use 5.008;
-our $VERSION = '0.55_02';
+our $VERSION = '0.58';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';
use Moose::Exporter;
-use Class::MOP 0.64;
+use Class::MOP 0.67;
use Moose::Meta::Class;
use Moose::Meta::TypeConstraint;
use Moose::Meta::Role::Application::ToClass;
use Moose::Meta::Role::Application::ToRole;
use Moose::Meta::Role::Application::ToInstance;
-use Moose::Meta::Role::Application::ToMetaclassInstance;
use Moose::Util::TypeConstraints;
use Moose::Util ();
+sub throw_error {
+ # FIXME This
+ shift;
+ goto \&confess
+}
+
sub extends {
my $class = shift;
# this checks the metaclass to make sure
# it is correct, sometimes it can get out
# of sync when the classes are being built
- my $meta = Moose::Meta::Class->initialize($class)->_fix_metaclass_incompatability(@supers);
+ my $meta = Moose::Meta::Class->initialize($class);
$meta->superclasses(@supers);
}
my %args = @_;
my $class = $args{for_class}
- or confess "Cannot call init_meta without specifying a for_class";
+ or Moose->throw_error("Cannot call init_meta without specifying a for_class");
my $base_class = $args{base_class} || 'Moose::Object';
my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
- confess
- "The Metaclass $metaclass must be a subclass of Moose::Meta::Class."
+ Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Class.")
unless $metaclass->isa('Moose::Meta::Class');
# make a subtype for each Moose class
if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
unless ( $meta->isa("Moose::Meta::Class") ) {
- confess "$class already has a metaclass, but it does not inherit $metaclass ($meta)";
+ Moose->throw_error("$class already has a metaclass, but it does not inherit $metaclass ($meta)");
}
} else {
# no metaclass, no 'meta' method
: ref($ancestor_meta));
# if we have an ancestor metaclass that inherits $metaclass, we use
- # that. This is like _fix_metaclass_incompatability, but we can do it now.
+ # that. This is like _fix_metaclass_incompatibility, but we can do it now.
# the case of having an ancestry is not very common, but arises in
# e.g. Reaction
my $method_meta = $class->meta;
( blessed($method_meta) && $method_meta->isa('Moose::Meta::Class') )
- || confess "$class already has a &meta function, but it does not return a Moose::Meta::Class ($meta)";
+ || Moose->throw_error("$class already has a &meta function, but it does not return a Moose::Meta::Class ($meta)");
$meta = $method_meta;
}
Moose::Meta::Role::Application::ToClass
Moose::Meta::Role::Application::ToRole
Moose::Meta::Role::Application::ToInstance
- Moose::Meta::Role::Application::ToMetaclassInstance
));
1;
The main goal of Moose is to make Perl 5 Object Oriented programming
easier, more consistent and less tedious. With Moose you can to think
-more about what you want to do and less about the mechanics of OOP.
+more about what you want to do and less about the mechanics of OOP.
-Additionally, Moose is built on top of L<Class::MOP>, which is a
-metaclass system for Perl 5. This means that Moose not only makes
-building normal Perl 5 objects better, but it provides the power of
-metaclass programming as well.
+Additionally, Moose is built on top of L<Class::MOP>, which is a
+metaclass system for Perl 5. This means that Moose not only makes
+building normal Perl 5 objects better, but it provides the power of
+metaclass programming as well.
=head2 New to Moose?
-If you're new to Moose, the best place to start is the
-L<Moose::Cookbook>. The recipes on Moose basics will get you up to
-speed with many of Moose's features quickly. Once you have an idea of
-what Moose can do, you can use the API documentation to get more
-detail on features which interest you.
+If you're new to Moose, the best place to start is the L<Moose::Intro>
+docs, followed by the L<Moose::Cookbook>. The intro will show you what
+Moose is, and how it makes Perl 5 OO better.
+
+The cookbook recipes on Moose basics will get you up to speed with
+many of Moose's features quickly. Once you have an idea of what Moose
+can do, you can use the API documentation to get more detail on
+features which interest you.
=head2 Moose Extensions
only). These will create either a read/write accessor or a read-only
accessor respectively, using the same name as the C<$name> of the attribute.
