(***********************************************************************)
(*                                                                     *)
(*                               TAToo                                 *)
(*                                                                     *)
(*                     Kim Nguyen, LRI UMR8623                         *)
(*                   Université Paris-Sud & CNRS                       *)
(*                                                                     *)
(*  Copyright 2010-2012 Université Paris-Sud and Centre National de la *)
(*  Recherche Scientifique. All rights reserved.  This file is         *)
(*  distributed under the terms of the GNU Lesser General Public       *)
(*  License, with the special exception on linking described in file   *)
(*  ../LICENSE.                                                        *)
(*                                                                     *)
(***********************************************************************)

type t = int

exception Overflow
let make_maker () =
  let _id = ref ~-1 in
    fun () ->
      incr _id;
      let i = !_id in
      if i < 0 then raise Overflow else i

let dummy = -1

external to_int : t -> int = "%identity"
external of_int : int -> t= "%identity"