From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#12314: 24.2.50; `add-to-history': use `setq' with `delete' Date: Mon, 10 Sep 2012 19:24:44 +0300 Message-ID: <83k3w1lub7.fsf@gnu.org> References: <7602D24B74DE42CF9901322634B85CA2@us.oracle.com> <87sjas4mc2.fsf@gnu.org> <83ipbomv6e.fsf@gnu.org> <2C45207ADF0E46BC98AF1B486695F632@us.oracle.com> <83fw6smti6.fsf@gnu.org> <9A8F619FD7584123A6319BD089E444E4@us.oracle.com> <83bohgmrdv.fsf@gnu.org> <83a9x0mq5e.fsf@gnu.org> <8E40573C868D4B339513A16A02588F5E@us.oracle.com> <837gs4mcqy.fsf@gnu.org> <83627nnc2l.fsf@gnu.org> <83392rm840.fsf@gnu.org> <83pq5ulchr.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1347294336 15519 80.91.229.3 (10 Sep 2012 16:25:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 10 Sep 2012 16:25:36 +0000 (UTC) Cc: 12314@debbugs.gnu.org, cyd@gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Sep 10 18:25:38 2012 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1TB6nq-00057u-5x for geb-bug-gnu-emacs@m.gmane.org; Mon, 10 Sep 2012 18:25:38 +0200 Original-Received: from localhost ([::1]:51027 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TB6nm-0002vB-Le for geb-bug-gnu-emacs@m.gmane.org; Mon, 10 Sep 2012 12:25:34 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:44049) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TB6ng-0002mS-87 for bug-gnu-emacs@gnu.org; Mon, 10 Sep 2012 12:25:32 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TB6nf-00036l-6z for bug-gnu-emacs@gnu.org; Mon, 10 Sep 2012 12:25:28 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:43009) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TB6nf-00036f-2l for bug-gnu-emacs@gnu.org; Mon, 10 Sep 2012 12:25:27 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.72) (envelope-from ) id 1TB6oE-000478-7L for bug-gnu-emacs@gnu.org; Mon, 10 Sep 2012 12:26:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 10 Sep 2012 16:26:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 12314 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 12314-submit@debbugs.gnu.org id=B12314.134729431815765 (code B ref 12314); Mon, 10 Sep 2012 16:26:02 +0000 Original-Received: (at 12314) by debbugs.gnu.org; 10 Sep 2012 16:25:18 +0000 Original-Received: from localhost ([127.0.0.1]:52555 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.72) (envelope-from ) id 1TB6nV-00046E-GV for submit@debbugs.gnu.org; Mon, 10 Sep 2012 12:25:17 -0400 Original-Received: from mtaout20.012.net.il ([80.179.55.166]:43912) by debbugs.gnu.org with esmtp (Exim 4.72) (envelope-from ) id 1TB6nT-000465-1i for 12314@debbugs.gnu.org; Mon, 10 Sep 2012 12:25:16 -0400 Original-Received: from conversion-daemon.a-mtaout20.012.net.il by a-mtaout20.012.net.il (HyperSendmail v2007.08) id <0MA500G006SR9X00@a-mtaout20.012.net.il> for 12314@debbugs.gnu.org; Mon, 10 Sep 2012 19:24:38 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout20.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0MA500FO06X1O4A0@a-mtaout20.012.net.il>; Mon, 10 Sep 2012 19:24:38 +0300 (IDT) In-reply-to: X-012-Sender: halo1@inter.net.il X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.13 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:64056 Archived-At: > From: Stefan Monnier > Cc: drew.adams@oracle.com, 12314@debbugs.gnu.org, cyd@gnu.org > Date: Mon, 10 Sep 2012 08:59:26 -0400 > > > See my other message: I think we are talking about 2 different > > things. My gripe was only about using the term "destructive > > modification", which muddies the waters without gaining anything. > > I don't know, to me "destructive modification" sounds like a very clear > term explaining the general kind of danger we're up against (the kind > that's summarized in Scheme by adding a "!" at the end of the > identifier). Alas, the manual itself gives no basis for such an interpretation. It says (in two different places): You can modify the CAR and CDR contents of a cons cell with the primitives `setcar' and `setcdr'. We call these "destructive" operations because they change existing list structure. Here are some functions that rearrange lists "destructively" by modifying the CDRs of their component cons cells. We call these functions "destructive" because they chew up the original lists passed to them as arguments, relinking their cons cells to form a new list that is the returned value. The only danger I glean from these is the "danger" of assigning any meaning to the original list.