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 071BDBCAF for ; Wed, 29 Jun 2005 12:06:13 +0200 (CEST) Received: from uni-sb.de (uni-sb.de [134.96.252.33]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j5TA6CEI012425 for ; Wed, 29 Jun 2005 12:06:12 +0200 Received: from cs.uni-sb.de (cs.uni-sb.de [134.96.252.31]) by uni-sb.de (8.13.4/2005060800) with ESMTP id j5TA6BAS027062 for ; Wed, 29 Jun 2005 12:06:12 +0200 (CEST) Received: from mail.cs.uni-sb.de (mail.cs.uni-sb.de [134.96.254.200]) by cs.uni-sb.de (8.13.4/2005033000) with ESMTP id j5TA6AaY020063 for ; Wed, 29 Jun 2005 12:06:11 +0200 (CEST) Received: from ps.uni-sb.de (grizzly.ps.uni-sb.de [134.96.186.68]) by mail.cs.uni-sb.de (8.13.4/2005060800) with ESMTP id j5TA6Ad7011638 for ; Wed, 29 Jun 2005 12:06:10 +0200 (CEST) X-Authentication-Warning: mail.cs.uni-sb.de: Host grizzly.ps.uni-sb.de [134.96.186.68] claimed to be ps.uni-sb.de Received: from [134.96.186.172] (groove.ps.uni-sb.de [134.96.186.172]) by ps.uni-sb.de (8.12.10/8.12.10) with ESMTP id j5TA68JU026713; Wed, 29 Jun 2005 12:06:08 +0200 Message-ID: <42C27290.1060701@ps.uni-sb.de> Date: Wed, 29 Jun 2005 12:06:08 +0200 From: Andreas Rossberg User-Agent: Mozilla Thunderbird 1.0.2 (X11/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 To: caml-list@yquem.inria.fr Subject: Re: [Caml-list] Type abstraction and (polymorphic) equality References: <20050629.023111.15476874.debian00@tiscali.be> <200506291012.30612.jon@ffconsultancy.com> In-Reply-To: <200506291012.30612.jon@ffconsultancy.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce with ID 42C27294.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; rossberg:01 rossberg:01 caml-list:01 abstraction:01 iirc:01 sml:01 wrote:01 uni-sb:01 equality:01 equality:01 uni-sb:01 polymorphic:01 polymorphic:01 andreas:01 andreas:01 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.2 X-Spam-Level: Jon Harrop wrote: > > I do not believe so. IIRC, SML has equality types to help with this problem. Equality types only provide half a solution (preventing accidental (ab)use of polymorphic equality). Solving the whole problem (enabling user-defined equality on user-defined types) requires something more general, e.g. type classes. - Andreas -- Andreas Rossberg, rossberg@ps.uni-sb.de Let's get rid of those possible thingies! -- TB