From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Emacs regexp scan (Sep 29) Date: Sat, 5 Oct 2019 02:52:34 -0700 Organization: UCLA Computer Science Department Message-ID: <6cf4485e-3d94-ce92-6342-d83cdc7f95d7@cs.ucla.edu> References: <1697CA97-B2E6-4202-B14D-99DCF93954FD@acm.org> <02405f0d-788f-1b87-0269-b06eb2d67ff8@cs.ucla.edu> <83zhif4nq6.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="50170"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 Cc: mattiase@acm.org, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Oct 05 11:52:58 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iGgkD-000CqR-F3 for ged-emacs-devel@m.gmane.org; Sat, 05 Oct 2019 11:52:57 +0200 Original-Received: from localhost ([::1]:55252 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iGgkB-0004pp-KM for ged-emacs-devel@m.gmane.org; Sat, 05 Oct 2019 05:52:55 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:37872) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iGgjy-0004pB-Ox for emacs-devel@gnu.org; Sat, 05 Oct 2019 05:52:43 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iGgjx-00085K-8X for emacs-devel@gnu.org; Sat, 05 Oct 2019 05:52:42 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:58074) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iGgjv-00081q-V5; Sat, 05 Oct 2019 05:52:40 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 5DCF81605B6; Sat, 5 Oct 2019 02:52:36 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 57Z130cFfM3b; Sat, 5 Oct 2019 02:52:35 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 901161605B7; Sat, 5 Oct 2019 02:52:35 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id FXRTwHwDk2e8; Sat, 5 Oct 2019 02:52:35 -0700 (PDT) Original-Received: from [192.168.1.9] (cpe-23-242-74-103.socal.res.rr.com [23.242.74.103]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 61BF51605B6; Sat, 5 Oct 2019 02:52:35 -0700 (PDT) In-Reply-To: <83zhif4nq6.fsf@gnu.org> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:240607 Archived-At: On 10/5/19 1:10 AM, Eli Zaretskii wrote: > both variants are valid, so it sounds like your personal stylistic > preference is for the latter. Is that the only reason? No. The "Special Characters in Regular Expressions" subsubsection of the Elisp manual recommends putting '-' at the end of bracket expressions, since putting '-' elsewhere can cause confusion (one or two examples of which caused bugs that was fixed in that patch). The patch did not systematically put "-" at the end of every bracket expression, only those reasonably near bugs and other glitches. > If the regexp scanner needs to be pacified, isn't it better to fix the > scanner instead? No, as the regexp scanner was right here: it complained about unescaped literal "+" in regexps, which is poor practice (and is documented as poor practice in the Elisp manual). > the > original code looks simpler to me than the new one, as the former is > just a simple while loop, whereas the latter is a nested dolist. Actually the old code was so confusing that it was a bit hard to see that it was a nested loop (not a simple while loop). I originally had the same confusion that you did, which is why I redid the loops to make the nesting more obvious and to lessen the number of lines of code.