From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id NAA15187; Fri, 1 Feb 2002 13:17:28 +0100 (MET)
X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f
Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id NAA15464 for <caml-list@pauillac.inria.fr>; Fri, 1 Feb 2002 13:17:27 +0100 (MET)
Received: from ebene.inrialpes.fr (ebene.inrialpes.fr [194.199.18.70])
	by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id g11CHQ512367
	for <caml-list@inria.fr>; Fri, 1 Feb 2002 13:17:26 +0100 (MET)
Received: from pop-serv.inrialpes.fr (pop-serv.inrialpes.fr [194.199.18.66])
	by ebene.inrialpes.fr (8.11.6/8.11.6) with ESMTP id g11CHBJ14124
	for <caml-list@inria.fr>; Fri, 1 Feb 2002 13:17:11 +0100 (MET)
Received: from inrialpes.fr (cime.inrialpes.fr [194.199.23.76])
	by pop-serv.inrialpes.fr (8.10.2+Sun/8.11.3/ImagV2) with ESMTP id g11CHAK22687
	for <caml-list@inria.fr>; Fri, 1 Feb 2002 13:17:10 +0100 (MET)
Message-ID: <3C5A8747.BE14426@inrialpes.fr>
Date: Fri, 01 Feb 2002 13:17:11 +0100
From: Frederic Tronel <Frederic.Tronel@inrialpes.fr>
X-Mailer: Mozilla 4.76 [en] (X11; U; SunOS 5.8 sun4u)
X-Accept-Language: en
MIME-Version: 1.0
To: caml-list@inria.fr
Subject: [Caml-list] Recursive classes and subtyping
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk

Hello,

A new question about classes in ocaml:

Why is it that these classes definitions are not accepted by
the compiler :

class a =
  object
    val mutable al = ([] : a list)
    method get_al = al
    method set_al x = al <- x 
  end
and b =
object (this)
  inherit a as super
  val mutable c = new c
  method get_c = c
  method set_c x = c <- x
  initializer this#set_al [(c :> a)] 
end
and c =
object 
  inherit a
  val mutable titi = ""
  method get_titi = titi
  method set_titi x = titi <- x
end

while these ones can be compiled:

class a =
  object
    val mutable al = ([] : a list)
    method get_al = al
    method set_al x = al <- x 
  end
class c =
object 
  inherit a
  val mutable titi = ""
  method get_titi = titi
  method set_titi x = titi <- x
end
class b =
object (this)
  inherit a as super
  val mutable c = new c
  method get_c = c
  method set_c x = c <- x
  initializer this#set_al [(c :> a)] 
end

Where is the fundamental difference ????

Best regards,

Frederic
-------------------
Bug reports: http://caml.inria.fr/bin/caml-bugs  FAQ: http://caml.inria.fr/FAQ/
To unsubscribe, mail caml-list-request@inria.fr  Archives: http://caml.inria.fr