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 JAA05685; Sun, 20 Oct 2002 09:28:28 +0200 (MET DST)
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 JAA01905 for <caml-list@pauillac.inria.fr>; Sun, 20 Oct 2002 09:28:28 +0200 (MET DST)
Received: from morgon.inria.fr (morgon.inria.fr [128.93.8.33])
	by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id g9K7SO526158;
	Sun, 20 Oct 2002 09:28:24 +0200 (MET DST)
Received: (from remy@localhost)
	by morgon.inria.fr (8.11.6/8.11.6) id g9JKmNf17602;
	Sat, 19 Oct 2002 22:48:23 +0200
Date: Sat, 19 Oct 2002 22:48:23 +0200
From: Didier Remy <Didier.Remy@inria.fr>
To: james woodyatt <jhw@wetware.com>
Cc: The Trade <caml-list@inria.fr>
Subject: Re: [Caml-list] functional objects
Message-ID: <20021019224823.A17599@morgon.inria.fr>
Reply-To: Didier.Remy@inria.fr
References: <5BF65502-E2FD-11D6-B29D-000393BA7EBA@wetware.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
User-Agent: Mutt/1.2.5i
In-Reply-To: <5BF65502-E2FD-11D6-B29D-000393BA7EBA@wetware.com>; from jhw@wetware.com on Fri, Oct 18, 2002 at 05:54:45PM -0700
Organization: INRIA, BP 105, F-78153 Le Chesnay Cedex
Phone: (33) 1 3963 5317 -- Sec: (33) 1 3963 5207 -- Fax: (33) 1 3963 5193
Web: http://cristal.inria.fr/~remy
Sender: owner-caml-list@pauillac.inria.fr
Precedence: bulk

> Anyway, one of the things I find lacking is a way to call a subclass 
> constructor in the copy constructor.  In other words, I'd like to have 
> some way to do the following:
> 
> 	(* class type with only public methods exposed *)
> 	class type foo = object method f: unit end
> 
> 	(* class with private members *)
> 	class foo x : foo = object
> 	  val x: int = x
> 	  method f = ()
> 	end
> 
> 	(* derived functional subclass (notice method g) *)
> 	class bar y = object
> 	  inherit foo 0
> 	  val y: int = y
> 	  method g a b = {< foo a; y = b >}
> 	end
> 
> What I want is for a superclass class to be able to expose an interface 
> to subclasses for constructing copies with arguments.  Is this a bad 
> idea?  Has it already been considered and rejected?  Just curious.

Would the following code makes you happy?

        (* class type with only public methods exposed,
           plus a private overriding method foo *)
        class type foo_ = 
          object ('a) method f : unit method private foo : int -> 'a end;;

        (* class with private members *)
        class foo x : foo_ = object
          val x: int = x
          private method foo a = {< x = a >}
          method f = ()
        end;;

        (* derived functional subclass (notice method g) *)
        class bar y = object
          inherit foo 0
          val y: int = y
          method g a b = {< y = b >} # foo a 
        end;;

Didier Rémy
-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners