GNU bug report logs - #2881
23.0.91; inconsistent regexps with "explicitly numbered group"

Previous Next

Package: emacs;

Reported by: Joe Corneli <holtzermann17 <at> gmail.com>

Date: Fri, 3 Apr 2009 19:20:03 UTC

Severity: normal

Done: Stefan Monnier <monnier <at> IRO.UMontreal.CA>

Bug is archived. No further changes may be made.

Full log

Message #10 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Andreas Schwab <schwab <at> linux-m68k.org>
To: Joe Corneli <holtzermann17 <at> gmail.com>
Cc: 2881 <at> debbugs.gnu.org, emacs-pretest-bug <at> gnu.org
Subject: Re: bug#2881: 23.0.91; inconsistent regexps with "explicitly numbered group"
Date: Fri, 03 Apr 2009 21:55:42 +0200

Joe Corneli <holtzermann17 <at> gmail.com> writes:

> Please execute the following forms with C-x C-e.  Form 1
> and Form 3 return `t' (Yes, we are looking at the
> indicated regular expression), whereas Form 2 returns
> `nil' (even though from the Elisp reference page "34.3.1.3
> Backslash Constructs in Regular Expressions", it appears
> that this form ought to return `t' like the others).

     `\|' applies to the largest possible surrounding expressions.
     Only a surrounding `\( ... \)' grouping can limit the grouping
     power of `\|'.

> (let ((possible-environments
>        "\\(?1:lisp\\)\\|\\(?1:idea\\)\\|\\(?1:common\\)") )
>       (looking-at
>             (concat "\n*?\\\\begin{"
>                     possible-environments
>                     "}")))


The three alternatives of this regexp are "\n*?\\\\begin{\\(?1:lisp\\)",
"\\(?1:idea\\)" and "\\(?1:common\\)".

Andreas.

-- 
Andreas Schwab, schwab <at> linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
This bug report was last modified 16 years and 54 days ago.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.