and misunderstandings from this thread, I emit two
  hypotheses:

  1) Memory consumption is not an issue in functional programming, for
     application areas that interest functional programmers.

  2) Memory management in OCaml is efficient in such a way that
     programmers do not need to think about it in their day-to-day
     programming activities in those terms.

  Hypothesis 2) could be explained for instance if OCaml programmers are
  already dealing with effects and thinking about the order in which
  their code executes (my experience), and are only used to deal with
  deallocation as an afterthought, e.g. when chasing leaks with a
  profiler.

  Let us turn towards two programming language experiments from the
  1990's that allow me to reject hypothesis 1). Both show what happens
  when one denies the status of deallocation as an effect controlled by
  the programmer.

  • Region-based memory management consisted in allocating in a stack of
    memory _regions_ deallocated at once, and determined by a
    whole-program static analysis. Now regarded as a failed idea but
    successful experiment (i.e. good science!), it taught us a lot about
    the structure of functional programs in relationship to memory
    management ([see this retrospective]). There were some good
    performance results, but also pathological cases _“where lifetimes
    were not nested or where higher-order functions were used
    extensively”_, sometimes requiring them to be altered to be _“region
    friendly”_, which was _“time-consuming”_ and required knowledge of
    the inference algorithm. In addition, the regions changed
    unpredictably when the programs evolved, and memory leaks appeared
    when the compiler inferred too wide regions.

  • Haskell was (at the time) an experiment with lazy functional
    programming. Pervasive laziness prevents reasoning about the
    lifetime of values, and purity is a central assumption used by the
    compiler for program transformations, which is antithetical with
    reasoning about deallocation as an effect. It is well-known that
    naive Haskell code has issues with memory leaks, and that realistic
    Haskell programs have to follow "best practices" to avoid leaks, by
    making extensive use of strictness annotations (e.g. bang
    patterns). Unfortunately, I found it hard to find reliable academic
    sources about lessons drawn from the experiment like the RBMM
    retrospective. The best I could find on the topic of memory leaks is
    the following blog post:
    <https://queue.acm.org/detail.cfm?id=2538488>, from a Haskell
    programmer who wrote in another post (linked from that one) _“My
    suspicion is that many (most?) large Haskell programs have space
    leaks, but they often go unnoticed”_. This is consistent with
    comments I received from people with Haskell experience (first-hand,
    one academic and one industrial) and about an industrial Haskell
    consultant (second-hand) who reportedly commented that their main
    job was to fix memory leaks (but maybe in jest). Of course, take
    this with a grain of salt. At least, I believe that the Haskell
    academic community has accumulated empirical evidence of the extent
    and manner in which deallocation voids purity assumptions. Having an
    authoritative source about it would be pretty important to me, given
    the initial promises of functional programs being more tractable
    mathematically specifically via “referential transparency” and
    independence of execution order, whose theoretical justification
    already looks shaky to me from a semantic point of view. Some parts
    of the literature continues to promise far-reaching consequences of
    equational reasoning, without clear statements of limitation of the
    application domain. I have the impression that the Haskell which is
    practiced in the real world is very different from what you can read
    in some academic papers.

  The hypothesis that deallocation matters as an effect, and that ML
  makes it easy to program and reason about effects, seems to me a
  strong argument explaining OCaml's predictable and competitive
  performance.

  So, thank you for your healthy scepticism.


[Morrisett, Felleisen and Harper, "Abstract Models of Memory
Management"] <https://dash.harvard.edu/handle/1/3293156>

[see this retrospective]
<https://link.springer.com/article/10.1023/B:LISP.0000029446.78563.a4>


Xavier Leroy replied
────────────────────

  Concerning the "don't scan local variables that are dead" trick:

  • Technically it is not "intended to be part of the language
    semantics" because the bytecode compiler (ocamlc) doesn't implement
    it, only the native-code compiler (ocamlopt).

  • As far as I remember, I reinvented this trick circa 1993, but it
    seems it was used earlier in the Lazy ML compiler by Augustsson and
    Johnsson. See Appel and Shao's paper "An Empirical and Analytic
    Study of Stack vs. Heap Cost for Languages with Closures", JFP,
    1996, end of section 5.


Guillaume Munch-Maccagnoni the asked
────────────────────────────────────

  TL;DR: the paper mentioned by @xavierleroy provides additional
  references regarding the importance of liveness analysis for GC,
  including a demonstration by Appel that this actually matters for
  space complexity (thanks!). I find that a link is still missing with
  an abstract semantics à la Morrisett, Felleisen & Harper. This seems
  important to me because more theoretical works about time & space
  complexity in the lambda-calculus seem to take for granted that
  garbage collection implements something like the latter (i.e., how
  does one specify and certify that a compiler is sound for space
  complexity?).


Xavier Leroy replied
────────────────────

  See for example [Closure Conversion is Safe for Space], by Zoe
  Paraskevopoulou and Andrew W. Appel, ICFP 2019.


[Closure Conversion is Safe for Space]
<https://www.cs.princeton.edu/~appel/papers/safe-closure.pdf>


A Lightweight OCaml Webapp Tutorial (Using Opium, Caqti, and Tyxml)
═══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/a-lightweight-ocaml-webapp-tutorial-using-opium-caqti-and-tyxml/4967/1>


Shon announced
──────────────

  The tutorial is [hosted on gitlab pages], out of [this repository].

  I put this together in response to some requests for introductory
  material on the topic (here and on [/r/ocaml]. I don't have much
  expertise to offer in this area, but I had hacked together some simple
  servers based on Opium in the past few months, so it seemed like I
  should be able to memorialize some of what I learned for the benefit
  of others. I received some critical guidance by the Opium maintainers,
  rgrinberg and anuragsoni, and from other resources online (mentioned
  at the end of the tutorial).

  Any feedback or improvements are welcome: this is my first time
  writing such lengthy instructional material, and I'm sure there's lots
  of room to make it better.


[hosted on gitlab pages] <https://shonfeder.gitlab.io/ocaml_webapp/>

[this repository] <https://gitlab.com/anuragsoni/ocaml_webapp>

[/r/ocaml] <https://www.reddit.com/r/ocaml/>


Release of owl-symbolic 0.1.0
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announce-release-of-owl-symbolic-0-1-0/4930/2>


jrzhao42 announced
──────────────────

  The Owl tutorial book URL address is now changed to:
  <https://ocaml.xyz/book/symbolic.html>.


Static lifetime
═══════════════

  Archive: <https://discuss.ocaml.org/t/static-lifetime/4908/19>


André asked and Guillaume Munch-Maccagnoni replied
──────────────────────────────────────────────────

  > Is it possible to “statically” allocate a value? By this I mean mark
    a value such that it gets ignored by the GC and lives until the
    program exits?

  This is indeed the purpose of Ancient, which comes with limitations
  and does not allow you to reclaim the memory until you exit the
  program. (I am curious to know how well it works with recent OCaml
  versions.)

  > it would be really interesting to learn whether Ocaml forbids blocks
    outside the heap.

  The OCaml runtime has two modes (chosen at compilation) for dealing
  with so-called "out-of-heap" pointers. In the legacy one that Chet
  remembers, the GC uses a page table when scanning to be able to tell
  which pointers it possesses. In the "no-naked-pointers" mode devised
  more recently for efficiency reasons, the page table is replaced by
  looking at the colour in the header of the dereferenced
  value. Out-of-heap values must be preceded by a header with colour
  black. The no-naked-pointer mode is more restricted, because once a
  static value is referenced, it can no longer be deallocated, as you
  never know whether it is still reachable by the GC. This should be
  enough to support Ancient.

  > One should verify such intuitions experimentally, before trying to
    fix them, but I’m not familiar with what OCaml profilers can do…

  Excluding large long-lived data from the GC is an old idea. Among
  recent developments, Nguyen et al. [1] distinguish a "control path"
  (where the generational hypothesis is assumed to hold) from a "data
  path" (where values are assumed to follow an "epochal" behaviour
  (long-lived, similar lifetimes, benefit from locality), and are
  excluded from GC). They give as motivation so-called "big data" and as
  figures of pathological GC usage up to 50% of total runtime. I
  remember reading similar figures from blog posts about large data sets
  in OCaml. In reality this indeed depends on knobs you can turn on your
  GC that can result in increased peak memory usage among
  others. (Assuming infinite available memory, it is even possible to
  let the GC share drop to 0%.)

  @ppedrot reported to me that in a recent experiment with Coq, using an
  Ancient-like trick to exclude some large, long-lived and
  rarely-accessed values from being scanned (namely serialising them
  into bigarrays), they saw an 8% performance improvement across the
  board in benchmarks.

  Multicore, if I understood correctly, aims to support only the
  no-naked-pointer mode, and I am not sure what the page table will
  become. Coq currently does some out-of-heap allocation in the VM, and
  has been adapted to be compatible with the no-naked-pointer mode by
  wrapping out-of-heap pointers into custom blocks. For scanning its
  custom stack (which mixes in-heap and out-of-heap values), Coq sets up
  a custom root-scanning function (`caml_scan_roots_hook`), which still
  relies on the page table.

  Note that having to wrap out-of-heap pointers in custom blocks is
  (much!) less expressive: for instance with Ancient you can call
  `List.filter` on a statically-allocated list (and correctly get a
  GC-allocated list of statically-allocated values). With custom blocks
  you cannot mix in-heap and out-of-heap values in this way.

  For a type system to deal with "statically" allocated values, have a
  look at Rust, which: 1) prevents cycles of reference-counting schemes
  thanks to uniqueness, 2) can treat GC roots as resources to deal with
  backpointers at the leaves of the value (cf. the interoperability with
  SpiderMonkey's GC in Servo). A point of view that I like is that
  tracing GCs and static allocation differ fundamentally by how they
  traverse values for collection: traversing live values for the first
  one, and traversing values at the moment of their death for the
  other. This gives them distinct advantages and drawbacks so one can
  see them as complementary. (See notably [2,3].) Static allocation is
  interesting for performance in some aspects (no tracing, no read-write
  barrier, reusability of memory cells, avoids calling the GC at
  inappropriate times), but I find it even more interesting for
  interoperability (e.g. exchanging values freely with C or Rust, or
  [applications from that other thread]). It is natural to want to mix
  them in a language.

  As far as I understand, developing the runtime capabilities for OCaml
  to deal with out-of-heap pointers without resorting to an expensive
  page table is an engineering problem, not a fundamental one. If anyone
  is interested in this, please contact me.

