10 $VERSION = eval $VERSION;
11 our $AUTHORITY = 'cpan:STEVAN';
13 use Scalar::Util 'blessed';
14 use Carp 'confess', 'croak', 'cluck';
20 use Moose::Meta::Class;
21 use Moose::Meta::TypeConstraint;
22 use Moose::Meta::TypeCoercion;
23 use Moose::Meta::Attribute;
24 use Moose::Meta::Instance;
28 use Moose::Meta::Role;
29 use Moose::Meta::Role::Composite;
30 use Moose::Meta::Role::Application;
31 use Moose::Meta::Role::Application::RoleSummation;
32 use Moose::Meta::Role::Application::ToClass;
33 use Moose::Meta::Role::Application::ToRole;
34 use Moose::Meta::Role::Application::ToInstance;
36 use Moose::Util::TypeConstraints;
48 croak "Must derive at least one class" unless @_;
51 foreach my $super (@supers) {
52 Class::MOP::load_class($super);
53 croak "You cannot inherit from a Moose Role ($super)"
54 if $super->can('meta') &&
55 blessed $super->meta &&
56 $super->meta->isa('Moose::Meta::Role')
61 # this checks the metaclass to make sure
62 # it is correct, sometimes it can get out
63 # of sync when the classes are being built
64 my $meta = Moose::Meta::Class->initialize($class);
65 $meta->superclasses(@supers);
70 Moose::Util::apply_all_roles(Class::MOP::Class->initialize($class), @_);
76 croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1;
78 my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
79 Class::MOP::Class->initialize($class)->add_attribute( $_, %options ) for @$attrs;
84 Moose::Util::add_method_modifier($class, 'before', \@_);
89 Moose::Util::add_method_modifier($class, 'after', \@_);
94 Moose::Util::add_method_modifier($class, 'around', \@_);
98 return unless our $SUPER_BODY; $SUPER_BODY->(our @SUPER_ARGS);
103 my ( $name, $method ) = @_;
104 Class::MOP::Class->initialize($class)->add_override_method_modifier( $name => $method );
109 our ( %INNER_BODY, %INNER_ARGS );
111 if ( my $body = $INNER_BODY{$pkg} ) {
112 my @args = @{ $INNER_ARGS{$pkg} };
113 local $INNER_ARGS{$pkg};
114 local $INNER_BODY{$pkg};
115 return $body->(@args);
123 my ( $name, $method ) = @_;
124 Class::MOP::Class->initialize($class)->add_augment_method_modifier( $name => $method );
129 cluck "The make_immutable keyword has been deprecated, " .
130 "please go back to __PACKAGE__->meta->make_immutable\n";
131 Class::MOP::Class->initialize($class)->make_immutable(@_);
134 Moose::Exporter->setup_import_methods(
136 qw( extends with has before after around override augment make_immutable )
141 \&Scalar::Util::blessed,
146 # This used to be called as a function. This hack preserves
147 # backwards compatibility.
148 if ( $_[0] ne __PACKAGE__ ) {
149 return __PACKAGE__->init_meta(
159 my $class = $args{for_class}
160 or Moose->throw_error("Cannot call init_meta without specifying a for_class");
161 my $base_class = $args{base_class} || 'Moose::Object';
162 my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
164 Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Class.")
165 unless $metaclass->isa('Moose::Meta::Class');
167 # make a subtype for each Moose class
169 unless find_type_constraint($class);
173 if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
174 unless ( $meta->isa("Moose::Meta::Class") ) {
175 Moose->throw_error("$class already has a metaclass, but it does not inherit $metaclass ($meta)");
178 # no metaclass, no 'meta' method
180 # now we check whether our ancestors have metaclass, and if so borrow that
181 my ( undef, @isa ) = @{ $class->mro::get_linear_isa };
183 foreach my $ancestor ( @isa ) {
184 my $ancestor_meta = Class::MOP::get_metaclass_by_name($ancestor) || next;
186 my $ancestor_meta_class = ($ancestor_meta->is_immutable
187 ? $ancestor_meta->get_mutable_metaclass_name
188 : ref($ancestor_meta));
190 # if we have an ancestor metaclass that inherits $metaclass, we use
191 # that. This is like _fix_metaclass_incompatibility, but we can do it now.
