GNU bug report logs - #15410
[:alnum:] is not [:alpha:] AND [:digit:]... [:alnum:] is [:alpha:] OR [:digit:]

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

From: Nick Aganan <thesysad <at> gmail.com>
To: bug-grep <at> gnu.org
Subject: [:alnum:] is not [:alpha:] AND [:digit:]... [:alnum:] is [:alpha:] OR
 [:digit:]
Date: Wed, 18 Sep 2013 12:07:00 -0400

[Message part 1 (text/plain, inline)]

[:alnum:] is defined as

Alphanumeric characters: ‘[:alpha:]’ *and* ‘[:digit:]’; in the ‘C’ locale
and ASCII character encoding, this is the same as ‘[0-9A-Za-z]’.



AND = need to satisfy *BOTH* alpha and digit

OR = need to satisfy *EITHER* alpha or digit





It looks like ‘[:alpha:]’ *AND* ‘[:digit:]’ functions as ‘[:alpha:]’ *OR* ‘
[:digit:]’, See example





Example:

# cat /tmp/c

adc

x1y1z123

456



# grep [[:alpha:]] /tmp/c

adc

x1y1z123



# grep [[:digit:]] /tmp/c

x1y1z123

456



# grep [[:alnum:]] /tmp/c

adc

x1y1z123

456





### if [:alnum] functions as ‘[:alpha:]’ *AND* ‘[:digit:]’, it should show
x1y1z123 only

[Message part 2 (text/html, inline)]

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