  [1] Nguyen et al., [Yak : A High-Performance Big-Data-Friendly Garbage
  Collector], 2016

  [2] Bacon, Cheng and Rajan, [A Unified Theory of Garbage Collection],
  2004

  [3] Shahriyar, Blackburn and Frampton, [Down for the Count? Getting
  Reference Counting Back in the Ring], 2012


[applications from that other thread]
<https://discuss.ocaml.org/t/using-a-bigarray-as-a-shared-memory-for-parallel-programming/4841/19>

[Yak : A High-Performance Big-Data-Friendly Garbage Collector]
<https://www.usenix.org/system/files/conference/osdi16/osdi16-nguyen.pdf>

[A Unified Theory of Garbage Collection]
<http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.439.1202&rep=rep1&type=pdf>

[Down for the Count? Getting Reference Counting Back in the Ring]
<https://dl.acm.org/citation.cfm?doid=2258996.2259008>


UnixJunkie also replied
───────────────────────

  If you can store your long-leaved data into a bigarray, I think you
  would reach the effect that you were looking for (no more GC scanning
  of this data).

  This was once advised to me by Oleg, for some performance-critical
  section of some code.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-12-31  9:18 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-12-31  9:18 UTC (permalink / raw)
  To: lwn, cwn, caml-list

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Hello

Here is the latest OCaml Weekly News, for the week of December 17 to 31,
2019.

Sorry for the hiatus last week, I was away with no internet
access. Happy new year!

Table of Contents
─────────────────

Internships at Be Sport (OCaml, Ocsigen)
ocaml-lsp preview
Reproducible builds with OCaml / opam and MirageOS
the OCaml Software Foundation
soupault: a static website generator based on HTML rewriting
Release of owl-symbolic 0.1.0
Old CWN


Internships at Be Sport (OCaml, Ocsigen)
════════════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2019-12/msg00023.html>


Be Sport announced
──────────────────

  Be Sport currently has several open internship positions for OCaml
  developers.

  Keywords: OCaml, Ocsigen, Mobile app development, Web, Database,
  Sport, Social networks

  Be Sport develops the first global platform dedicated to sport, in
  collaboration with prominent actors of sport in France and in the
  world.  All our development is done in OCaml. Our Web and mobile apps
  (iOS, Android) are developed as a multi-tier app using the Ocsigen
  framework.  Our premises are located in the center of Paris.

  Please contact me for more information.


ocaml-lsp preview
═════════════════

  Archive: <https://discuss.ocaml.org/t/ann-ocaml-lsp-preview/4876/1>


Rudi Grinberg announced
───────────────────────

  I'm excited to announce [ocaml-lsp]. This project contains an
  implementation of an LSP server for the OCaml language. The current
  implementation piggy backs on the widely successful [merlin] tool to
  provide completion & type inference. In the future, we'd like to use
  all other essential tools such as ocamlformat, odoc, dune to provide
  more functionality in your editors.

  For now, the project isn't yet available on opam as we're still
  polishing some rough edges in the release process. Nevertheless, I
  invite all brave souls who are ready to experiment to give this lsp
  server a try. Your feedback & contributions are most welcome
  :slight_smile:


[ocaml-lsp] <https://github.com/ocaml/ocaml-lsp>

[merlin] <https://github.com/ocaml/merlin>


UnixJunkie asked and Anton Kochkov replied
──────────────────────────────────────────

        This project looks nice.

        If I am an Emacs or Vi user, can I take advantage of an
        LSP server?

        Or, is this only for some new editors like Atom or VScode?

  @UnixJunkie of course! That's the whole point of this tooling.

  For Vim you can choose between:
  • [Coc.nvim] - most powerful of all, but written in TypeScript and
    heaviest of all
  • [Ale] - pure VimL
  • [vim-lsp] - pure VimL
  • [LanguageClient-neovim] - written in Rust
  • Some other implementations

  I am not an Emacs expert, but there is amazing LSP integration too:
  • [lsp-mode]

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/b/b8acd745527e801fef1eb3d4e8722d49c5c2ed1a.png>


[Coc.nvim] <https://github.com/neoclide/coc.nvim>

[Ale] <https://github.com/dense-analysis/ale>

[vim-lsp] <https://github.com/prabirshrestha/vim-lsp>

[LanguageClient-neovim]
<https://github.com/autozimu/LanguageClient-neovim>

[lsp-mode] <https://github.com/emacs-lsp/lsp-mode>


Pau Ruiz Safont said
────────────────────

  Neovim 0.5.0 (now pre-released) has native LSP support as well:
  <https://github.com/neovim/neovim/pull/11336>

  Not sure how well integrated is it going to be with various plugins
  ([example])


[example] <https://github.com/Shougo/deoplete-lsp>


Anton Kochkov added
───────────────────

  NeoVim 0.5.0 will also include the [tree-sitter] parser for syntax
  highlighting, which will allow way better coloring. And tree-sitter
  already has [OCaml grammar], so implementing semantics-aware syntax
  highlighter will be easier. But I expect the support more or less
  ready for external contributions only in 0.6.0, sadly. Integrating the
  tool with something like [GitHub Semantic] (*Haskell alert*) will
  greatly improve OCaml experience on GitHub too, see the [corresponding
  issue].


[tree-sitter] <https://tree-sitter.github.io/tree-sitter/>

[OCaml grammar] <https://github.com/tree-sitter/tree-sitter-ocaml>

[GitHub Semantic] <https://github.com/github/semantic>

[corresponding issue] <https://github.com/github/semantic/issues/138>


Pieter Goetschalckx said
────────────────────────

  The next step for Semantic support is documented [here], but I'm
  working on some [improvements] of the tree-sitter parser first.


[here]
<https://github.com/tree-sitter/haskell-tree-sitter/blob/master/docs/codegen.md>

[improvements]
<https://github.com/tree-sitter/tree-sitter-ocaml/pull/36>


Carlos D'Agostino said
──────────────────────

  For Emacs there is also `eglot': <https://github.com/joaotavora/eglot>
  – As the README says, it's quite minimalist compared to `lsp-mode'.


Reproducible builds with OCaml / opam and MirageOS
══════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/reproducible-builds-with-ocaml-opam-and-mirageos/4877/1>


Hannes Mehnert announced
────────────────────────

  I wrote up recent developments about reproducible builds with opam –
  including some tooling <https://hannes.nqsb.io/Posts/ReproducibleOPAM>

  Thanks to everyone involved in the effort to get OCaml and opam
  deterministic
  • Nov 2015 [I collected downstream patches and asked kindly to get
    them upstream] (temporary flle names in binaries, timestamps)
  • Dec 2017 [BUILD_PATH_PREFIX_MAP support] (and further patches for
    that)
  • Dec 2018 Paris summit [opam reproducibility] [MirageOS]
  • [`orb'] tool for reproducibility testing (so much better than the
    shell scripts I used in the meantime)
  • Dec 2019 [Marrakesh summit]

  The journey is not yet finished, we're in a pretty good shape, but
  further testing and tooling is needed to expose the information "is my
  library reproducible?" to OCaml developers.

  I'm interested in feedback, please let us discuss this further here in
  case you're interested. :D


[I collected downstream patches and asked kindly to get them upstream]
<https://github.com/ocaml/ocaml/issues/7037>

[BUILD_PATH_PREFIX_MAP support]
<https://github.com/ocaml/ocaml/pull/1515>

[opam reproducibility]
<https://reproducible-builds.org/events/paris2018/report/#Toc11410_331763073>

[MirageOS]
<https://reproducible-builds.org/events/paris2018/report/#Toc11681_331763073>

[`orb'] <https://github.com/rjbou/orb>

[Marrakesh summit]
<https://reproducible-builds.org/events/Marrakesh2019/>


Anil Madhavapeddy added
───────────────────────

  An absolutely amazing cross-layer effort; well done on pushing all
  this through @hannes!  I really enjoyed reading the minutes of the
  Paris summit last year:
  <https://reproducible-builds.org/events/paris2018/report/#Toc11681_331763073>


the OCaml Software Foundation
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-the-ocaml-software-foundation/4476/13>


Continuing this thread, gasche announced
────────────────────────────────────────

  A small report on the actions that we launched since my initial
  posting.

  (There was also some progress on the "enabling individual donations"
  front, maybe something will be possible in the next few months. Don't
  start holding your breath yet.)

  • We are funding the "Leafs" research project in Lisbon to develop
    teaching material for theoretical-computer-science courses (automata
    and stuff) in OCaml, with interactive visualization components, some
    of which will hopefully be integrated in the [Learn-OCaml] platform
    over the course of 2020/2021.
  • We provide funding for the [Gallium/Cambium] research team at INRIA
    Paris (France), an active place for OCaml-related fundamental
    research (some of the team members are also very active on the
    implementation front, for example Xavier Leroy, Damien Doligez,
    Florian @octachron Angeletti, and Sébastien Hinderer).
  • We sponsor the [SWERC] programming contest for 2019-2020, and in
    return the contest added OCaml to the list of available
    languages. Most participants to these competitive-programming events
    use C++, but we talked to past and active participants who said they
    would be interested in using OCaml on some problems with more
    symbolic computation.
  • Over the course of the 4.10 release process, we are funding work by
    @kit-ty-kate to have a wide look at the ecosystem and improve
    compatibility with the upcoming release. (I believe that the
    upstream PR [#9176] is a first result of this effort.)
  • In reaction to the Discourse thread [Suggestions for OCaml
    documentation], we are planning to fund further work by @sanette to
    experiment with the HTML rendering of the OCaml manual, in
    coordination with @octachron to try to upstream improvements when
    reasonably possible.
  • We got in touch with the [Owl] project to sponsor a development
    sprint in 2020.


[Learn-OCaml] <http://ocaml-sf.org/learn-ocaml.html>

[Gallium/Cambium] <http://cambium.inria.fr/>

[SWERC] <https://swerc.eu/2019/about/>

[#9176] <https://github.com/ocaml/ocaml/pull/9176>

[Suggestions for OCaml documentation]
<https://discuss.ocaml.org/t/suggestions-for-ocaml-documentation/4504>

[Owl]
<https://discuss.ocaml.org/t/suggestions-for-ocaml-documentation/4504>


soupault: a static website generator based on HTML rewriting
════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-soupault-a-static-website-generator-based-on-html-rewriting/4126/10>


Daniil Baturin announced
────────────────────────

  Made a [1.7.0 release].

