From: <tomas@tuxteam.de>
To: 36251@debbugs.gnu.org
Subject: bug#36251: Regex library doesn't recognize ']' in a character class
Date: Sun, 16 Jun 2019 21:40:08 +0200 [thread overview]
Message-ID: <20190616194008.GA2901@tuxteam.de> (raw)
In-Reply-To: <ad11135c-ebba-4ffb-827d-a8eebd7fa023@Canary>
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On Sun, Jun 16, 2019 at 08:16:29PM +0300, Abdulrahman Semrie wrote:
>
> I am using the pattern [\\[\\]a-zA-Z]+ to match a string with left or right bracket in it. However, the string-match function doesn’t match the ‘]’ character. To demonstrate with an example, try the following funciton:
>
> (string-match "[\\[\\]a-zA-Z]+" "Text[ab]”)
>
> The result for the above function should have been a match structure with Text[ab] matched. However, the string-match returns #f which is incorrect. To test if the pattern I am using was right, I tried on regex101.com and it works. Here (https://regex101.com/r/VAl6aI/1) is the link that demonstrates that it works.
>
> Hence, the above leads me to believe there is a bug in the regex library that mishandles ] character in character-classes
If I understood you correctly, you are using POSIX regular
expressions. Within a bracket expression ([...]), you can't
escape ']' with a backslash. Just put the ] as first character,
like so:
[][a-zA-Z]
Quoting the man page (regex(7)):
A bracket expression is a list of characters enclosed in "[]".
It normally matches any single character from the list (but see
below). If the list begins with '^', it matches any single
character (but see below) not from the rest of the list. [...]
To include a literal ']' in the list, make it the first
character (following a possible '^'). To include a literal
'-', make it the first or last character, or the second endpoint
of a range [...]
See also [1], but the man page is more complete.
(I'm assuming your Guile is linked against some POSIX regex library).
Cheers
-- t
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next prev parent reply other threads:[~2019-06-16 19:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-16 17:16 bug#36251: Regex library doesn't recognize ']' in a character class Abdulrahman Semrie
2019-06-16 19:40 ` tomas [this message]
2019-06-18 11:08 ` Mark H Weaver
2019-06-18 11:20 ` tomas
2019-06-28 11:21 ` David Pirotte
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