193 # the case of having an ancestry is not very common, but arises in
195 unless ( $metaclass->isa( $ancestor_meta_class ) ) {
196 if ( $ancestor_meta_class->isa($metaclass) ) {
197 $metaclass = $ancestor_meta_class;
202 $meta = $metaclass->initialize($class);
205 if ( $class->can('meta') ) {
206 # check 'meta' method
208 # it may be inherited
211 # this is the case where the metaclass pragma
212 # was used before the 'use Moose' statement to
213 # override a specific class
214 my $method_meta = $class->meta;
216 ( blessed($method_meta) && $method_meta->isa('Moose::Meta::Class') )
217 || Moose->throw_error("$class already has a &meta function, but it does not return a Moose::Meta::Class ($meta)");
219 $meta = $method_meta;
222 unless ( $meta->has_method("meta") ) { # don't overwrite
223 # also check for inherited non moose 'meta' method?
224 # FIXME also skip this if the user requested by passing an option
227 # re-initialize so it inherits properly
228 $metaclass->initialize( ref($_[0]) || $_[0] );
233 # make sure they inherit from Moose::Object
234 $meta->superclasses($base_class)
235 unless $meta->superclasses();
240 # This may be used in some older MooseX extensions.
242 goto &Moose::Exporter::_get_caller;
245 ## make 'em all immutable
247 $_->meta->make_immutable(
248 inline_constructor => 1,
249 constructor_name => "_new",
250 inline_accessors => 1, # these are Class::MOP accessors, so they need inlining
253 Moose::Meta::Attribute
255 Moose::Meta::Instance
257 Moose::Meta::TypeConstraint
258 Moose::Meta::TypeConstraint::Union
259 Moose::Meta::TypeConstraint::Parameterized
260 Moose::Meta::TypeConstraint::Parameterizable
261 Moose::Meta::TypeConstraint::Enum
262 Moose::Meta::TypeConstraint::Class
263 Moose::Meta::TypeConstraint::Role
264 Moose::Meta::TypeConstraint::Registry
265 Moose::Meta::TypeCoercion
266 Moose::Meta::TypeCoercion::Union
269 Moose::Meta::Method::Accessor
270 Moose::Meta::Method::Constructor
271 Moose::Meta::Method::Destructor
272 Moose::Meta::Method::Overriden
273 Moose::Meta::Method::Augmented
276 Moose::Meta::Role::Method
277 Moose::Meta::Role::Method::Required
279 Moose::Meta::Role::Composite
281 Moose::Meta::Role::Application
282 Moose::Meta::Role::Application::RoleSummation
283 Moose::Meta::Role::Application::ToClass
284 Moose::Meta::Role::Application::ToRole
285 Moose::Meta::Role::Application::ToInstance
296 Moose - A postmodern object system for Perl 5
301 use Moose; # automatically turns on strict and warnings
303 has 'x' => (is => 'rw', isa => 'Int');
304 has 'y' => (is => 'rw', isa => 'Int');
317 has 'z' => (is => 'rw', isa => 'Int');
319 after 'clear' => sub {
326 Moose is an extension of the Perl 5 object system.
328 The main goal of Moose is to make Perl 5 Object Oriented programming
329 easier, more consistent and less tedious. With Moose you can to think
330 more about what you want to do and less about the mechanics of OOP.
332 Additionally, Moose is built on top of L<Class::MOP>, which is a
333 metaclass system for Perl 5. This means that Moose not only makes
334 building normal Perl 5 objects better, but it provides the power of
335 metaclass programming as well.
