NAME
    String::Filter - a regexp-based string filter

SYNOPSIS
        # define the rules that convert tweets to HTML
        # (handles url, @user, #hash)
        my $sf = String::Filter->new(
            rules        => [
                'http://[A-Za-z0-9_\-\~\.\%\?\#\@/]+' => sub {
                    my $url = shift;
                    sprintf(
                        '<a href="%s">%s</a>',
                        encode_entities($url),
                        encode_entities($url),
                    );
                },
                '(?:^|\s)\@[A-Za-z0-9_]+' => sub {
                    $_[0] =~ /^(.*?\@)(.*)$/;
                    my ($prefix, $user) = ($1, $2);
                    sprintf(
                        '%s<a href="http://twitter.com/%s">%s</a>',
                        encode_entities($prefix),
                        encode_entities($user),
                        encode_entities($user),
                    );
                },
                '(?:^|\s)#[A-Za-z0-9_]+' => sub {
                    $_[0] =~ /^(.?)(#.*)$/;
                    my ($prefix, $hashtag) = ($1, $2);
                    sprintf(
                        '%s<a href="http://twitter.com/search?q=%s">%s</a>',
                        encode_entities($prefix),
                        encode_entities(uri_escape($hashtag)),
                        $hashtag,
                    );
                },
            ],
            default_rule => sub {
                my $text = shift;
                encode_entities($text);
            },
        );
    
        # convert a tweet to HTML
        my $html = $sf->filter($tweet);

DESCRIPTION
    The module is a regexp-based string filter, that can merge multiple
    conversion rules for converting strings. The primary target of the
    module is to convert inline markups (such as the tweets of Twitter) to
    HTML.

FUNCTIONS
  new
    instantiates the filter object. Takes a hash as an argument recognizing
    the attributes below.

   rules
    arrayref of more than zero "regexp => subref"s. For more information see
    add_rule.

   default_rule
    default filter function. See the default_rule accessor for more
    information.

  filter($input)
    Converts the input string using the given rules and returns it.

  add_rule($regexp => $subref)
    adds a conversion rule. For each substring matching the regular
    expression the subref will be invoked with the substring as the only
    argument. The subref should return the filtered output of the substring.

   default_rule([$subref])
    setter / getter for the default conversion function. The subref should
    accept a string and return the filtered output of the input.

COPYRIGHT
    Copyright (C) 2010 Cybozu Labs, Inc. Written by Kazuho Oku.

LICENSE
    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    See <http://www.perl.com/perl/misc/Artistic.html>