From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14116 invoked by alias); 4 Jul 2013 07:42:57 -0000 Mailing-List: contact glibc-bugs-regex-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: glibc-bugs-regex-owner@sourceware.org Received: (qmail 14071 invoked by uid 48); 4 Jul 2013 07:42:53 -0000 From: "bonzini at gnu dot org" To: glibc-bugs-regex@sourceware.org Subject: [Bug regex/52] Repeated and nested subexpressions (reproducible in most other engines) Date: Thu, 04 Jul 2013 07:42:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: glibc X-Bugzilla-Component: regex X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: minor X-Bugzilla-Who: bonzini at gnu dot org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: gotom at debian dot or.jp X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2013-07/txt/msg00006.txt.bz2 http://sourceware.org/bugzilla/show_bug.cgi?id=52 --- Comment #13 from Paolo Bonzini --- At the time I reported the bug, I'm pretty sure I checked a few proprietary Unices. Also, even though it is not POSIX RE, Perl regular expressions have the same behavior. While it is true that backreferences can make this bug affect the overall outcome of the match, it is still a very weird regular expression. Thanks for mentioning musl's matcher, I'll check it out. Matching backreferences at a decent speed _and_ obeying the POSIX leftmost/longest rules is very hard to do. The glibc matcher unfortunately is very badly documented and the backreference part of it is basically black magic. :( -- You are receiving this mail because: You are on the CC list for the bug.