From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: Using empty_string as the only "" string Date: Tue, 24 Apr 2007 23:57:23 +0200 Message-ID: <85k5w1cu64.fsf@lola.goethe.zz> References: <462E310C.20400@yandex.ru> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1177451872 17034 80.91.229.12 (24 Apr 2007 21:57:52 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 24 Apr 2007 21:57:52 +0000 (UTC) Cc: Juanma Barranquero , Dmitry Antipov , emacs-devel@gnu.org To: Andreas Schwab Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Apr 24 23:57:50 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 1HgT1B-0005NC-SD for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 23:57:50 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgT6j-0006XH-R2 for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 18:03:33 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HgT6T-0006SJ-JK for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:03:17 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HgT6R-0006RV-Ro for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:03:17 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgT6R-0006RO-KC for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:03:15 -0400 Original-Received: from mail-in-04.arcor-online.net ([151.189.21.44]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1HgT0s-0007oi-Ru for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:57:31 -0400 Original-Received: from mail-in-03-z2.arcor-online.net (mail-in-03-z2.arcor-online.net [151.189.8.15]) by mail-in-04.arcor-online.net (Postfix) with ESMTP id 3BFD5278AB6; Tue, 24 Apr 2007 23:57:29 +0200 (CEST) Original-Received: from mail-in-10.arcor-online.net (mail-in-10.arcor-online.net [151.189.21.50]) by mail-in-03-z2.arcor-online.net (Postfix) with ESMTP id 104BE2D3915; Tue, 24 Apr 2007 23:57:29 +0200 (CEST) Original-Received: from lola.goethe.zz (dslb-084-061-058-028.pools.arcor-ip.net [84.61.58.28]) by mail-in-10.arcor-online.net (Postfix) with ESMTP id DD61C2351A3; Tue, 24 Apr 2007 23:57:28 +0200 (CEST) Original-Received: by lola.goethe.zz (Postfix, from userid 1002) id E6D4C1C4610D; Tue, 24 Apr 2007 23:57:25 +0200 (CEST) In-Reply-To: (Andreas Schwab's message of "Tue\, 24 Apr 2007 23\:38\:17 +0200") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.98 (gnu/linux) X-detected-kernel: Linux 2.4-2.6 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:69999 Archived-At: Andreas Schwab writes: > "Juanma Barranquero" writes: > >> On 4/24/07, Andreas Schwab wrote: >> >>> I see nothing wrong with that. >> >> I do see it. The issue is not string comparison, but object identity. >> It's no different from >> >> (eq 0.0 0.0) => nil >> >> 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. > > In which way is this different from > > (eq (cdr '(a)) (cdr '(b))) => t '(a) is (cons 'a nil), '(b) is (cons 'b nil), so indeed the cdr of both lists is the identically same value. Lists are _identically_ grounded. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum