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Subject: 
Re: Perl5 regexen: exponential backtracking behavior when mixing \n and \s
Newsgroups: 
lugnet.off-topic.geek
Date: 
Sun, 17 Dec 2000 15:37:08 GMT
Viewed: 
77 times
  
In lugnet.off-topic.geek, Christopher Lindsey writes:
Todd Lehman wrote:
Anyone out there running Perl 5.6 or higher?  Try running this little test
proggy that compares the approximate CPU execution times of two regexen:

[lindsey@wolrab ~]$ uname -a
Linux wolrab 2.2.16-22smp #1 SMP Tue Aug 22 16:39:21 EDT 2000 i686 unknown
[lindsey@wolrab ~]$ cat /etc/redhat-release
Red Hat Linux release 7.0 (Guinness)

[...]
17 0.00
18 0.00
19 0.00
20 0.00
21 0.00
22 0.00

Awesome.  Was that Perl 5.6?  So it's smart enough to compile \n\s into a
DFA instead of an NDFA?  Wow.

--Todd



Message has 2 Replies:
  Re: Perl5 regexen: exponential backtracking behavior when mixing \n and \s
 
(...) yah, that's what I got as well: greywolf$ perl -v This is perl, v5.6.0 built for i686-linux guess 5.6 kicks bootie :) (24 years ago, 17-Dec-00, to lugnet.off-topic.geek)
  Re: Perl5 regexen: exponential backtracking behavior when mixing \n and \s
 
(...) Yup! lindsey@wolrab|/afs/...dsey|[65]> /usr/bin/perl -v This is perl, v5.6.0 built for i386-linux Chris (24 years ago, 18-Dec-00, to lugnet.off-topic.geek)

Message is in Reply To:
  Re: Perl5 regexen: exponential backtracking behavior when mixing \n and \s
 
(...) [lindsey@wolrab ~]$ uname -a Linux wolrab 2.2.16-22smp #1 SMP Tue Aug 22 16:39:21 EDT 2000 i686 unknown [lindsey@wolrab ~]$ cat /etc/redhat-release Red Hat Linux release 7.0 (Guinness) s/(?:\n[ \t]*)+$// 0 0.00 1 0.00 2 0.00 3 0.00 4 0.00 5 (...) (24 years ago, 17-Dec-00, to lugnet.off-topic.geek)

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