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

This document describes Versionify::Dispatch version 0.2.4

    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);

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.

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.

No valid functions stored

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

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

Moose

MooseX::FollowPBP

Sort::Versions

None reported.

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.

Glenn Fowler <cebjyre@cpan.org>

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

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.

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