8 $VERSION = eval $VERSION;
9 our $AUTHORITY = 'cpan:STEVAN';
11 use Scalar::Util 'blessed';
18 use Moose::Meta::Class;
19 use Moose::Meta::TypeConstraint;
20 use Moose::Meta::TypeCoercion;
21 use Moose::Meta::Attribute;
22 use Moose::Meta::Instance;
26 use Moose::Meta::Role;
27 use Moose::Meta::Role::Composite;
28 use Moose::Meta::Role::Application;
29 use Moose::Meta::Role::Application::RoleSummation;
30 use Moose::Meta::Role::Application::ToClass;
31 use Moose::Meta::Role::Application::ToRole;
32 use Moose::Meta::Role::Application::ToInstance;
34 use Moose::Util::TypeConstraints;
37 use Moose::Meta::Attribute::Native;
48 Moose->throw_error("Must derive at least one class") unless @_;
50 # this checks the metaclass to make sure
51 # it is correct, sometimes it can get out
52 # of sync when the classes are being built
53 $meta->superclasses(@_);
57 Moose::Util::apply_all_roles(shift, @_);
64 Moose->throw_error('Usage: has \'name\' => ( key => value, ... )')
67 my %options = ( definition_context => Moose::Util::_caller_info(), @_ );
68 my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
69 $meta->add_attribute( $_, %options ) for @$attrs;
73 Moose::Util::add_method_modifier(shift, 'before', \@_);
77 Moose::Util::add_method_modifier(shift, 'after', \@_);
81 Moose::Util::add_method_modifier(shift, 'around', \@_);
89 # This check avoids a recursion loop - see
90 # t/100_bugs/020_super_recursion.t
91 return if defined $SUPER_PACKAGE && $SUPER_PACKAGE ne caller();
92 return unless $SUPER_BODY; $SUPER_BODY->(@SUPER_ARGS);
97 my ( $name, $method ) = @_;
98 $meta->add_override_method_modifier( $name => $method );
103 our ( %INNER_BODY, %INNER_ARGS );
105 if ( my $body = $INNER_BODY{$pkg} ) {
106 my @args = @{ $INNER_ARGS{$pkg} };
107 local $INNER_ARGS{$pkg};
108 local $INNER_BODY{$pkg};
109 return $body->(@args);
117 my ( $name, $method ) = @_;
118 $meta->add_augment_method_modifier( $name => $method );
121 Moose::Exporter->setup_import_methods(
123 qw( extends with has before after around override augment )
128 \&Scalar::Util::blessed,
133 # This used to be called as a function. This hack preserves
134 # backwards compatibility.
135 if ( $_[0] ne __PACKAGE__ ) {
136 return __PACKAGE__->init_meta(
146 my $class = $args{for_class}
147 or Moose->throw_error("Cannot call init_meta without specifying a for_class");
148 my $base_class = $args{base_class} || 'Moose::Object';
149 my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
151 Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Class.")
152 unless $metaclass->isa('Moose::Meta::Class');
154 # make a subtype for each Moose class
156 unless find_type_constraint($class);
160 if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
161 unless ( $meta->isa("Moose::Meta::Class") ) {
162 my $error_message = "$class already has a metaclass, but it does not inherit $metaclass ($meta).";
163 if ( $meta->isa('Moose::Meta::Role') ) {
164 Moose->throw_error($error_message . ' You cannot make the same thing a role and a class. Remove either Moose or Moose::Role.');
166 Moose->throw_error($error_message);
170 # no metaclass, no 'meta' method
172 # now we check whether our ancestors have metaclass, and if so borrow that
173 my ( undef, @isa ) = @{ $class->mro::get_linear_isa };
175 foreach my $ancestor ( @isa ) {
176 my $ancestor_meta = Class::MOP::get_metaclass_by_name($ancestor) || next;
178 my $ancestor_meta_class = ($ancestor_meta->is_immutable
179 ? $ancestor_meta->_get_mutable_metaclass_name
180 : ref($ancestor_meta));
182 # if we have an ancestor metaclass that inherits $metaclass, we use
183 # that. This is like _fix_metaclass_incompatibility, but we can do it now.
