7 use Scalar::Util 'blessed';
10 use Moose::Deprecated;
16 die "Class::MOP version $Moose::VERSION required--this is version $Class::MOP::VERSION"
17 if $Moose::VERSION && $Class::MOP::VERSION ne $Moose::VERSION;
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;
39 use Moose::Meta::Attribute::Native;
50 Moose->throw_error("Must derive at least one class") unless @_;
52 # this checks the metaclass to make sure
53 # it is correct, sometimes it can get out
54 # of sync when the classes are being built
55 $meta->superclasses(@_);
59 Moose::Util::apply_all_roles(shift, @_);
66 Moose->throw_error('Usage: has \'name\' => ( key => value, ... )')
69 my %options = ( definition_context => Moose::Util::_caller_info(), @_ );
70 my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
71 $meta->add_attribute( $_, %options ) for @$attrs;
75 Moose::Util::add_method_modifier(shift, 'before', \@_);
79 Moose::Util::add_method_modifier(shift, 'after', \@_);
83 Moose::Util::add_method_modifier(shift, 'around', \@_);
91 # This check avoids a recursion loop - see
92 # t/bugs/super_recursion.t
93 return if defined $SUPER_PACKAGE && $SUPER_PACKAGE ne caller();
94 return unless $SUPER_BODY; $SUPER_BODY->(@SUPER_ARGS);
99 my ( $name, $method ) = @_;
100 $meta->add_override_method_modifier( $name => $method );
105 our ( %INNER_BODY, %INNER_ARGS );
107 if ( my $body = $INNER_BODY{$pkg} ) {
108 my @args = @{ $INNER_ARGS{$pkg} };
109 local $INNER_ARGS{$pkg};
110 local $INNER_BODY{$pkg};
111 return $body->(@args);
119 my ( $name, $method ) = @_;
120 $meta->add_augment_method_modifier( $name => $method );
123 Moose::Exporter->setup_import_methods(
125 qw( extends with has before after around override augment )
130 \&Scalar::Util::blessed,
138 my $class = $args{for_class}
139 or Moose->throw_error("Cannot call init_meta without specifying a for_class");
140 my $base_class = $args{base_class} || 'Moose::Object';
141 my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
142 my $meta_name = exists $args{meta_name} ? $args{meta_name} : 'meta';
144 Moose->throw_error("The Metaclass $metaclass must be loaded. (Perhaps you forgot to 'use $metaclass'?)")
145 unless Class::MOP::is_class_loaded($metaclass);
147 Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Class.")
148 unless $metaclass->isa('Moose::Meta::Class');
150 # make a subtype for each Moose class
152 unless find_type_constraint($class);
156 if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
157 unless ( $meta->isa("Moose::Meta::Class") ) {
158 my $error_message = "$class already has a metaclass, but it does not inherit $metaclass ($meta).";
159 if ( $meta->isa('Moose::Meta::Role') ) {
160 Moose->throw_error($error_message . ' You cannot make the same thing a role and a class. Remove either Moose or Moose::Role.');
162 Moose->throw_error($error_message);
168 # now we check whether our ancestors have metaclass, and if so borrow that
169 my ( undef, @isa ) = @{ mro::get_linear_isa($class) };
171 foreach my $ancestor ( @isa ) {
172 my $ancestor_meta = Class::MOP::get_metaclass_by_name($ancestor) || next;
174 my $ancestor_meta_class = $ancestor_meta->_real_ref_name;
176 # if we have an ancestor metaclass that inherits $metaclass, we use
177 # that. This is like _fix_metaclass_incompatibility, but we can do it now.
179 # the case of having an ancestry is not very common, but arises in
181 unless ( $metaclass->isa( $ancestor_meta_class ) ) {
182 if ( $ancestor_meta_class->isa($metaclass) ) {
183 $metaclass = $ancestor_meta_class;
188 $meta = $metaclass->initialize($class);
191 if (defined $meta_name) {
192 # also check for inherited non moose 'meta' method?
