From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Tomohiro Matsuyama Newsgroups: gmane.emacs.devel Subject: Re: Patch for lookaround assertion in regexp Date: Wed, 26 Sep 2012 15:55:41 +0900 Message-ID: <20120926155541.e52fb09f40eb0d836e07ec94@cx4a.org> References: <009001ccd9c0$9bde09f0$d39a1dd0$@cfraizer.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1348642552 848 80.91.229.3 (26 Sep 2012 06:55:52 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 26 Sep 2012 06:55:52 +0000 (UTC) Cc: t.matsuyama.pub@gmail.com, emacs-devel@gnu.org To: "Colin Fraizer" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Sep 26 08:55:56 2012 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 1TGlXG-0000XB-Oy for ged-emacs-devel@m.gmane.org; Wed, 26 Sep 2012 08:55:54 +0200 Original-Received: from localhost ([::1]:43944 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGlXB-0001eN-SY for ged-emacs-devel@m.gmane.org; Wed, 26 Sep 2012 02:55:49 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:54854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGlX9-0001eI-23 for emacs-devel@gnu.org; Wed, 26 Sep 2012 02:55:47 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TGlX7-0002Bl-DU for emacs-devel@gnu.org; Wed, 26 Sep 2012 02:55:46 -0400 Original-Received: from www6399u.sakura.ne.jp ([59.106.183.193]:54194 helo=cx4a.org) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TGlX7-00028l-0U for emacs-devel@gnu.org; Wed, 26 Sep 2012 02:55:45 -0400 Original-Received: from thinkpad (p28087-ipngn1601hodogaya.kanagawa.ocn.ne.jp [180.0.57.87]) by cx4a.org (Postfix) with ESMTPSA id 70E75D8938; Wed, 26 Sep 2012 15:55:41 +0900 (JST) In-Reply-To: <009001ccd9c0$9bde09f0$d39a1dd0$@cfraizer.com> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 59.106.183.193 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:153556 Archived-At: Just reminder. I'd like to see soon the regexp lookaround assertion feature in trunk. As Stefan said, the feature could be a bottleneck of the regexp engine replacement. So, when such the replacement would happen? I'm feeling I have to wait more 10 years. I'm also skeptical in technical that Tompson's NFA is really good for Emacs. In my understand, Tompson's NFA is an algorithm that reduces backtracks with restricting dynamism, and may require cpu and memory overhead in many cases. Is that really what we want for regexp engines to improve scalability? Tomohiro