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MooseX-Attribute-Prototype-0.04
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/ MooseX::Attribute::Prototype

NAME

MooseX::Attribute::Prototype - Borrow and Extend Moose Attrtibutes

VERSION

0.03 - Released 2009-01-26

SYNOPSIS

    package MyClass;
        use Moose;
        use MooseX::Attribute::Prototype;

        has 'my_attr' => (
                is                => 'rw' ,
                isa               => 'Str' ,
                prototype => 'MyRole/MyAttr' ,
        );

DESCRIPTION

This module loads a metaclass role that supports attribute prototyping, the practice of borrowing and (possibly) extending/overriding a predefined attributes. It works much like extending a class.

When you have a prototype in your attribute definition, you borrow the settings from the prototype. In many situations, this is all you will need. But sometimes you want to tweak beahaviors and/or defaults. MooseX::Attribute::Prototype allows the defaults to be overridden with those defined in the class. The resulting attribute specification is installed in the class.

How to use Attribute Prototypes

Prototypes are just any ole attributes in any ole Moose::Role. To use them simply specify the prototype in your attribute definitions:

        prototype => 'role/attribute'

where c<role> is the name of the role and c<attribute> is the name of the attribute.

WHY?

MooseX::Role::Parameterized and MooseX::Types abstract the roles and types, respectively. But surprisinly, there is no similar functionality for attributes. Moose leans towards viewing attributes as containers for data. However, it also provides the ability to store full-blown objects. And as they become more complex the can become unweildy. In fact, the attribute specifications, can often become the majority of code for a given application. Why not seperate these attributes into horizontally-reusable roles?

MooseX::Attribute::Prototype takes a functional view of attributes -- slots that can contain anything -- and provides an easy interface for making these slots reusable.

Why Not Moose's Attribute Clone Mechanism?

Moose's attribute cloning does not allow you to change the name of the derived attribute. You can take the defaults of an attribute from a role and change it's default, but good luck in changing the name of the attribute.

Subclassing Benefit

Moose makes subclassing easy through the c<extends> sugar. More often than not, however, Moose applications are an amalgam of objects including other Moose classes and other CPAN modules. In these cases, one often places the objects in the the attributes. MooseX::Attributes::Prototypes allows for the Moosifying of these CPAN classes in a reusable way.

SEE ALSO

MooseX::Attribute::Prototype::Meta,

MooseX::Attribute::Prototype::Object,

MooseX::Attribute::Prototype::Collection,

Moose

MooseX::Role::Parameterized

MooseX::Types

AUTHOR

Christopher Brown, <ctbrown at cpan.org>

BUGS

Please report any bugs or feature requests to bug-moosex-attribute-prototype at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=MooseX-Attribute-Prototype. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc MooseX::Attribute::Prototype

You can also look for information at:

ACKNOWLEDGEMENTS

Though they would probably cringe to hear it, this effort would not have been possible without:

Shawn Moore

David Rolsky

Thomas Doran

Stevan Little

COPYRIGHT & LICENSE

Copyright 2008 Christopher Brown and Open Data Group http://opendatagroup.com.

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