From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Regular expression libraries Date: Thu, 15 Dec 2016 23:20:28 -0800 Organization: UCLA Computer Science Department Message-ID: <460074d9-394a-5c0c-33f3-6be16e7082bb@cs.ucla.edu> References: <01d7e608-04d2-84a4-6143-e954bc9d569f@mit.edu> <2212c006-4a4d-a649-5857-01f4249d1e29@cs.ucla.edu> <874m24svia.fsf@linux-m68k.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1481872873 5761 195.159.176.226 (16 Dec 2016 07:21:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 16 Dec 2016 07:21:13 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 Cc: Emacs developers , =?UTF-8?Q?Cl=c3=a9ment_Pit--Claudel?= To: Andreas Schwab Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Dec 16 08:21:08 2016 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 1cHmpG-0000UO-TS for ged-emacs-devel@m.gmane.org; Fri, 16 Dec 2016 08:21:07 +0100 Original-Received: from localhost ([::1]:58802 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cHmpL-0006Ag-83 for ged-emacs-devel@m.gmane.org; Fri, 16 Dec 2016 02:21:11 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35009) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cHmol-00067M-1K for emacs-devel@gnu.org; Fri, 16 Dec 2016 02:20:35 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cHmoh-0004oC-T7 for emacs-devel@gnu.org; Fri, 16 Dec 2016 02:20:35 -0500 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:40820) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cHmoh-0004nl-Me for emacs-devel@gnu.org; Fri, 16 Dec 2016 02:20:31 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id ED37716008F; Thu, 15 Dec 2016 23:20:29 -0800 (PST) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id FqPAgsMKgPHU; Thu, 15 Dec 2016 23:20:29 -0800 (PST) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 4BD181600EC; Thu, 15 Dec 2016 23:20:29 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id Aw1cRSmLuvB8; Thu, 15 Dec 2016 23:20:29 -0800 (PST) Original-Received: from [192.168.1.9] (unknown [47.153.178.162]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 2BF9316008F; Thu, 15 Dec 2016 23:20:29 -0800 (PST) In-Reply-To: <874m24svia.fsf@linux-m68k.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 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:210498 Archived-At: Andreas Schwab wrote: >> Another library is in that list: >> >> - The GNU C library, which ordinarily uses a DFA but which uses >> backtracking if needed. > But it doesn't support a gap. True, but none of the others do either. Only the old glibc code (which survives only in Emacs now) does that, as far as I know. I doubt whether it'd be that hard to add gap support to any regexp matcher, as it's simply interposing an address calculation.