Re: [Boost-users] [regex] problem w/ regex::extended

Subject: Re: [Boost-users] [regex] problem w/ regex::extended
From: Mark R Stallard (stallard_at_[hidden])
Date: 2015-02-16 08:57:50

U. Mutlu <for-gmane_at_[hidden]> wrote:

> Thank you.
> But on the "POSIX Extended Regular Expression Syntax" page
> the escape sequence \w is very well listed:

I should have explained this more thoroughly. I did not say
that POSIX does not support \w at all.  What I said was:

> I suspected that Perl would support the escape sequence \w
> inside a [] character set, but POSIX extended might not.
> The tests I ran affirmed those suspicions.

POSIX extended supports \w, but NOT inside a [] character set.
For POSIX extended, the regex [\w\-\.~/]+ is the same as
[w\-\.~/]+.  Inside of [], POSIX extended sees \w as a
literal "w".

You can test this yourself if you have an up-to-date version
of the egrep shell command.

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