193 my $existing = $meta->get_method($meta_name);
194 if ($existing && !$existing->isa('Class::MOP::Method::Meta')) {
195 Carp::cluck "Moose is overwriting an existing method named "
196 . "$meta_name in class $class with a method "
197 . "which returns the class's metaclass. If this is "
198 . "actually what you want, you should remove the "
199 . "existing method, otherwise, you should rename or "
200 . "disable this generated method using the "
201 . "'-meta_name' option to 'use Moose'.";
203 $meta->_add_meta_method($meta_name);
206 # make sure they inherit from Moose::Object
207 $meta->superclasses($base_class)
208 unless $meta->superclasses();
213 # This may be used in some older MooseX extensions.
215 goto &Moose::Exporter::_get_caller;
218 ## make 'em all immutable
221 inline_constructor => 1,
222 constructor_name => "_new",
223 # these are Class::MOP accessors, so they need inlining
224 inline_accessors => 1
225 ) for grep { $_->is_mutable }
228 Moose::Meta::Attribute
230 Moose::Meta::Instance
232 Moose::Meta::TypeCoercion
233 Moose::Meta::TypeCoercion::Union
236 Moose::Meta::Method::Constructor
237 Moose::Meta::Method::Destructor
238 Moose::Meta::Method::Overridden
239 Moose::Meta::Method::Augmented
242 Moose::Meta::Role::Attribute
243 Moose::Meta::Role::Method
244 Moose::Meta::Role::Method::Required
245 Moose::Meta::Role::Method::Conflicting
247 Moose::Meta::Role::Composite
249 Moose::Meta::Role::Application
250 Moose::Meta::Role::Application::RoleSummation
251 Moose::Meta::Role::Application::ToClass
252 Moose::Meta::Role::Application::ToRole
253 Moose::Meta::Role::Application::ToInstance
257 inline_constructor => 0,
258 constructor_name => undef,
259 # these are Class::MOP accessors, so they need inlining
260 inline_accessors => 1
261 ) for grep { $_->is_mutable }
264 Moose::Meta::Method::Accessor
265 Moose::Meta::Method::Delegation
266 Moose::Meta::Mixin::AttributeCore
271 # ABSTRACT: A postmodern object system for Perl 5
280 use Moose; # automatically turns on strict and warnings
282 has 'x' => (is => 'rw', isa => 'Int');
283 has 'y' => (is => 'rw', isa => 'Int');
296 has 'z' => (is => 'rw', isa => 'Int');
298 after 'clear' => sub {
305 Moose is an extension of the Perl 5 object system.
307 The main goal of Moose is to make Perl 5 Object Oriented programming
308 easier, more consistent, and less tedious. With Moose you can think
309 more about what you want to do and less about the mechanics of OOP.
311 Additionally, Moose is built on top of L<Class::MOP>, which is a
312 metaclass system for Perl 5. This means that Moose not only makes
313 building normal Perl 5 objects better, but it provides the power of
314 metaclass programming as well.
318 If you're new to Moose, the best place to start is the
319 L<Moose::Manual> docs, followed by the L<Moose::Cookbook>. The intro
320 will show you what Moose is, and how it makes Perl 5 OO better.
322 The cookbook recipes on Moose basics will get you up to speed with
323 many of Moose's features quickly. Once you have an idea of what Moose
324 can do, you can use the API documentation to get more detail on
325 features which interest you.
327 =head2 Moose Extensions
329 The C<MooseX::> namespace is the official place to find Moose extensions.
330 These extensions can be found on the CPAN. The easiest way to find them
331 is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
332 or to examine L<Task::Moose> which aims to keep an up-to-date, easily
333 installable list of Moose extensions.
337 Much of the Moose documentation has been translated into other languages.
343 Japanese docs can be found at
344 L<http://perldoc.perlassociation.org/pod/Moose-Doc-JA/index.html>. The
345 source POD files can be found in GitHub:
346 L<http://github.com/jpa/Moose-Doc-JA>
350 =head1 BUILDING CLASSES WITH MOOSE
352 Moose makes every attempt to provide as much convenience as possible during
353 class construction/definition, but still stay out of your way if you want it
354 to. Here are a few items to note when building classes with Moose.
356 When you C<use Moose>, Moose will set the class's parent class to
357 L<Moose::Object>, I<unless> the class using Moose already has a parent
358 class. In addition, specifying a parent with C<extends> will change the parent
361 Moose will also manage all attributes (including inherited ones) that are
362 defined with C<has>. And (assuming you call C<new>, which is inherited from
363 L<Moose::Object>) this includes properly initializing all instance slots,
364 setting defaults where appropriate, and performing any type constraint checking
367 =head1 PROVIDED METHODS
369 Moose provides a number of methods to all your classes, mostly through the
370 inheritance of L<Moose::Object>. There is however, one exception.