185 # the case of having an ancestry is not very common, but arises in
187 unless ( $metaclass->isa( $ancestor_meta_class ) ) {
188 if ( $ancestor_meta_class->isa($metaclass) ) {
189 $metaclass = $ancestor_meta_class;
194 $meta = $metaclass->initialize($class);
197 if ( $class->can('meta') ) {
198 # check 'meta' method
200 # it may be inherited
203 # this is the case where the metaclass pragma
204 # was used before the 'use Moose' statement to
205 # override a specific class
206 my $method_meta = $class->meta;
208 ( blessed($method_meta) && $method_meta->isa('Moose::Meta::Class') )
209 || Moose->throw_error("$class already has a &meta function, but it does not return a Moose::Meta::Class ($method_meta)");
211 $meta = $method_meta;
214 unless ( $meta->has_method("meta") ) { # don't overwrite
215 # also check for inherited non moose 'meta' method?
216 # FIXME also skip this if the user requested by passing an option
219 # re-initialize so it inherits properly
220 $metaclass->initialize( ref($_[0]) || $_[0] );
225 # make sure they inherit from Moose::Object
226 $meta->superclasses($base_class)
227 unless $meta->superclasses();
232 # This may be used in some older MooseX extensions.
234 goto &Moose::Exporter::_get_caller;
237 ## make 'em all immutable
240 inline_constructor => 1,
241 constructor_name => "_new",
242 # these are Class::MOP accessors, so they need inlining
243 inline_accessors => 1
244 ) for grep { $_->is_mutable }
247 Moose::Meta::Attribute
249 Moose::Meta::Instance
251 Moose::Meta::TypeCoercion
252 Moose::Meta::TypeCoercion::Union
255 Moose::Meta::Method::Accessor
256 Moose::Meta::Method::Constructor
257 Moose::Meta::Method::Destructor
258 Moose::Meta::Method::Overridden
259 Moose::Meta::Method::Augmented
262 Moose::Meta::Role::Method
263 Moose::Meta::Role::Method::Required
264 Moose::Meta::Role::Method::Conflicting
266 Moose::Meta::Role::Composite
268 Moose::Meta::Role::Application
269 Moose::Meta::Role::Application::RoleSummation
270 Moose::Meta::Role::Application::ToClass
271 Moose::Meta::Role::Application::ToRole
272 Moose::Meta::Role::Application::ToInstance
283 Moose - A postmodern object system for Perl 5
288 use Moose; # automatically turns on strict and warnings
290 has 'x' => (is => 'rw', isa => 'Int');
291 has 'y' => (is => 'rw', isa => 'Int');
304 has 'z' => (is => 'rw', isa => 'Int');
306 after 'clear' => sub {
313 Moose is an extension of the Perl 5 object system.
315 The main goal of Moose is to make Perl 5 Object Oriented programming
316 easier, more consistent and less tedious. With Moose you can to think
317 more about what you want to do and less about the mechanics of OOP.
319 Additionally, Moose is built on top of L<Class::MOP>, which is a
320 metaclass system for Perl 5. This means that Moose not only makes
321 building normal Perl 5 objects better, but it provides the power of
322 metaclass programming as well.
326 If you're new to Moose, the best place to start is the
327 L<Moose::Manual> docs, followed by the L<Moose::Cookbook>. The intro
328 will show you what Moose is, and how it makes Perl 5 OO better.
330 The cookbook recipes on Moose basics will get you up to speed with
331 many of Moose's features quickly. Once you have an idea of what Moose
332 can do, you can use the API documentation to get more detail on
333 features which interest you.
335 =head2 Moose Extensions
337 The C<MooseX::> namespace is the official place to find Moose extensions.
338 These extensions can be found on the CPAN. The easiest way to find them
339 is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
340 or to examine L<Task::Moose> which aims to keep an up-to-date, easily
341 installable list of Moose extensions.
345 Much of the Moose documentation has been translated into other languages.
351 Japanese docs can be found at L<http://perldoc.perlassociation.org/pod/Moose-Doc-JA/index.html>. The source POD files can be found in GitHub: L<http://github.com/jpa/Moose-Doc-JA>
355 =head1 BUILDING CLASSES WITH MOOSE
357 Moose makes every attempt to provide as much convenience as possible during
358 class construction/definition, but still stay out of your way if you want it
359 to. Here are a few items to note when building classes with Moose.