-If you need more control over how your accessors are named, you can use the
-I<reader>, I<writer> and I<accessor> options inherited from
-L<Class::MOP::Attribute>, however if you use those, you won't need the I<is>
-option.
+If you need more control over how your accessors are named, you can
+use the L<reader|Class::MOP::Attribute/reader>,
+L<writer|Class::MOP::Attribute/writer> and
+L<accessor|Class::MOP::Attribute/accessor> options inherited from
+L<Class::MOP::Attribute>, however if you use those, you won't need the
+I<is> option.
=item I<isa =E<gt> $type_name>
the attribute is set. The CODE ref will be passed the instance itself, the
updated value and the attribute meta-object (this is for more advanced fiddling
and can typically be ignored). You B<cannot> have a trigger on a read-only
-attribute.
+attribute.
+
+B<NOTE:> Triggers will only fire when you B<assign> to the attribute,
+either in the constructor, or using the writer. Default and built values will
+B<not> cause the trigger to be fired.
=item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE>
Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
example.
+=item I<builder>
+
+The value of this key is the name of the method that will be called to
+obtain the value used to initialize the attribute. See the L<builder
+option docs in Class::MOP::Attribute|Class::MOP::Attribute/builder>
+for more information.
+
+=item I<default>
+
+The value of this key is the default value which will initialize the attribute.
+
+NOTE: If the value is a simple scalar (string or number), then it can
+be just passed as is. However, if you wish to initialize it with a
+HASH or ARRAY ref, then you need to wrap that inside a CODE reference.
+See the L<default option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/default> for more
+information.
+
+=item I<initializer>
+
+This may be a method name (referring to a method on the class with
+this attribute) or a CODE ref. The initializer is used to set the
+attribute value on an instance when the attribute is set during
+instance initialization (but not when the value is being assigned
+to). See the L<initializer option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/initializer> for more
+information.
+
+=item I<clearer>
+
+Allows you to clear the value, see the L<clearer option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/clearer> for more
+information.
+
+=item I<predicate>
+
+Basic test to see if a value has been set in the attribute, see the
+L<predicate option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/predicate> for more
+information.
+
=back
=item B<has +$name =E<gt> %options>
=head1 EXTENDING AND EMBEDDING MOOSE
-Moose also offers some options for extending or embedding it into your
-own framework. There are several things you might want to do as part
-of such a framework. First, you probably want to export Moose's sugar
-functions (C<has>, C<extends>, etc) for users of the
-framework. Second, you may want to provide additional sugar of your
-own. Third, you may want to provide your own object base class instead
-of L<Moose::Object>, and/or your own metaclass class instead of
-L<Moose::Meta::Class>.
-
-The exporting needs can be asily satisfied by using
-L<Moose::Exporter>, which is what C<Moose.pm> itself uses for
-exporting. L<Moose::Exporter> lets you "export like Moose".
-
-If you define an C<init_meta> method in a module that uses
-L<Moose::Exporter>, then this method will be called I<before>
-C<Moose.pm>'s own C<init_meta>. This gives you a chance to provide an
-alternate object base class or metaclass class.
-
-Here is a simple example:
-
- package MyFramework;
-
- use strict;
- use warnings;
-
- use Moose (); # no need to get Moose's exports
- use Moose::Exporter;
-
- Moose::Exporter->setup_import_methods( also => 'Moose' );
-
- sub init_meta {
- shift;
- return Moose->init_meta( @_, base_class => 'MyFramework::Base' );
- }
-
-In this example, any class that includes C<use MyFramework> will get
-all of C<Moose.pm>'s sugar functions, and will have their superclass
-set to C<MyFramework::Base>.
-
-Additionally, that class can include C<no MyFramework> to unimport
+To learn more about extending Moose, we recommend checking out the
+"Extending" recipes in the L<Moose::Cookbook>, starting with
+L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
+all the different ways you might extend Moose.
=head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
sanely. It handles getting the exported functions into the right place
for you.
+=head2 B<throw_error>
+
+An alias for C<confess>, used by internally by Moose.
+
+=head1 METACLASS COMPATIBILITY AND MOOSE
+
+Metaclass compatibility is a thorny subject. You should start by
+reading the "About Metaclass compatibility" section in the
+C<Class::MOP> docs.
