Re: [Caml-list] A functor to produce recursive modules ?

[Alain Frisch]

Fabrice Marchant wrote:
Hi !

   Apologize. This topic isnt't exactly at its right place : belongs to 
Beginners-list.
However no answer about this question there and so much clever people here, a 
denser traffic...

   Please how to define recursive modules that are parametrized by an 
OrderedType ?
Say these modules types are Mod and ModSet.
(Because a function f in module Mod uses a Set of Mod)

The problem is I need recursive functors that returns 2 modules.

I'm not sure to understand. Maybe a functor that returns a pair of 
mutually recursive modules is what you want.

module F(X : Set.OrderedType) = struct
  module rec Mod : sig
    type t = X of int * ModSet.t
    val compare: t -> t -> int
    val of_list: t list -> t
  end
    =
  struct
    type t = X of int * ModSet.t
    let compare (X (i, _)) (X (j, _)) = compare i j
    let of_list i l = X (i, List.fold_right ModSet.add l ModSet.empty)
  end
  and ModSet : Set.S with type elt = Mod.t = Set.Make(Mod)
end

-- Alain

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