NAME
MooseX::RelatedClasses - Parameterized role for related class attributes
VERSION
This document describes version 0.004 of MooseX::RelatedClasses -
released April 22, 2013 as part of MooseX-RelatedClasses.
SYNOPSIS
# a related class...
package My::Framework::Thinger;
# ...
# our "parent" class...
package My::Framework;
use Moose;
use namespace::autoclean;
# with this...
with 'MooseX::RelatedClasses' => {
name => 'Thinger',
};
# ...we get:
has thinger_class => (
traits => [ Shortcuts ], # MooseX::AttributeShortcuts
is => 'lazy',
isa => LoadableClass, # MooseX::Types::LoadableClass
constraint => sub { $_->isa('Thinger') }, # MX::AttributeShortcuts
builder => sub { ... compose original class and traits ... },
);
has thinger_class_traits => (
traits => [ Shortcuts ],
is => 'lazy',
isa => ArrayRef[LoadableRole],
builder => sub { [ ] },
);
has original_thinger_class => (
traits => [ Shortcuts ],
is => 'lazy',
isa => LoadableClass,
constraint => sub { $_->isa('Thinger') },
coerce => 1,
init_arg => undef,
builder => sub { 'My::Framework::Thinger' },
);
# multiple related classes can be handled in one shot:
with 'MooseX::RelatedClasses' => {
names => [ qw{ Thinger Dinger Finger } ],
};
# if you're using this role and the name of the class is _not_ your
# related namespace, then you can specify it:
with 'MooseX::RelatedClasses' => {
# e.g. My::Framework::Recorder::Thinger
name => 'Thinger',
namespace => 'My::Framework::Recorder',
};
# if you want to specify another class w/o any common namespace as
# related:
with 'MooseX::RelatedClasses' => {
namespace => undef,
name => 'LWP::UserAgent',
};
DESCRIPTION
Have you ever built out a framework, or interface API of some sort, to
discover either that you were hardcoding your related class names (not
very extension-friendly) or writing the same code for the same type of
attributes to specify what related classes you're using?
Alternatively, have you ever been using a framework, and wanted to tweak
one tiny bit of behaviour in a subclass, only to realize it was written
in such a way to make that difficult-to-impossible without a significant
effort?
This package aims to end that, by providing an easy, flexible way of
defining "related classes", their base class, and allowing traits to be
specified.
This is early code!
This package is very new, and is still being vetted "in use", as it
were. The documentation (or tests) may not be 100%, but it's in active
use. Pull requests are happily received :)
Documentation
See the SYNOPSIS for information; the tests are also useful here as
well.
I _did_ warn you this is a very early release, right?
ROLE PARAMETERS
Parameterized roles accept parameters that influence their construction.
This role accepts the following parameters.
name
The name of a class, without the prefix, to consider related. e.g. if
My::Foo is our namespace and My::Foo::Bar is the related class:
name => 'Bar'
...is the correct specification.
This parameter is optional, so long as either the names or
all_in_namespace parameters are given.
names [ ... ]
One or more names that would be legal for the name parameter.
all_in_namespace (Bool)
True if all findable packages under the namespace should be used as
related classes. Defaults to false.
namespace
The namespace our related classes live in. If this is not given
explicitly, the name of the consuming class will be used as the
namespace. If the consuming class is not available (e.g. it's being
constructed by something other than a consumer), then this parameter is
mandatory.
This parameter will also accept an explicit 'undef'. If this is the
case, then related classes must be specified by their full name and it
is an error to attempt to enable the all_in_namespace option.
e.g.:
with 'MooseX::RelatedClasses' => {
namespace => undef,
name => 'LWP::UserAgent',
};
...will provide the "lwp__user_agent_class", "lwp__user_agent_traits"
and "original_lwp__user_agent_class" attributes.
load_all (Bool)
If set to true, all related classes are loaded as we find them. Defaults
to false.
private (Bool)
If true, attributes, accessors and builders will all be named according
to the same rules MooseX::AttributeShortcuts uses. (That is, in general
prefixed with an "_".)
INSPIRATION / MADNESS
The Class::MOP / Moose MOP show the beginnings of this: with attributes
or methods named a certain way (e.g. *_metaclass()) the class to be used
for a particular thing (e.g. attribute metaclass) is stored in a fashion
such that a subclass (or trait) may overwrite and provide a different
class name to be used.
So too, here, we do this, but in a more flexible way: we track the
original related class, any additional traits that should be applied,
and the new (anonymous, typically) class name of the related class.
Another example is the (very useful and usable) Net::Amazon::EC2. It
uses Moose, is nicely broken out into discrete classes, etc, but does
not lend itself to easy on-the-fly extension by developers with traits.
ANONYMOUS CLASS NAMES
Note that we use MooseX::Traitor to compose anonymous classes, so the
"anonymous names" will look less like:
Moose::Meta::Package::__ANON__::SERIAL::...
And more like:
My::Framework::Thinger::__ANON__::SERIAL::...
Anonymous classes are only ever composed if traits for a related class
are supplied.
SOURCE
The development version is on github at
<http://github.com/RsrchBoy/moosex-relatedclasses> and may be cloned
from <git://github.com/RsrchBoy/moosex-relatedclasses.git>
BUGS
Please report any bugs or feature requests on the bugtracker website
https://github.com/RsrchBoy/moosex-relatedclasses/issues
When submitting a bug or request, please include a test-file or a patch
to an existing test-file that illustrates the bug or desired feature.
AUTHOR
Chris Weyl <cweyl@alumni.drew.edu>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2012 by Chris Weyl.
This is free software, licensed under:
The GNU Lesser General Public License, Version 2.1, February 1999