339 If you're new to Moose, the best place to start is the L<Moose::Intro>
340 docs, followed by the L<Moose::Cookbook>. The intro will show you what
341 Moose is, and how it makes Perl 5 OO better.
343 The cookbook recipes on Moose basics will get you up to speed with
344 many of Moose's features quickly. Once you have an idea of what Moose
345 can do, you can use the API documentation to get more detail on
346 features which interest you.
348 =head2 Moose Extensions
350 The C<MooseX::> namespace is the official place to find Moose extensions.
351 These extensions can be found on the CPAN. The easiest way to find them
352 is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
353 or to examine L<Task::Moose> which aims to keep an up-to-date, easily
354 installable list of Moose extensions.
356 =head1 BUILDING CLASSES WITH MOOSE
358 Moose makes every attempt to provide as much convenience as possible during
359 class construction/definition, but still stay out of your way if you want it
360 to. Here are a few items to note when building classes with Moose.
362 Unless specified with C<extends>, any class which uses Moose will
363 inherit from L<Moose::Object>.
365 Moose will also manage all attributes (including inherited ones) that are
366 defined with C<has>. And (assuming you call C<new>, which is inherited from
367 L<Moose::Object>) this includes properly initializing all instance slots,
368 setting defaults where appropriate, and performing any type constraint checking
371 =head1 PROVIDED METHODS
373 Moose provides a number of methods to all your classes, mostly through the
374 inheritance of L<Moose::Object>. There is however, one exception.
380 This is a method which provides access to the current class's metaclass.
384 =head1 EXPORTED FUNCTIONS
386 Moose will export a number of functions into the class's namespace which
387 may then be used to set up the class. These functions all work directly
388 on the current class.
392 =item B<extends (@superclasses)>
394 This function will set the superclass(es) for the current class.
396 This approach is recommended instead of C<use base>, because C<use base>
397 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
398 replace it. This is important to ensure that classes which do not have
399 superclasses still properly inherit from L<Moose::Object>.
401 =item B<with (@roles)>
403 This will apply a given set of C<@roles> to the local class.
405 =item B<has $name =E<gt> %options>
407 This will install an attribute of a given C<$name> into the current class.
408 The C<%options> are the same as those provided by
409 L<Class::MOP::Attribute>, in addition to the list below which are provided
410 by Moose (L<Moose::Meta::Attribute> to be more specific):
414 =item I<is =E<gt> 'rw'|'ro'>
416 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
417 only). These will create either a read/write accessor or a read-only
418 accessor respectively, using the same name as the C<$name> of the attribute.
420 If you need more control over how your accessors are named, you can use the
421 I<reader>, I<writer> and I<accessor> options inherited from
422 L<Class::MOP::Attribute>, however if you use those, you won't need the I<is>
425 =item I<isa =E<gt> $type_name>
427 The I<isa> option uses Moose's type constraint facilities to set up runtime
428 type checking for this attribute. Moose will perform the checks during class
429 construction, and within any accessors. The C<$type_name> argument must be a
430 string. The string may be either a class name or a type defined using
431 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
432 for information on how to define a new type, and how to retrieve type meta-data).
434 =item I<coerce =E<gt> (1|0)>
436 This will attempt to use coercion with the supplied type constraint to change
437 the value passed into any accessors or constructors. You B<must> have supplied
438 a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5>
441 =item I<does =E<gt> $role_name>
443 This will accept the name of a role which the value stored in this attribute
444 is expected to have consumed.
