From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Juri Linkov Newsgroups: gmane.emacs.devel Subject: Re: Looking at function Date: Mon, 11 Jul 2022 22:14:48 +0300 Organization: LINKOV.NET Message-ID: <86y1wzv4uv.fsf@mail.linkov.net> References: <86edz8k6q1.fsf@mail.linkov.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="40576"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (x86_64-pc-linux-gnu) Cc: emacs-devel@gnu.org To: Dmitry Gutov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Jul 11 21:17:46 2022 Return-path: Envelope-to: ged-emacs-devel@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 1oAyuf-000AQb-FW for ged-emacs-devel@m.gmane-mx.org; Mon, 11 Jul 2022 21:17:45 +0200 Original-Received: from localhost ([::1]:43008 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oAyue-0005K2-4t for ged-emacs-devel@m.gmane-mx.org; Mon, 11 Jul 2022 15:17:44 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44970) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oAyse-0004Tr-8s for emacs-devel@gnu.org; Mon, 11 Jul 2022 15:15:40 -0400 Original-Received: from relay3-d.mail.gandi.net ([217.70.183.195]:50049) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oAysc-0004T3-FW for emacs-devel@gnu.org; Mon, 11 Jul 2022 15:15:39 -0400 Original-Received: (Authenticated sender: juri@linkov.net) by mail.gandi.net (Postfix) with ESMTPSA id 751C660002; Mon, 11 Jul 2022 19:15:32 +0000 (UTC) In-Reply-To: (Dmitry Gutov's message of "Mon, 11 Jul 2022 04:26:15 +0300") Received-SPF: pass client-ip=217.70.183.195; envelope-from=juri@linkov.net; helo=relay3-d.mail.gandi.net X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:292062 Archived-At: >> 1. Replace ‘looking-at’ with a call to the search function, >> but keep it at point by prepending ‘\\=’ to the regexp. >> Can it break a complex regexp? > > I suppose it can. Even a simple one (that has \\| inside without > a grouping). This is what the fix for xref successfully uses in bug#53758 with changes in perform-replace from bug#14013. (However, none of these variants is suitable for replacing another call of looking-at in isearch-search-and-update.) > Do we have a clear understanding of the idea behind this looking-at call? > > The comment says: > > ;; Otherwise, if matching a regular expression, do the next > ;; match now, since the replacement for this match may > ;; affect whether the next match is adjacent to this one. > ;; If that match is empty, don't use it. > > What happens if there are multiple adjacent matches in a row, not just 2? > I suppose the replacement could be performed for the first one, then the > next one is "popped" becoming the current and looking-at is called again > near its end? > > If so, perhaps a good alternative is to stop caring about whether those > matches are adjacent and always store the latest two matches, whether they > are next to each other or not. The sole purpose of this "do the next match now" hack is to handle a special use case that is tested in test/lisp/replace-tests.el: ;; Test case from commit 5632eb272c7 ("a a a " "C-M-% \\ba SPC RET c RET !" "ccc") ; not "ca c" ;; Test case from commit 5632eb272c7 ("a a a " "\\ba " "c" nil t nil nil nil nil nil nil nil "ccc") ; not "ca c"