Regexp::Common::balanced(3pm)  User Contributed Perl Documentation  Regexp::Common::balanced(3pm)



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 AT conway.org)

MAINTAINANCE
       This package is maintained by Abigail (regexp-common AT abigail.be).

BUGS AND IRRITATIONS
       Bound to be plenty.

       For a start, there are many common regexes missing.  Send them in to
       regexp-common AT 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.



perl v5.14.2                                2013-03-09              Regexp::Common::balanced(3pm)