361 Unless specified with C<extends>, any class which uses Moose will
362 inherit from L<Moose::Object>.
364 Moose will also manage all attributes (including inherited ones) that are
365 defined with C<has>. And (assuming you call C<new>, which is inherited from
366 L<Moose::Object>) this includes properly initializing all instance slots,
367 setting defaults where appropriate, and performing any type constraint checking
370 =head1 PROVIDED METHODS
372 Moose provides a number of methods to all your classes, mostly through the
373 inheritance of L<Moose::Object>. There is however, one exception.
379 This is a method which provides access to the current class's metaclass.
383 =head1 EXPORTED FUNCTIONS
385 Moose will export a number of functions into the class's namespace which
386 may then be used to set up the class. These functions all work directly
387 on the current class.
391 =item B<extends (@superclasses)>
393 This function will set the superclass(es) for the current class.
395 This approach is recommended instead of C<use base>, because C<use base>
396 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
397 replace it. This is important to ensure that classes which do not have
398 superclasses still properly inherit from L<Moose::Object>.
400 =item B<with (@roles)>
402 This will apply a given set of C<@roles> to the local class.
404 =item B<has $name|@$names =E<gt> %options>
406 This will install an attribute of a given C<$name> into the current class. If
407 the first parameter is an array reference, it will create an attribute for
408 every C<$name> in the list. The C<%options> are the same as those provided by
409 L<Class::MOP::Attribute>, in addition to the list below which are provided by
410 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
421 use the L<reader|Class::MOP::Attribute/reader>,
422 L<writer|Class::MOP::Attribute/writer> and
423 L<accessor|Class::MOP::Attribute/accessor> options inherited from
424 L<Class::MOP::Attribute>, however if you use those, you won't need the
427 =item I<isa =E<gt> $type_name>
429 The I<isa> option uses Moose's type constraint facilities to set up runtime
430 type checking for this attribute. Moose will perform the checks during class
431 construction, and within any accessors. The C<$type_name> argument must be a
432 string. The string may be either a class name or a type defined using
433 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
434 for information on how to define a new type, and how to retrieve type meta-data).
436 =item I<coerce =E<gt> (1|0)>
438 This will attempt to use coercion with the supplied type constraint to change
439 the value passed into any accessors or constructors. You B<must> have supplied
440 a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5>
443 =item I<does =E<gt> $role_name>
445 This will accept the name of a role which the value stored in this attribute
446 is expected to have consumed.
448 =item I<required =E<gt> (1|0)>
450 This marks the attribute as being required. This means a value must be
451 supplied during class construction, I<or> the attribute must be lazy
452 and have either a default or a builder. Note that c<required> does not
453 say anything about the attribute's value, which can be C<undef>.
455 =item I<weak_ref =E<gt> (1|0)>
457 This will tell the class to store the value of this attribute as a weakened
458 reference. If an attribute is a weakened reference, it B<cannot> also be
461 =item I<lazy =E<gt> (1|0)>
463 This will tell the class to not create this slot until absolutely necessary.
464 If an attribute is marked as lazy it B<must> have a default supplied.
466 =item I<auto_deref =E<gt> (1|0)>
468 This tells the accessor to automatically dereference the value of this
469 attribute when called in list context. The accessor will still return a
470 reference when called in scalar context. If this behavior isn't desirable,
471 L<Moose::Meta::Attribute::Native::Trait::Array/elements> or
472 L<Moose::Meta::Attribute::Native::Trait::Hash/elements> may be a better
473 choice. The I<auto_deref> option is only legal if your I<isa> option is
474 either C<ArrayRef> or C<HashRef>.
476 =item I<trigger =E<gt> $code>
478 The I<trigger> option is a CODE reference which will be called after
479 the value of the attribute is set. The CODE ref will be passed the
480 instance itself and the updated value. If the attribute already had a
481 value, this will be passed as the third value to the trigger.
483 You B<can> have a trigger on a read-only attribute.
485 B<NOTE:> Triggers will only fire when you B<assign> to the attribute,
486 either in the constructor, or using the writer. Default and built values will
487 B<not> cause the trigger to be fired.
489 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | DUCKTYPE | CODE>
491 The I<handles> option provides Moose classes with automated delegation features.
492 This is a pretty complex and powerful option. It accepts many different option
493 formats, each with its own benefits and drawbacks.
