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.

AUTHOR

Damian Conway (damian@conway.org)

MAINTENANCE

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 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 License.               See the file COPYRIGHT.BSD.
 4) The MIT License.               See the file COPYRIGHT.MIT.