From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Delivered-To: caml-list@yquem.inria.fr Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by yquem.inria.fr (Postfix) with ESMTP id 34A07BB81 for ; Fri, 17 Dec 2004 08:42:07 +0100 (CET) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id iBH7g6Wa006695 for ; Fri, 17 Dec 2004 08:42:07 +0100 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 IAA16853 for ; Fri, 17 Dec 2004 08:42:06 +0100 (MET) Received: from alex.barettalocal.com (h213-255-109-130.albacom.net [213.255.109.130] (may be forged)) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id iBH7g5Dv006689 for ; Fri, 17 Dec 2004 08:42:06 +0100 Received: from [127.0.0.1] (localhost.localdomain [127.0.0.1]) by alex.barettalocal.com (Postfix) with ESMTP id D98C52BAA94 for ; Fri, 17 Dec 2004 08:42:04 +0100 (CET) Message-ID: <41C28DCB.3050409@barettadeit.com> Date: Fri, 17 Dec 2004 08:42:03 +0100 From: Alex Baretta User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20041007 Debian/1.7.3-5 X-Accept-Language: it, en-us, en MIME-Version: 1.0 To: Ocaml Subject: Re: [Caml-list] Dummy polymorphic constructors References: <41C1E091.1040508@barettadeit.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce with ID 41C28DCE.001 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 41C28DCD.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; baretta:01 caml-list:01 constructors:01 prevost:01 wrote:01 sig:01 struct:01 struct:01 baretta:01 polymorphic:01 opaque:01 opaque:01 defined:01 declaring:02 construct:02 X-Spam-Checker-Version: SpamAssassin 3.0.0 (2004-09-13) on yquem.inria.fr X-Spam-Status: No, score=0.1 required=5.0 tests=FORGED_RCVD_HELO autolearn=disabled version=3.0.0 X-Spam-Level: John Prevost wrote: >>type empty = [ ] > > I'm somewhat confused as to why this is different from simply > declaring a new opaque type: > > type empty Ah, this is interesting! > Since there is no way to construct a value of the type, nor any way to > deconstruct such a value, how is it different? > > John. > Not much, actually. I thought opaque types could only be *declared*. module M : sig type t end = struct type t = *** end I never realized that a type could be *defined* as opaque. module M = struct type t end Alex -- ********************************************************************* http://www.barettadeit.com/ Baretta DE&IT A division of Baretta SRL tel. +39 02 370 111 55 fax. +39 02 370 111 54 Our technology: The Application System/Xcaml (AS/Xcaml) The FreerP Project