[Caml-list] Batteries Included syntax extensions?

[Caml-list] Batteries Included syntax extensions?

[Yotam Barnoy]

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I have a question about Batteries Included. Specifically, how do I get the
syntax extensions working and which syntax extensions are available? The
various bits of documentation I've found seemed either contradictory or did
not mention any syntax extensions at all. I'm specifically interested in
things like automatic rope generation and list comprehensions.

I have the latest version installed from opam.

Thanks
Yotam

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Re: [Caml-list] Batteries Included syntax extensions?

[Simon Cruanes]

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Le Fri, 07 Mar 2014, Yotam Barnoy a écrit :

> I have a question about Batteries Included. Specifically, how do I get the
> syntax extensions working and which syntax extensions are available? The
> various bits of documentation I've found seemed either contradictory or did
> not mention any syntax extensions at all. I'm specifically interested in
> things like automatic rope generation and list comprehensions.

Hi!

The current version of Batteries is 2.2.0 and its documentation is here:
http://ocaml-batteries-team.github.io/batteries-included/hdoc2/ . As far
as I know, there are no more syntax extensions in Batteries since 2.0.0
(which explains why it doesn't depend on camlp4). I don't know much
about the "rope generation" you talk about, but list comprehensions are
nicely replaced (imho) by the |> operator:

List.range 1 `To 10
    |> List.filter (< 5)
    |> List.map string_of_int

You can ask more questions on the Batteries mailing list
( https://lists.forge.ocamlcore.org/cgi-bin/listinfo/batteries-devel ).
Hope you will find it helpful!

Cheers,

-- 
Simon

http://weusepgp.info/
key 49AA62B6
fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6

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Re: [Caml-list] Batteries Included syntax extensions?

[Arnaud Spiwack]

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List comprehension in a few (non-syntax checked) lines. TL;DR: list
comprehension = monadic combinators.

let return a = [a]
let (>>=) x f = List.(flatten (map f x))
let (>>) x y = x >>= fun () -> y
let guard b = if b then [()] else []

With these combinators

[ f (x,y) | x <- l ; y <-r ; x=y+1 ]

then translates to

l >>= fun x ->
r >>= fun y ->
guard (x=y+1) >>
return (f x)

Less compact, no doubt, but still reasonably practical.


On 7 March 2014 23:12, Simon Cruanes <simon.cruanes.2007@m4x.org> wrote:

> Le Fri, 07 Mar 2014, Yotam Barnoy a écrit :
>
> > I have a question about Batteries Included. Specifically, how do I get
> the
> > syntax extensions working and which syntax extensions are available? The
> > various bits of documentation I've found seemed either contradictory or
> did
> > not mention any syntax extensions at all. I'm specifically interested in
> > things like automatic rope generation and list comprehensions.
>
> Hi!
>
> The current version of Batteries is 2.2.0 and its documentation is here:
> http://ocaml-batteries-team.github.io/batteries-included/hdoc2/ . As far
> as I know, there are no more syntax extensions in Batteries since 2.0.0
> (which explains why it doesn't depend on camlp4). I don't know much
> about the "rope generation" you talk about, but list comprehensions are
> nicely replaced (imho) by the |> operator:
>
> List.range 1 `To 10
>     |> List.filter (< 5)
>     |> List.map string_of_int
>
> You can ask more questions on the Batteries mailing list
> ( https://lists.forge.ocamlcore.org/cgi-bin/listinfo/batteries-devel ).
> Hope you will find it helpful!
>
> Cheers,
>
> --
> Simon
>
> http://weusepgp.info/
> key 49AA62B6
> fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6
>

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Re: [Caml-list] Batteries Included syntax extensions?

[Ivan Gotovchits]

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By the way, list comprehension is already included in standard ocaml distribution. It is not as mighty as batteries one, and slightly differs in syntax:

[ x / 2 | x <- [ 2;4;6] ]

> On 10 марта 2014 г., at 13:17, Arnaud Spiwack <aspiwack@lix.polytechnique.fr> wrote:
> 
> List comprehension in a few (non-syntax checked) lines. TL;DR: list comprehension = monadic combinators.
> 
> let return a = [a]
> let (>>=) x f = List.(flatten (map f x))
> let (>>) x y = x >>= fun () -> y
> let guard b = if b then [()] else []
> 
> With these combinators
> 
> [ f (x,y) | x <- l ; y <-r ; x=y+1 ]
> 
> then translates to
> 
> l >>= fun x ->
> r >>= fun y ->
> guard (x=y+1) >>
> return (f x)
> 
> Less compact, no doubt, but still reasonably practical.
> 
> 
>> On 7 March 2014 23:12, Simon Cruanes <simon.cruanes.2007@m4x.org> wrote:
>> Le Fri, 07 Mar 2014, Yotam Barnoy a écrit :
>> 
>> > I have a question about Batteries Included. Specifically, how do I get the
>> > syntax extensions working and which syntax extensions are available? The
>> > various bits of documentation I've found seemed either contradictory or did
>> > not mention any syntax extensions at all. I'm specifically interested in
>> > things like automatic rope generation and list comprehensions.
>> 
>> Hi!
>> 
>> The current version of Batteries is 2.2.0 and its documentation is here:
>> http://ocaml-batteries-team.github.io/batteries-included/hdoc2/ . As far
>> as I know, there are no more syntax extensions in Batteries since 2.0.0
>> (which explains why it doesn't depend on camlp4). I don't know much
>> about the "rope generation" you talk about, but list comprehensions are
>> nicely replaced (imho) by the |> operator:
>> 
>> List.range 1 `To 10
>>     |> List.filter (< 5)
>>     |> List.map string_of_int
>> 
>> You can ask more questions on the Batteries mailing list
>> ( https://lists.forge.ocamlcore.org/cgi-bin/listinfo/batteries-devel ).
>> Hope you will find it helpful!
>> 
>> Cheers,
>> 
>> --
>> Simon
>> 
>> http://weusepgp.info/
>> key 49AA62B6
>> fingerprint 949F EB87 8F06 59C6 D7D3  7D8D 4AC0 1D08 49AA 62B6
> 

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Re: [Caml-list] Batteries Included syntax extensions?

[ygrek]

On Mon, 10 Mar 2014 14:12:07 +0400
Ivan Gotovchits <ivg@ieee.org> wrote:

> By the way, list comprehension is already included in standard ocaml distribution. It is not as mighty as batteries one, and slightly differs in syntax:
> 
> [ x / 2 | x <- [ 2;4;6] ]

Wut?
Can you elaborate on this?

$ ocaml -init -
        OCaml version 4.01.0

# [ x / 2 | x <- [ 2;4;6] ];;
Characters 8-9:
  [ x / 2 | x <- [ 2;4;6] ];;
          ^
Error: Syntax error

-- 

Re: [Caml-list] Batteries Included syntax extensions?

[ygrek]

On Mon, 10 Mar 2014 18:19:36 +0800
ygrek <ygrek@autistici.org> wrote:

> Can you elaborate on this?

Answering my own question.. :)

$ ocaml
        OCaml version 4.00.1

.ocamlinit done
# #camlp4o;;
	Camlp4 Parsing version 4.00.1

# #require "camlp4.listcomprehension";;
# [ x / 2 | x <- [ 2;4;6] ];;
- : int list = [1; 2; 3]

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