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Message-ID: <351A9141.3D52@loria.fr>
Date: Thu, 26 Mar 1998 18:32:49 +0100
From: Sorin Stratulat <Sorin.Stratulat@loria.fr>
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To: caml-list@inria.fr
Subject: operational semantics of = for objects
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Hello !

After comparing the results of the code (see below) executed on
different versions of OCAML (1.05 and 1.07), I would like to know if
anybody can explain me how the equality operator works for objects (if
it is possible in both versions). As I understood from a previous
message, overloading the operators is not supported yet.

Here you have two examples where I mainly created a class and some
instances that are further compared:

example 1 ------------
        Objective Caml version 1.07

# class point x_init =
  val mutable x = x_init
  method get_x = x
  	method move d = x <- x + d
  end;;
class point (int) =
  val mutable x : int
  method get_x : int
  method move : int -> unit
end
# let p = new point 7;;
val p : point = <obj>
# let q = new point 7;;
val q : point = <obj>
# p=q;;
- : bool = false
# List.mem (new point 7) [p;q];;
- : bool = false
#  let r = p;;
val r : point = <obj>
# p=r;;
- : bool = true
# 

example 2 -----------------
	Objective Caml version 1.05

# class point x_init =
  val mutable x = x_init
  method get_x = x
  	method move d = x <- x + d
  end;;
        class point (int) =
  val mutable x : int
  method get_x : int
  method move : int -> unit
end
# let p = new point 7;;
val p : point = <obj>
# let q = new point 7;;
val q : point = <obj>
# p=q;;
- : bool = true
#  List.mem (new point 7) [p;q];;
- : bool = true
# let r = p;;
val r : point = <obj>
# p = r;;
- : bool = true
# 

Thank you,

Sorin


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