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From: Alan Mackenzie <acm@muc.de>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: 18577@debbugs.gnu.org
Subject: bug#18577: Regexp I-search: [(error Stack overflow in regexp matcher)]
Date: Sun, 28 Sep 2014 12:37:17 +0000	[thread overview]
Message-ID: <20140928123717.GC3157@acm.acm> (raw)
In-Reply-To: <87mw9kt3m7.fsf@igel.home>

Good afternoon, Andreas!

On Sun, Sep 28, 2014 at 12:56:48PM +0200, Andreas Schwab wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > With point at BOB, do C-M-s and enter this regular expression at the
> > prompt:

> > /\*\(\([^'*]\|\*[^/']\)*\*?'\([^'*]\|\*[^/']\)*\*?'\)*\([^'*]\|\*[^'/]\)*\*?'\([^'*]\|\*[^/']\)*\*?\*/

> \(...\(...\)*...\)* is bad.  \(...\)*\(...\)* is also bad.

But they both seem essential to the regexp's purpose.

> Both can cause combinatorial explosions in backtracking.

Is this a defect in my regexp or in the regexp engine?  If the former,
how could I rewrite the regexp so that it would not hit these problems?

> Andreas.

> -- 
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
> "And now for something completely different."

-- 
Alan Mackenzie (Nuremberg, Germany).





  reply	other threads:[~2014-09-28 12:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-28  8:55 bug#18577: Regexp I-search: [(error Stack overflow in regexp matcher)] Alan Mackenzie
2014-09-28 10:56 ` Andreas Schwab
2014-09-28 12:37   ` Alan Mackenzie [this message]
2014-09-28 12:48     ` Andreas Schwab
2014-09-28 17:35       ` Stefan Monnier
2014-11-27  8:44         ` Tassilo Horn
2021-10-23  2:47         ` Stefan Kangas
2021-10-23  7:32           ` Eli Zaretskii
2021-10-23  8:30             ` Stefan Kangas
2021-10-23  8:39               ` Eli Zaretskii
2021-10-23  9:32                 ` Stefan Kangas
2021-10-23 11:27                   ` Eli Zaretskii
2021-10-24 22:08                     ` Stefan Kangas

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