GNU bug report logs - #18817
\w is not synonym for [[:alnum:]] in UTF-8 locales

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Jaroslav Skarvada <jskarvad <at> redhat.com>
To: bug-grep <at> gnu.org
Subject: \w is not synonym for [[:alnum:]] in UTF-8 locales
Date: Fri, 24 Oct 2014 10:19:49 -0400 (EDT)

Hi,

in the man page there is the following sentence:

"The symbol \w is a synonym for [_[:alnum:]] and \W is a synonym for [^_[:alnum:]]"

Not counting that in man pages for some other languages (e.g. czech) there is written
that \w is a synonym for [[:alnum:]] and \W is a synonym for [^[:alnum:]], but
none of them seems to be synonym for \w | \W in UTF-8 locales:

$ export LANG=en_US.UTF-8

$ echo 'á' | grep '[[:alnum:]]'
á
$ echo 'á' | grep '[_[:alnum:]]'
á
$ echo 'á' | grep '\w'

$ echo 'á' | grep '[^[:alnum:]]'
$ echo 'á' | grep '[^_[:alnum:]]'
$ echo 'á' | grep '\W'
á

$ grep --version
grep (GNU grep) 2.20
...

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