Re: [Caml-list] What am I reinventing here?

[Arnaud Spiwack <aspiwack@lix.polytechnique.fr>]

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You're probably trying to use functors (
http://caml.inria.fr/pub/docs/manual-ocaml/manual004.html#toc15 ). Though
your example code isn't doing anything in particular.

On 14 February 2012 00:33, Andre Nathan <andre@digirati.com.br> wrote:

> Hello
>
> I have some code that behaves like the following.
>
> module M = struct
>  type ('a, 'b) ops = {
>    bar_of_foo : 'a -> 'b;
>    foo_of_bar : 'b -> 'a
>  }
>
>  let foo ops x = ops.bar_of_foo x
>  let bar ops x = ops.foo_of_bar x
> end
>
> type foo = A | B
> type bar = C | D
>
> let ops = {
>  M.bar_of_foo = (function A -> C | B -> D);
>  M.foo_of_bar = (function C -> A | D -> B)
> }
>
> let () =
>  match M.foo ops A with
>  | C -> ()
>  | D -> ()
>
> The idea is to parametrize the behavior of some module M on two types and
> a set of operations involving these two types, with the catch that I want
> to keep the ability to pattern-match on the possible values of these types
> in the code that handles the return values from the functions exported by M.
>
> With the scheme above I can do this, but passing a table of functions
> around doesn't look very nice. Is there any way I can use functors to do
> what this code does, while still being able to use pattern-matching? Would
> I have to resort to objects to be able to do this?
>
> Thanks in advance,
> Andre
>
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