NAME
    MooseX::Role::AttributeOverride - Allow roles to modify attributes

VERSION
      This document describes v0.0.8 of MooseX::Role::AttributeOverride - released June 22, 2011 as part of MooseX-Role-AttributeOverride.

SYNOPSIS
        {
            package MyApp::Role;
            use Moose::Role;
            use MooseX::Role::AttributeOverride;

            has_plus 'fun' => ( default => 'yep', );

            has_plus 'alive' => (
                default => 'yep',
                override_ignore_missing => 1,
            );
        }
        {
            package MyApp::Trait;
            use Moose::Role;
            use MooseX::Role::AttributeOverride;

            has_plus default => (
                default => sub {
                    my $attr = shift;
                    return sub { $attr->name }
                }
            );
        }
        {
            package MyApp;
            use Moose 1.9900;

            has nolife => (
                is     => 'rw',
                isa    => 'Str',
                traits => ['MyApp::Trait'],
            );

            has 'fun' => (
                is  => 'rw',
                isa => 'Str'
            );

            with qw(MyApp::Role);
        }
        {
            package main;
            use feature 'say';

            my $test = MyApp->new();

            say "I have " . $test->nolife;
            # Says I have nolife
            say "Are you having fun? " . $test->fun;
            # Says Are you having fun? yep

        }

DESCRIPTION
    Moose doesn't allow roles to override attributes using the has '+attr'
    method. There are several good reasons for that. Basically, "that's not
    what a role is for." A role is a set of requirements with defaults. A
    class should always be able to override a role.

    But sometimes you want a role to add features to a class. This is why
    Moose has method modifiers. This extension adds attribute modifiers.

INTERFACE
    has_plus
        This has exactly the same syntax as the Moose has command, except
        you should not use a plus to indicate you are overriding an
        attribute.

    has_plus options

        override_ignore_missing
            Setting this to a true value will allow your role to have
            modifications to attributes that may not exist in the class it
            is applied to. The default is to die in these cases.

            For example:

                package MyApp::Role;
                use Moose::Role;
                use MooseX::Role::AttributeOverride;

                has_plus 'alive' => (
                    default => 'yep',
                    override_ignore_missing => 1,
                );

                package MyApp;
                use Moose;

                with qw(MyApp::Role);
                # I'm not dead yet.

            The above would not die, even though the MyApp package has no
            attribute named 'fun.'

IMPORTANT NOTE
    Always apply a role that uses this module after defining attributes.

META USAGE
    This role can be used in traits. For example, the following works:

        {
            package MyApp::Trait;
            use Moose::Role;
            use MooseX::Role::AttributeOverride;

            has_plus default => (
                default => sub {
                    my $attr = shift;
                    return sub { $attr->name }
                }
            );
        }
        {
            package MyApp;
            use Moose 1.9900;

            has nolife => (
                is     => 'rw',
                isa    => 'Str',
                traits => ['MyApp::Trait'],
            );

            with qw(MyApp::Role);
        }
        {
            package main;
            use feature 'say';

            my $test = MyApp->new();

            say "I have " . $test->nolife;
            # Says I have nolife
        }

DIAGNOSTICS
    Can't find attribute $attr required by $role
        You will see this error if your role has an attribute modification
        for an attribute that is not in the class. You can squash this by
        setting the 'override_ignore_missing' option in your 'has_plus'
        command.

    Attempt to call has_plus on an invalid object
        You really should never see this. Please file a bug report if you
        do. A test case would be nice as well.

    Illegal inherited options
        Moose will throw this error if you try to change an accessor option.
        See the Moose manual for more details.

    Do not use a plus prefix with the has_plus sugar
        There is no need for a plus sign on your attribute:

            # Good
            has 'children', trait => ['good']

            # Bad. Will die.
            has '+children', trait => ['naughty']

DEPENDENCIES
    Moose 1.9900 or newer. Older versions may be supported in a future
    version of this module.

INCOMPATIBILITIES
    I am sure that there are some MooseX modules that will not work with
    this. Please let me know, and I will at least document them.

BUGS AND LIMITATIONS
    This is not the intended use of roles. As a result, take into account
    the following:

    *   Order matters! If two roles modify the same attribute in the same
        way, the second one applied will be the one that is used. This
        behavior, however, relies on Moose keeping track of order, which it
        generally does a good job of, but no guarantees.

    *   Currently, the value of the attribute is clobbered when the role is
        applied. This may change in the future.

    *   This works the same as '+has'. This means that you can't override
        accessor methods. This is a very sensible Moose limitation.

    *   After having an issue with Moose, clone_and_inherit_options, and
        traits that use _process_options, I reimplemented
        clone_and_inherit_optiosn in a way that fixes it. Sort of. A side
        effect of this is that has_plus will not allow you to override the
        lazy option, without a default or builder option.

    *   If you try adding this role before adding the attributes, it won't
        work.

    I am relatively new to Moose. I had an itch, and wrote this Module to
    scratch it. Please let me know how to make this module better.

    For bugs, test cases are great!

SEE ALSO
    Please see those modules/websites for more information related to this
    module.

    *   Moose

    *   Moose::Manual::Attributes

SUPPORT
  Websites
    The following websites have more information about this module, and may
    be of help to you. As always, in addition to those websites please use
    your favorite search engine to discover more resources.

    *   Search CPAN

        The default CPAN search engine, useful to view POD in HTML format.

        <http://search.cpan.org/dist/MooseX-Role-AttributeOverride>

    *   CPAN Testers Dependencies

        The CPAN Testers Dependencies is a website that shows a chart of the
        test results of all dependencies for a distribution.

        <http://deps.cpantesters.org/?module=MooseX::Role::AttributeOverride
        >

    *   CPANTS

        The CPANTS is a website that analyzes the Kwalitee ( code metrics )
        of a distribution.

        <http://cpants.perl.org/dist/overview/MooseX-Role-AttributeOverride>

    *   CPAN Testers

        The CPAN Testers is a network of smokers who run automated tests on
        uploaded CPAN distributions.

        <http://www.cpantesters.org/distro/M/MooseX-Role-AttributeOverride>

    *   CPAN Testers Matrix

        The CPAN Testers Matrix is a website that provides a visual way to
        determine what Perls/platforms PASSed for a distribution.

        <http://matrix.cpantesters.org/?dist=MooseX-Role-AttributeOverride>

  Email
    You can email the author of this module at "EALLENIII at cpan.org"
    asking for help with any problems you have.

  Bugs / Feature Requests
    Please report any bugs or feature requests by email to
    "bug-moosex-role-attributeoverride at rt.cpan.org", or through the web
    interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=MooseX-Role-AttributeOve
    rride>. You will be automatically notified of any progress on the
    request by the system.

  Source Code
    The code is open to the world, and available for you to hack on. Please
    feel free to browse it and play with it, or whatever. If you want to
    contribute patches, please send me a diff or prod me to pull from your
    repository :)

    <http://github.com/riemann42/MooseX-Role-AttributeOverride>

      git clone git://github.com/riemann42/MooseX-Role-AttributeOverride.git

AUTHOR
    Edward Allen <ealleniii_at_cpan_dot_org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2011 by Edward J. Allen III.

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

DISCLAIMER OF WARRANTY
    BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
    FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
    PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER
    EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
    ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH
    YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
    NECESSARY SERVICING, REPAIR, OR CORRECTION.

    IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
    WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
    REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE
    TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR
    CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
    SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
    RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
    FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
    SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
    DAMAGES.