446 =item I<required =E<gt> (1|0)>
448 This marks the attribute as being required. This means a I<defined> value must be
449 supplied during class construction, and the attribute may never be set to
450 C<undef> with an accessor.
452 =item I<weak_ref =E<gt> (1|0)>
454 This will tell the class to store the value of this attribute as a weakened
455 reference. If an attribute is a weakened reference, it B<cannot> also be
458 =item I<lazy =E<gt> (1|0)>
460 This will tell the class to not create this slot until absolutely necessary.
461 If an attribute is marked as lazy it B<must> have a default supplied.
463 =item I<auto_deref =E<gt> (1|0)>
465 This tells the accessor whether to automatically dereference the value returned.
466 This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>.
468 =item I<trigger =E<gt> $code>
470 The I<trigger> option is a CODE reference which will be called after the value of
471 the attribute is set. The CODE ref will be passed the instance itself, the
472 updated value and the attribute meta-object (this is for more advanced fiddling
473 and can typically be ignored). You B<cannot> have a trigger on a read-only
476 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE>
478 The I<handles> option provides Moose classes with automated delegation features.
479 This is a pretty complex and powerful option. It accepts many different option
480 formats, each with its own benefits and drawbacks.
482 B<NOTE:> The class being delegated to does not need to be a Moose based class,
483 which is why this feature is especially useful when wrapping non-Moose classes.
485 All I<handles> option formats share the following traits:
487 You cannot override a locally defined method with a delegated method; an
488 exception will be thrown if you try. That is to say, if you define C<foo> in
489 your class, you cannot override it with a delegated C<foo>. This is almost never
490 something you would want to do, and if it is, you should do it by hand and not
493 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
494 and C<DEMOLISH> methods. These will not throw an exception, but will silently
495 move on to the next method in the list. My reasoning for this is that you would
496 almost never want to do this, since it usually breaks your class. As with
497 overriding locally defined methods, if you do want to do this, you should do it
498 manually, not with Moose.
500 You do not I<need> to have a reader (or accessor) for the attribute in order
501 to delegate to it. Moose will create a means of accessing the value for you,
502 however this will be several times B<less> efficient then if you had given
503 the attribute a reader (or accessor) to use.
505 Below is the documentation for each option format:
511 This is the most common usage for I<handles>. You basically pass a list of
512 method names to be delegated, and Moose will install a delegation method
517 This is the second most common usage for I<handles>. Instead of a list of
518 method names, you pass a HASH ref where each key is the method name you
519 want installed locally, and its value is the name of the original method
520 in the class being delegated to.
522 This can be very useful for recursive classes like trees. Here is a
523 quick example (soon to be expanded into a Moose::Cookbook recipe):
528 has 'node' => (is => 'rw', isa => 'Any');
533 default => sub { [] }
541 parent_node => 'node',
542 siblings => 'children',
546 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
547 which delegate to the C<node> and C<children> methods (respectively) of the Tree
548 instance stored in the C<parent> slot.
552 The regexp option works very similar to the ARRAY option, except that it builds
553 the list of methods for you. It starts by collecting all possible methods of the
554 class being delegated to, then filters that list using the regexp supplied here.
556 B<NOTE:> An I<isa> option is required when using the regexp option format. This
557 is so that we can determine (at compile time) the method list from the class.
558 Without an I<isa> this is just not possible.
562 With the role option, you specify the name of a role whose "interface" then
563 becomes the list of methods to handle. The "interface" can be defined as; the
564 methods of the role and any required methods of the role. It should be noted
565 that this does B<not> include any method modifiers or generated attribute
566 methods (which is consistent with role composition).
570 This is the option to use when you really want to do something funky. You should
571 only use it if you really know what you are doing, as it involves manual
574 This takes a code reference, which should expect two arguments. The first is the
575 attribute meta-object this I<handles> is attached to. The second is the
576 metaclass of the class being delegated to. It expects you to return a hash (not
577 a HASH ref) of the methods you want mapped.
581 =item I<metaclass =E<gt> $metaclass_name>
583 This tells the class to use a custom attribute metaclass for this particular
584 attribute. Custom attribute metaclasses are useful for extending the
585 capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
586 but they are still a fairly advanced topic and too much to cover here, see
587 L<Moose::Cookbook::Meta::Recipe1> for more information.
589 The default behavior here is to just load C<$metaclass_name>; however, we also
590 have a way to alias to a shorter name. This will first look to see if
591 B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose
592 will then check to see if that has the method C<register_implementation>, which
593 should return the actual name of the custom attribute metaclass. If there is no
594 C<register_implementation> method, it will fall back to using
595 B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name.
597 =item I<traits =E<gt> [ @role_names ]>
599 This tells Moose to take the list of C<@role_names> and apply them to the
600 attribute meta-object. This is very similar to the I<metaclass> option, but
601 allows you to use more than one extension at a time.
