I try to write my regexen backtracking-free, as, I believe, anyone should. And in that case greediness is very desired and useful most of the time. Non-greediness basically means that you match broader than you really need to - it works because you "forwardtrack", you gobble the string one submatch at a time. It is better to match more narrowly and greedily, since a greedy match will gobble up a lot of the string in one fell swoop and do less superfluous searching. In simple cases the regex optimizer is smart enough to simplify a non-greedy match into a Boyer-Moore search, but when you're working with a complex regex you really want to match narrowly and greedily.

Regexen are a tricky art.

Makeshifts last the longest.


In reply to Re: Perl6: too bad non-greediness is not made the default by Aristotle
in thread Parsing with Perl 6 by jryan

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