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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