From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: c-forward-sws: Is the code right? Date: Tue, 03 Apr 2018 17:03:46 -0400 Message-ID: References: <20180327164156.GA4105@ACM> <20180328190518.GA6592@ACM> <83d0zndv5a.fsf@gnu.org> <20180402195816.GB16027@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1522789433 9938 195.159.176.226 (3 Apr 2018 21:03:53 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 3 Apr 2018 21:03:53 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Apr 03 23:03:49 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1f3T5k-0002KT-3q for ged-emacs-devel@m.gmane.org; Tue, 03 Apr 2018 23:03:44 +0200 Original-Received: from localhost ([::1]:36204 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3T7p-0006PY-Jv for ged-emacs-devel@m.gmane.org; Tue, 03 Apr 2018 17:05:53 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60807) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3T62-00059b-QW for emacs-devel@gnu.org; Tue, 03 Apr 2018 17:04:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f3T5x-0004m0-Lp for emacs-devel@gnu.org; Tue, 03 Apr 2018 17:04:02 -0400 Original-Received: from [195.159.176.226] (port=47364 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1f3T5x-0004l2-Eb for emacs-devel@gnu.org; Tue, 03 Apr 2018 17:03:57 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1f3T3o-0007G8-VO for emacs-devel@gnu.org; Tue, 03 Apr 2018 23:01:45 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 21 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:2DOoqNXnUqH+J4p6DtqTLe/T7Cw= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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:224283 Archived-At: >>> I've just commented these "a\\`"s everywhere, and committed the fixes to >>> master. >> Maybe we should have a >> >> (defconst empty-regexp "\\`\\'a" >> "Regular expression which cannot match anything.") >> >> in subr.el? > Perhaps "nomatch-regexp" would be a better name ? There are several > regexp constructs that match an empty string, rather than failing to > match anything. Right, I was thinking of regexps in the mathematical sense where they describe a "set of strings", hence the "nomatch" regexp corresponds to an "empty" regexp. IIRC Brzozovski used ∅ for this empty regexp and ε for the regexp which matches the empty string. "nomatch" would be less confusing, indeed. Stefan