376 This is a method which provides access to the current class's metaclass.
380 =head1 EXPORTED FUNCTIONS
382 Moose will export a number of functions into the class's namespace which
383 may then be used to set up the class. These functions all work directly
384 on the current class.
388 =item B<extends (@superclasses)>
390 This function will set the superclass(es) for the current class.
392 This approach is recommended instead of C<use base>, because C<use base>
393 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
394 replace it. This is important to ensure that classes which do not have
395 superclasses still properly inherit from L<Moose::Object>.
397 Each superclass can be followed by a hash reference with options. Currently,
398 only L<-version|Class::MOP/Class Loading Options> is recognized:
400 extends 'My::Parent' => { -version => 0.01 },
401 'My::OtherParent' => { -version => 0.03 };
403 An exception will be thrown if the version requirements are not
406 =item B<with (@roles)>
408 This will apply a given set of C<@roles> to the local class.
410 Like with C<extends>, each specified role can be followed by a hash
411 reference with a L<-version|Class::MOP/Class Loading Options> option:
413 with 'My::Role' => { -version => 0.32 },
414 'My::Otherrole' => { -version => 0.23 };
416 The specified version requirements must be satisfied, otherwise an
417 exception will be thrown.
419 If your role takes options or arguments, they can be passed along in the
420 hash reference as well.
422 =item B<has $name|@$names =E<gt> %options>
424 This will install an attribute of a given C<$name> into the current class. If
425 the first parameter is an array reference, it will create an attribute for
426 every C<$name> in the list. The C<%options> will be passed to the constructor
427 for L<Moose::Meta::Attribute> (which inherits from L<Class::MOP::Attribute>),
428 so the full documentation for the valid options can be found there. These are
429 the most commonly used options:
433 =item I<is =E<gt> 'rw'|'ro'>
435 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
436 only). These will create either a read/write accessor or a read-only
437 accessor respectively, using the same name as the C<$name> of the attribute.
439 If you need more control over how your accessors are named, you can
440 use the L<reader|Class::MOP::Attribute/reader>,
441 L<writer|Class::MOP::Attribute/writer> and
442 L<accessor|Class::MOP::Attribute/accessor> options inherited from
443 L<Class::MOP::Attribute>, however if you use those, you won't need the
446 =item I<isa =E<gt> $type_name>
448 The I<isa> option uses Moose's type constraint facilities to set up runtime
449 type checking for this attribute. Moose will perform the checks during class
450 construction, and within any accessors. The C<$type_name> argument must be a
451 string. The string may be either a class name or a type defined using
452 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
453 for information on how to define a new type, and how to retrieve type meta-data).
455 =item I<coerce =E<gt> (1|0)>
457 This will attempt to use coercion with the supplied type constraint to change
458 the value passed into any accessors or constructors. You B<must> supply a type
459 constraint, and that type constraint B<must> define a coercion. See
460 L<Moose::Cookbook::Basics::Recipe5> for an example.
462 =item I<does =E<gt> $role_name>
464 This will accept the name of a role which the value stored in this attribute
465 is expected to have consumed.
467 =item I<required =E<gt> (1|0)>
469 This marks the attribute as being required. This means a value must be
470 supplied during class construction, I<or> the attribute must be lazy
471 and have either a default or a builder. Note that c<required> does not
472 say anything about the attribute's value, which can be C<undef>.
474 =item I<weak_ref =E<gt> (1|0)>
476 This will tell the class to store the value of this attribute as a weakened
477 reference. If an attribute is a weakened reference, it B<cannot> also be
478 coerced. Note that when a weak ref expires, the attribute's value becomes
479 undefined, and is still considered to be set for purposes of predicate,
482 =item I<lazy =E<gt> (1|0)>
484 This will tell the class to not create this slot until absolutely necessary.
485 If an attribute is marked as lazy it B<must> have a default or builder
488 =item I<trigger =E<gt> $code>
490 The I<trigger> option is a CODE reference which will be called after
491 the value of the attribute is set. The CODE ref is passed the
492 instance itself, the updated value, and the original value if the
493 attribute was already set.
