\b matches a word boundary. It's a zero width anchor. It works like qr/(?<=\w)(?=\W)|(?<=\W)(?=\w)/ which is likely to blow your mind unless you are comfortable with look around matches.

Premature optimization is the root of all job security

In reply to Re^2: Regular Expression, substitution by GrandFather
in thread Regular Expression, substitution by lobs

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