Text::Pipe - Common text filter API


    my $pipe = Text::Pipe->new('List::First', code => { $_ < 7 });
    my $result = $pipe->filter('foo');

    # or

    use Web::Scraper;
    my $scraper = scraper {
        process '//p/a',
            'texts[]' => [ 'TEXT', PIPE('Trim'), PIPE('Uppercase') ];


This class is a factory for text pipes. A pipe has a filter() method through which input can pass. The input can be a string or a reference to an array of strings. Pipes can be stacked together using Text::Pipe::Stackable.

The problem that this distribution tries to solve is that there are several distributions on CPAN which use text filtering in some way or other, for example the Template Toolkit or Web::Scraper. But each distribution is somewhat different, and they have to reimplement the same text filters over and over again.

This distribution aims at offering a common text filter API. So if you want to use text pipes with Template Toolkit, you just need to write an adapter. With Web::Scraper, you can even use text pipes directly Using the PIPE() function, as shown in the synopsis.

Text pipe segments live in the Text::Pipe:: namespace. So if you implement a Text::Pipe::Foo::Bar pipe segment, you can instantiate it with

    my $pipe = Text::Pipe->new('Foo::Bar');

Some pipe segments take arguments. These are described in their respective class documentations.


    my $pipe = PIPE('Reverse', times => 2, join => ' = ');
    my $pipe = PIPE('UppercaseFirst');

Text::Pipe exports, on request, the function PIPE() that makes it easier to construct pipes. It takes the same arguments as new() and returns the corresponding pipe.


    my $pipe = Text::Pipe->new('List::First', code => { $_ < 7 });

Constructs a new pipe. The first argument is the pipe segment type - in the example above a Text::Pipe::List::First would be constructed. The remaining arguments are passed to that segment's constructor.

    Text::Pipe->def_pipe('Foobar', sub { lc $_[1] });
    my $pipe_lowercase = Text::Pipe->new('Foobar');
    is($pipe_lowercase->filter('A TEST'), 'a test', 'lowercase pipe');

This method provides a lightweight way to define a new pipe segment class. The first argument is the segment type - in the example above, a new segment class Text::Pipe::Foobar would be defined. The second argument is a coderef that acts as the segment's filter. The segment class will subclass Text::Pipe::Base.


No bugs have been reported.

Please report any bugs or feature requests through the web interface at


See perlmodinstall for information and options on installing Perl modules.


The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit to find a CPAN site near you. Or see

The development version lives at Instead of sending patches, please fork this project using the standard git and github infrastructure.


Marcel Grünauer, <>


Copyright 2007-2009 by the authors.

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