[Caml-list] OCaml release 4.02.0+beta1

[Damien Doligez <damien.doligez@inria.fr>]

Dear OCaml users,

The release of OCaml version 4.02.0 will take place around the beginning of July. We have created a beta version to get your feedback. Please download the sources, compile, install, and test your favourite software with it. Then let us know what doesn't work by posting bugs to the BTS.

This is a major release with several big changes, so it is particurarly important for us to get feedback from you.

Happy hacking,

-- Damien Doligez for the OCaml team.



sources and documentation of 4.02.0+beta1:
  http://caml.inria.fr/pub/distrib/ocaml-4.02/

Bug-tracking system (BTS):
  http://caml.inria.fr/mantis/my_view_page.php



OCaml 4.02.0+beta1:
-------------------

(Changes that can break existing programs are marked with a "*")

Language features:
- Attributes and extension nodes
- Generative functors
- Module aliases
* Alternative syntax for string literals {id|...|id} (can break comments)
- Separation between read-only strings (type string) and read-write byte
  sequences (type bytes). Activated by command-line option -safe-string.
- Exception cases in pattern matching (patch by Jeremy Yallop).
- Extensible open datatypes (patch by Leo White).

Build system for the OCaml distribution:
- Use -bin-annot when building.
- Use GNU make instead of portable makefiles.

Shedding weight:
* Removed Camlp4 from the distribution, now available as third-party software.
* Removed Labltk from the distribution, now available as a third-party library.

Type system:
* Keep typing of pattern cases independent in principal mode
  (i.e. information from previous cases is no longer used when typing
  patterns; cf. 'PR#6235' in testsuite/test/typing-warnings/records.ml)
- Allow opening a first-class module or applying a generative functor
  in the body of a generative functor. Allow it also in the body of
  an applicative functor if no types are created
* Module aliases are now typed in a specific way, which remembers their
  identity. In particular this changes the signature inferred by
  "module type of"
- PR#6331: Slight change in the criterion to distinguish private
  abbreviations and private row types: create a private abbreviation for
  closed objects and fixed polymorphic variants.
* PR#6333: Compare first class module types structurally rather than
  nominally. Value subtyping allows module subtyping as long as the internal
  representation is unchanged.

Compilers:
- More aggressive constant propagation, including float and
  int32/int64/nativeint arithmetic.  Constant propagation for floats
  can be turned off with option -no-float-const-prop, for codes that
  change FP rounding modes at run-time.
- New back-end optimization pass: common subexpression elimination (CSE).
  (Reuses results of previous computations instead of recomputing them.)
- New back-end optimization pass: dead code elimination.
  (Removes arithmetic and load instructions whose results are unused.)
- PR#6269 Optimization of string matching (patch by Benoit Vaugon
  and Luc Maranget)
- Experimental native code generator for AArch64 (ARM 64 bits)
- Optimization of integer division and modulus by constant divisors
  (feature wish PR#6042)
- Add "-open" command line flag for opening a single module before typing
* "-o" now sets module name to the output file name up to the first "."
  (it also applies when "-o" is not given, i.e. the module name is then
   the input file name up to the first ".")
* PR#5779: better sharing of structured constants
- PR#6182: better message for virtual objects and class types
  (Leo P. White, Stephen Dolan)
- PR#5817: new flag to keep locations in cmi files
- PR#5854: issue warning 3 when referring to a value marked with
  the [@@deprecated] attribute
* PR#6203: Constant exception constructor no longer allocate
- PR#6311: Improve signature mismatch error messages
- PR#6345: Better compilation of optional arguments with default values
- PR#6260: Unnecessary boxing in let (patch by vbrankov)
- PR#6017: a new format implementation based on GADTs
  (initial patch by Benoît Vaugon, review by Gabriel Scherer)

Toplevel interactive system:
- PR#5377: New "#show_*" directives

Runtime system:
- New configure option "-no-naked-pointers" to improve performance by
  avoiding page table tests during block darkening and the marking phase
  of the major GC.  In this mode, all out-of-heap pointers must point at
  things that look like OCaml values: in particular they must have a valid
  header.  The colour of said headers should be black.
- Fixed bug in native code version of [caml_raise_with_string] that could
  potentially lead to heap corruption.
- Blocks initialized by [CAMLlocal*] and [caml_alloc] are now filled with
  [Val_unit] rather than zero.
- Fixed a major performance problem on large heaps (~1GB) by making heap
  increments proportional to heap size by default
- PR#4765: Structural equality should treat exception specifically
- PR#5009: Extending exception tag blocks
- PR#6075: avoid using unsafe C library functions (strcpy, strcat, sprintf)
- An ISO C99-compliant C compiler and standard library is now assumed.
  (Plus special exceptions for MSVC.)  In particular, emulation code for
  64-bit integer arithmetic was removed, the C compiler must support a
  64-bit integer type.

