From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Embedded modifiers in the regex engine Date: Thu, 25 Feb 2016 16:05:03 -0500 Message-ID: References: <87ziupinhq.fsf@secretsauce.net> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1456434332 10044 80.91.229.3 (25 Feb 2016 21:05:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 25 Feb 2016 21:05:32 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Feb 25 22:05:25 2016 Return-path: Envelope-to: ged-emacs-devel@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 1aZ36D-00043i-2t for ged-emacs-devel@m.gmane.org; Thu, 25 Feb 2016 22:05:25 +0100 Original-Received: from localhost ([::1]:45876 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aZ36C-0008MK-DF for ged-emacs-devel@m.gmane.org; Thu, 25 Feb 2016 16:05:24 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35335) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aZ367-0008MC-Tr for emacs-devel@gnu.org; Thu, 25 Feb 2016 16:05:20 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aZ363-0001u7-Jw for emacs-devel@gnu.org; Thu, 25 Feb 2016 16:05:19 -0500 Original-Received: from plane.gmane.org ([80.91.229.3]:56279) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aZ363-0001tq-DJ for emacs-devel@gnu.org; Thu, 25 Feb 2016 16:05:15 -0500 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1aZ35w-0003t2-R5 for emacs-devel@gnu.org; Thu, 25 Feb 2016 22:05:08 +0100 Original-Received: from modemcable022.171-203-24.mc.videotron.ca ([24.203.171.22]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 25 Feb 2016 22:05:08 +0100 Original-Received: from monnier by modemcable022.171-203-24.mc.videotron.ca with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 25 Feb 2016 22:05:08 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 11 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: modemcable022.171-203-24.mc.videotron.ca User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) Cancel-Lock: sha1:g3j+FyOne4cqjGCasXLj5EHMzOo= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:200680 Archived-At: > There's also been talking of rewriting the regex code, since it has acquired > much baggage over the years. Actually, I don't think it has much baggage, because it mostly hasn't been touched over the years (at least the regexp.c code). The main problem with it is the fact that it's a plain backtracking algorithm (i.e. exponential worst case), and that it's our own so it doesn't benefit from improvements added to other regexp engines. Stefan