MooseX::Types::VariantUsereContributed Perl DocuMooseX::Types::VariantTable(3)NAMEMooseX::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.
perl v5.14.1 2010-01-05 MooseX::Types::VariantTable(3)
