From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Dmitry Gutov Newsgroups: gmane.emacs.devel Subject: Re: Ugly regexps Date: Wed, 3 Mar 2021 14:17:39 +0200 Message-ID: <79673252-c43d-6916-69d9-a46207137c85@yandex.ru> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="7222"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 To: Stefan Monnier , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Mar 03 13:18:35 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 1lHQSZ-0001kv-9g for ged-emacs-devel@m.gmane-mx.org; Wed, 03 Mar 2021 13:18:35 +0100 Original-Received: from localhost ([::1]:39422 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lHQSY-0007eT-C7 for ged-emacs-devel@m.gmane-mx.org; Wed, 03 Mar 2021 07:18:34 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:35576) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lHQRn-0007Er-8E for emacs-devel@gnu.org; Wed, 03 Mar 2021 07:17:47 -0500 Original-Received: from mail-wr1-x435.google.com ([2a00:1450:4864:20::435]:38083) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lHQRl-0006Ss-H0 for emacs-devel@gnu.org; Wed, 03 Mar 2021 07:17:47 -0500 Original-Received: by mail-wr1-x435.google.com with SMTP id d15so8197069wrv.5 for ; Wed, 03 Mar 2021 04:17:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=6sKHo3H2YXJVZcMkwWHw3CGBnGvmuXj38OBUH8HrPBs=; b=j57o7MkLP5KRDDu783KSY51bb5pglEllMd0untKR0fHpTHBS4fN6CbiRnNYdHb3e3z 8xuzay2NpqKxbiaI9GCffOYWqA5xkd2WT42mJPeU+KjKJR/qpyNMxZoSKFGWZ5REIj5S nJHEGYOLp8zFyKQm+N/qTWhZS0C8Mhu+Uvv2yEy57e0AGr6Ct/rKd+AwKeDqWO6mMcS4 gqH5Qw1t+L7BDTcFsyuYtqH7vHmv4+PQ3k5wxv4i9HH+PccPEg6Pq29Ie4TTPVwwjbzv uOFCZx3ol29C/36RRKlVELotaZUen2clXceF/ViF7T4Q3RZ62dQL6XbwrNlD6uU0EG17 nUTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:references:from:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6sKHo3H2YXJVZcMkwWHw3CGBnGvmuXj38OBUH8HrPBs=; b=gxYtsuXXoLNQuInvifYO1KdDIkmQ/CAMEiCUTQM8tu4JzUgckT6PLtz+Bl1rAmbG9w EsVzUYduheXhtwAh7M3Z2vsgiXyKrBgQfb6KSOJbgcgW0LbfHW4IAY5veXodPpmkXNtE uapNz9GvQ/0nOVwbLwCY63eZM0PDTDmBMJQ6sHeRXth1SImQa3rBOpo5geJI3QoQ+a/R pNulqHgB+K7JWr/mjqw66P4ur4HScrcLpDmuvkKPEfcHTloWhwIiB80a+YQogxqYEsLD /omHs1wkcbc37SmrddWiuoCj0puKrBtq70hqWO5E6vMFcN3bHWVLly0aDuCyRJMRwjbT jHBg== X-Gm-Message-State: AOAM533h1A03vKuVT5qQ+D7BaIffqKHr4vUBYpG1AFxto2JjOZDCM0Jo JCSuInKt1syM1jb0RqvD1dYAqebJdIA= X-Google-Smtp-Source: ABdhPJwqYX+B8AurQO5RNtCieaEeFkbAHyacU0H546BrI2dvqzbHcJhTF0uhm2BEpHgOPytduh6MIA== X-Received: by 2002:a5d:4904:: with SMTP id x4mr27047331wrq.69.1614773863599; Wed, 03 Mar 2021 04:17:43 -0800 (PST) Original-Received: from [192.168.0.6] ([46.251.119.176]) by smtp.googlemail.com with ESMTPSA id r11sm9464500wrm.26.2021.03.03.04.17.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Mar 2021 04:17:42 -0800 (PST) In-Reply-To: Content-Language: en-US Received-SPF: pass client-ip=2a00:1450:4864:20::435; envelope-from=raaahh@gmail.com; helo=mail-wr1-x435.google.com X-Spam_score_int: -14 X-Spam_score: -1.5 X-Spam_bar: - X-Spam_report: (-1.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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:265876 Archived-At: On 03.03.2021 02:32, Stefan Monnier wrote: > (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)) ""))) See also xref--regexp-to-extended, my last attempt at RE->ERE conversion, though woefully lacking in tests. Its goal was to move in the other direction, but (unless I'm missing something about the syntax differences) this function is reversible.