From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?iso-8859-1?Q?Court=E8s?=) Newsgroups: gmane.lisp.guile.devel Subject: Re: truth of %nil Date: Thu, 02 Jul 2009 16:50:49 +0200 Message-ID: <87eiszyw8m.fsf@gnu.org> References: <87k52uvhnt.fsf@arudy.ossau.uklinux.net> <20090702142823.GA1401@fibril.netris.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1246548164 5432 80.91.229.12 (2 Jul 2009 15:22:44 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 2 Jul 2009 15:22:44 +0000 (UTC) To: guile-devel@gnu.org Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Thu Jul 02 17:22:37 2009 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1MMO7J-0004Bj-0l for guile-devel@m.gmane.org; Thu, 02 Jul 2009 17:22:29 +0200 Original-Received: from localhost ([127.0.0.1]:42672 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MMO7I-0000i8-7i for guile-devel@m.gmane.org; Thu, 02 Jul 2009 11:22:28 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MMNd3-0005qY-21 for guile-devel@gnu.org; Thu, 02 Jul 2009 10:51:13 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MMNcy-0005oi-4d for guile-devel@gnu.org; Thu, 02 Jul 2009 10:51:12 -0400 Original-Received: from [199.232.76.173] (port=32950 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MMNcx-0005oc-UI for guile-devel@gnu.org; Thu, 02 Jul 2009 10:51:07 -0400 Original-Received: from main.gmane.org ([80.91.229.2]:37214 helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MMNcx-0006EQ-Aw for guile-devel@gnu.org; Thu, 02 Jul 2009 10:51:07 -0400 Original-Received: from list by ciao.gmane.org with local (Exim 4.43) id 1MMNcr-0002O2-8F for guile-devel@gnu.org; Thu, 02 Jul 2009 14:51:01 +0000 Original-Received: from 193.50.110.109 ([193.50.110.109]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 02 Jul 2009 14:51:01 +0000 Original-Received: from ludo by 193.50.110.109 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 02 Jul 2009 14:51:01 +0000 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 25 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 193.50.110.109 X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 14 Messidor an 217 de la =?iso-8859-1?Q?R=E9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 821D 815D 902A 7EAB 5CEE D120 7FBA 3D4F EB1F 5364 X-OS: x86_64-unknown-linux-gnu User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) Cancel-Lock: sha1:dSUboW7ErInp4wmjtpcd3zrPFyU= X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:8824 Archived-At: Hi, Mark H Weaver writes: > I've been considering writing a python compiler for guile. For python > (and others) there are several values considered to be false, such as > 0 and various empty collections, and so a different approach will have > to be taken to this problem. [...] > So how about having elisp `if' and `cond' compile not to scheme `if' > and `cond', but rather to scheme `elisp-if' and `elisp-cond'? Or > perhaps compile `(if c a b)' to `(if (elisp-true? c) a b)'. I concur (but I haven't followed the elisp discussion closely). Regardless of which approach the elisp front-end takes, this is something other languages can already do. This is something the ECMAScript front-end does: see how `if' is handled in `language/ecmascript/compile-ghil.scm' and the definition of `->boolean' in `language/ecmascript/base.scm'. Thanks, Ludo'.