From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Miles Bader Newsgroups: gmane.emacs.devel Subject: Re: Using empty_string as the only "" string Date: Wed, 25 Apr 2007 06:39:15 +0900 Message-ID: <87vefliha4.fsf@catnip.gol.com> References: <462E310C.20400@yandex.ru> Reply-To: Miles Bader NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1177451028 12364 80.91.229.12 (24 Apr 2007 21:43:48 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 24 Apr 2007 21:43:48 +0000 (UTC) Cc: Andreas Schwab , Dmitry Antipov , emacs-devel@gnu.org To: "Juanma Barranquero" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Apr 24 23:43:36 2007 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1HgSnP-0006Eh-VA for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 23:43:36 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgSsx-0001n5-TY for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 17:49:19 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HgSou-0007em-KX for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:45:08 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HgSos-0007dq-KE for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:45:07 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgSos-0007dl-Gq for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:45:06 -0400 Original-Received: from smtp02.dentaku.gol.com ([203.216.5.72]) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1HgSjI-0004Xk-U5; Tue, 24 Apr 2007 17:39:21 -0400 Original-Received: from 203-216-97-156.dsl.gol.ne.jp ([203.216.97.156] helo=catnip.gol.com) by smtp02.dentaku.gol.com with esmtpa (Dentaku) id 1HgSjD-0004lb-Ve; Wed, 25 Apr 2007 06:39:16 +0900 Original-Received: by catnip.gol.com (Postfix, from userid 1000) id 7C1C92F43; Wed, 25 Apr 2007 06:39:15 +0900 (JST) System-Type: i686-pc-linux-gnu In-Reply-To: (Juanma Barranquero's message of "Tue\, 24 Apr 2007 20\:50\:26 +0200") Original-Lines: 20 X-Abuse-Complaints: abuse@gol.com X-detected-kernel: Linux 2.6, seldom 2.4 (older, 4) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:69995 Archived-At: "Juanma Barranquero" writes: >> I see nothing wrong with that. > > I do see it. The issue is not string comparison, but object identity. > I would be mightily surprised if > > (eq (- 2.0 0.0) (- 2.0 0.0)) => nil > (eq (- 2.0 1.0) (- 2.0 1.0)) => nil > (eq (- 2.0 2.0) (- 2.0 2.0)) => t > > were true. If so, it's because you misunderstand lisp. There's absolutely nothing wrong with canonicalizing immutable objects in lisp (and many implementations in fact do so). -miles -- Is it true that nothing can be known? If so how do we know this? -Woody Allen