gistfile2.txt

x.ml

module type Message = 
sig 
  type t
  val make : unit -> t
  val print : t -> unit
end

module Server (Req : Message) (Rep : Message) =
struct 
  let server convert dispatch = 
    while true do
      let req = Req.make () in
      let var = convert req in
      let rep = dispatch var in
      Req.print req;
      Rep.print rep
    done
end

module MyRequest =
struct
  type t = int
  let make () = (1 : t)
  let print o = ()
end

module MyReply =
struct
  type t = int
  let make () = (2 : t)
  let print o = ()
end

(* 
Given that I will never use MyServer with convert and dispatch 
other than the ones below, is there a way to functorize this?
I would love to join types req and rep, as well as convert
and dispatch into a module that I could specializer Server on.
*)

type req = | A of MyRequest.t
type rep = | B of MyReply.t

let convert req = A req 

let dispatch = function
  | A _ -> MyReply.make ()

module MyServer = Server (MyRequest) (MyReply) 

let _ = MyServer.server convert dispatch