495 B<NOTE:> The class being delegated to does not need to be a Moose based class,
496 which is why this feature is especially useful when wrapping non-Moose classes.
498 All I<handles> option formats share the following traits:
500 You cannot override a locally defined method with a delegated method; an
501 exception will be thrown if you try. That is to say, if you define C<foo> in
502 your class, you cannot override it with a delegated C<foo>. This is almost never
503 something you would want to do, and if it is, you should do it by hand and not
506 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
507 and C<DEMOLISH> methods. These will not throw an exception, but will silently
508 move on to the next method in the list. My reasoning for this is that you would
509 almost never want to do this, since it usually breaks your class. As with
510 overriding locally defined methods, if you do want to do this, you should do it
511 manually, not with Moose.
513 You do not I<need> to have a reader (or accessor) for the attribute in order
514 to delegate to it. Moose will create a means of accessing the value for you,
515 however this will be several times B<less> efficient then if you had given
516 the attribute a reader (or accessor) to use.
518 Below is the documentation for each option format:
524 This is the most common usage for I<handles>. You basically pass a list of
525 method names to be delegated, and Moose will install a delegation method
530 This is the second most common usage for I<handles>. Instead of a list of
531 method names, you pass a HASH ref where each key is the method name you
532 want installed locally, and its value is the name of the original method
533 in the class being delegated to.
535 This can be very useful for recursive classes like trees. Here is a
536 quick example (soon to be expanded into a Moose::Cookbook recipe):
541 has 'node' => (is => 'rw', isa => 'Any');
546 default => sub { [] }
554 parent_node => 'node',
555 siblings => 'children',
559 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
560 which delegate to the C<node> and C<children> methods (respectively) of the Tree
561 instance stored in the C<parent> slot.
563 You may also use an array reference to curry arguments to the original method.
567 handles => { set_foo => [ set => 'foo' ] },
570 # $self->set_foo(...) calls $self->thing->set('foo', ...)
572 The first element of the array reference is the original method name, and the
573 rest is a list of curried arguments.
577 The regexp option works very similar to the ARRAY option, except that it builds
578 the list of methods for you. It starts by collecting all possible methods of the
579 class being delegated to, then filters that list using the regexp supplied here.
581 B<NOTE:> An I<isa> option is required when using the regexp option format. This
582 is so that we can determine (at compile time) the method list from the class.
583 Without an I<isa> this is just not possible.
587 With the role option, you specify the name of a role whose "interface" then
588 becomes the list of methods to handle. The "interface" can be defined as; the
589 methods of the role and any required methods of the role. It should be noted
590 that this does B<not> include any method modifiers or generated attribute
591 methods (which is consistent with role composition).
595 With the duck type option, you pass a duck type object whose "interface" then
596 becomes the list of methods to handle. The "interface" can be defined as; the
597 list of methods passed to C<duck_type> to create a duck type object. For more
598 information on C<duck_type> please check
599 L<Moose::Util::TypeConstraints>.
603 This is the option to use when you really want to do something funky. You should
604 only use it if you really know what you are doing, as it involves manual
607 This takes a code reference, which should expect two arguments. The first is the
608 attribute meta-object this I<handles> is attached to. The second is the
609 metaclass of the class being delegated to. It expects you to return a hash (not
610 a HASH ref) of the methods you want mapped.
614 =item I<metaclass =E<gt> $metaclass_name>
616 This tells the class to use a custom attribute metaclass for this particular
617 attribute. Custom attribute metaclasses are useful for extending the
618 capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
619 but they are still a fairly advanced topic and too much to cover here, see
620 L<Moose::Cookbook::Meta::Recipe1> for more information.
622 See L<Metaclass and Trait Name Resolution> for details on how a metaclass name
623 is resolved to a class name.
625 =item I<traits =E<gt> [ @role_names ]>
627 This tells Moose to take the list of C<@role_names> and apply them to the
628 attribute meta-object. This is very similar to the I<metaclass> option, but
629 allows you to use more than one extension at a time.
631 See L<Metaclass and Trait Name Resolution> for details on how a trait name is
632 resolved to a role name.
