(***********************************************************************)
(*                                                                     *)
(*                                OCaml                                *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the Q Public License version 1.0.               *)
(*                                                                     *)
(***********************************************************************)

module IntMap = Map.Make(struct type t = int let compare x y = x-y end)

let m1 = IntMap.add 4 "Y" (IntMap.singleton 3 "X1")
let m2 = IntMap.add 4 "Y" (IntMap.singleton 5 "X2")

let show m = IntMap.iter (fun k v -> Printf.printf "%d %s\n" k v) m

let () =
  print_endline "Union+concat";
  let f1 _ l r =
    match l, r with
    | Some x, None | None, Some x -> Some x
    | Some x, Some y -> Some (x ^ x)
    | _ -> assert false
  in
  show (IntMap.merge f1 m1 m2);
  print_endline "Inter";
  let f2 _ l r =
    match l, r with
    | Some x, Some y when x = y -> Some x
    | _ -> None
  in
  show (IntMap.merge f2 m1 m2);
  ()