(***********************************************************************)
(*                                                                     *)
(*            cast objet en O'Caml                                     *)
(*                                                                     *)
(*            Emmanuel Chailloux, Equipe PPS, universite P7            *)
(*                                                                     *)
(*                                                                     *)
(***********************************************************************)

(* $Id: test2.ml,v 1.2 2001/08/30 15:40:37 emmanuel Exp $ *)

(* test2.ml : fichier de test 
 
           top
         /    \
        /      \
    left      right

*)

class virtual top = 
  object(self) 
    method virtual to_string :  string
    method print = print_string (self#to_string)
    method clone = Oo.copy(self)
    method eq (a : top) = true
 end;;

class left (x : int) = 
  object (self  ) 
  subinherit top 
  val l = x
  method get_l = l
  method to_string = string_of_int l
  method eq ( x : top) = 
    let xl = cast x  to left in 
        l = (xl#get_l)
end;;

class right (x : int) = 
  object (self  ) 
  subinherit top 
  val l = x
  method get_l = l
  method to_string = string_of_int l
  method eq (x:top) = 
    let xl = cast x to right in 
        l = (xl#get_l)
end;;

let l = new left 10;;
let l2 = new left 10;;
let t1 = ( l :> top);;
let r =  new right 10;;
let t2 = ( r :>  top);;

l#print;; print_newline();;
l2#print;; print_newline();;

if l#eq(l2 :> top) then print_string "OK"
else print_string "PB";;

print_newline();;

try 
  ignore(l#eq ( r :>  top));
  print_string "PB"
with Cast.Cast_failure _ -> print_string "OK";;

print_newline();;