495 You B<can> have a trigger on a read-only attribute.
497 B<NOTE:> Triggers will only fire when you B<assign> to the attribute,
498 either in the constructor, or using the writer. Default and built values will
499 B<not> cause the trigger to be fired.
501 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | ROLETYPE | DUCKTYPE | CODE>
503 The I<handles> option provides Moose classes with automated delegation features.
504 This is a pretty complex and powerful option. It accepts many different option
505 formats, each with its own benefits and drawbacks.
507 B<NOTE:> The class being delegated to does not need to be a Moose based class,
508 which is why this feature is especially useful when wrapping non-Moose classes.
510 All I<handles> option formats share the following traits:
512 You cannot override a locally defined method with a delegated method; an
513 exception will be thrown if you try. That is to say, if you define C<foo> in
514 your class, you cannot override it with a delegated C<foo>. This is almost never
515 something you would want to do, and if it is, you should do it by hand and not
518 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
519 and C<DEMOLISH> methods. These will not throw an exception, but will silently
520 move on to the next method in the list. My reasoning for this is that you would
521 almost never want to do this, since it usually breaks your class. As with
522 overriding locally defined methods, if you do want to do this, you should do it
523 manually, not with Moose.
525 You do not I<need> to have a reader (or accessor) for the attribute in order
526 to delegate to it. Moose will create a means of accessing the value for you,
527 however this will be several times B<less> efficient then if you had given
528 the attribute a reader (or accessor) to use.
530 Below is the documentation for each option format:
536 This is the most common usage for I<handles>. You basically pass a list of
537 method names to be delegated, and Moose will install a delegation method
542 This is the second most common usage for I<handles>. Instead of a list of
543 method names, you pass a HASH ref where each key is the method name you
544 want installed locally, and its value is the name of the original method
545 in the class being delegated to.
547 This can be very useful for recursive classes like trees. Here is a
548 quick example (soon to be expanded into a Moose::Cookbook recipe):
553 has 'node' => (is => 'rw', isa => 'Any');
558 default => sub { [] }
566 parent_node => 'node',
567 siblings => 'children',
571 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
572 which delegate to the C<node> and C<children> methods (respectively) of the Tree
573 instance stored in the C<parent> slot.
575 You may also use an array reference to curry arguments to the original method.
579 handles => { set_foo => [ set => 'foo' ] },
582 # $self->set_foo(...) calls $self->thing->set('foo', ...)
584 The first element of the array reference is the original method name, and the
585 rest is a list of curried arguments.
589 The regexp option works very similar to the ARRAY option, except that it builds
590 the list of methods for you. It starts by collecting all possible methods of the
591 class being delegated to, then filters that list using the regexp supplied here.
593 B<NOTE:> An I<isa> option is required when using the regexp option format. This
594 is so that we can determine (at compile time) the method list from the class.
595 Without an I<isa> this is just not possible.
597 =item C<ROLE> or C<ROLETYPE>
599 With the role option, you specify the name of a role or a
600 L<role type|Moose::Meta::TypeConstraint::Role> whose "interface" then becomes
601 the list of methods to handle. The "interface" can be defined as; the methods
602 of the role and any required methods of the role. It should be noted that this
603 does B<not> include any method modifiers or generated attribute methods (which
604 is consistent with role composition).
608 With the duck type option, you pass a duck type object whose "interface" then
609 becomes the list of methods to handle. The "interface" can be defined as the
610 list of methods passed to C<duck_type> to create a duck type object. For more
611 information on C<duck_type> please check
612 L<Moose::Util::TypeConstraints>.
616 This is the option to use when you really want to do something funky. You should
617 only use it if you really know what you are doing, as it involves manual
620 This takes a code reference, which should expect two arguments. The first is the
621 attribute meta-object this I<handles> is attached to. The second is the
622 metaclass of the class being delegated to. It expects you to return a hash (not
623 a HASH ref) of the methods you want mapped.
627 =item I<traits =E<gt> [ @role_names ]>
629 This tells Moose to take the list of C<@role_names> and apply them to the
630 attribute meta-object. Custom attribute metaclass traits are useful for
631 extending the capabilities of the I<has> keyword: they are the simplest way to
632 extend the MOP, but they are still a fairly advanced topic and too much to
635 See L<Metaclass and Trait Name Resolution> for details on how a trait name is
636 resolved to a role name.