634 Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
637 =item I<builder> => Str
639 The value of this key is the name of the method that will be called to
640 obtain the value used to initialize the attribute. See the L<builder
641 option docs in Class::MOP::Attribute|Class::MOP::Attribute/builder>
642 and/or L<Moose::Cookbook::Basics::Recipe8> for more information.
644 =item I<default> => SCALAR | CODE
646 The value of this key is the default value which will initialize the attribute.
648 NOTE: If the value is a simple scalar (string or number), then it can
649 be just passed as is. However, if you wish to initialize it with a
650 HASH or ARRAY ref, then you need to wrap that inside a CODE reference.
651 See the L<default option docs in
652 Class::MOP::Attribute|Class::MOP::Attribute/default> for more
655 =item I<clearer> => Str
657 Creates a method allowing you to clear the value, see the L<clearer option
658 docs in Class::MOP::Attribute|Class::MOP::Attribute/clearer> for more
661 =item I<predicate> => Str
663 Creates a method to perform a basic test to see if a value has been set in the
664 attribute, see the L<predicate option docs in
665 Class::MOP::Attribute|Class::MOP::Attribute/predicate> for more information.
667 =item I<lazy_build> => (0|1)
669 Automatically define lazy => 1 as well as builder => "_build_$attr", clearer =>
670 "clear_$attr', predicate => 'has_$attr' unless they are already defined.
672 =item I<initializer> => Str
674 This may be a method name (referring to a method on the class with
675 this attribute) or a CODE ref. The initializer is used to set the
676 attribute value on an instance when the attribute is set during
677 instance initialization (but not when the value is being assigned
678 to). See the L<initializer option docs in
679 Class::MOP::Attribute|Class::MOP::Attribute/initializer> for more
682 =item I<documentation> => $string
684 An arbitrary string that can be retrieved later by calling C<<
685 $attr->documentation >>.
691 =item B<has +$name =E<gt> %options>
693 This is variation on the normal attribute creator C<has> which allows you to
694 clone and extend an attribute from a superclass or from a role. Here is an
695 example of the superclass usage:
703 default => 'Hello, I am a Foo'
711 has '+message' => (default => 'Hello I am My::Foo');
713 What is happening here is that B<My::Foo> is cloning the C<message> attribute
714 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
715 'Str'> characteristics, but changing the value in C<default>.
717 Here is another example, but within the context of a role:
725 default => 'Hello, I am a Foo'
733 has '+message' => (default => 'Hello I am My::Foo');
735 In this case, we are basically taking the attribute which the role supplied
736 and altering it within the bounds of this feature.
738 Note that you can only extend an attribute from either a superclass or a role,
739 you cannot extend an attribute in a role that composes over an attribute from
742 Aside from where the attributes come from (one from superclass, the other
743 from a role), this feature works exactly the same. This feature is restricted
744 somewhat, so as to try and force at least I<some> sanity into it. You are only
745 allowed to change the following attributes:
751 Change the default value of an attribute.
755 Change whether the attribute attempts to coerce a value passed to it.
759 Change if the attribute is required to have a value.
761 =item I<documentation>
763 Change the documentation string associated with the attribute.
767 Change if the attribute lazily initializes the slot.
771 You I<are> allowed to change the type without restriction.
773 It is recommended that you use this freedom with caution. We used to
774 only allow for extension only if the type was a subtype of the parent's
775 type, but we felt that was too restrictive and is better left as a
780 You are allowed to B<add> a new C<handles> definition, but you are B<not>
781 allowed to I<change> one.
785 You are allowed to B<add> a new C<builder> definition, but you are B<not>
786 allowed to I<change> one.
790 You are allowed to B<add> a new C<metaclass> definition, but you are
791 B<not> allowed to I<change> one.
795 You are allowed to B<add> additional traits to the C<traits> definition.
796 These traits will be composed into the attribute, but preexisting traits
797 B<are not> overridden, or removed.
801 =item B<before $name|@names =E<gt> sub { ... }>
803 =item B<after $name|@names =E<gt> sub { ... }>
805 =item B<around $name|@names =E<gt> sub { ... }>
807 These three items are syntactic sugar for the before, after, and around method
808 modifier features that L<Class::MOP> provides. More information on these may be
809 found in L<Moose::Manual::MethodModifiers> and the
810 L<Class::MOP::Class documentation|Class::MOP::Class/"Method Modifiers">.
814 The keyword C<super> is a no-op when called outside of an C<override> method. In
815 the context of an C<override> method, it will call the next most appropriate
816 superclass method with the same arguments as the original method.
