From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: Performance of `re-search-backward' vs `re-search-forward' Date: Mon, 12 Apr 2021 11:13:34 -0400 Message-ID: References: <87czv0awpq.fsf@mbork.pl> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="18118"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:+uwrygr9ColvGqaADeEESvWvxEo= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Apr 12 17:14:51 2021 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lVyH5-0004b5-0T for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 12 Apr 2021 17:14:51 +0200 Original-Received: from localhost ([::1]:52846 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lVyH4-0003ZS-21 for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 12 Apr 2021 11:14:50 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55464) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lVyFz-00035r-Gi for help-gnu-emacs@gnu.org; Mon, 12 Apr 2021 11:13:43 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:54802) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lVyFx-0004aY-Ez for help-gnu-emacs@gnu.org; Mon, 12 Apr 2021 11:13:43 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lVyFv-0003EG-Dg for help-gnu-emacs@gnu.org; Mon, 12 Apr 2021 17:13:39 +0200 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.io gmane.emacs.help:128969 Archived-At: > I seem to (very vaguely) remember reading that `re-search-backward' is > significantly slower than `re-search-forward'. However, I can't find > anything about it in the docstring (nor in the Elisp reference) now. Am > I even correct? I haven't looked at the code recently so my memory might be off, but I can't think of any reason why it should be noticeably slower, no. Maybe you're confusing it with `looking-back` which is much slower than `looking-at`? Stefan