638 Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
641 =item I<builder> => Str
643 The value of this key is the name of the method that will be called to
644 obtain the value used to initialize the attribute. See the L<builder
645 option docs in Class::MOP::Attribute|Class::MOP::Attribute/builder>
646 and/or L<Moose::Cookbook::Basics::Recipe8> for more information.
648 =item I<default> => SCALAR | CODE
650 The value of this key is the default value which will initialize the attribute.
652 NOTE: If the value is a simple scalar (string or number), then it can
653 be just passed as is. However, if you wish to initialize it with a
654 HASH or ARRAY ref, then you need to wrap that inside a CODE reference.
655 See the L<default option docs in
656 Class::MOP::Attribute|Class::MOP::Attribute/default> for more
659 =item I<clearer> => Str
661 Creates a method allowing you to clear the value. See the L<clearer option
662 docs in Class::MOP::Attribute|Class::MOP::Attribute/clearer> for more
665 =item I<predicate> => Str
667 Creates a method to perform a basic test to see if a value has been set in the
668 attribute. See the L<predicate option docs in
669 Class::MOP::Attribute|Class::MOP::Attribute/predicate> for more information.
671 Note that the predicate will return true even for a C<weak_ref> attribute
672 whose value has expired.
674 =item I<documentation> => $string
676 An arbitrary string that can be retrieved later by calling C<<
677 $attr->documentation >>.
683 =item B<has +$name =E<gt> %options>
685 This is variation on the normal attribute creator C<has> which allows you to
686 clone and extend an attribute from a superclass or from a role. Here is an
687 example of the superclass usage:
695 default => 'Hello, I am a Foo'
703 has '+message' => (default => 'Hello I am My::Foo');
705 What is happening here is that B<My::Foo> is cloning the C<message> attribute
706 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
707 'Str'> characteristics, but changing the value in C<default>.
709 Here is another example, but within the context of a role:
717 default => 'Hello, I am a Foo'
725 has '+message' => (default => 'Hello I am My::Foo');
727 In this case, we are basically taking the attribute which the role supplied
728 and altering it within the bounds of this feature.
730 Note that you can only extend an attribute from either a superclass or a role,
731 you cannot extend an attribute in a role that composes over an attribute from
734 Aside from where the attributes come from (one from superclass, the other
735 from a role), this feature works exactly the same. This feature is restricted
736 somewhat, so as to try and force at least I<some> sanity into it. Most options work the same, but there are some exceptions:
750 These options can be added, but cannot override a superclass definition.
754 You are allowed to B<add> additional traits to the C<traits> definition.
755 These traits will be composed into the attribute, but preexisting traits
756 B<are not> overridden, or removed.
760 =item B<before $name|@names|\@names|qr/.../ =E<gt> sub { ... }>
762 =item B<after $name|@names|\@names|qr/.../ =E<gt> sub { ... }>
764 =item B<around $name|@names|\@names|qr/.../ =E<gt> sub { ... }>
766 These three items are syntactic sugar for the before, after, and around method
767 modifier features that L<Class::MOP> provides. More information on these may be
768 found in L<Moose::Manual::MethodModifiers> and the
769 L<Class::MOP::Class documentation|Class::MOP::Class/"Method Modifiers">.
771 =item B<override ($name, &sub)>
773 An C<override> method is a way of explicitly saying "I am overriding this
774 method from my superclass". You can call C<super> within this method, and
775 it will work as expected. The same thing I<can> be accomplished with a normal
776 method call and the C<SUPER::> pseudo-package; it is really your choice.
780 The keyword C<super> is a no-op when called outside of an C<override> method. In
781 the context of an C<override> method, it will call the next most appropriate
782 superclass method with the same arguments as the original method.
784 =item B<augment ($name, &sub)>
786 An C<augment> method, is a way of explicitly saying "I am augmenting this
787 method from my superclass". Once again, the details of how C<inner> and
788 C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
792 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
793 an C<augment> method. You can think of C<inner> as being the inverse of
794 C<super>; the details of how C<inner> and C<augment> work is best described in
795 the L<Moose::Cookbook::Basics::Recipe6>.
