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

[Gabriel Scherer <gabriel.scherer@gmail.com>]

Here is an attempt at a functor translation. Note that's it's mostly a
glorified way to do exactly the same thing. Passing a module or a
record of operation is not very different; yet a module can carry
types so you don't have to parametrize your operations explicitly.

module type OPS = sig
  type bar
  type foo
  val bar_of_foo : foo -> bar
  val foo_of_bar : bar -> foo
end

module Make (O : OPS) = struct
  let foo = O.bar_of_foo
  let bar = O.foo_of_bar
end

module Op1 = struct
  type foo = A | B
  type bar = C | D
  let bar_of_foo = function A -> C | B -> D
  let foo_of_bar = function C -> A | D -> B
end

let () =
 let module M = Make(Op1) in
 (* you may want to open Op1 locally here *)
 match M.foo Op1.A with
 | Op1.C -> ()
 | Op1.D -> ()


On Tue, Feb 14, 2012 at 10:59 AM, Andre Nathan <andre@digirati.com.br> wrote:
> On Tue, 2012-02-14 at 08:03 +0100, Arnaud Spiwack wrote:
>> 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.
>
> Can you give me an example? How can I retain the possibility of
> pattern-matching on the types of the resulting module?
>
> Thanks,
> Andre
>>
>
>
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