NAME

Versionify::Dispatch - A function dispatcher that respects versions, with fallback.

VERSION

This document describes Versionify::Dispatch version 0.2.4

SYNOPSIS

    use Versionify::Dispatch;
    
    my $dispatcher = Versionify::Dispatch->new(
        function => {
            1.0 => \&some_function,
            1.6 => \$sub_ref,
        }
    );
    
    $dispatcher->register(
        1.8 => sub {
            ...
        }
    );
    
    $dispatcher->get_function($desired_version)->(@args);

DESCRIPTION

This module is designed to allow a version friendly approach to dispatching function calls. One possible use of this is in an API situation, where the behaviour of functionality with a similar purpose may change over time.

When the function of a specific version is requested, the reference to the function with the highest version equal to or less than the requested version is returned by the get_function method. If no specific version is supplied, the default version is used (if set), otherwise the maximum version is used.

INTERFACE

new
    $dispatcher = Versionify::Dispatch->new(default_version => $some_version, function => \%function_mapping);

The constructor, which has two named parameters - the default version, and a hashref of the version to function mapping. Both parameters are optional, but calling get_function without having initialised the function mapping (either in the constructor, or in set_function) will not work well.

set_function
    $dispatcher->set_function(\%function_mapping);

Used to set the version -> function mapping inside the dispatcher object. This will remove any existing mapping.

set_default_version
    $dispatcher->set_default_version($some_version);

Sets the default version to be used when no version is explicitly set in the get_function call.

register
    $dispatcher->register(%function_mapping)

Registers additional version -> function mappings. This does not remove existing mappings, except when a version conflict arises - the newly registered function takes precedence.

get_function
    $return = $dispatcher->get_function($version)->(@args);
    # or
    $sub_ref = $dispatcher->get_function($version);

Returns the appropriate function. If the version string is not supplied the default version is used. The highest versioned function reference that is less than or equal to the version (or highest in general if no version was supplied and no default is set) is returned.

The version comparisons are done by the Sort::Versions module.

DIAGNOSTICS

No valid functions stored

There are no functions of a version less than or equal to the desired version (possibly no functions at all).

CONFIGURATION AND ENVIRONMENT

Versionify::Dispatch requires no configuration files or environment variables.

DEPENDENCIES

Moose
MooseX::FollowPBP
Sort::Versions

INCOMPATIBILITIES

None reported.

BUGS AND LIMITATIONS

No bugs have been reported.

Please report any bugs or feature requests to bug-versionify-dispatch@rt.cpan.org, or through the web interface at http://rt.cpan.org.

AUTHOR

Glenn Fowler <cebjyre@cpan.org>

Thanks to http://www.hiivesystems.com.

LICENCE AND COPYRIGHT

Copyright (c) 2009, Glenn Fowler <cebjyre@cpan.org>. All rights reserved.

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

DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.