  First improvement is that you now can pipe the content of any element
  through any external program with `preprocess_element' widget (PR by
  Martin Karlsson).  For example, insert inline SVG versions of all
  graphviz graphs from `<pre class="language-graphviz">' and also
  highlight the Dot source itself with [highlight] (or any other tool of
  your choice):

  ┌────
  │ [widgets.graphviz-svg]
  │   widget = 'preprocess_element'
  │   selector = 'pre.language-graphviz'
  │   command = 'dot -Tsvg'
  │   action = 'insert_after'
  │ 
  │ [widgets.highlight]
  │   after = "graphviz-svg"
  │   widget = "preprocess_element"
  │   selector = '*[class^="language-"]'
  │   command = 'highlight -O html -f --syntax=$(echo $ATTR_CLASS | sed -e "s/language-//")'
  │   action = "replace_content" # default
  └────

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/a/a4d8cc05d65634de0faf3c05b16e0de8d27a78a3.png>

  Two other improvements are multiple index "views" and default value
  option for custom index fields, like
  ┌────
  │ [index.custom_fields]
  │   category = { selector = "span#category", default = "Misc" }
  └────


[1.7.0 release]
<https://soupault.neocities.org/blog/soupault-1.7.0-release>

[highlight] <http://andre-simon.de>


Release of owl-symbolic 0.1.0
═════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/announce-release-of-owl-symbolic-0-1-0/4930/1>


jrzhao42 announced
──────────────────

  We are please to release [owl-symbolic 0.1.0]. It fully supports
  defining a computation graph and running on accelerators (TPU/GPU) via
  [ONNX] specification. It also aims to support converting an Owl
  computation graph into symbolic representation and then to ONNX
  model. The module also has some cool features like converting a
  computation graph into LaTeX string, and then showing the result in a
  web UI, etc.

  We implements a full neural network module atop of it (the interface
  of which is basically identical to that in Owl's core). It turns out
  that the design of `owl-symbolic' is so nice that the DNN module only
  has 179 LOC! You can easily define popular DNN architectures such as
  Inception, ResNet, VGG, etc. just like in Owl.

  This is still an on-going project and a lot remains to be
  done. Despite its name, `owl-symbolic' does not do any useful computer
  algebra (CAS) stuff at the moment, but CAS is indeed on our TODO.

  For more information, please check out the related section in [Owl
  tutorial book].


[owl-symbolic 0.1.0] <https://opam.ocaml.org/packages/owl-symbolic/>

[ONNX] <https://onnx.ai/>

[Owl tutorial book] <https://ocaml.xyz/owl_tutorials/symbolic.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-12-17  8:52 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-12-17  8:52 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of December 10 to 17,
2019.

Table of Contents
─────────────────

Is there a good way to encode linear types in OCaml?
Arch Linux installer written in OCaml
batteries batteries.2.11.0
Old CWN


Is there a good way to encode linear types in OCaml?
════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/is-there-a-good-way-to-encode-linear-types-in-ocaml/1292/7>


Continuing this old thread, Konstantin Olkhovskiy said
──────────────────────────────────────────────────────

  I've stumbled upon a library that implements linear types for OCaml,
  using monads, lens and some ppx to make it more lightweight. Might be
  of interest: <https://github.com/keigoi/linocaml>


Anton Kochkov added
───────────────────

  It is the part of even more interesting system - [OCaml MPST]
  (Multiparty Session Types) See the [slides].


[OCaml MPST] <https://github.com/keigoi/ocaml-mpst>

[slides]
<https://www.slideshare.net/keigoi/ocamlmpst-global-protocol-combinators-175519214>


Guillaume Munch-Maccagnoni then said
────────────────────────────────────

  (The paper linked on that page is dated 2011/2014. In case anyone
  wonders whether the authors have found a time machine in a barn to be
  able to cite papers from 2018, there just seems to be an error in the
  preparation. It is freshly published, and a PDF with correct dates is
  available [here].)


[here]
<https://www.jstage.jst.go.jp/article/ipsjjip/27/0/27_431/_article>


Arch Linux installer written in OCaml
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/arch-linux-installer-written-in-ocaml/4388/12>


Darren announced
────────────────

  I'm doing a short update here as Oali has seen some significant
  changes. This update is also the last one here to avoid being too
  annoying, and also since I won't be add too much new stuff to Oali in
  foreseeable future.

  Major changes since last time
  • SaltStack files and script files (or profiles) now live in a
    separate [repo]
    • Oali accepts custom profile repo URL to facilitate using your own
      SaltStack files without forking Oali itself
  • Semi self-documentation
    • Added mechanism to facilitate inline documentation inside
      `oali.ml' itself
    • The generated markdown doc is stored as [OALI_DOC] in repo, it
      lists all the steps (or tasks) Oali does, along with descriptions
  • Added LVM support
    • Works with all 3 disk layouts, and encryption
    • See [here] for details on added logical volumes
  • Answer remembering of dialogues when appropriate
    • Relatively static answers (e.g. hostname, whether to use
      encryption, LVM) are stored in `oali_answers' directory, with a
      JSON file for each task
    • The "answer store" can be used in new session of Oali. The old
      answer store is wiped accordingly if user changes their answer.
  • Added SSH server setup and public key transfer code (ported from old
    server bash script)
    • See [here] for details
    • Mainly useful for when you have (virtual) console access to live
      CD/Oali install screen, and want to add needed public key to the
      user's `.ssh/authorized_keys' via network instead of loading from
      physical medium

  I've used Oali to install in various configurations in past couple of
  days, and have yet to notice major defects. That being said, exercise
  caution as you would for installing an OS.


[repo] <https://github.com/darrenldl/oali-profiles>

[OALI_DOC] <https://github.com/darrenldl/oali/blob/master/OALI_DOC.md>

[here]
<https://github.com/darrenldl/oali/blob/master/OALI_DOC.md#20-set-up-disk>

[here]
<https://github.com/darrenldl/oali/blob/master/OALI_DOC.md#54-transfer-ssh-public-keys>


batteries batteries.2.11.0
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-batteries-batteries-2-11-0/4871/1>


UnixJunkie announced
────────────────────

  The latest 2.x release of batteries is available in opam.  OCaml
  batteries included is a community maintained extended standard
  library.

  <https://github.com/ocaml-batteries-team/batteries-included>

  The API documentation is hosted here:
  <https://ocaml-batteries-team.github.io/batteries-included/hdoc2/>

  Here is the changelog:
  ┌────
  │ v2.11.0 (minor release)
  │ 
  │ This minor release fixes a few bugs or interface mismatch with OCaml stdlib,
  │ and is compatible with BER MetaOCaml.
  │ 
  │ This is the last planned release of the v2 series.
  │ Next planned release (v3.0.0) will introduce some API changes.
  │ 
  │ Notable changes:
  │ 
  │     Add Unix.with_locked_file
  │     #904
  │     (Simon Cruanes, Cedric Cellier, review by Francois Berenger)
  │ 
  │     Build with -strict-sequence
  │     #927
  │     (Armaël Guéneau, review by Francois Berenger)
  │ 
  │     Add Legacy.Result for OCaml >= 4.8.0
  │     #913
  │     (Cedric Cellier, review by Francois Berenger)
  │ 
  │     Remove BatOo
  │     #915
  │     (Cedric Cellier, review by Francois Berenger)
  │ 
  │     Add BatFilename
  │     #910
  │     (Cedric Cellier, review by Francois Berenger)
  │ 
  │     Make batteries usable with BER MetaOCaml
  │     #909
  │     (Cedric Cellier, review by Francois Berenger and Gabriel Scherer)
  │ 
  │     Unix.sleepf is provided across all OCaml versions;
  │     previously it was only for OCaml >= 4.03.0
  │     #930
  │     (Francois Berenger, review by Cedric Cellier)
  └────


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-12-10  8:21 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-12-10  8:21 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of December 03 
to 10,
2019.

Table of Contents
─────────────────

Internships at Nomadic-labs
Interesting OCaml Articles
Next OUPS meetup December 18th 2019
Old CWN


Internships at Nomadic-labs
═══════════════════════════

  Archive: 
  <https://discuss.ocaml.org/t/internship-at-nomadic-labs/4819>


Julien Tesson announced
───────────────────────

  Nomadic Labs is currently looking for students with an interest 
  in
  functional programming for internships that would take place in 
  our
  offices in Paris or Grenoble.

  We have a catalog of internships topics available at [1] The
  internships topics are mainly addressed to master student but 
  other
  well motivated application will be considered.

  A first selection phase on received résumé will occur on 
  december
  15th.  Please contact us at contact@nomadic-labs.com by 
  specifying
  which topics in the catalog you're interested in.

  [1]: <https://nomadic-labs.com/download/internship_catalog.pdf>

  Please, feel free to redistribute widely.


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/57>


james woodyatt announced
────────────────────────

  Found on *Lobste.rs*: Mark Karpov writes yet another [Haskell
  vs. OCaml] for old time's sake. I found it worth a read and a 
  mention
  here.

  p.s. He spends a bit of time in the intro lamenting the lack of 
  a
  conventional Unicode string library for OCaml, and I feel that 
  pain
  acutely, especially since I'm the author of an *unconventional* 
  one,
  i.e. the [Ucs_text] module in my [Orsetto] project.


[Haskell vs. OCaml] 
<https://markkarpov.com/post/haskell-vs-ocaml.html>

[Ucs_text]
<https://bitbucket.org/jhw/orsetto/src/default/src/ucs/ucs_text.mli>

[Orsetto] <https://bitbucket.org/jhw/orsetto>


Next OUPS meetup December 18th 2019
═══════════════════════════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2019-12/msg00009.html>


Bruno Bernardo announced
────────────────────────

  The OUPS meetup is back. The next one will take place on 
  Wednesday,
  December 18, 7pm at IRILL on the Jussieu campus. As usual, we 
  will
  have a few talks, followed by pizzas and drinks.

  The talks will be the following:

  • Nathan Rebours, The future of OCaml-PPX

  • Guillaume Claret, coq-of-ocaml
    (<https://clarus.github.io/coq-of-ocaml/>)

  And possibly a third talk. Contact us if you want to present
  something, especially if you have a small project you want to 
  show in
  10-15min.

  To register, or for more information, go here:
  <https://www.meetup.com/ocaml-paris/events/267019458>

  *Registration is required! Access is not guaranteed after 7pm if
  you're not registered.* (It also helps us to order the right 
  amount of
  food.)

  Access map:
  IRILL - Université Pierre et Marie Curie (Paris VI)
  Barre 15-16 1er étage
  4 Place Jussieu
  75005 Paris
  <https://www.irill.org/pages/access.html>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and 
  I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed 
  of the
  archives].

  If you also wish to receive it every week by mail, you may 
  subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] 
<http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-12-03 15:42 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-12-03 15:42 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Hello

Here is the latest OCaml Weekly News, for the week of November 26 
to
December 03, 2019.

