Hi

I just stumbled over an example for something even worse:

infinite loops

perlre#Repeated Patterns Matching a Zero-length Substring

> A common abuse of this power stems from the ability to make infinite loops using regular expressions, with something as innocuous as:

> "foo" =~ m{ ( o? )* }x;

> The o? matches at the beginning of "foo", and since the position in the string is not moved by the match, o? would match again and again because of the "*" quantifier. Another common way to create a similar cycle is with the looping modifier /g:

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^2: Is it safe to use external strings for regexes? (infinite loops) by LanX
in thread Is it safe to use external strings for regexes? by stevieb

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