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in reply to Re^2: What perl operations will consume C stack space?
in thread What perl operations will consume C stack space?

Aren't Perl regexes compiled into NFAs, and matching NFAs requires backtracking ? So I guess backtracking-heavy regexes like [a-e][r-z][4-9][^xyz] should eat up lots of stack.

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Re^4: What perl operations will consume C stack space?
by BrowserUk (Patriarch) on Feb 25, 2006 at 08:03 UTC

    Hmm. I guess I didn't realise I was asking for trade secrets here.

    Your example is incomplete as you don't say what string you would need to run it against for it to produce pathological behaviour.

    As I've mentioned, I've produced many that take a long time to process, but I'm failing to grasp the significance of what aspects take time, and which consume stack. Maybe this should be obvious to me, but it isn't.

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