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.devel Subject: Ugly regexps Date: Tue, 02 Mar 2021 19:32:20 -0500 Message-ID: Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="23610"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Mar 03 01:33:34 2021 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 1lHFSH-00065D-I8 for ged-emacs-devel@m.gmane-mx.org; Wed, 03 Mar 2021 01:33:33 +0100 Original-Received: from localhost ([::1]:40186 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lHFSG-0005Nq-Gy for ged-emacs-devel@m.gmane-mx.org; Tue, 02 Mar 2021 19:33:32 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:37174) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lHFRN-0004mm-Nb for emacs-devel@gnu.org; Tue, 02 Mar 2021 19:32:38 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:6038) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lHFRA-0005FM-Ki for emacs-devel@gnu.org; Tue, 02 Mar 2021 19:32:36 -0500 Original-Received: from pmg1.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 89EA410023D; Tue, 2 Mar 2021 19:32:23 -0500 (EST) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 04A5F100062; Tue, 2 Mar 2021 19:32:22 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1614731542; bh=vOg/tqBWDMQgr43NodO4iviP4OQ0AdWRYw3mZIRQU/I=; h=From:To:Subject:Date:From; b=ZEX00l36PJ5ARd0F0ZoZs2aU7/6lHGES2mRB5xvICIwCTBgOMQp12bBZmFp4pdAxW cB1P+hjdGKG2Yi3R7eGdCgA/TlBSyQz7E1tTuMwp0eDuFrNOVXZWjYPWKJ/EYMFc6Q GXxSBQaailXH2FhkdD5DR2IpjUt+41J2EF2SRJanQuVE6H6G6Cca0UXbJ386VOghem 6RQllpw38+OR2fxlDHDjVLofOCuJq5tVE0axoWyanqiTJQth06mQyFj5IyWl8vbq8h 7BIGeO9J0eIGFprBZGrqBU97GYTRrf8LoIkC2UwS7Pgm2cfAPWafEY9B9JhQOpdYIm Pn7qsLcP30a5g== Original-Received: from alfajor (unknown [216.154.41.47]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id CF5C61201FF; Tue, 2 Mar 2021 19:32:21 -0500 (EST) Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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:265851 Archived-At: BTW, while this theme of ugly regexps keeps coming up, how 'bout we add a new function `ere` which converts between the ERE style of regexps where grouping parens are not escaped (and plain chars meant to match an actual paren need to be escaped instead) to ELisp-style regexps? So you can do (string-match (ere "\\(def(macro|un|subst) .{1,}")) instead of (string-match "(def\\(macro\\|un\\|subst\\) .\\{1,\\}") ? Stefan (defun ere (re) "Convert an ERE-style regexp RE to an Emacs-style regexp." (let ((pos 0) (last 0) (chunks '())) (while (string-match "\\\\.\\|[{}()|]" re pos) (let ((beg (match-beginning 0)) (end (match-end 0))) (when (subregexp-context-p re beg) (cond ;; A normal paren: add a backslash. ((= (1+ beg) end) (push (substring re last beg) chunks) (setq last beg) (push "\\" chunks)) ;; A grouping paren: skip the backslash. ((memq (aref re (1+ beg)) '(?\( ?\) ?\{ ?\} ?\|)) (push (substring re last beg) chunks) (setq last (1+ beg))))) (setq pos end))) (mapconcat #'identity (nreverse (cons (substring re last) chunks)) "")))