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

[Ivan Gotovchits <ivg@ieee.org>]

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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/
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> 

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