Standard library:
* Add new modules: Bytes and BytesLabels.
- PR#4986: add List.sort_uniq and Set.of_list
- PR#5935: a faster version of "raise" which does not maintain the backtrace
- PR#6146: support "Unix.kill pid Sys.sigkill" under Windows
- PR#6148: speed improvement for Buffer (patch by John Whitington)
- PR#6180: efficient creation of uninitialized float arrays

OCamldoc:
- PR#6257: handle full doc comments for variant constructors and
           record fields
- PR#6310: fix ocamldoc's subscript/superscript CSS font size
           (patch by Anil Madhavapeddy)
- PR#6273: fix Sys.file_exists on large files (Win32)
           (patch by Christoph Bauer)

Bug fixes:
- PR#4719: Sys.executable_name wrong if executable name contains dots (Windows)
- PR#4855: 'camlp4 -I +dir' accepted, dir is relative to 'camlp4 -where'
- PR#5201: ocamlbuild: add --norc to the bash invocation to help performances
- PR#5598: follow-up fix related to PR#6165
- PR#5820: Fix camlp4 lexer roll back problem
- PR#6062: Fix a regression bug caused by commit 13047
- PR#6109: Typos in ocamlbuild error messages
- PR#6116: more efficient implementation of Digest.to_hex (patch by ygrek)
- PR#6165: Alterations to handling of \013 in source files breaking other tools
- PR#6173: Typing error message is worse that before
- PR#6174: OCaml compiler loops on an example using GADTs (-rectypes case)
- PR#6175: Fix open!
- PR#6183: enhanced documentation for 'Unix.shutdown_connection'
- PR#6184: ocamlbuild: `ocamlfind ocamldep` does not support -predicate
           (report and patch by Jacques-Pascal Deplaix)
- PR#6194: Incorrect unused warning with first-class modules in patterns
- PR#6216: inlining of GADT matches generates invalid assembly
- PR#6233: out-of-bounds exceptions lose their locations on ARM, PowerPC
- PR#6235: Issue with type information flowing through a variant pattern
- PR#6239: sometimes wrong stack alignment when raising exceptions
           in -g mode with backtraces active
- PR#6240: Fail to expand module type abbreviation during substyping
- PR#6241: Assumed inequality between paths involving functor arguments
- PR#6243: Make "ocamlopt -g" more resistant to ill-formed locations
- PR#6262: equality of first-class modules take module aliases into account
- PR#6267: more information printed by "bt" command of ocamldebug
- PR#6275: Soundness bug related to type constraints
- PR#6293: Assert_failure with invalid package type
- PR#6302: bytecode debug information re-read from filesystem every time
  (Jacques-Henri Jourdan)
- PR#6307: Behavior of 'module type of' w.r.t. module aliases
- PR#6332: Unix.open_process fails to pass empty arguments under Windows
- PR#6346: Build failure with latest version of xcode on OSX
- PR#6348: Unification failure for GADT when original definition is hidden
- PR#6352: Automatic removal of optional arguments and sequencing
- PR#6361: Hashtbl.hash not terminating on some lazy values w/ recursive types
- PR#6383: Exception Not_found when using object type in absent module
- PR#6384: Uncaught Not_found exception with a hidden .cmi file
- PR#6385: wrong allocation of large closures by the bytecode interpreter
- PR#6394: Assertion failed in Typecore.expand_path
- PR#6405: unsound interaction of -rectypes and GADTs
- PR#6408: Optional arguments given as ~?arg instead of ?arg in message
- fix -dsource printing of "external _pipe = ..."
  (Gabriel Scherer)
- bound-checking bug in caml_string_{get,set}{16,32,64}
  (Pierre Chambart and Gabriel Scherer, report by Nicolas Trangez)
- sometimes wrong stack alignment at out-of-bounds array access
  (Gabriel Scherer, review by Xavier Leroy, report by Pierre Chambart)

Features wishes:
- PR#4243: make the Makefiles parallelizable
- PR#4323: have "of_string" in Num and Big_int work with binary and
           hex representations (patch by Zoe Paraskevopoulou)
- PR#5547: Enable the "-use-ocamlfind" option by default
- PR#5650: Camlp4FoldGenerator doesn't handle well "abstract" types
- PR#5808: allow simple patterns, not just identifiers, in "let p : t = ..."
- PR#6000: add a warning for non-principal coercions to format
- PR#6054: add support for M.[ foo ], M.[| foo |] etc.
           (patch by Kaustuv Chaudhuri)
- PR#6064: GADT representation for Bigarray.kind + CAML_BA_CHAR runtime kind
- PR#6071: Add a -noinit option to the toplevel (patch by David Sheets)
- PR#6166: document -ocamldoc option of ocamlbuild
- PR#6187: ocamlbuild: warn when using -plugin-tag(s) without myocamlbuild.ml
  (patch by Jacques-Pascal Deplaix)
- PR#6246: allow wilcard _ as for-loop index
- PR#6270: remove need for -I directives to ocamldebug in common case
  (patch by Josh Watzman, review by Xavier Clerc and Alain Frisch)
- PR#6358: obey DESTDIR in install targets
  (Gabriel Scherer)
- PR#5899: a programmer-friendly access to backtrace information
  (Jacques-Henri Jourdan and Gabriel Scherer)
- ocamllex: user-definable refill action
  (patch by Frédéric Bour, review by Gabriel Scherer and Luc Maranget)
- shorten syntax for functor signatures: "functor (M1:S1) (M2:S2) .. -> .."
  (patches by Thomas Gazagnaire and Jeremy Yallop, review by Gabriel Scherer)