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 EAA09982; Mon, 22 Mar 2004 04:26:33 +0100 (MET) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f 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 EAA10121 for ; Mon, 22 Mar 2004 04:26:32 +0100 (MET) Received: from smtp1.adl2.internode.on.net (smtp1.adl2.internode.on.net [203.16.214.181]) by nez-perce.inria.fr (8.12.10/8.12.10) with ESMTP id i2M3R2KW004947 for ; Mon, 22 Mar 2004 04:27:03 +0100 Received: from [192.168.1.200] (ppp114-118.lns1.syd3.internode.on.net [150.101.114.118]) by smtp1.adl2.internode.on.net (8.12.9/8.12.9) with ESMTP id i2M3QKwn063911; Mon, 22 Mar 2004 13:56:21 +1030 (CST) Subject: Re: [Caml-list] extensible records again From: skaller Reply-To: skaller@users.sourceforge.net To: Michael Vanier Cc: oleg_trott@columbia.edu, caml-list In-Reply-To: <20040321223401.392519BBA2@orchestra.cs.caltech.edu> References: <20040321062143.BE7D29BBA2@orchestra.cs.caltech.edu> <405D4D77.2030403@columbia.edu> <20040321084008.429279BBA2@orchestra.cs.caltech.edu> <405DBE78.5020609@columbia.edu> <20040321223401.392519BBA2@orchestra.cs.caltech.edu> Content-Type: text/plain Message-Id: <1079926276.3165.49.camel@pelican.wigram> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-4) Date: 22 Mar 2004 14:31:16 +1100 Content-Transfer-Encoding: 7bit X-Miltered: at nez-perce by Joe's j-chkmail ("http://j-chkmail.ensmp.fr")! X-Loop: caml-list@inria.fr X-Spam: no; 0.00; caml-list:01 extensible:01 sourceforge:01 2004:99 vanier:01 implemented:01 covariant:01 subtyping:01 fixpoints:01 camlp:01 9660:01 glebe:01 variants:01 variants:01 nsw:01 Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk X-Status: X-Keywords: X-UID: 293 On Mon, 2004-03-22 at 09:34, Michael Vanier wrote: > If I understand you correctly, then you're arguing that *all* my "core > types" should be implemented using polymorphic variants. I use Polymorphic Variants almost exclusively in Felix. They're more flexible but also give nastier error messages. The main downside is that to make covariant subtyping you need to use fixpoints, which is fine for a single parameter but unworkable for a more complex term structure. It would be interesting if Camlp4 could solve this problem somehow. -- John Skaller, mailto:skaller@users.sf.net voice: 061-2-9660-0850, snail: PO BOX 401 Glebe NSW 2037 Australia Checkout the Felix programming language http://felix.sf.net ------------------- 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