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Re: regexp word boundaries

On Mon, Dec 03, 2012 at 12:16:57AM +0100, Alistair Crooks wrote:
> It's long been a pet peeve of mine that regexp matching for word
> boundaries has an annoying dependency on the implementation.
> My thanks to the many people hwo helped out with this table, reproduced
> below, which shows what works, and what doesn't work, when attempting
> to match the zero-width pattern at a word boundary.
\b is a perl feature

man perlre explains about that, and \<
(BRE's versus ERE's, essentially).

> regexp word boundaries
>                 \<      \b      [[:<:]]
> perl            not     works   not

(see manpage, as noted)

> freebsd vile    not     works   not
> netbsd vile     works   not     not

without version numbers, I can only guess what you're referring to with
vile.  \< has been part of vile for a long time; \b is different from perl
(vile matches whitespace rather than a word boundary).  Both are in the
help-file.  See

Thomas E. Dickey

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