From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: weis
Received: (from weis@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id RAA00724 for caml-redistribution; Tue, 23 Jun 1998 17:44:47 +0200 (MET DST)
Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id MAA32536 for <caml-list@pauillac.inria.fr>; Tue, 23 Jun 1998 12:04:44 +0200 (MET DST)
Received: from mail.uni-muenster.de (MAIL.UNI-MUENSTER.DE [128.176.188.76])
	by nez-perce.inria.fr (8.8.7/8.8.7) with ESMTP id MAA20099
	for <caml-list@inria.fr>; Tue, 23 Jun 1998 12:04:43 +0200 (MET DST)
Received: from helios.uni-muenster.de (HELIOS.UNI-MUENSTER.DE [128.176.158.86])
	by mail.uni-muenster.de (8.8.7/8.8.7) with SMTP id MAA37010;
	Tue, 23 Jun 1998 12:04:37 +0200
Received: from pan.uni-muenster.de by helios.uni-muenster.de (SMI-8.6/SMI-SVR4)
	id MAA11323; Tue, 23 Jun 1998 12:01:12 +0100
Received: from pan by pan.uni-muenster.de (SMI-8.6/SMI-SVR4)
	id MAA12573; Tue, 23 Jun 1998 12:01:49 +0100
Message-Id: <199806231101.MAA12573@pan.uni-muenster.de>
X-Mailer: exmh version 1.6.9 8/22/96
To: Emmanuel Engel <Emmanuel.Engel@lri.fr>
cc: caml-list@inria.fr
Subject: Re: Classe recursive et heritage 
In-reply-to: (Your message of Sun, 21 Jun 1998 16:05:37 +0200.)
             <358D1330.89DB13F9@lri.fr> 
References: <358D1330.89DB13F9@lri.fr>
Reply-to: lux@helios.uni-muenster.de
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Date: Tue, 23 Jun 1998 12:01:49 +0100
From: Wolfgang Lux <lux@pan.uni-muenster.de>
Sender: weis

[Sorry, for the answer not being in french, but I'm still better in 
reading french than in writing :-(]
> [...] 
> Mais cela ne correspond  pas a mon  besoin puisque les fils gauches et
> droit de cette nouvelle classe ne sont que des  arbres non decores. En
> fait il  me semble que, ce  dont  j'ai besoin c'est,  dans la premiere
> definition, d'une variable de type (type au sens typage) "self" qui me
> permettrai alors de  dire que les fils  gauche  et droit sont  du meme
> type  que  la classe (soit  le point  fixe de  cette definition). Cela
> donnerai alors
> 
> class ('a) tree as 'self (g:'self) (d:'self) =
>   val fg = g
>   val fd = d
> end;;
> 
> class ('a) labelled_tree g d (i:int) =
>   inherit ('a)tree g d
>   val un_entier = i
> end;;
> 
> Dans ce  cadre la, le  inherit aurait pour   consequence de modifer le
> point  fixe  de   la definition    pour  creer  la    nouvelle  classe
> labelled_tree.  Mon probleme est que je n'ai  pas trouve comment faire
> en  O'caml.  Est-ce possible? Si  non ou est  le probleme  ? Le typage

You can simply define this in OCaml as follows (Note that I've also 
added accessor methods to the classes):

class 'a tree (g : 'b) (d : 'b) : 'b =
  val fg = g
  val fd = d
  method fg = fg
  method fd = fd
end;;

class 'a labeled_tree g d (i : int) =
  inherit ('a) tree g d
  val un_entier = i
  method label = un_entier
end;;

Regards
Wolfgang Lux
--
Wolfgang Lux				  Phone: +49-251-83-38263
Institut fuer Wirtschaftinformatik	    FAX: +49-251-83-38259
Universitaet Muenster		Email: lux@helios.uni-muenster.de