603 See L<TRAIT NAME RESOLUTION> for details on how a trait name is
604 resolved to a class name.
606 Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
611 =item B<has +$name =E<gt> %options>
613 This is variation on the normal attibute creator C<has> which allows you to
614 clone and extend an attribute from a superclass or from a role. Here is an
615 example of the superclass usage:
623 default => 'Hello, I am a Foo'
631 has '+message' => (default => 'Hello I am My::Foo');
633 What is happening here is that B<My::Foo> is cloning the C<message> attribute
634 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
635 'Str'> characteristics, but changing the value in C<default>.
637 Here is another example, but within the context of a role:
645 default => 'Hello, I am a Foo'
653 has '+message' => (default => 'Hello I am My::Foo');
655 In this case, we are basically taking the attribute which the role supplied
656 and altering it within the bounds of this feature.
658 Aside from where the attributes come from (one from superclass, the other
659 from a role), this feature works exactly the same. This feature is restricted
660 somewhat, so as to try and force at least I<some> sanity into it. You are only
661 allowed to change the following attributes:
667 Change the default value of an attribute.
671 Change whether the attribute attempts to coerce a value passed to it.
675 Change if the attribute is required to have a value.
677 =item I<documentation>
679 Change the documentation string associated with the attribute.
683 Change if the attribute lazily initializes the slot.
687 You I<are> allowed to change the type without restriction.
689 It is recommended that you use this freedom with caution. We used to
690 only allow for extension only if the type was a subtype of the parent's
691 type, but we felt that was too restrictive and is better left as a
696 You are allowed to B<add> a new C<handles> definition, but you are B<not>
697 allowed to I<change> one.
701 You are allowed to B<add> a new C<builder> definition, but you are B<not>
702 allowed to I<change> one.
706 You are allowed to B<add> a new C<metaclass> definition, but you are
707 B<not> allowed to I<change> one.
711 You are allowed to B<add> additional traits to the C<traits> definition.
712 These traits will be composed into the attribute, but pre-existing traits
713 B<are not> overridden, or removed.
717 =item B<before $name|@names =E<gt> sub { ... }>
719 =item B<after $name|@names =E<gt> sub { ... }>
721 =item B<around $name|@names =E<gt> sub { ... }>
723 This three items are syntactic sugar for the before, after, and around method
724 modifier features that L<Class::MOP> provides. More information on these may be
725 found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method
730 The keyword C<super> is a no-op when called outside of an C<override> method. In
731 the context of an C<override> method, it will call the next most appropriate
732 superclass method with the same arguments as the original method.
734 =item B<override ($name, &sub)>
736 An C<override> method is a way of explicitly saying "I am overriding this
737 method from my superclass". You can call C<super> within this method, and
738 it will work as expected. The same thing I<can> be accomplished with a normal
739 method call and the C<SUPER::> pseudo-package; it is really your choice.
743 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
744 an C<augment> method. You can think of C<inner> as being the inverse of
745 C<super>; the details of how C<inner> and C<augment> work is best described in
746 the L<Moose::Cookbook::Basics::Recipe6>.
748 =item B<augment ($name, &sub)>
750 An C<augment> method, is a way of explicitly saying "I am augmenting this
751 method from my superclass". Once again, the details of how C<inner> and
752 C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
756 This is the C<Carp::confess> function, and exported here because I use it
761 This is the C<Scalar::Util::blessed> function, it is exported here because I
762 use it all the time. It is highly recommended that this is used instead of
763 C<ref> anywhere you need to test for an object's class name.
767 =head1 METACLASS TRAITS
769 When you use Moose, you can also specify traits which will be applied
772 use Moose -traits => 'My::Trait';
774 This is very similar to the attribute traits feature. When you do
775 this, your class's C<meta> object will have the specified traits
776 applied to it. See L<TRAIT NAME RESOLUTION> for more details.
