(***********************************************************************)

(*                                                                     *)

(*                 MLTk, Tcl/Tk interface of OCaml                     *)

(*                                                                     *)

(*    Francois Rouaix, Francois Pessaux, Jun Furuse and Pierre Weis    *)

(*               projet Cristal, INRIA Rocquencourt                    *)

(*            Jacques Garrigue, Kyoto University RIMS                  *)

(*                                                                     *)

(*  Copyright 2002 Institut National de Recherche en Informatique et   *)

(*  en Automatique and Kyoto University.  All rights reserved.         *)

(*  This file is distributed under the terms of the GNU Library        *)

(*  General Public License, with the special exception on linking      *)

(*  described in file LICENSE found in the OCaml source tree.          *)

(*                                                                     *)

(***********************************************************************)

open Camltk;;

let main () =

  let top = opentk ()  in

  (* The widgets. They all have "top" as parent widget. *)

  let en1 = Entry.create top [TextWidth 6; Relief Sunken] in

  let lab1 = Label.create top [Text "plus"] in

  let en2 = Entry.create top [TextWidth 6 ; Relief Sunken] in

  let lab2 = Label.create top [Text "="] in

  let result_display = Label.create top [] in

  (* References holding values of entry widgets *)

  let n1 = ref 0

  and n2 = ref 0  in

  (* Refresh result *)

  let refresh () =

    Label.configure result_display [Text (string_of_int (!n1 + !n2))]  in

  (* Electric *)

  let get_and_refresh (w,r) =

    fun _ _ ->

      try

       r := int_of_string (Entry.get w);

       refresh ()

      with

        Failure "int_of_string" ->

          Label.configure result_display [Text "error"]

  in

  (* Set the callbacks *)

  Entry.configure en1 [XScrollCommand (get_and_refresh (en1,n1)) ];

  Entry.configure en2 [XScrollCommand (get_and_refresh (en2,n2)) ];

  (* Map the widgets *)

  pack [en1;lab1;en2;lab2;result_display] [];

  (* Make the window resizable *)

  Wm.minsize_set top 1 1;

  (* Start interaction (event-driven program) *)

  mainLoop ()

;;

Printexc.catch main ()

;;