issue now for well over a year.
At C<$work> we are re-writing our core offering to use Moose,
-so it's continued development is assured.
+so its continued development is assured.
Several other people on #moose either have apps in production
which use Moose, or are in the process of deploying sites
(in the correct order) immediately after the instance is constructed.
This allows you to ensure that all your superclasses are initialized
properly as well. This is the best approach to take (when possible)
-because it makes sub classing your class much easier.
+because it makes subclassing your class much easier.
If you need to affect the constructor's parameters prior to the
instance actually being constructed, you have a number of options.
or any other format
To change the handling of individual parameters, there are I<coercions>
-(See the L<Moose::Cookbook::Recipe5> for a complete example and
-explaination of coercions). With coercions it is possible to morph
+(See the L<Moose::Cookbook::Basics::Recipe5> for a complete example and
+explanation of coercions). With coercions it is possible to morph
argument values into the correct expected types. This approach is the
most flexible and robust, but does have a slightly higher learning
curve.
=head3 How do I make non-Moose constructors work with Moose?
-Moose provides its own constructor, but it does it by making all
-Moose-based classes inherit from L<Moose::Object>. When inheriting
-from a non-Moose class, the inheritance chain to L<Moose::Object>
-is broken. The simplest way to fix this is to simply explicitly
-inherit from L<Moose::Object> yourself. However, this does not
-always fix the issue of a constructor. Here is a basic example of
-how this can be worked around:
+Usually the correct approach to subclassing a non Moose class is
+delegation. Moose makes this easy using the C<handles> keyword,
+coercions, and C<lazy_build>, so subclassing is often not the
+ideal route.
+
+That said, the default Moose constructor is inherited from
+L<Moose::Object>. When inheriting from a non-Moose class, the
+inheritance chain to L<Moose::Object> is broken. The simplest way
+to fix this is to simply explicitly inherit from L<Moose::Object>
+yourself.
+
+However, this does not always fix the issue of actually calling the Moose
+constructor. Fortunately L<Class::MOP::Class/new_object>, the low level
+constructor, accepts the special C<__INSTANCE__> parameter, allowing you to
+instantiate your Moose attributes:
package My::HTML::Template;
use Moose;
return $class->meta->new_object(
# pass in the constructed object
# using the special key __INSTANCE__
- __INSTANCE__ => $obj, @_
+ __INSTANCE__ => $obj,
+ @_, # pass in the normal args
);
}
Of course, this only works if both your Moose class and the
inherited non-Moose class use the same instance type (typically
-HASH refs).
+HASH refs).
+
+Note that this doesn't call C<BUILDALL> automatically, you must do that
+yourself.
Other techniques can be used as well, such as creating the object
using C<Moose::Object::new>, but calling the inherited non-Moose
Moose will still take advantage of type constraints, triggers, etc.
when creating these methods.
-If you do not like this much typing, and wish it to be a default for
-your class, please see L<Moose::Policy>, and more specifically
-L<Moose::Policy::FollowPBP>. This will allow you to write:
+If you do not like this much typing, and wish it to be a default for your
+class, please see L<MooseX::FollowPBP>. This will allow you to write:
has 'bar' => (
isa => 'Baz',
is => 'rw',
);
-And have Moose create seperate C<get_bar> and C<set_bar> methods
+And have Moose create separate C<get_bar> and C<set_bar> methods
instead of a single C<bar> method.
NOTE: This B<cannot> be set globally in Moose, as that would break
in the C<via> block.
For a more comprehensive example of using coercions, see the
-L<Moose::Cookbook::Recipe5>.
+L<Moose::Cookbook::Basics::Recipe5>.
If you need to deflate your attribute, the current best practice is to
add an C<around> modifier to your accessor. Here is some example code:
=head3 How do I get Moose to call BUILD in all my composed roles?
-See L<Moose::Cookbook::WTF> and specifically the B<How come BUILD
-is not called for my composed roles?> question in the B<Roles> section.
+See L<Moose::Cookbook::WTF> and specifically the B<Why is BUILD
+not called for my composed roles?> question in the B<Roles> section.
+
+=head3 What are Traits, and how are they different from Roles?
+
+In Moose, a trait is almost exactly the same thing as a role, except
+that traits typically register themselves, which allows you to refer
+to them by a short name ("Big" vs "MyApp::Role::Big").
+
+In Moose-speak, a I<Role> is usually composed into a I<class> at
+compile time, whereas a I<Trait> is usually composed into an instance
+of a class at runtime to add or modify the behavior of B<just that
+instance>.
+
+Outside the context of Moose, traits and roles generally mean exactly the
+same thing. The original paper called them Traits, however Perl 6 will call
+them Roles.
=head1 AUTHOR
=head1 COPYRIGHT AND LICENSE
-Copyright 2006-2008 by Infinity Interactive, Inc.
+Copyright 2006-2009 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
projects / gitmo/Moose.git / blobdiff