phpman > perldoc > Moose::Meta::Attribute::Native(3pm)

NAME
    Moose::Meta::Attribute::Native - Delegate to native Perl types

VERSION
    version 2.2200

SYNOPSIS
      package MyClass;
      use Moose;

      has 'mapping' => (
          traits  => ['Hash'],
          is      => 'rw',
          isa     => 'HashRef[Str]',
          default => sub { {} },
          handles => {
              exists_in_mapping => 'exists',
              ids_in_mapping    => 'keys',
              get_mapping       => 'get',
              set_mapping       => 'set',
              set_quantity      => [ set => 'quantity' ],
          },
      );

      my $obj = MyClass->new;
      $obj->set_quantity(10);      # quantity => 10
      $obj->set_mapping('foo', 4); # foo => 4
      $obj->set_mapping('bar', 5); # bar => 5
      $obj->set_mapping('baz', 6); # baz => 6

      # prints 5
      print $obj->get_mapping('bar') if $obj->exists_in_mapping('bar');

      # prints 'quantity, foo, bar, baz'
      print join ', ', $obj->ids_in_mapping;

DESCRIPTION
    Native delegations allow you to delegate to native Perl data structures as if they were objects.
    For example, in the "SYNOPSIS" you can see a hash reference being treated as if it has methods
    named "exists()", "keys()", "get()", and "set()".

    The delegation methods (mostly) map to Perl builtins and operators. The return values of these
    delegations should be the same as the corresponding Perl operation. Any deviations will be
    explicitly documented.

API
    Native delegations are enabled by passing certain options to "has" when creating an attribute.

  traits
    To enable this feature, pass the appropriate name in the "traits" array reference for the
    attribute. For example, to enable this feature for hash reference, we include 'Hash' in the list
    of traits.

  isa
    You will need to make sure that the attribute has an appropriate type. For example, to use this
    with a Hash you must specify that your attribute is some sort of "HashRef".

  handles
    This is just like any other delegation, but only a hash reference is allowed when defining
    native delegations. The keys are the methods to be created in the class which contains the
    attribute. The values are the methods provided by the associated trait. Currying works the same
    way as it does with any other delegation.

    See the docs for each native trait for details on what methods are available.

TRAITS FOR NATIVE DELEGATIONS
    Below are some simple examples of each native trait. More features are available than what is
    shown here; this is just a quick synopsis.

    Array (Moose::Meta::Attribute::Native::Trait::Array)
            has 'queue' => (
                traits  => ['Array'],
                is      => 'ro',
                isa     => 'ArrayRef[Str]',
                default => sub { [] },
                handles => {
                    add_item  => 'push',
                    next_item => 'shift',
                    # ...
                }
            );

    Bool (Moose::Meta::Attribute::Native::Trait::Bool)
            has 'is_lit' => (
                traits  => ['Bool'],
                is      => 'ro',
                isa     => 'Bool',
                default => 0,
                handles => {
                    illuminate  => 'set',
                    darken      => 'unset',
                    flip_switch => 'toggle',
                    is_dark     => 'not',
                    # ...
                }
            );

    Code (Moose::Meta::Attribute::Native::Trait::Code)
            has 'callback' => (
                traits  => ['Code'],
                is      => 'ro',
                isa     => 'CodeRef',
                default => sub {
                    sub {'called'}
                },
                handles => {
                    call => 'execute',
                    # ...
                }
            );

    Counter (Moose::Meta::Attribute::Native::Trait::Counter)
            has 'counter' => (
                traits  => ['Counter'],
                is      => 'ro',
                isa     => 'Num',
                default => 0,
                handles => {
                    inc_counter   => 'inc',
                    dec_counter   => 'dec',
                    reset_counter => 'reset',
                    # ...
                }
            );

    Hash (Moose::Meta::Attribute::Native::Trait::Hash)
            has 'options' => (
                traits  => ['Hash'],
                is      => 'ro',
                isa     => 'HashRef[Str]',
                default => sub { {} },
                handles => {
                    set_option => 'set',
                    get_option => 'get',
                    has_option => 'exists',
                    # ...
                }
            );

    Number (Moose::Meta::Attribute::Native::Trait::Number)
            has 'integer' => (
                traits  => ['Number'],
                is      => 'ro',
                isa     => 'Int',
                default => 5,
                handles => {
                    set => 'set',
                    add => 'add',
                    sub => 'sub',
                    mul => 'mul',
                    div => 'div',
                    mod => 'mod',
                    abs => 'abs',
                    # ...
                }
            );

    String (Moose::Meta::Attribute::Native::Trait::String)
            has 'text' => (
                traits  => ['String'],
                is      => 'ro',
                isa     => 'Str',
                default => q{},
                handles => {
                    add_text     => 'append',
                    replace_text => 'replace',
                    # ...
                }
            );

COMPATIBILITY WITH MooseX::AttributeHelpers
    This feature used to be a separated CPAN distribution called MooseX::AttributeHelpers.

    When the feature was incorporated into the Moose core, some of the API details were changed. The
    underlying capabilities are the same, but some details of the API were changed.

BUGS
    See "BUGS" in Moose for details on reporting bugs.

AUTHORS
    *   Stevan Little <stevan AT cpan.org>

    *   Dave Rolsky <autarch AT urth.org>

    *   Jesse Luehrs <doy AT cpan.org>

    *   Shawn M Moore <sartak AT cpan.org>

    *   יובל קוג'מן (Yuval Kogman) <nothingmuch AT woobling.org>

    *   Karen Etheridge <ether AT cpan.org>

    *   Florian Ragwitz <rafl AT debian.org>

    *   Hans Dieter Pearcey <hdp AT cpan.org>

    *   Chris Prather <chris AT prather.org>

    *   Matt S Trout <mstrout AT cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2006 by Infinity Interactive, Inc.

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