[http://textism.com/tools/textile/|Textile] is a a simple syntax for nudging plain text into structurally sound and stylistically rich web content. The functionality is provided via CPAN module [cpan://Text::Textile].

Now I want to include a shortcut for a link to a page to view an item to which I have the key. As documentation is rather thin I provide the snippet to demonstrate the use of a filter.

Example source text:

See ==|item|12== for details

This shall be replaced with:

See <a href="http://localhost:3000/item/view/12">Item 12</a> for details

Filters are stored in a hash with their name as key and a coderef to be called when the text is to be processed. Special parameters can be passed with the filter_param method, e.g. a base URL in my case.

I hope the example is self-explaining enough.

Edit: sorry, preview is missing

use warnings;
use strict;

use Text::Textile;

my $textile = new Text::Textile;

# to be used as a parameter
my $base_url = 'http://localhost:3000';

# This is my source text
my $source = '==|item|12==';

# define a hash of filters,
# here we just have one
$textile->filters(
    {   item => sub {
            my ( $text, $r_param_list ) = (@_);
            my $url = $param->[0];
            # $text contains the string between the last
            # '|' and the '==', here I expect a number
            $text =~ s/(\d+)/$url\/item\/view\/$1/;
            return $text;
            }
    }
);

# Set the base URL as parameter (localhost for test)
$textile->filter_param( [ $base_url ] );

# generate the result
$dest = $textile->process($source);

# $dest is the result