778 =head1 TRAIT NAME RESOLUTION
780 By default, when given a trait name, Moose simply tries to load a
781 class of the same name. If such a class does not exist, it then looks
782 for for a class matching
783 B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
784 variable here will be one of B<Attribute> or B<Class>, depending on
785 what the trait is being applied to.
787 If a class with this long name exists, Moose checks to see if it has
788 the method C<register_implementation>. This method is expected to
789 return the I<real> class name of the trait. If there is no
790 C<register_implementation> method, it will fall back to using
791 B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
793 If all this is confusing, take a look at
794 L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
797 =head1 UNIMPORTING FUNCTIONS
801 Moose offers a way to remove the keywords it exports, through the C<unimport>
802 method. You simply have to say C<no Moose> at the bottom of your code for this
803 to work. Here is an example:
808 has 'first_name' => (is => 'rw', isa => 'Str');
809 has 'last_name' => (is => 'rw', isa => 'Str');
813 $self->first_name . ' ' . $self->last_name
816 no Moose; # keywords are removed from the Person package
818 =head1 EXTENDING AND EMBEDDING MOOSE
820 To learn more about extending Moose, we recommend checking out the
821 "Extending" recipes in the L<Moose::Cookbook>, starting with
822 L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
823 all the different ways you might extend Moose.
825 =head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
827 The C<init_meta> method sets up the metaclass object for the class
828 specified by C<for_class>. This method injects a a C<meta> accessor
829 into the class so you can get at this object. It also sets the class's
830 superclass to C<base_class>, with L<Moose::Object> as the default.
832 You can specify an alternate metaclass with the C<metaclass> parameter.
834 For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>.
836 This method used to be documented as a function which accepted
837 positional parameters. This calling style will still work for
838 backwards compatibility, but is deprecated.
842 Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
843 and C<{into_level =E<gt> 1}>.
845 B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter>
846 instead, which lets you stack multiple C<Moose.pm>-alike modules
847 sanely. It handles getting the exported functions into the right place
850 =head2 B<throw_error>
852 An alias for C<confess>, used by internally by Moose.
854 =head1 METACLASS COMPATIBILITY AND MOOSE
856 Metaclass compatibility is a thorny subject. You should start by
857 reading the "About Metaclass compatibility" section in the
860 Moose will attempt to resolve a few cases of metaclass incompatibility
861 when you set the superclasses for a class, unlike C<Class::MOP>, which
862 simply dies if the metaclasses are incompatible.
864 In actuality, Moose fixes incompatibility for I<all> of a class's
865 metaclasses, not just the class metaclass. That includes the instance
866 metaclass, attribute metaclass, as well as its constructor class and
867 destructor class. However, for simplicity this discussion will just
868 refer to "metaclass", meaning the class metaclass, most of the time.
870 Moose has two algorithms for fixing metaclass incompatibility.
872 The first algorithm is very simple. If all the metaclass for the
873 parent is a I<subclass> of the child's metaclass, then we simply
874 replace the child's metaclass with the parent's.
876 The second algorithm is more complicated. It tries to determine if the
877 metaclasses only "differ by roles". This means that the parent and
878 child's metaclass share a common ancestor in their respective
879 hierarchies, and that the subclasses under the common ancestor are
880 only different because of role applications. This case is actually
881 fairly common when you mix and match various C<MooseX::*> modules,
882 many of which apply roles to the metaclass.
884 If the parent and child do differ by roles, Moose replaces the
885 metaclass in the child with a newly created metaclass. This metaclass
886 is a subclass of the parent's metaclass, does all of the roles that
887 the child's metaclass did before being replaced. Effectively, this
888 means the new metaclass does all of the roles done by both the
889 parent's and child's original metaclasses.
