Note that it's only ‘pure’ regexes (for which Ratazong did indicate a preference) that are equivalent to finite automata. I know that back-references make regexes essentially push-down automata. Are Perl's regexes still ‘only’ that powerful? I guess that they're not, really, because they can execute embedded code; but that's not playing fair.

In reply to Re^2: check for square-number with a regex by JadeNB
in thread check for square-number with a regex by Ratazong

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