phpman > perldoc > 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.

SEE ALSO
    Regexp::Common for a general description of how to use this interface.

AUTHOR
    Damian Conway (damian AT conway.org)

MAINTENANCE
    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 - 2017, 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 License.               See the file COPYRIGHT.BSD.
     4) The MIT License.               See the file COPYRIGHT.MIT.