891 Ultimately, this is all transparent to you except in the case of an
892 unresolvable conflict.
900 It should be noted that C<super> and C<inner> B<cannot> be used in the same
901 method. However, they may be combined within the same class hierarchy; see
902 F<t/014_override_augment_inner_super.t> for an example.
904 The reason for this is that C<super> is only valid within a method
905 with the C<override> modifier, and C<inner> will never be valid within an
906 C<override> method. In fact, C<augment> will skip over any C<override> methods
907 when searching for its appropriate C<inner>.
909 This might seem like a restriction, but I am of the opinion that keeping these
910 two features separate (yet interoperable) actually makes them easy to use, since
911 their behavior is then easier to predict. Time will tell whether I am right or
912 not (UPDATE: so far so good).
916 =head1 ACKNOWLEDGEMENTS
920 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
922 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
924 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
925 and it certainly wouldn't have this name ;P
927 =item The basis of the TypeContraints module was Rob Kinyon's idea
928 originally, I just ran with it.
930 =item Thanks to mst & chansen and the whole #moose posse for all the
931 early ideas/feature-requests/encouragement/bug-finding.
933 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
941 =item L<http://www.iinteractive.com/moose>
943 This is the official web home of Moose, it contains links to our public SVN repo
944 as well as links to a number of talks and articles on Moose and Moose related
947 =item L<Moose::Cookbook> - How to cook a Moose
949 =item The Moose is flying, a tutorial by Randal Schwartz
951 Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
953 Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
955 =item L<Class::MOP> documentation
957 =item The #moose channel on irc.perl.org
959 =item The Moose mailing list - moose@perl.org
961 =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose>
963 =item Several Moose extension modules in the C<MooseX::> namespace.
965 See L<http://search.cpan.org/search?query=MooseX::> for extensions.
973 =item The Art of the MetaObject Protocol
975 I mention this in the L<Class::MOP> docs too, this book was critical in
976 the development of both modules and is highly recommended.
984 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
986 This paper (suggested by lbr on #moose) was what lead to the implementation
987 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
988 want to understand them, I suggest you read this.
994 All complex software has bugs lurking in it, and this module is no
995 exception. If you find a bug please either email me, or add the bug
998 =head1 FEATURE REQUESTS
1000 We are very strict about what features we add to the Moose core, especially
1001 the user-visible features. Instead we have made sure that the underlying
1002 meta-system of Moose is as extensible as possible so that you can add your
1003 own features easily. That said, occasionally there is a feature needed in the
1004 meta-system to support your planned extension, in which case you should
1005 either email the mailing list or join us on irc at #moose to discuss.
1009 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1011 B<with contributions from:>
1015 Adam (Alias) Kennedy
1017 Anders (Debolaz) Nor Berle
1019 Nathan (kolibre) Gray
1021 Christian (chansen) Hansen
1023 Hans Dieter (confound) Pearcey
1025 Eric (ewilhelm) Wilhelm
1027 Guillermo (groditi) Roditi
1029 Jess (castaway) Robinson
1033 Robert (phaylon) Sedlacek
1037 Scott (konobi) McWhirter
1039 Shlomi (rindolf) Fish
1041 Yuval (nothingmuch) Kogman
1043 Chris (perigrin) Prather
1045 Wallace (wreis) Reis
1047 Jonathan (jrockway) Rockway
1049 Dave (autarch) Rolsky
1051 Piotr (dexter) Roszatycki
1053 Sam (mugwump) Vilain
1055 Shawn (sartak) Moore
1057 ... and many other #moose folks
1059 =head1 COPYRIGHT AND LICENSE
1061 Copyright 2006-2008 by Infinity Interactive, Inc.
1063 L<http://www.iinteractive.com>
1065 This library is free software; you can redistribute it and/or modify
1066 it under the same terms as Perl itself.