Table of Contents
─────────────────

Irmin 2.0.0 release
How viable is delivering binaries linked to Cygwin to Windows 
customers?
Dune 2.0.0
Advanced C binding using ocaml-ctypes and dune
Upcoming breaking change in Base/Core v0.14
CI/CD Pipelines: Monad, Arrow or Dart?
Use of functors to approximate F# statically resolved type 
parameters
Old CWN


Irmin 2.0.0 release
═══════════════════

  Archive: 
  <https://discuss.ocaml.org/t/ann-irmin-2-0-0-release/4746/5>


Continuing this thread, samoht announced
────────────────────────────────────────

  And there is now a follow-up blog post, explaining how to use 
  the new
  GraphQL API available in Irmin2:
  <https://tarides.com/blog/2019-11-27-introducing-irmin-graphql>.


How viable is delivering binaries linked to Cygwin to Windows 
customers?
════════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/how-viable-is-delivering-binaries-linked-to-cygwin-to-windows-customers/4775>


mbacarella asked
────────────────

  I’m in the early stages of planning a deliverable binary product 
  that
  will run on Linux, Mac and Windows.

  My brief sniff of the air around the OCaml ecosystem says I 
  should
  expect to target Cygwin to get Windows going (although there’s
  impressive work to get native Windows stuff done that can become 
  the
  preferred approach in a few years).

  My experience using Cygwin as an operating environment is that 
  it’s
  pretty darn sluggish compared to Linux on the same computer.

  Why is this? There’s an anecdote that says Cygwin can only fork 
  at
  about 30-50x a second on Windows, due to how it has to adapt it 
  to
  work within Windows’ task spawning model. (For contrast, Linux 
  can
  achieve thousands of forks per second if you play around with 
  it).

  I understand from another product developer that when they build
  binaries to deliver to Windows/Cygwin, they actually 
  cross-compile on
  Linux because of how slowly the toolchain runs on Cygwin.

  That sounds like bad news if you want to do UNIXy things, but 
  for a
  single standalone application this might not be so bad? I assume 
  if I
  ship a deliverable to Windows/Cygwin, the end user may enjoy 
  good
  performance, so long as I’m not spawning tons of processes or 
  relying
  on fork for multi-programming. Is this a safe assumptions?

  Any other gotchas when it comes to OCaml on Cygwin w.r.t. 
  performance?

  The app pretty much has real-time gaming requirements (though 
  it’s not
  a game so can side-step worrying about access to GPUs and
  what-not). Stated another way, although my application will 
  depend on
  the POSIX layer offered by Cygwin, I expect it not to crunch 
  POSIX
  related stuff in the main loop.

  How has your experience gone?


John Whitington replied
───────────────────────

  I have been shipping commercial binaries for Linux (32 and 64 
  bit),
  Windows (32 and 64bit) and OS X for years. For example:
  <https://github.com/coherentgraphics/cpdf-binaries>

  And even static or shared libraries in binary form:
  <https://github.com/coherentgraphics/cpdflib-binary>

  On OS X, you need to use MACOSX_DEPLOYMENT_TARGET or similar to 
  make
  sure your builds will run on older systems. And, in fact, you 
  need to
  use MACOSX_DEPLOYMENT_TARGET when asking OPAM to compile the 
  OCaml
  compiler itself. And, you will need to deal with codesigning and
  notarization. But it’s all doable.

  For linux, you may need to build under older linux versions, to 
  make
  sure that the glibc in use is old enough. This is not an
  ocaml-specific problem. I have a 64 bit and 32 bit VM with 
  old-ish
  glibc versions for this purpose.

  Under Windows, there are no such backward-compatibility 
  problems. I
  use the new OCaml for windows system, which comes with OPAM, and 
  is
  mingw-based. No cygwin remains in the final binary.

  For more obscure systems (AIX, HPUX, Sparc etc) customers 
  compile from
  source (with help from me). Not once in more than ten years has 
  anyone
  cared that it was written in OCaml.


dbuenzli also replied
─────────────────────

  remember that on the Windows native port, the Unix module 
  distributed
  with OCaml is your POSIX compatibility layer. There are a few 
  entry
  points to avoid though, the list is at the bottom of [this 
  page].


[this page] 
<https://caml.inria.fr/pub/docs/manual-ocaml/libunix.html>


nojb also replied
─────────────────

  At LexiFi our main application is developed and shipped on 
  Windows. We
  use the msvc port of OCaml. This means that you need Cygwin to
  develop, but the resulting application is fully native and does 
  not
  depend on the Cygwin DLL. As @dbuenzli mentioned, the Unix 
  module *is*
  the POSIX compatibility layer.

  Compilation speed is slower on Windows because process creation 
  is
  slower on Windows as a general rule, but it is manageable (our
  application has around 2000 modules + Js_of_ocaml + C bindings + 
  C#
  component).

  We don’t have any issues with runtime performance. The `Unix' 
  library
  mentioned above implements Windows support directly without 
  going
  through any compatibility layer and is quite efficient.


BikalGurung also replied
────────────────────────

  There is an editor being built in ocaml/reasonml which currently
  targets windows, linux and macos -
  <https://github.com/onivim/oni2>. However, the binary is native
  windows rather than cygwin derivative. So if you don’t have to 
  use
  cygwin dependencies then native windows binary could be the way 
  to go.

  Also esy - <https://github.com/esy/esy> makes developing
  ocaml/reasonml on windows viable.


keleshev also replied
─────────────────────

  *TLDR*: Install the [Mingw port of OCaml 4], freely use most 
  opam
   libraries, and compile to native Windows binaries, without 
   licensing
   issues.

  I recommend you read the “Release notes for Windows”:
  <https://github.com/ocaml/ocaml/blob/trunk/README.win32.adoc>

  To summarise, there are three Windows ports:

  • Native Microsoft port,
  • Native Mingw port,
  • Cygwin port.

  All three require Cygwin for development purposes. I recommend 
  using
  the Native Mingw, as:

  • it *doesn’t* require Visual Studio (it uses a mingw fork of 
  GCC that
    “cross-compiles” native Windows executables),
  • it *doesn’t* rely on the dreaded cygwin.dll
  • it has good opam support with opam-repository-mingw:
    <https://github.com/fdopen/opam-repository-mingw>
  • it has a convenient installer:
    <https://fdopen.github.io/opam-repository-mingw/> 5.

  To contrast, Native Microsoft requires Visual Studio, and 
  doesn’t have
  opam. You can still vendor pure OCaml packages, but as soon as 
  you
  want to use some C bindings you’re in trouble, because of the 
  “minor”
  differences between Visual C and GCC. And everything assumes GCC
  nowadays.

  Cygwin port is the one I don’t have experience with, but 
  re-reading
  the “Release notes for Windows” above it strikes me that it 
  mentions
  that Cygwin was re-licensed from GPL to LGPL with static linking
  exception. So it looks like the Cygwin port could be viable for
  commercial use, but I never tried to statically linked 
  `cygwin.dll',
  and I’m not sure what are the benefits of Cygwin port over the 
  Mingw
  port.


[Mingw port of OCaml 4]
<https://fdopen.github.io/opam-repository-mingw/>


dmbaturin also replied
──────────────────────

  With [soupault 4], I decided to ship prebuilt binaries for all
  platforms including Windows. Mostly to see if I can, all its 
  users I
  know of are on UNIX-like systems and know how to build from 
  source,
  but that’s beside the point. :wink:

  I can confirm everything @keleshev says: fdopen’s package just 
  works,
  opam works exactly like it does on UNIX, pure OCaml libraries 
  are
  trivial to install, and the binaries don’t depend on cygwin. 
  Note
  that “opam switch create” also just works, you can install 
  either
  MinGW or MSVC compiler versions as opam switches.  I only ever 
  start
  the Windows VM to make release builds, and the workflow is 
  exactly the
  same as on Linux where I’m actually writing code.

  My only obstacle on that path was that FileUtils lost its 
  Windows
  compatibility, but I wanted to use it, so I worked with 
  @gildor478 to
  make it cross-platform again. Uncovered a bug in the 
  implementation of
  Unix.utimes in the process, but it’s hardly a commonly used 
  function.

  You can also setup AppVeyor builds. It’s not as simple as I wish 
  it
  would be, but there are projects doing it that you can steal the 
  setup
  from.

  There’s also opam-cross-windows, but it’s very incomplete and 
  needs
  work to be practical. There are no big obstacles, it just needs
  work. While files in opam-repository-mingw are normally 
  identical to
  the default opam repository, the cross one needs small 
  adjustments in
  every package to specify the toolchain to use, so the required 
  work is
  mostly a lot of trivial but manual actions. I hope eventually it
  reaches parity with fdopen’s one and we’ll be able to easily 
  build for
  Windows without ever touching Windows.

  As of static Linux builds, @JohnWhitington’s approach can work, 
  but
  there’s a better option if you don’t need anything from glibc
  specifically and don’t link against any C libs: build statically 
  with
  musl. There’s a `+musl+static+flambda' compiler flavour. You 
  need musl
  and gcc-musl to install it, but after that, just build with 
  `-ccopt
  -static' flag and you get a binary that doesn’t depend on 
  anything.


[soupault 4] <https://soupault.neocities.org/>


Dune 2.0.0
══════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-2-0-0/4758>


rgrinberg announced
───────────────────

  On behalf of the dune team, I’m delighted to announce the 
  release of
  dune 2.0. This release is the culmination of 4 months of hard 
  work by
  the dune team and contains new features, bug fixes, and 
  performance
  improvements . Here’s a selection of new features that I 
  personally
  find interesting:

  • New boostrap procedure that works in low memory environments
  • (`deprecated_library_name' ..) stanza to properly deprecate 
  old
    library names
  • (`foreign_library' ..) stanza to define C/C++ libraries.
  • C stubs directly in OCaml executables

  Refer to the change log for an exhaustive list.

  We strive for a good out of the box experience that requires no
  configuration, so we’ve also tweaked a few defaults. In 
  particular, `$
  dune build' will now build `@all' instead of `@install', and
  ocamlformat rules are setup by default.

  Lastly, dune 2.0 sheds all the legacy related to jbuilder and 
  will no
  longer build jbuilder projects. This change is necessary to ease
  maintenance and make it easier to add new features down the
  line. There are a few other minor breaking changes. Refer to the
  change log for the full list. We apologize in advance for any
  convenience this might cause.

  [Changelog]


[Changelog] <https://discuss.ocaml.org/t/ann-dune-2-0-0/4758>


Advanced C binding using ocaml-ctypes and dune
══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/advanced-c-binding-using-ocaml-ctypes-and-dune/4805>


toots announced
───────────────

  I worked on a socket.h binding last summer and had a great 
  experience
  integrating ocaml-ctypes with dune, I thought that might be of
  interest to other developers so I wrote about it:
  <https://medium.com/@romain.beauxis/advanced-c-binding-using-ocaml-ctypes-and-dune-cc3f4cbab302>


rgrinberg replied
─────────────────

  This is a good article. I encourage anyone who writes C bindings 
  with
  ctypes to study it carefully.

