From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Juanma Barranquero" Newsgroups: gmane.emacs.devel Subject: Re: Using empty_string as the only "" string Date: Tue, 24 Apr 2007 23:54:00 +0200 Message-ID: References: <462E310C.20400@yandex.ru> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1177451659 15898 80.91.229.12 (24 Apr 2007 21:54:19 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 24 Apr 2007 21:54:19 +0000 (UTC) Cc: 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 23:54:18 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 1HgSxl-0003ge-7O for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 23:54:17 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgT3I-0005c8-7Z for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 18:00:00 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HgT3E-0005bG-FA for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:59:56 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HgT3C-0005ae-VK for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:59:56 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgT3C-0005aW-P6 for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:59:54 -0400 Original-Received: from wr-out-0506.google.com ([64.233.184.226]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1HgSxc-0007Lf-OG for emacs-devel@gnu.org; Tue, 24 Apr 2007 17:54:09 -0400 Original-Received: by wr-out-0506.google.com with SMTP id i23so2081895wra for ; Tue, 24 Apr 2007 14:54:02 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=G1guwOM0TJN6lve1Wgl2sRYhkDRiJUYuq7T3WBUlA4ZNibDN+4EZpb1wnVCchVTnvHXmIItRHQFCyv5BshnyN9rvT0a3fmSfcx1jREpfOI3Q1NFLBDbkLbfIDnxtmYyuBxG94bR51TO+E/f8ybNLITv2s/Kf/CozXpIeI1S9OtE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ttWmIcxuZicgh7zXz3b5JvQMT/5evAGgvpUQiUJIf8K2Q67QM9iFdJaQZTdpjk2bC99ILsSujBZN5OqTnD3Y7vTgHCsbMl6rK1sNtddEdRXd1SmI6khN+y5tn47cwT675G8/2V7M1RPHv+63++kZeKksDWR492F+Nw5kPsKyBwA= Original-Received: by 10.90.115.9 with SMTP id n9mr1278739agc.1177451640870; Tue, 24 Apr 2007 14:54:00 -0700 (PDT) Original-Received: by 10.90.87.8 with HTTP; Tue, 24 Apr 2007 14:54:00 -0700 (PDT) In-Reply-To: Content-Disposition: inline X-detected-kernel: Linux 2.4-2.6 (Google crawlbot) 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:69998 Archived-At: On 4/24/07, Andreas Schwab wrote: > In which way is this different from > > (eq (cdr '(a)) (cdr '(b))) => t > Well, that's non-optional, according to the Emacs Lisp documentation: "Also, since symbol names are normally unique, if the arguments are symbols with the same name, they are `eq'." The doc also says: "For other types (e.g., lists, vectors, strings), two arguments with the same contents or elements are not necessarily `eq' to each other: they are `eq' only if they are the same object, meaning that a change in the contents of one will be reflected by the same change in the contents of the other." So, as I said, it is an issue of object identity. I didn't say that the results above would be "wrong", only surprising, and a noticeable change in the current behaviour. Juanma