From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: efficient regular expression that never matches Date: Sat, 21 Nov 2015 10:04:14 -0500 Message-ID: References: <2929ffa3-d339-43c3-84e8-2211dcc53695@googlegroups.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1448118306 25727 80.91.229.3 (21 Nov 2015 15:05:06 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 21 Nov 2015 15:05:06 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Nov 21 16:04:58 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1a09if-0005Kn-Ao for geh-help-gnu-emacs@m.gmane.org; Sat, 21 Nov 2015 16:04:53 +0100 Original-Received: from localhost ([::1]:52577 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a09ie-0003Uj-I6 for geh-help-gnu-emacs@m.gmane.org; Sat, 21 Nov 2015 10:04:52 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:55171) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a09iT-0003Ud-9R for help-gnu-emacs@gnu.org; Sat, 21 Nov 2015 10:04:41 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a09iO-0006o5-AZ for help-gnu-emacs@gnu.org; Sat, 21 Nov 2015 10:04:41 -0500 Original-Received: from plane.gmane.org ([80.91.229.3]:47405) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a09iO-0006o1-3R for help-gnu-emacs@gnu.org; Sat, 21 Nov 2015 10:04:36 -0500 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1a09iG-0004fc-52 for help-gnu-emacs@gnu.org; Sat, 21 Nov 2015 16:04:28 +0100 Original-Received: from 23-91-153-239.cpe.pppoe.ca ([23.91.153.239]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 21 Nov 2015 16:04:28 +0100 Original-Received: from monnier by 23-91-153-239.cpe.pppoe.ca with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 21 Nov 2015 16:04:28 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 8 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 23-91-153-239.cpe.pppoe.ca User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) Cancel-Lock: sha1:hDzliAU5bkT+SAgctH/KlOCHWeM= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:108175 Archived-At: > until the end of the line. So, if I can do something like "^ OR CONDITION IMPOSSIBLE>", then the engine should detect before reading all > characters of the line, I presume. Perhaps "^\uFFFFF" can be a solution? That's what the \\` is for in my solution. Stefan