  A little bit of advice to shorten your dune files:

  ┌────
  │ (deps    (:gen ./gen_constants_c.exe))
  └────

  This line isn’t necessary. Dune is smart enough to know that 
  running a
  binary in a rule incurs a dependency on it.

        dune has a truly amazing [support for cross-compiling],
        which we do not cover here, but, unfortunately, its
        primitives for building and executing binaries do not yet
        cover this use case.

  Indeed, we don’t have any primitives for running binaries on the
  target platform. Perhaps we should add some. However, we do in 
  fact
  have some features in dune to solve this concrete cross 
  compilation
  problem. As far as I understand, the goal is to obtain some 
  compile
  time values such as #define constants and field offsets for the 
  target
  platform. This does not in fact require to run anything on the 
  cross
  compilation target. In configurator, we have a primitive
  `C_define.import' to extract this information. The end result is 
  that
  these configurator scripts are completely compatible with cross
  compilation.

  Perhaps this could be generalized to work with ctypes generators 
  as
  well?

  Funny bit of trivia: The hack in configurator required to do 
  this is
  in fact something I extracted from ctypes itself. The original 
  author
  is [whitequark], who in turn wrote it to make ctypes itself 
  amendable
  to cross compilation.


[support for cross-compiling]
<https://dune.readthedocs.io/en/latest/cross-compilation.html>

[whitequark] <https://github.com/whitequark>


emillon then added
──────────────────

        This does not in fact require to run anything on the cross
        compilation target. In configurator, we have a primitive
        `C_define.import' to extract this information. The end
        result is that these configurator scripts are completely
        compatible with cross compilation.

  If anybody wants to know more about this bit, I wrote an article 
  about
  this last year: 
  <https://dune.build/blog/configurator-constants/>


Upcoming breaking change in Base/Core v0.14
═══════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/upcoming-breaking-change-in-base-core-v0-14/4806>


bcc32 announced
───────────────

  We’re changing functions in Base that used to use the 
  polymorphic
  variant type `[ `Fst of 'a | `Snd of 'b ]' to use `('a, 'b) 
  Either.t'
  instead. As well as enabling the use of all of the functions in 
  the
  Either module, this makes the functions consistent with other
  functions that already use `Either.t', (currently just
  `Set.symmetric_diff')

  The following functions’ types will change:
  • `Result.ok_fst'
  • `List.partition_map'
  • `Map.partition_map', `Map.partition_mapi'
  • `Hashtbl.partition_map', `Hashtbl.partition_mapi'

  The type of List.partition3_map will not change:

  ┌────
  │ val partition3_map
  │   :  'a t
  │   -> f:('a -> [ `Fst of 'b | `Snd of 'c | `Trd of 'd ])
  │   -> 'b t * 'c t * 'd t
  └────

  We don’t have a generic ternary variant, and it doesn’t seem 
  worth it
  to mint one just for this purpose.

  Since this change is pretty straightforward, we expect that a 
  simple
  find/replace will be sufficient to update any affected call 
  sites.


CI/CD Pipelines: Monad, Arrow or Dart?
══════════════════════════════════════

  Archive: 
  <https://roscidus.com/blog/blog/2019/11/14/cicd-pipelines/>


Thomas Leonard announced
────────────────────────

  In this post I describe three approaches to building a language 
  for
  writing CI/CD pipelines. My first attempt used a monad, but this
  prevented static analysis of the pipelines. I then tried using 
  an
  arrow, but found the syntax very difficult to use. Finally, I 
  ended up
  using a light-weight alternative to arrows that I will refer to 
  here
  as a dart (I don’t know if this has a name already). This allows 
  for
  static analysis like an arrow, but has a syntax even simpler 
  than a
  monad.

  <https://roscidus.com/blog/blog/2019/11/14/cicd-pipelines/>


Use of functors to approximate F# statically resolved type 
parameters
═════════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/use-of-functors-to-approximate-f-statically-resolved-type-parameters/4782>


cmxa asked
──────────

  I am learning OCaml coming from F#. In F#, to calculate the 
  average of
  an array whose element type supports addition and division, one 
  can
  write

  ┌────
  │ let inline average (arr: 'a[]) : 'a
  │     when ^a : (static member DivideByInt : ^a * int -> ^a)
  │     and  ^a : (static member (+) : ^a * ^a -> ^a)
  │     and  ^a : (static member Zero : ^a)
  │     =
  │     if Array.length arr = 0 then 
  (LanguagePrimitives.GenericZero) else
  │     LanguagePrimitives.DivideByInt (Array.fold (+) 
  (LanguagePrimitives.GenericZero) arr) (Array.length arr)
  └────

  My understanding is that in OCaml, one would have a module type 
  like
  so:

  ┌────
  │ module type Averagable = sig
  │   type 'a t
  │
  │   val divide_by_int : 'a -> int -> 'a
  │   val plus : 'a -> 'a -> 'a
  │   val zero : 'a
  │ end
  └────

  My question is how the corresponding function would be written:

  ┌────
  │ let average arr =
  │   ???
  └────


smolkaj replied
───────────────

  First, `Averagable' should look like this:

  ┌────
  │ module type Averagable = sig
  │   type t
  │   val divide_by_int : t -> int -> t
  │   val plus : t -> t -> t
  │   val zero : t
  │ end
  └────

  Then average will look something like this:

  ┌────
  │ let average (type t) (module A : Averagable with type t = t) 
  (arr : t array) : t =
  │   Array.fold ~init:A.zero ~f:A.plus arr
  └────

  (The code above uses Jane Street’s Base/Core library.)


ivg then added
──────────────

  While @smolkaj’s answer is a correct and direct implementation 
  of your
  F# code, it might be nicer if your code can interplay with 
  existing
  abstractions in the OCaml infrastructure. For example,

  ┌────
  │ open Base
  │
  │ let average (type a) (module T : Floatable.S with type t = a) 
  xs =
  │   Array.fold ~init:0. ~f:(fun s x -> s +. T.to_float x) xs /.
  │   Float.of_int (Array.length xs)
  └────

  and now it could be used with any existing numeric data in 
  Base/Core

  ┌────
  │ average (module Int) [|1;2;3;4|];;
  │ - : Base.Float.t = 2.5
  └────

  and even adapted to non-numbers,

  ┌────
  │ let average_length = average (module struct
  │     include String
  │     let to_float x = Float.of_int (String.length x)
  │     let of_float _ = assert false
  │   end)
  └────

  The latter example shows that we requested more interface than 
  need, a
  cost that we have to pay for using an existing definition. In 
  cases
  when it matters, you can specify the specific interface, e.g.,

  ┌────
  │ module type Floatable = sig
  │   type t
  │   val to_float : t -> float
  │ end
  │
  │ let average (type a) (module T : Floatable with type t = a) xs 
  =
  │   Array.fold ~init:0. ~f:(fun s x -> s +. T.to_float x) xs /.
  │   Float.of_int (Array.length xs)
  └────

  But we reached the point where using first class modules is 
  totally
  unnecessary. Our interface has only one function, so the 
  following
  definition of average, is much more natural

  ┌────
  │ let average xs ~f =
  │   Array.fold ~init:0. ~f:(fun s x -> s +. f x) xs /.
  │   Float.of_int (Array.length xs)
  └────

  it has type `'a array -> f:('a -> float) -> float' and computes 
  an
  average of `f x_i' for all elements in the array.


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and 
  I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed 
  of the
  archives].

  If you also wish to receive it every week by mail, you may 
  subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] 
<http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-11-26  8:33 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-11-26  8:33 UTC (permalink / raw)
  To: lwn, cwn, caml-list


[-- Attachment #1.1.1: Type: text/plain, Size: 28861 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of November 19 
to 26,
2019.

Table of Contents
─────────────────

tiny_httpd 0.1
printbox.0.3
v0.13 release of Jane Street packages
opam2nix (v1)
GitHub Actions for OCaml / opam now available
OCurrent 0.1 (CI/CD pipeline eDSL)
New pages for OCaml API
Irmin 2.0.0 release
Tail cascade: a new indentation style for some OCaml constructs
Old CWN


tiny_httpd 0.1
══════════════

  Archive: <https://discuss.ocaml.org/t/ann-tiny-httpd-0-1/4727/1>


Simon Cruanes announced
───────────────────────

  Hello and good morning, I'm pleased to announce that 
  [tiny_httpd] 0.1
  has been released and is on opam.

  The goal is to emulate python's standard `http.server' by 
  providing a
  0-dependencies, minimalist, simple HTTP server for embedding in
  applications that are not primarily a website, with very basic 
  routing
  (thanks to `Scanf'). A binary `http_of_dir' is also distributed 
  and
  can be used to serve a directory, with optional upload of files.


[tiny_httpd] <https://github.com/c-cube/tiny_httpd>


printbox.0.3
════════════

  Archive: <https://discuss.ocaml.org/t/ann-printbox-0-3/4731/1>


Simon Cruanes announced
───────────────────────

  <https://aws1.discourse-cdn.com/standard11/uploads/ocaml/original/2X/8/8e7c55c5ab69c12f53a7862d2f84dd6e0cfc0dc0.png>

  ┌────
  │ let b =
  │   let open PrintBox in
  │   PrintBox_unicode.setup();
  │   frame @@ grid_l [
  │     [text "subject"; text_with_style Style.bold "announce: 
  printbox 0.3"];
  │     [text "explanation";
  │     frame @@ text {|PrintBox is a library for rendering nested 
  tables,
  │     trees, and similar structures in monospace text or 
  HTML.|}];
  │     [text "github";
  │     text_with_style Style.(bg_color Blue) 
  "https://github.com/c-cube/printbox/releases/tag/0.3"];
  │     [text "contributors";
  │      vlist_map (text_with_style Style.(fg_color Green)) 
  ["Simon"; "Guillaume"; "Matt"]];
  │     [text "dependencies";
  │     tree empty
  │       [tree (text "mandatory")
  │ 	 [text "dune"; text "bytes"];
  │        tree (text "optional")
  │ 	 [text "uutf"; text "uucp"; text "tyxml"]]];
  │     [text "expected reaction"; text "🎉"];
  │   ]
  │
  │ let () = print_endline @@ PrintBox_text.to_string b
  └────

  ([actual link to the release])


[actual link to the release]
<https://github.com/c-cube/printbox/releases/tag/0.3>


v0.13 release of Jane Street packages
═════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-v0-13-release-of-jane-street-packages/4735/1>


Xavier Clerc announced
──────────────────────

  We are pleased to announce the v0.13 release of Jane Street 
  packages!