+
+Moose will attempt to resolve a few cases of metaclass incompatibility
+when you set the superclasses for a class, unlike C<Class::MOP>, which
+simply dies if the metaclasses are incompatible.
+
+In actuality, Moose fixes incompatibility for I<all> of a class's
+metaclasses, not just the class metaclass. That includes the instance
+metaclass, attribute metaclass, as well as its constructor class and
+destructor class. However, for simplicity this discussion will just
+refer to "metaclass", meaning the class metaclass, most of the time.
+
+Moose has two algorithms for fixing metaclass incompatibility.
+
+The first algorithm is very simple. If all the metaclass for the
+parent is a I<subclass> of the child's metaclass, then we simply
+replace the child's metaclass with the parent's.
+
+The second algorithm is more complicated. It tries to determine if the
+metaclasses only "differ by roles". This means that the parent and
+child's metaclass share a common ancestor in their respective
+hierarchies, and that the subclasses under the common ancestor are
+only different because of role applications. This case is actually
+fairly common when you mix and match various C<MooseX::*> modules,
+many of which apply roles to the metaclass.
+
+If the parent and child do differ by roles, Moose replaces the
+metaclass in the child with a newly created metaclass. This metaclass
+is a subclass of the parent's metaclass, does all of the roles that
+the child's metaclass did before being replaced. Effectively, this
+means the new metaclass does all of the roles done by both the
+parent's and child's original metaclasses.
+
+Ultimately, this is all transparent to you except in the case of an
+unresolvable conflict.
+
=head1 CAVEATS
=over 4
their behavior is then easier to predict. Time will tell whether I am right or
not (UPDATE: so far so good).
-=item *
-
-It is important to note that we currently have no simple way of combining
-multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above),
-and that in many cases they will conflict with one another. We are working on
-developing a way around this issue, but in the meantime, you have been warned.
-
-=back
-
-=head1 JUSTIFICATION
-
-In case you are still asking yourself "Why do I need this?", then this
-section is for you. This used to be part of the main DESCRIPTION, but
-I think Moose no longer actually needs justification, so it is included
-(read: buried) here for those who are still not convinced.
-
-=over 4
-
-=item Another object system!?!?
-
-Yes, I know there has been an explosion recently of new ways to
-build objects in Perl 5, most of them based on inside-out objects
-and other such things. Moose is different because it is not a new
-object system for Perl 5, but instead an extension of the existing
-object system.
-
-Moose is built on top of L<Class::MOP>, which is a metaclass system
-for Perl 5. This means that Moose not only makes building normal
-Perl 5 objects better, but it also provides the power of metaclass
-programming.
-
-=item Is this for real? Or is this just an experiment?
-
-Moose is I<based> on the prototypes and experiments I did for the Perl 6
-meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>.
-
-=item Is this ready for use in production?
-
-Yes, I believe that it is.
-
-Moose has been used successfully in production environemnts by several people
-and companies (including the one I work for). There are Moose applications
-which have been in production with little or no issue now for well over two years.
-I consider it highly stable and we are commited to keeping it stable.
-
-Of course, in the end, you need to make this call yourself. If you have
-any questions or concerns, please feel free to email me, or even the list
-or just stop by #moose and ask away.
-
-=item Is Moose just Perl 6 in Perl 5?
-
-No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
-Instead, it is an OO system for Perl 5. I built Moose because I was tired of
-writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
-instead of switching to Ruby, I wrote Moose :)
-
-=item Wait, I<post> modern, I thought it was just I<modern>?
-
-So I was reading Larry Wall's talk from the 1999 Linux World entitled
-"Perl, the first postmodern computer language" in which he talks about how
-he picked the features for Perl because he thought they were cool and he
-threw out the ones that he thought sucked. This got me thinking about how
-we have done the same thing in Moose. For Moose, we have "borrowed" features
-from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and
-the bits we didn't like (cause they sucked) we tossed aside. So for this
-reason (and a few others) I have re-dubbed Moose a I<postmodern> object system.
-
-Nuff Said.
-
=back
=head1 ACKNOWLEDGEMENTS
Jonathan (jrockway) Rockway
+Dave (autarch) Rolsky
+
Piotr (dexter) Roszatycki
Sam (mugwump) Vilain