From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Lennart Borgman (gmail)" Newsgroups: gmane.emacs.devel Subject: Re: Using empty_string as the only "" string Date: Wed, 25 Apr 2007 00:40:05 +0200 Message-ID: <462E8745.2010309@gmail.com> References: <462E310C.20400@yandex.ru> <85k5w1cu64.fsf@lola.goethe.zz> <462E7FB5.7090905@gmail.com> <857is1csoy.fsf@lola.goethe.zz> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1177454426 31047 80.91.229.12 (24 Apr 2007 22:40:26 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 24 Apr 2007 22:40:26 +0000 (UTC) Cc: Andreas Schwab , Dmitry Antipov , emacs-devel@gnu.org, Juanma Barranquero To: David Kastrup Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Apr 25 00:40:24 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 1HgTgJ-0007TA-Bb for ged-emacs-devel@m.gmane.org; Wed, 25 Apr 2007 00:40:19 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgTlr-000199-Ii for ged-emacs-devel@m.gmane.org; Tue, 24 Apr 2007 18:46:03 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HgTlk-00018F-U7 for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:45:56 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HgTli-00017z-E3 for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:45:55 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HgTli-00017w-5c for emacs-devel@gnu.org; Tue, 24 Apr 2007 18:45:54 -0400 Original-Received: from ch-smtp01.sth.basefarm.net ([80.76.149.212]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1HgTg8-0004ve-Ea; Tue, 24 Apr 2007 18:40:08 -0400 Original-Received: from c83-254-145-24.bredband.comhem.se ([83.254.145.24]:63765 helo=[127.0.0.1]) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.63) (envelope-from ) id 1HgTg6-0007oE-4z; Wed, 25 Apr 2007 00:40:07 +0200 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.3) Gecko/20070326 Thunderbird/2.0.0.0 Mnenhy/0.7.5.666 In-Reply-To: <857is1csoy.fsf@lola.goethe.zz> X-Antivirus: avast! (VPS 000735-2, 2007-04-23), Outbound message X-Antivirus-Status: Clean X-Scan-Result: No virus found in message 1HgTg6-0007oE-4z. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1HgTg6-0007oE-4z ccfd6e2fad4d5fdde146237acb8363f4 X-detected-kernel: Linux 2.6? (barebone, rare!) 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:70010 Archived-At: David Kastrup wrote: > "Lennart Borgman (gmail)" writes: > >> David Kastrup wrote: >> >>> '(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. >> And strings? > > Aren't grounded at all. (concat "a" "b") does not make "b" part of > the result. So (concat "a" "") and (concat "b" "") would not share > the same "" even if one replaced both of them by the same object. > > Every created string is a separate object not containing any other > string as a part. The same is not true for lists. You can, for > example, modify a sublist and in the process change the list > containing it. > > This does not happen for substrings. I am not sure I understand that this means that "" and "" can't be seen as equal. Is there any theoritical wrong with thinking about a vector as a list with certain restrictions, properties and special access routines? But I am not into this at all so I do not know.