  This release comes with 14 new packages, and a number of fixes 
  and
  enhancements. The documentation for this release is available on 
  our
  website:

  <https://ocaml.janestreet.com/ocaml-core/v0.13/doc/>

  The remainder of this mail highlights the main changes since the 
  v0.12
  release; we hope it will be useful to developers in the process 
  of
  migrating to the new version. A comprehensive changelog is 
  available
  at the end.


Notable changes
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Changed `Base', `Core_kernel', and `Core' functions to raise
    `Not_found_s' instead of `Not_found'.  `Hashtbl.find_exn' and
    `Map.find_exn' now include the key in their error message.

  • Changed `Core' and `Core_kernel' to export `int' comparison 
  rather
    than polymorphic comparison.

  • Removed the "robust" float comparison operators (`>.', `=.', 
  …)
    from the default namespace.

  • Replaced `sexp_*' types (`sexp_list', `sexp_option', 
  `sexp_opaque',
    …) with preprocessor attributes (`[@sexp.list]', 
    `[@sexp.option]',
    `[@sexp.opaque]', …).

  • Changed `let%map' syntax from `let%map.Foo.Let_syntax' to
    `let%map.Foo'.

  • Added to `match%optional' support for specifying a path, so 
  you can
    write `match%optional.Foo foo_option' rather than `let open
    Foo.Optional_syntax in match%optional foo_option'.

  • Improved `Base.Backtrace' so that it enables recording of 
  backtraces
    in more situations, specifically when `OCAMLRUNPARAM' is 
    defined but
    doesn't mention the backtrace flag, `b'.

  • Added javascript support for `Zarith', `Bigint', `Bignum', and
    `Bigdecimal'.

  • Changed `Hashtbl.create''s default `size' from 128 to 0.

  • Changed `Core_kernel.Command' so that all commands accept 
  double
    dash flags: `--help', `--version', and `--build-info'.


New packages
╌╌╌╌╌╌╌╌╌╌╌╌

  • async_udp (<https://github.com/janestreet/async_udp>): UDP 
  support
    for Async.

  • async_websocket 
  (<https://github.com/janestreet/async_websocket>): A
    library that implements the websocket protocol on top of 
    Async.

  • bonsai (<https://github.com/janestreet/bonsai>): A library for
    building dynamic webapps, using Js_of_ocaml.

  • postgres_async 
  (<https://github.com/janestreet/postgres_async>):
    OCaml/async implementation of the postgres protocol (i.e., 
    does not
    use C-bindings to libpq).

  • ppx_cold (<https://github.com/janestreet/ppx_cold>): Expands
    `[@cold]' into `[@inline never][@specialise never][@local 
    never]'.

  • ppx_pattern_bind 
  (<https://github.com/janestreet/ppx_pattern_bind>):
    A ppx for writing fast incremental bind nodes in a pattern 
    match.

  • ppx_python (<https://github.com/janestreet/ppx_python>):
    `[@@deriving]' plugin to generate Python conversion functions.

  • ppx_yojson_conv 
  (<https://github.com/janestreet/ppx_yojson_conv>):
    `[@@deriving]' plugin to generate Yojson conversion functions.

  • ppx_yojson_conv_lib
    (<https://github.com/janestreet/ppx_yojson_conv_lib>): Runtime 
    lib
    for `ppx_yojson_conv'.

  • pythonlib (<https://github.com/janestreet/pythonlib>): A 
  library to
    help writing wrappers around OCaml code for python.

  • sexp_select (<https://github.com/janestreet/sexp_select>): A 
  library
    to use CSS-style selectors to traverse sexp trees.

  • timezone (<https://github.com/janestreet/timezone>): Time-zone
    handling.

  • toplevel_backend 
  (<https://github.com/janestreet/toplevel_backend>):
    Shared backend for setting up toplevels.

  • zarith_stubs_js 
  (<https://github.com/janestreet/zarith_stubs_js>):
    Javascript stubs for the Zarith library.


Deprecations / Removals
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  `Async_kernel':

  • Deprecated monadic `ignore' functions in favor of `ignore_m'.

  `Base':

  • Deleted `Array.replace' and `replace_all' functions, which 
  have been
    deprecated since before the last public release.

  • Deprecated `Result.ok_unit'; use `Ok ()'.

  • Removed the `Monad' and `Applicative' interfaces' `all_ignore'
    function; it was previously deprecated and replaced by 
    `all_unit'.

  • Removed `List.dedup', which has been deprecated since 2017-04.

  • Removed `String' mutation functions, which have been 
  deprecated in
    favor of `Bytes' since 2017-10.

  • Deprecated `Array.truncate', `Obj_array.unsafe_truncate', and
    `Uniform_array.unsafe_truncate'.

  • Deprecated `Sys.argv', which has been superseded by 
  `get_argv',
    which is a function, reflecting the fact that `argv' can 
    change (as
    of OCaml 4.09).

  `Core_kernel':

  • Removed `Core_kernel.Std', which had been deprecated for a 
  year.

  • Deprecated type `Command.Spec.param' in favor of 
  `Command.Param.t'.

  • Removed `Hashtbl' functions that had been deprecated for 
  years.

  • Removed `Float.to_string_round_trippable', which has been 
  deprecated
    in favor of `to_string' since 2017-04.

  • Deprecated `Fqueue' functions where one should use `Fdeque' 
  instead:
    `bot', `bot_exn', and `enqueue_top'.

  • Deleted `Bus.unsubscribes', which will be obviated by a 
  performance
    improvement to `Bus.unsubscribe'.

  `Timing_wheel':

  • Removed the `alarm_upper_bound' function, which has been 
  deprecated
    for 6 months, and superseded by `max_allowed_alarm_time'.


Moves
╌╌╌╌╌

  `Core_kernel':

  • Moved `Bounded_int_table' to a standalone library.

  • Moved the `Pool' and `Tuple_type' modules to a standalone 
  library,
    `Tuple_pool'.

  `Async_unix':

  • Moved `Unix.Fd.replace' into a `Private' submodule.


Changelog
╌╌╌╌╌╌╌╌╌

  Please visit
  <https://discuss.ocaml.org/t/ann-v0-13-release-of-jane-street-packages/4735>


opam2nix (v1)
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-opam2nix-v1/4741/1>


Tim Cuthbertson announced
─────────────────────────

  Anouncing opam2nix (v1)

  [opam2nix] generates [nix] expressions from the [opam] OCaml 
  package
  repository. It works similarly to [bundix], [node2nix], etc:

  You run an (impure) command to resolve all transitive dependency
  versions using the current opam repository, generating a .nix 
  file
  that locks down the exact package sources and versions. Then 
  this file
  can be imported to provide `buildInputs' for building your ocaml
  project in nix.

  *What is nix and why would I care?* Well, that's a long story 
  but the
   headline benefits of nix are:

  • reproducible builds (if it builds for me, it builds for you)
  • stateless (you don't set up switches and then install 
  packages, each
    expression specifies everything it needs, and anything you 
    don't
    have is fetched/built on demand)
  • language agnostic (takes care of non-ocaml dependencies)

  It's sadly not a shallow learning curve, but those benefits are 
  hard
  to find elsewhere, so I obviously think it's worthwhile. So if 
  you use
  nix (or would like to), please give it a try and provide
  feedback. I'll (slowly) start working on upstreaming it into 
  nixpkgs.


[opam2nix] <https://github.com/timbertson/opam2nix>

[nix] <https://nixos.org/>

[opam] <https://opam.ocaml.org/>

[bundix] <https://github.com/nix-community/bundix>

[node2nix] <https://github.com/svanderburg/node2nix>


GitHub Actions for OCaml / opam now available
═════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/github-actions-for-ocaml-opam-now-available/4745/1>


Anil Madhavapeddy announced
───────────────────────────

  I was in the [GitHub Actions] beta program and forward ported my 
  code
  to the latest version that just went public.  It's a pretty 
  simple way
  to get your OCaml code tested on Linux, macOS and Windows, 
  without
  requiring an external CI service.  The action attempts to 
  provide a
  homogenous interface across all three operating systems, so 
  invoking
  'opam' from subsequent actions should "just work".

  You can find it here:
  • In the GitHub Marketplace at
    <https://github.com/marketplace/actions/setup-ocaml>
  • Source code on <https://github.com/avsm/setup-ocaml/>
  • Hello World usage on
    <https://github.com/avsm/hello-world-action-ocaml>
  • Usage in ocaml-yaml:
    • 
    <https://github.com/avsm/ocaml-yaml/blob/master/.github/workflows/test.yml>
    • An [example ocaml-yaml run]

  This should be considered fairly experimental as GH Actions is 
  so new.
  If you do use it, then consider [updating this issue with your 
  usage].
  It does not current supporting caching yet, but is pretty fast 
  to
  bootstrap (~4minutes).

  It also doesn't have any higher level purpose other than to set 
  up an
  opam environment, since most of the additional functionality 
  such as
  revdeps testing is planned for addition to the [ocurrent DSL].
  Nevertheless, this GH feature will hopefully be useful for 
  smaller
  projects without a lot of computational requirements.  Let me 
  know how
  it goes!

  Windows is currently supported through @fdopen's excellent fork 
  that
  uses Cygwin.  As Windows support is being mainlined into opam 
  itself
  at the moment, I'm hoping that we will gradually move over to 
  that.
  That should eventually remove the need for two separate
  opam-repositories, so I won't be adding any features that are 
  Linux or
  macOS-specific and do not work on the Cygwin version.


[GitHub Actions] <https://github.com/actions>

[example ocaml-yaml run]
<https://github.com/avsm/ocaml-yaml/runs/314055554>

[updating this issue with your usage]
<https://github.com/avsm/setup-ocaml/issues/4>

[ocurrent DSL]
<https://discuss.ocaml.org/t/ann-ocurrent-0-1-ci-cd-pipeline-edsl/4742/2>


OCurrent 0.1 (CI/CD pipeline eDSL)
══════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocurrent-0-1-ci-cd-pipeline-edsl/4742/1>


Thomas Leonard announced
────────────────────────

  [OCurrent] 0.1 has just been released to opam-repository.

  OCurrent is an OCaml eDSL intended for writing build/test/deploy
  pipelines. It is being used as the engine for [ocaml-ci] and the
  [docker-base-images] builder (used to build the OCaml Docker 
  images,
  such as `ocurrent/opam:alpine-3.10-ocaml-4.08'). Other good uses 
  might
  be building and redeploying a Docker service or a unikernel 
  whenever
  its source repository changes. It can be run locally as a single 
  Unix
  process.

