(* Module *)

module Monmodule = struct
  type t = A | B of int
  type u = char
  let f x = if x=A then B(0) else A
  let g x = x
end;;

f;;
Monmodule.f;;
Monmodule.f (Monmodule.B 10);;

open Monmodule;;

f;;
f (B 10);;



(* Signature *)

module type MASIG = sig
  type t
  type u = char
  val g : t -> t
end;;

module Monmodule2 : MASIG = struct
  type t = A | B of int
  type u = char
  let f x = if x=A then B(0) else A
  let g x = x
end;;

Monmodule2.f;;
Monmodule2.A;;
Monmodule2.g;;