NAME

       MooseX::Types::VariantTable - Type constraint based variant table

SYNOPSIS

           # see also MooseX::Types::VariantTable::Declare for a way to
           # declare variant table based methods

               use MooseX::Types::VariantTable;

           my $dispatch_table = MooseX::Types::VariantTable->new(
               variants => [
                   { type => "Foo", value => \&foo_handler },
                   { type => "Bar", value => \&bar_handler },
                   { type => "Item", value => \&fallback },
               ],
           );

           # look up the correct handler for $thingy based on the type constraints it passes
           my $entry = $dispatch_table->find_variant($thingy);

           # or use the 'dispatch' convenience method if the entries are code refs
           $dispatch_table->dispatch( $thingy, @args );

DESCRIPTION

       This object implements a simple dispatch table based on Moose type constraints.

       Subtypes will be checked before their parents, meaning that the order of the declaration
       does not matter.

       This object is used internally by Moose::Meta::Method::VariantTable and
       MooseX::Types::VariantTable::Declare to provide primitive multi sub support.

ATTRIBUTES

   ambigious_match_callback
       A code reference that'll be executed when find_variant found more than one matching
       variant for a value. It defaults to something that simply croaks with an error message
       like this:

         Ambiguous match %s

       where %s contains a list of stringified types that matched.

METHODS

       new
       add_variant $type, $value
           Registers $type, such that $value will be returned by "find_variant" for items passing
           $type.

           Subtyping is respected in the table.

       find_variant $value
           Returns the registered value for the most specific type that $value passes.

       dispatch $value, @args
           A convenience method for when the registered values are code references.

           Calls "find_variant" and if the result is a code reference, it will "goto" this code
           reference with the value and any additional arguments.

       has_type $type
           Returns true if an entry for $type is registered.

       has_parent $type
           Returns true if a parent type of $type is registered.

TODO

       The meta method composes in multiple inheritence but not yet with roles due to
       extensibility issues with the role application code.

       When Moose::Meta::Role can pluggably merge methods variant table methods can gain role
       composition.

AUTHOR

       Yuval Kogman <nothingmuch@woobling.org>

       Florian Ragwitz <rafl@debian.org>

COPYRIGHT

               Copyright (c) 2008 Yuval Kogman. All rights reserved
               This program is free software; you can redistribute
               it and/or modify it under the same terms as Perl itself.