1MooseX::Types::VariantTUasbelre(C3o)ntributed Perl DocumMeonotsaetXi:o:nTypes::VariantTable(3)
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NAME

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

9           # see also MooseX::Types::VariantTable::Declare for a way to
10           # declare variant table based methods
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12               use MooseX::Types::VariantTable;
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14           my $dispatch_table = MooseX::Types::VariantTable->new(
15               variants => [
16                   { type => "Foo", value => \&foo_handler },
17                   { type => "Bar", value => \&bar_handler },
18                   { type => "Item", value => \&fallback },
19               ],
20           );
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22           # look up the correct handler for $thingy based on the type constraints it passes
23           my $entry = $dispatch_table->find_variant($thingy);
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25           # or use the 'dispatch' convenience method if the entries are code refs
26           $dispatch_table->dispatch( $thingy, @args );
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DESCRIPTION

29       This object implements a simple dispatch table based on Moose type
30       constraints.
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32       Subtypes will be checked before their parents, meaning that the order
33       of the declaration does not matter.
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35       This object is used internally by Moose::Meta::Method::VariantTable and
36       MooseX::Types::VariantTable::Declare to provide primitive multi sub
37       support.
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ATTRIBUTES

40   ambigious_match_callback
41       A code reference that'll be executed when find_variant found more than
42       one matching variant for a value. It defaults to something that simply
43       croaks with an error message like this:
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45         Ambiguous match %s
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47       where %s contains a list of stringified types that matched.
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METHODS

50       new
51       add_variant $type, $value
52           Registers $type, such that $value will be returned by
53           "find_variant" for items passing $type.
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55           Subtyping is respected in the table.
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57       find_variant $value
58           Returns the registered value for the most specific type that $value
59           passes.
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61       dispatch $value, @args
62           A convenience method for when the registered values are code
63           references.
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65           Calls "find_variant" and if the result is a code reference, it will
66           "goto" this code reference with the value and any additional
67           arguments.
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69       has_type $type
70           Returns true if an entry for $type is registered.
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72       has_parent $type
73           Returns true if a parent type of $type is registered.
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TODO

76       The meta method composes in multiple inheritence but not yet with roles
77       due to extensibility issues with the role application code.
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79       When Moose::Meta::Role can pluggably merge methods variant table
80       methods can gain role composition.
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AUTHOR

83       Yuval Kogman <nothingmuch@woobling.org>
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85       Florian Ragwitz <rafl@debian.org>
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88               Copyright (c) 2008 Yuval Kogman. All rights reserved
89               This program is free software; you can redistribute
90               it and/or modify it under the same terms as Perl itself.
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94perl v5.34.0                      2022-01-21    MooseX::Types::VariantTable(3)
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