799 This is the C<Scalar::Util::blessed> function. It is highly recommended that
800 this is used instead of C<ref> anywhere you need to test for an object's class
805 This is the C<Carp::confess> function, and exported here for historical
812 When you use Moose, you can specify traits which will be applied to your
815 use Moose -traits => 'My::Trait';
817 This is very similar to the attribute traits feature. When you do
818 this, your class's C<meta> object will have the specified traits
819 applied to it. See L<Metaclass and Trait Name Resolution> for more
822 =head2 Metaclass and Trait Name Resolution
824 By default, when given a trait name, Moose simply tries to load a
825 class of the same name. If such a class does not exist, it then looks
826 for for a class matching
827 B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
828 variable here will be one of B<Attribute> or B<Class>, depending on
829 what the trait is being applied to.
831 If a class with this long name exists, Moose checks to see if it has
832 the method C<register_implementation>. This method is expected to
833 return the I<real> class name of the trait. If there is no
834 C<register_implementation> method, it will fall back to using
835 B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
837 The lookup method for metaclasses is the same, except that it looks
838 for a class matching B<Moose::Meta::$type::Custom::$metaclass_name>.
840 If all this is confusing, take a look at
841 L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
844 =head1 UNIMPORTING FUNCTIONS
848 Moose offers a way to remove the keywords it exports, through the C<unimport>
849 method. You simply have to say C<no Moose> at the bottom of your code for this
850 to work. Here is an example:
855 has 'first_name' => (is => 'rw', isa => 'Str');
856 has 'last_name' => (is => 'rw', isa => 'Str');
860 $self->first_name . ' ' . $self->last_name
863 no Moose; # keywords are removed from the Person package
865 =head1 EXTENDING AND EMBEDDING MOOSE
867 To learn more about extending Moose, we recommend checking out the
868 "Extending" recipes in the L<Moose::Cookbook>, starting with
869 L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
870 all the different ways you might extend Moose. L<Moose::Exporter> and
871 L<Moose::Util::MetaRole> are the modules which provide the majority of the
872 extension functionality, so reading their documentation should also be helpful.
874 =head2 The MooseX:: namespace
876 Generally if you're writing an extension I<for> Moose itself you'll want
877 to put your extension in the C<MooseX::> namespace. This namespace is
878 specifically for extensions that make Moose better or different in some
879 fundamental way. It is traditionally B<not> for a package that just happens
880 to use Moose. This namespace follows from the examples of the C<LWPx::>
881 and C<DBIx::> namespaces that perform the same function for C<LWP> and C<DBI>
884 =head1 METACLASS COMPATIBILITY AND MOOSE
886 Metaclass compatibility is a thorny subject. You should start by
887 reading the "About Metaclass compatibility" section in the
890 Moose will attempt to resolve a few cases of metaclass incompatibility
891 when you set the superclasses for a class, in addition to the cases that
892 C<Class::MOP> handles.
894 Moose tries to determine if the metaclasses only "differ by roles". This
895 means that the parent and child's metaclass share a common ancestor in
896 their respective hierarchies, and that the subclasses under the common
897 ancestor are only different because of role applications. This case is
898 actually fairly common when you mix and match various C<MooseX::*>
899 modules, many of which apply roles to the metaclass.
901 If the parent and child do differ by roles, Moose replaces the
902 metaclass in the child with a newly created metaclass. This metaclass
903 is a subclass of the parent's metaclass which does all of the roles that
904 the child's metaclass did before being replaced. Effectively, this
905 means the new metaclass does all of the roles done by both the
906 parent's and child's original metaclasses.
908 Ultimately, this is all transparent to you except in the case of an
909 unresolvable conflict.
917 It should be noted that C<super> and C<inner> B<cannot> be used in the same
918 method. However, they may be combined within the same class hierarchy; see
919 F<t/basics/override_augment_inner_super.t> for an example.
921 The reason for this is that C<super> is only valid within a method
922 with the C<override> modifier, and C<inner> will never be valid within an
923 C<override> method. In fact, C<augment> will skip over any C<override> methods
924 when searching for its appropriate C<inner>.
926 This might seem like a restriction, but I am of the opinion that keeping these
927 two features separate (yet interoperable) actually makes them easy to use, since
928 their behavior is then easier to predict. Time will tell whether I am right or
929 not (UPDATE: so far so good).
