From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: "Perry E. Metzger" Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 938d252 4/4: Make regex matching reentrant; update syntax during match Date: Tue, 19 Jun 2018 12:27:00 -0400 Message-ID: <20180619122700.6e15d6d2@jabberwock.cb.piermont.com> References: <20180616204650.8423.73499@vcs0.savannah.gnu.org> <20180616204653.86AFC203CB@vcs0.savannah.gnu.org> <04e89d2beffedcc102b811863910c1ec.squirrel@dancol.org> <20180618115941.4f22a9d3@jabberwock.cb.piermont.com> <1de38eca2662563e9e08006c88a6d2e5.squirrel@dancol.org> <20180619094005.11465a87@jabberwock.cb.piermont.com> <20180619094442.41287e4b@jabberwock.cb.piermont.com> <20180619103002.4f000018@jabberwock.cb.piermont.com> <20180619103325.7d79befb@jabberwock.cb.piermont.com> <9a5f3904-8298-b5e3-cd97-b525f602cc63@dancol.org> <20180619113729.3d1a4c0b@jabberwock.cb.piermont.com> <68752b66-75d2-a732-6ce2-3d8a13b7ff37@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1529426298 26467 195.159.176.226 (19 Jun 2018 16:38:18 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 19 Jun 2018 16:38:18 +0000 (UTC) Cc: Daniel Colascione , Stefan Monnier , emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jun 19 18:38:14 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 1fVJdz-0006l4-Dl for ged-emacs-devel@m.gmane.org; Tue, 19 Jun 2018 18:38:11 +0200 Original-Received: from localhost ([::1]:43739 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVJg6-0000IP-FE for ged-emacs-devel@m.gmane.org; Tue, 19 Jun 2018 12:40:22 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52765) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVJTJ-0008CE-Ht for emacs-devel@gnu.org; Tue, 19 Jun 2018 12:27:10 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fVJTI-0004wS-Kw for emacs-devel@gnu.org; Tue, 19 Jun 2018 12:27:09 -0400 Original-Received: from hacklheber.piermont.com ([2001:470:30:84:e276:63ff:fe62:3400]:55336) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fVJTI-0004mZ-H0 for emacs-devel@gnu.org; Tue, 19 Jun 2018 12:27:08 -0400 Original-Received: from snark.cb.piermont.com (localhost [127.0.0.1]) by hacklheber.piermont.com (Postfix) with ESMTP id C890419F; Tue, 19 Jun 2018 12:27:00 -0400 (EDT) Original-Received: from jabberwock.cb.piermont.com (jabberwock.cb.piermont.com [10.160.2.107]) by snark.cb.piermont.com (Postfix) with ESMTP id AC0872DEC77; Tue, 19 Jun 2018 12:27:00 -0400 (EDT) In-Reply-To: <68752b66-75d2-a732-6ce2-3d8a13b7ff37@cs.ucla.edu> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2001:470:30:84:e276:63ff:fe62:3400 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:226516 Archived-At: On Tue, 19 Jun 2018 09:20:43 -0700 Paul Eggert wrote: > If we're going to go to that much work, why not use glibc regex? It > uses a DFA and falls back on backtracking only when needed. > Although glibc regex isn't maintained that well, it's at least > maintained, which TRE is not. And it does have some advantages: it > has an API that is like Emacs src/regex.c, and it won't have any > licensing issues. Its main disadvantage (it doesn't support split > buffers) could be overcome fairly easily, either by adding support > for that back into the library, or arranging for a single array > whenever the regex matcher is called. That's also an option. I really like the idea of being able to do approximate searches in files, but it's not that big a deal. (Does the glibc stuff have appropriate unicode support etc?) Truthfully, my biggest interest is in seeing the default regex syntax migrate to something much more modern, and that can be done regardless of which engine we use. Perry -- Perry E. Metzger perry@piermont.com