  An OCurrent pipeline is written as an OCaml program, but the 
  OCurrent
  engine ensures that it is kept up-to-date by re-running stages 
  when
  their inputs change. A web UI is available so you can view your
  pipeline and see its current state.

  OCurrent can statically analyse the pipelines before they have 
  run,
  allowing it to run steps in parallel automatically and to 
  display the
  whole pipeline. It does this using a light-weight alternative to
  arrows, which doesn't require programming in an awkward 
  point-free
  style. See [CI/CD Pipelines: Monad, Arrow or Dart?] for more 
  about
  that.

  The basic functionality can be extended using "plugins" (just 
  normal
  OCaml libraries). Plugins are available for interacting with 
  Docker,
  Git, GitHub and Slack. These are in separate packages
  (e.g. `current_github') to avoid having the base package pull in 
  too
  many dependencies).

  There is also an optional Cap'n Proto RPC interface, in the
  `current_rpc' opam package. This is used, for example, by 
  [citty] to
  provide a TTY interface to ocaml-ci.

  [The OCurrent wiki] contains examples, and documentation on the
  various plugins.

  Here's an example pipeline (from the base image builder):

  <https://roscidus.com/blog/images/cicd/docker-base-images-thumb.png>


[OCurrent] <https://github.com/ocurrent/ocurrent>

[ocaml-ci] <https://github.com/ocurrent/ocaml-ci/>

[docker-base-images] 
<https://github.com/ocurrent/docker-base-images>

[CI/CD Pipelines: Monad, Arrow or Dart?]
<https://roscidus.com/blog/blog/2019/11/14/cicd-pipelines/>

[citty] <https://github.com/ocurrent/citty>

[The OCurrent wiki] <https://github.com/ocurrent/ocurrent/wiki>


Anil Madhavapeddy then added
────────────────────────────

  For those curious about the relation to the existing CI used in
  opam-repository, then it is no coincidence that @talex5 is the 
  author
  of both :-)

  This DSL is the next iteration of the [datakit-ci], but 
  specialised to
  be faster and simpler for extending with OCaml and more complex
  workflows that our OCaml Platform tools need these days (like
  ocamlformat linting, or dune expect promotion, or odoc
  cross-referenced doc generation).  We are planning a smooth 
  migration
  next year over to the new system, but wanted to release this 
  early to
  show you some of the pieces going into this new iteration.  I am
  particularly excited about the new tty-based interface that 
  saves an
  awful lot of clicking around on web UIs for CI results…


[datakit-ci] <https://github.com/moby/datakit>


New pages for OCaml API
═══════════════════════

  Archive: 
  <https://discuss.ocaml.org/t/new-pages-for-ocaml-api/4720/13>


Continuing this thread, sanette announced
─────────────────────────────────────────

  I have uploaded a new version (same link
  <https://sanette.github.io/ocaml-api/>)
  • background color for links in the TOC @Maelan
  • more indentation for value descriptions @Maelan, @grayswandyr
  • word wrapping long `<pre>' codes @grayswandyr
  • type table: remove `(*' and `*)', give more space to code wrt
    comments, diminish comment's color @grayswandyr

  searching is not ready yet… please wait suggestions for dark 
  theme
  welcome


sanette later added
───────────────────

  I have just uploaded a new version with a basic search engine.
  • for each page, you can search values/modules
  • in the general index page, the search includes also the 
  descriptions
  • search results are ranked by relevance

  the downside is that each page now comes with an index of about 
  570Kb
  in the form of an index.js file. I'm kind of hoping that the 
  browser
  will cache this, but I'm not sure. It would be maybe better to 
  only
  load the index file on demand.


Irmin 2.0.0 release
═══════════════════

  Archive: 
  <https://discuss.ocaml.org/t/ann-irmin-2-0-0-release/4746/1>


Thomas Gazagnaire announced
───────────────────────────

  On behalf of the Irmin development team, I am very happy to 
  announce
  the release of Irmin 2.0.0, a major release of the Git-like
  distributed branching and storage substrate that underpins
  [MirageOS]. We began the release process for all the components 
  that
  make up Irmin [back in May 2019], and there have been close to 
  1000
  commits since Irmin 1.4.0 released back in June 2018. To 
  celebrate
  this milestone, we have a new logo and opened a dedicated 
  website:
  [irmin.org].

  More details here: 
  <https://tarides.com/blog/2019-11-21-irmin-v2>


[MirageOS] <https://mirage.io/>

[back in May 2019]
<https://tarides.com/blog/2019-05-13-on-the-road-to-irmin-v2>

[irmin.org] <https://irmin.org/>


Tail cascade: a new indentation style for some OCaml constructs
═══════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/tail-cascade-a-new-indentation-style-for-some-ocaml-constructs/4736/1>


gasche announced
────────────────

  I recently decided to change my indentation style for certain 
  OCaml
  constructs in a way that I'm going to describe below. I just 
  coined a
  name for this approach, "tail cascade". I'm creating this topic 
  to
  convince everyone that this is a cool idea you should adopt as
  well. Or at least tolerate it when you review other people's 
  code.


Problem
╌╌╌╌╌╌╌

  Programs that heavily use `match' often see a shift to the right 
  due
  to nested indentation.

  ┌────
  │ match foo with
  │ | Foo -> ...
  │ | Bar x ->
  │   match bar x with
  │   | FooBar -> ...
  │   | Blah y ->
  │     match f y with
  │     | Some z ->
  │       ...
  └────

  Another problem with this style is that it suffers from the 
  "dangling
  bar" issue: if you try to add a new case for one of the exterior
  `match', it is parsed as belonging to the innermost `match'. 
  People
  have been recommending (rightly) to use `begin match .. end' for 
  all
  nested match constructs to avoid this issue.

  ┌────
  │ match foo with
  │ | Foo -> ...
  │ | Bar x ->
  │   begin match bar x with
  │   | FooBar -> ...
  │   | Blah y ->
  │     begin match f y with
  │     | None -> ...
  │     | Some z ->
  │       ...
  │     end
  │   (* now this is safe *)
  │   | FooBlah -> ...
  │   end
  └────

  But still the unpleasant shift to the right remains.


Proposal: cascading tail case
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  We should in general use `begin match .. end' for nested 
  matches. But
  the "cascading tail case" proposal is to *not* do it for the 
  *last*
  case of the pattern-matching, and instead *de-indent* (dedent) 
  this
  last case – tail case.

  ┌────
  │ match foo with
  │ | Foo -> ...
  │ | Bar x ->
  │ match bar x with
  │ | FooBar -> ...
  │ | Blah y ->
  │ match f y with
  │ | None -> ...
  │ | Some z ->
  │ ...
  └────

  Note that with this indentation style, the "dangling match" 
  problem is
  also avoided: unlike with the original, non `end'-protected 
  program,
  the indentation makes it immediately obvious that any further 
  case
  will be attached to the innermost match, and not any of the 
  exterior
  ones.

  A program using this "cascading tail" approach should always use
  `begin match .. end' for nested matches, except for a nested 
  match
  returned within the last branch of an outer match, which can
  (optionally) be dedented instead.

  The choice to dedent the last case corresponds to encouraging a
  sequential reading of the program, where the other cases are
  "auxiliary cases" checked first and dispatched quickly, and the 
  last
  case is the "main part" where the "rest" of the logic of the 
  program
  lies. This pattern is typical of nested pattern-matching on the
  `option' or `result' type for example:

  ┌────
  │ match foo x with
  │ | Error err ->
  │   fail_foo_error err
  │ | Ok y ->
  │ match bar y with
  │ | Error err ->
  │   fail_bar_error err
  │ | Ok () ->
  │ ...
  └────

  Remark: it is *not* always the case that the `Error' constructor 
  is
  the auxiliary case, and the `Ok' constructor is the main case;
  sometimes we implement fallback logic like "if `foo' work then 
  we are
  good, but otherwise we have to do this and that", and the error 
  case
  is the most salient (and longer) part of the program logic. I 
  would
  recommend being mindful, when you write code, of whether there 
  is a
  most convincing way to "sequentialize" it (distinguish auxiliary 
  and
  main/tail case), and avoid using cascading tails when there is 
  no
  clear sequentialization choice.

  Remark: some cases of tail cascades can be linearized by using a 
  good
  definition of "bind" and a monadic style. This tends to be very
  limited however: it fixes one of the constructors to always be 
  the
  "tail" constructor (always `Some', always `Ok'), and it only 
  works
  when the handling of the other constructors is very homogeneous
  (typically: return directly). In real code, many situations 
  occur
  where the monadic style doesn't fit the problem, but tail 
  cascade does
  help writing a readable program.


Generalization: tail cascade
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  While I have never seen cascading tail cases in real-world OCaml 
  code
  before (I'm happy to be given pointers; I think that the idea is 
  not
  new, but I'm not aware of previous attempts to give it a catchy 
  name
  and spread the cascade love), this is in fact a new (to me) 
  instance
  of a common technique that is used for other OCaml constructs:

  ┌────
  │ if foo x then ...
  │ else if bar x then ...
  │ else ... (* this `tail else` was dedented *)
  │
  │ let x = foo in
  │ let y = bar in (* this `tail let` was dedented *)
  │ ...            (* and the rest as well *)
  │
  │ bind foo @@ fun x ->
  │ bind bar @@ fun y -> (* this "tail function body" was dedented 
  *)
  │ ...                  (* and the rest as well *)
  └────

  I would call "tail cascade" (or maybe: "cascading tail") the 
  idea of
  dedenting the "rest" of an OCaml expression (compared to a 
  strict
  tree-nesting-based approach) when it morally describes the 
  "rest" of
  the expression. I use the name "tail" because those expressions 
  are
  almost always in tail-position in the sense of tail-calls.

  This general approach legitimizes some styles that I have seen, 
  and
  sometimes used, in the wild, while at the same time considering 
  that I
  may have been doing something improper, for example:

  ┌────
  │ if foo then blah else
  │ ... (* dedented *)
  │
  │
  │ Fun.protect
  │   ~finally:(...)
  │ @@ fun () ->
  │ ... (* dedented *)
  │
  │
  │ try simple_approach with exn ->
  │ ... (* dedented *)
  │
  │
  │ 1 +
  │ 2 + (* dedented *)
  │ ... (* dedented *)
  └────

  Remark: after a `then' or `else', many people share the 
  reasonable
  view that any expression containing imperative constructs (`foo; 
  bar')
  should be enclosed in a `begin .. end' block to avoid
  surprising-precedence issue. Just as for nested `match', this
  recommendation should be lifted for "tail else" constructs.

  Remark: The last example is a case where the dedented 
  expressions are
  *not* in tail-position from a runtime-evaluation point of view. 
  I am
  not sure as whether the two notions should be made to coincide 
  more
  strongly, but in any case I'm not fond of the style in this 
  particular
  example, I prefer to move the infix operator to the beginning of 
  the
  next line instead, following a different style and 
  justification.

