Regexp::Common::balanced
Section: User Contributed Perl Documentation (3pm)
Updated: 2013-03-09
Index
Return to Main Contents
NAME
Regexp::Common::balanced -- provide regexes for strings with balanced
parenthesized delimiters or arbitrary delimiters.
SYNOPSIS
use Regexp::Common qw /balanced/;
while (<>) {
/$RE{balanced}{-parens=>'()'}/
and print q{balanced parentheses\n};
}
DESCRIPTION
Please consult the manual of Regexp::Common for a general description
of the works of this interface.
Do not use this module directly, but load it via Regexp::Common.
$RE{balanced}{-parens}
Returns a pattern that matches a string that starts with the nominated
opening parenthesis or bracket, contains characters and properly nested
parenthesized subsequences, and ends in the matching parenthesis.
More than one type of parenthesis can be specified:
$RE{balanced}{-parens=>'(){}'}
in which case all specified parenthesis types must be correctly balanced within
the string.
Since version 2013030901, $1 will always be set (to the entire
matched substring), regardless whether "{-keep}" is used or not.
$RE{balanced}{-begin => begin}{-end => end}
Returns a pattern that matches a string that is properly balanced
using the
begin and
end strings as start and end delimiters.
Multiple sets of begin and end strings can be given by separating
them by
"|"s (which can be escaped with a backslash).
qr/$RE{balanced}{-begin => "do|if|case"}{-end => "done|fi|esac"}/
will match properly balanced strings that either start with do and
end with done, start with if and end with fi, or start with
case and end with esac.
If -end contains less cases than -begin, the last case of -end
is repeated. If it contains more cases than -begin, the extra cases
are ignored. If either of -begin or -end isn't given, or is empty,
-begin => '(' and -end => ')' are assumed.
Since version 2013030901, $1 will always be set (to the entire
matched substring), regardless whether "{-keep}" is used or not.
Note
Since version 2013030901 the pattern will make of the recursive construct
"(?-1)", instead of using the problematic
"(??{ })" construct.
This fixes an problem that was introduced in the 5.17 development track.
This also means the pattern is no longer available for Perls older than 5.010.
SEE ALSO
Regexp::Common for a general description of how to use this interface.
AUTHOR
Damian Conway (
damian@conway.org)
MAINTAINANCE
This package is maintained by Abigail (
regexp-common@abigail.be).
BUGS AND IRRITATIONS
Bound to be plenty.
For a start, there are many common regexes missing.
Send them in to regexp-common@abigail.be.
LICENSE and COPYRIGHT
This software is Copyright (c) 2001 - 2013, Damian Conway and Abigail.
This module is free software, and maybe used under any of the following
licenses:
1) The Perl Artistic License. See the file COPYRIGHT.AL.
2) The Perl Artistic License 2.0. See the file COPYRIGHT.AL2.
3) The BSD Licence. See the file COPYRIGHT.BSD.
4) The MIT Licence. See the file COPYRIGHT.MIT.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- $RE{balanced}{-parens}
-
- $RE{balanced}{-begin => begin}{-end => end}
-
- Note
-
- SEE ALSO
-
- AUTHOR
-
- MAINTAINANCE
-
- BUGS AND IRRITATIONS
-
- LICENSE and COPYRIGHT
-