I'd prefer to use this instead of Sidhekin's because it lets your pattern start it's match normally and doesn't require retrying at ever offset. The following lets the pattern match however it normally would but fails when it succeeds.

/(?(??{...})(?!))/;

In Perl 5.10, this is especially nice [Updated: Oops. Forgot the (?:...|) to have a success branch]

/...(*COMMIT)(?!)/;/(?:...(*COMMIT)(?!)|)/

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In reply to Re: Negating Regexes: Tips, Tools, And Tricks Of The Trade by diotalevi
in thread Negating Regexes: Tips, Tools, And Tricks Of The Trade by Limbic~Region

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