  The possibility this "cascading tail" style today crucially 
  relies on
  the nesting properties of open-ended syntactic constructs, 
  notably
  `let' (commonly cascaded), and now `match' and `if
  ... else'. Proposals to transition to a syntax where `match' and
  `else' are forced to take a closing marker are incompatible with 
  the
  cascading style. I have not made my mind on whether this should 
  be
  considered a blocker for those proposals, but at least it shows 
  that
  having the open-ended form available has value for certain 
  programs.


Louis Gesbert then said
───────────────────────

  @gasche I prototyped a dedicated option in `ocp-indent', if 
  you're
  interested in trying it out :)
  ┌────
  │ opam pin 
  git+https://github.com/OCamlPro/ocp-indent#match-tail-cascade
  │ echo "match_tail_cascade=true" >> ~/.ocp-indent
  └────


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and 
  I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed 
  of the
  archives].

  If you also wish to receive it every week by mail, you may 
  subscribe
  [online].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <http://alan.petitepomme.net/cwn/>

[RSS feed of the archives] 
<http://alan.petitepomme.net/cwn/cwn.rss>

[online] <http://lists.idyll.org/listinfo/caml-news-weekly/>

[Alan Schmitt] <http://alan.petitepomme.net/>


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^ permalink raw reply	[flat|nested] 112+ messages in thread
* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-11-12 13:21 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-11-12 13:21 UTC (permalink / raw)
  To: lwn, cwn, caml-list


[-- Attachment #1.1.1: Type: text/plain, Size: 2875 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of November 05 
to 12,
2019.

Table of Contents
─────────────────

Mirage 3.7.1 released
Old CWN


Mirage 3.7.1 released
═════════════════════

  Archive: 
  <https://discuss.ocaml.org/t/mirage-3-7-1-released/4634/1>


Hannes Mehnert announced
────────────────────────

  MirageOS 3.7.1 is released to opam repository now.

  Breaking change:
  • The hooks previously defined in
    OS.Main.at_enter/at_enter_iter/at_exit/at_exit_iter are now 
    part of
    Mirage_runtime (only used by mirage-entropy)
    <https://github.com/mirage/mirage/pull/1010>

  Behaviour changes of MirageOS unikernels:
  • A unikernel now always calls the Mirage_runtime.at_exit 
  registered
    hooks – once a unikernel succesfully executed its `start' in
    `Lwt_main.run', `exit 0' is called to ensure this behaviour
    <https://github.com/mirage/mirage/pull/1011>
  • Top-level exceptions are no longer caught (there used to be in
    mirage-unix/mirage-xen/mirage-solo5 custom handlers). The 
    OCaml
    runtime prints the exception and backtrace on stdout and calls 
    exit
    2 (from 4.10.0, abort() will be called).

  Deprecations (being removed from Mirage 4.0)
  • All Mirage_YYY_lwt are deprecated, Mirage_YYY interfaces are 
  no
    longer astracted over 'a io and buffer. This reduces the 
    amount of
    opam packages - mirage-yyy-lwt are no longer part of the 
    release
    (each mirage-yyy package provides a Mirage_yyy_lwt module for
    backwards compatibility). Motivation was discussed in
    <https://github.com/mirage/mirage/issues/1004>
  • mirage-types and mirage-types-lwt are deprecated, please use 
  the
    Mirage_YYY signatures directly instead.

  Other observable changes
  • `mirage configure' now deletes all exising opam files

  Most reverse dependencies are already released to opam, have a 
  look at
  <https://github.com/mirage/mirage/issues/1012> for progress (and 
  the
  temporary <https://github.com/mirage/mirage-dev.git#easy> opam
  overlay).


Old CWN
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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-11-05  6:55 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-11-05  6:55 UTC (permalink / raw)
  To: lwn, cwn, caml-list


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Here is the latest OCaml Weekly News, for the week of October 29 
to
November 05, 2019.

Table of Contents
─────────────────

vim-ocaml - new home
Old CWN


vim-ocaml - new home
════════════════════

  Archive: 
  <https://discuss.ocaml.org/t/ann-vim-ocaml-new-home/4615/1>


Rudi Grinberg announced
───────────────────────

  Dear Vim & Neovim users,

  I would like to announce that I've officially moved the 
  [vim-ocaml]
  repository under the control of the OCaml organization on
  github. Please direct your bug reports and pull requests to this
  repository. This move is done not because vim-ocaml is being
  neglected, on the contrary, there's an active team of 
  maintainers that
  recently expanded. I simply want to take this opportunity to 
  draw more
  Vim & Noevim users to this project, as I suspect many users 
  aren't
  aware of recent efforts.


[vim-ocaml] <https://github.com/ocaml/vim-ocaml>


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@ 2019-10-15  7:28 Alan Schmitt
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From: Alan Schmitt @ 2019-10-15  7:28 UTC (permalink / raw)
  To: lwn, cwn, caml-list


[-- Attachment #1.1.1: Type: text/plain, Size: 5627 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of October 08 
to 15,
2019.

Table of Contents
─────────────────

capnp-rpc 0.4.0
Ocaml-protoc.plugin.1.0.0
Old CWN


capnp-rpc 0.4.0
═══════════════

  Archive: 
  <https://discuss.ocaml.org/t/ann-capnp-rpc-0-4-0/4524/1>


Thomas Leonard announced
────────────────────────

  I'm pleased to announce the release of [capnp-rpc 0.4.0], an 
  OCaml
  implementation of the Cap'n Proto RPC specification.

  If you haven't used the library before, please see the 
  [documentation
  and tutorial]. Cap'n Proto RPC aims to provide secure, 
  efficient,
  typed communications between multiple parties.

  This library is now being used to build [ocaml-ci], where it is 
  used
  for all communication between the web frontend and backend 
  services,
  and to provide a command-line client.


[capnp-rpc 0.4.0]
<https://github.com/mirage/capnp-rpc/releases/tag/v0.4.0>

[documentation and tutorial]
<https://github.com/mirage/capnp-rpc/blob/master/README.md>

[ocaml-ci] <https://github.com/ocaml-ci/ocaml-ci>

Main changes since v0.3
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  Breaking changes:

  • Wrap errors with the ``Capnp' tag to make it easier to compose 
  with
    other types of error.

  • Prefix all command-line options with `capnp-'.
    e.g. `--listen-address' is now `--capnp-listen-address'.  The 
    old
    names were confusing for applications that supported other 
    protocols
    too (e.g. a web server).

  New features:

  • Add `Capability.with_ref' convenience function.  This 
  automatically
    calls `dec_ref' when done.

  • Add Unix `Cap_file' module to load and save `Sturdy_refs'.  In
    particular, this ensures that saved cap files get a mode of 
    `0o600',
    since they contain secrets.

  • Export cmdliner network address parsing.  This is useful if 
  you
    don't want to use the default option parsing.  For example, if 
    you
    want to make Cap'n Proto an optional feature of your program.

  • Upgrade from `uint' (which is deprecated) to the newer 
  `stdint'.
    The latest version of `uint' is just a wrapper around 
    `stdint', so
    this shouldn't break anything if you are using the latest 
    version.

  • Put cmdliner options in their own man-page section.  Use
    `Capnp_rpc_unix.manpage_capnp_options' to control where in 
    your
    man-page they appear.

  • Enable `SO_KEEPALIVE' for TCP connections.  For use with 
  Docker's
    libnetwork, try something like this in your `stack.yml':
    ┌────
    │ sysctls:
    │   - 'net.ipv4.tcp_keepalive_time=60'
    └────


Ocaml-protoc.plugin.1.0.0
═════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-ocaml-protoc-plugin-1-0-0/4535/1>


Anders Fugmann announced
────────────────────────

  I'm happy to announce the second release of 
  [ocaml-protoc-plugin].

  Ocaml-protoc-plugin is a plugin to googles `protoc' compiler 
  which
  generates type idiomatic to ocaml from `.proto' files including 
  full
  compliant serialization and deserialization functions.


[ocaml-protoc-plugin] 
<https://github.com/issuu/ocaml-protoc-plugin>

Most noteworthy changes in this release:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Full proto2 support.
  • The list of dependencies has been slimmed way down, and now 
  only
    depends on `conf-protoc' (the `protoc' compiler and googles 
    *well
    known types*).
  • Buckescript support.
  • Added options to change the ocaml (type for scalar types (int, 
  int64
    or int32).

  Many thanks to Wojtek Czekalski for helping trimming 
  dependencies and
  for Buclescript support.


Full changelog:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Support enum aliasing
  • Avoid name clash with on 'name'
  • Fix code generation when argument contains a path
  • Refactor internal types to make serialization and 
  deserialization
    type spec symmetrical.
  • Optimize deserialization for messages with max_id < 1024
  • Don't depend on Base in runtime
  • Slim runtime dependencies: Remove need for base, ocplib-endian 
  and
    ppx_let
  • Honor [packed=…] flag.
  • Make fixed scalar types default to int32 and int64
  • Support proto2 specification
  • Add options to switch between int64|int32 and int
  • Fix name clash problem with special enum names
  • Refactor serialization and deserialization to simplify emitted 
  code
  • Eagerly evaluate serialization (for speed).


Old CWN
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  [Alan Schmitt]


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* [Caml-list] Attn: Development Editor, Latest OCaml Weekly News
@ 2019-09-03  7:35 Alan Schmitt
  0 siblings, 0 replies; 112+ messages in thread
From: Alan Schmitt @ 2019-09-03  7:35 UTC (permalink / raw)
  To: lwn, cwn, caml-list


[-- Attachment #1.1.1: Type: text/plain, Size: 1966 bytes --]

Hello

Here is the latest OCaml Weekly News, for the week of August 27 to
September 03, 2019.

Table of Contents
─────────────────

Ocaml-multicore: report on a June 2018 development meeting in 
Paris
Interesting OCaml Articles
Old CWN


Ocaml-multicore: report on a June 2018 development meeting in 
Paris
═══════════════════════════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ocaml-multicore-report-on-a-june-2018-development-meeting-in-paris/2202/10>


Deep in this thread, sid announced
──────────────────────────────────

  As a small step towards multicore, its interesting to note that
  <https://github.com/ocaml/ocaml/pull/8713> just got merged to 
  master!


Interesting OCaml Articles
══════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/interesting-ocaml-articles/1867/46>


Yotam Barnoy announced
──────────────────────

  <https://www.ocamlpro.com/2019/08/30/ocamlpros-compiler-team-work-update/>


Old CWN
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  [Alan Schmitt]


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