Re^3: Perl module search engine

[jacques]

in reply to Re^2: Perl module search engine
in thread Perl module search engine

...endlessly backtracking regexes.

Could you please provide an example? I would like to investigate it and see if there's a problem. Thanks.

I always envisioned HTML::Perlinfo::Modules as something Perl developers might use, not the general public (which is why I wasn't too concerned that the HTML was absolutely perfect). You know, something you could install in your local intranet to see what's on your system.

[moritz]

Could you please provide an example?

perl -wle '$_="abc" x $ARGV[0]; m/(((.){1,20}.+){1,34}){2,4}[d]/' 10

And now tell me how long your perl takes to find out that this regex fails ;-)

$ARGV[0]	time in s
3	0.003
4	0.016
5	0.167
6	2.0
7	23.8
8	146

I wasn't patient enough to see how long it takes to match with $ARGV[0] == 9, or in other words against 27 characters of input.

[jacques]

Yes, it's a problem. I just tested your example. I am going to have to figure out a way to sniff it out and upload a new version. Maybe I should just not allow regexps? Thanks for the info.