x.ml

module type MESSAGE = 
sig 
  type obj 
  type variant
  val make : unit -> obj
  (* encapsulate object in a variant type *)
  val convert : obj -> variant
  val print : obj -> unit
end

module type REQUEST = 
sig 
  include Message
end

(* dispatches based on a request *)

module type REPLY =
sig 
  include Message
  val dispatch : request_variant -> obj
end
module type REPLY_FUNCTOR = functor (Req : REQUEST) ->
struct
  module Rep : REPLY
  module Req : REQUEST
end


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