In the case you mentioned, you can avoid zero-lengths. However, negative look{ahead,behind}s are sometimes more difficult to convert.

Simple zero-length assertions like \w are present in many other programs using regexps (sometimes called \<,\>), what proves that they are useful and neccessary.

In reply to Re: lookahead / lookbehind vs other regex methods by ambrus
in thread lookahead / lookbehind vs other regex methods by shemp

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