935 We offer both a mailing list and a very active IRC channel.
937 The mailing list is L<moose@perl.org>. You must be subscribed to send
938 a message. To subscribe, send an empty message to
939 L<moose-subscribe@perl.org>
941 You can also visit us at C<#moose> on L<irc://irc.perl.org/#moose>
942 This channel is quite active, and questions at all levels (on Moose-related
943 topics ;) are welcome.
945 =head1 ACKNOWLEDGEMENTS
949 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
951 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
953 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
954 and it certainly wouldn't have this name ;P
956 =item The basis of the TypeContraints module was Rob Kinyon's idea
957 originally, I just ran with it.
959 =item Thanks to mst & chansen and the whole #moose posse for all the
960 early ideas/feature-requests/encouragement/bug-finding.
962 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
970 =item L<http://www.iinteractive.com/moose>
972 This is the official web home of Moose, it contains links to our public git repository
973 as well as links to a number of talks and articles on Moose and Moose related
976 =item The Moose is flying, a tutorial by Randal Schwartz
978 Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
980 Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
982 =item Several Moose extension modules in the C<MooseX::> namespace.
984 See L<http://search.cpan.org/search?query=MooseX::> for extensions.
992 =item The Art of the MetaObject Protocol
994 I mention this in the L<Class::MOP> docs too, as this book was critical in
995 the development of both modules and is highly recommended.
1003 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
1005 This paper (suggested by lbr on #moose) was what lead to the implementation
1006 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
1007 want to understand them, I suggest you read this.
1013 All complex software has bugs lurking in it, and this module is no
1016 Please report any bugs to C<bug-moose@rt.cpan.org>, or through the web
1017 interface at L<http://rt.cpan.org>.
1019 You can also discuss feature requests or possible bugs on the Moose mailing
1020 list (moose@perl.org) or on IRC at L<irc://irc.perl.org/#moose>.
1022 =head1 FEATURE REQUESTS
1024 We are very strict about what features we add to the Moose core, especially
1025 the user-visible features. Instead we have made sure that the underlying
1026 meta-system of Moose is as extensible as possible so that you can add your
1027 own features easily.
1029 That said, occasionally there is a feature needed in the meta-system
1030 to support your planned extension, in which case you should either
1031 email the mailing list (moose@perl.org) or join us on IRC at
1032 L<irc://irc.perl.org/#moose> to discuss. The
1033 L<Moose::Manual::Contributing> has more detail about how and when you
1038 There are only a few people with the rights to release a new version
1039 of Moose. The Moose Cabal are the people to go to with questions regarding
1040 the wider purview of Moose. They help maintain not just the code
1041 but the community as well.
1043 Stevan (stevan) Little E<lt>stevan@iinteractive.comE<gt>
1045 Jesse (doy) Luehrs E<lt>doy at tozt dot netE<gt>
1047 Yuval (nothingmuch) Kogman
1049 Shawn (sartak) Moore E<lt>sartak@bestpractical.comE<gt>
1051 Hans Dieter (confound) Pearcey E<lt>hdp@pobox.comE<gt>
1053 Chris (perigrin) Prather
1055 Florian Ragwitz E<lt>rafl@debian.orgE<gt>
1057 Dave (autarch) Rolsky E<lt>autarch@urth.orgE<gt>
1063 Adam (Alias) Kennedy
1065 Anders (Debolaz) Nor Berle
1067 Chris (perigrin) Prather
1069 Christian (chansen) Hansen
1073 Dylan Hardison (doc fixes)
1075 Eric (ewilhelm) Wilhelm
1079 Florian (rafl) Ragwitz
1081 Guillermo (groditi) Roditi
1087 Jess (castaway) Robinson
1089 Jonathan (jrockway) Rockway
1093 Nathan (kolibrie) Gray
1095 Paul (frodwith) Driver
1097 Piotr (dexter) Roszatycki
1101 Robert (phaylon) Sedlacek
1105 Sam (mugwump) Vilain
1107 Scott (konobi) McWhirter
1109 Shawn (Sartak) Moore
1111 Shlomi (rindolf) Fish
1115 Wallace (wreis) Reis
1117 ... and many other #moose folks