From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: How are regexen implemented in Emacs? Date: Mon, 12 Dec 2022 20:09:42 +0100 Message-ID: <877cywe8w9.fsf@mbork.pl> References: <87a63see6m.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="35917"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: mu4e 1.1.0; emacs 29.0.50 Cc: help-gnu-emacs@gnu.org To: Stefan Monnier Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Mon Dec 12 20:10:36 2022 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 1p4oCB-00095I-2X for geh-help-gnu-emacs@m.gmane-mx.org; Mon, 12 Dec 2022 20:10:35 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p4oBV-0003eW-2U; Mon, 12 Dec 2022 14:09:53 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p4oBS-0003e1-S2 for help-gnu-emacs@gnu.org; Mon, 12 Dec 2022 14:09:50 -0500 Original-Received: from mail.mojserwer.eu ([195.110.48.8]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p4oBR-0000Ou-0c for help-gnu-emacs@gnu.org; Mon, 12 Dec 2022 14:09:50 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 4661C2271598; Mon, 12 Dec 2022 20:09:47 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EaJJylxsZ2F4; Mon, 12 Dec 2022 20:09:41 +0100 (CET) Original-Received: from localhost (178235147188.dynamic-3-poz-k-0-1-0.vectranet.pl [178.235.147.188]) by mail.mojserwer.eu (Postfix) with ESMTPSA id C442C2271597; Mon, 12 Dec 2022 20:09:41 +0100 (CET) In-reply-to: Received-SPF: pass client-ip=195.110.48.8; envelope-from=mbork@mbork.pl; helo=mail.mojserwer.eu 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 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:141686 Archived-At: On 2022-12-12, at 19:16, Stefan Monnier via Users list for the GNU Emacs text editor wrote: >> https://www.gnu.org/software/emacs/manual/html_node/elisp/Regexp-Problems.html >> and started to wonder if the hints there mean that Emacs has a "naive", >> backtracking regex engine or a FA-based one? > > Naive! And what are the reasons? Out of curiosity: would implementing a FA-based one be a very big undertaking? (And no, I won't do it, if only because I don't know C.) Best, -- Marcin Borkowski http://mbork.pl