Beau E. Cox wrote: >> Reading over Friedl's "Mastering Regular Expressions", and he gives a >> problem on pp. 143-144 where a poorly formed expression takes >> might-as-well-be-forever to finish. >> >> I can't replicate the problem. >> >> I'm using 5.8. Have they upgraded that problem away? >> I wanted to duplicate the results as practice, but can't make the >> pattern *ever* take so much as a whole second. >> >> What am I doing right? :) >> > > Interesting. Since I don't have the book, can you > post a snippet as am example?
here is one(from Programming Perl) that takes "forever" to fail: #!/usr/bin/perl -w use strict; $_ = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'; /a*a*a*a*a*a*a*a*a*a*a*a*a*a*a*a*a*[b]/; __END__ the backtracking nature of Perl's reg. engine makes it forever to fail. generally, the solution will be using one of the reg. extension, negative/positive lookhead/lookbehind david -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