818 =item B<override ($name, &sub)>
820 An C<override> method is a way of explicitly saying "I am overriding this
821 method from my superclass". You can call C<super> within this method, and
822 it will work as expected. The same thing I<can> be accomplished with a normal
823 method call and the C<SUPER::> pseudo-package; it is really your choice.
827 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
828 an C<augment> method. You can think of C<inner> as being the inverse of
829 C<super>; the details of how C<inner> and C<augment> work is best described in
830 the L<Moose::Cookbook::Basics::Recipe6>.
832 =item B<augment ($name, &sub)>
834 An C<augment> method, is a way of explicitly saying "I am augmenting this
835 method from my superclass". Once again, the details of how C<inner> and
836 C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
840 This is the C<Carp::confess> function, and exported here because I use it
845 This is the C<Scalar::Util::blessed> function, it is exported here because I
846 use it all the time. It is highly recommended that this is used instead of
847 C<ref> anywhere you need to test for an object's class name.
853 When you use Moose, you can specify which metaclass to use:
855 use Moose -metaclass => 'My::Meta::Class';
857 You can also specify traits which will be applied to your metaclass:
859 use Moose -traits => 'My::Trait';
861 This is very similar to the attribute traits feature. When you do
862 this, your class's C<meta> object will have the specified traits
863 applied to it. See L<Metaclass and Trait Name Resolution> for more
866 =head2 Metaclass and Trait Name Resolution
868 By default, when given a trait name, Moose simply tries to load a
869 class of the same name. If such a class does not exist, it then looks
870 for for a class matching
871 B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
872 variable here will be one of B<Attribute> or B<Class>, depending on
873 what the trait is being applied to.
875 If a class with this long name exists, Moose checks to see if it has
876 the method C<register_implementation>. This method is expected to
877 return the I<real> class name of the trait. If there is no
878 C<register_implementation> method, it will fall back to using
879 B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
881 The lookup method for metaclasses is the same, except that it looks
882 for a class matching B<Moose::Meta::$type::Custom::$metaclass_name>.
884 If all this is confusing, take a look at
885 L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
888 =head1 UNIMPORTING FUNCTIONS
892 Moose offers a way to remove the keywords it exports, through the C<unimport>
893 method. You simply have to say C<no Moose> at the bottom of your code for this
894 to work. Here is an example:
899 has 'first_name' => (is => 'rw', isa => 'Str');
900 has 'last_name' => (is => 'rw', isa => 'Str');
904 $self->first_name . ' ' . $self->last_name
907 no Moose; # keywords are removed from the Person package
909 =head1 EXTENDING AND EMBEDDING MOOSE
911 To learn more about extending Moose, we recommend checking out the
912 "Extending" recipes in the L<Moose::Cookbook>, starting with
913 L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
914 all the different ways you might extend Moose.
916 =head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
918 The C<init_meta> method sets up the metaclass object for the class
919 specified by C<for_class>. This method injects a a C<meta> accessor
920 into the class so you can get at this object. It also sets the class's
921 superclass to C<base_class>, with L<Moose::Object> as the default.
923 C<init_meta> returns the metaclass object for C<$class>.
925 You can specify an alternate metaclass with the C<metaclass> option.
927 For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>.
929 This method used to be documented as a function which accepted
930 positional parameters. This calling style will still work for
931 backwards compatibility, but is deprecated.
935 Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
936 and C<{into_level =E<gt> 1}>.
938 B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter>
939 instead, which lets you stack multiple C<Moose.pm>-alike modules
940 sanely. It handles getting the exported functions into the right place
943 =head2 B<throw_error>
945 An alias for C<confess>, used by internally by Moose.
947 =head1 METACLASS COMPATIBILITY AND MOOSE
949 Metaclass compatibility is a thorny subject. You should start by
950 reading the "About Metaclass compatibility" section in the
953 Moose will attempt to resolve a few cases of metaclass incompatibility
954 when you set the superclasses for a class, unlike C<Class::MOP>, which
955 simply dies if the metaclasses are incompatible.
957 In actuality, Moose fixes incompatibility for I<all> of a class's
958 metaclasses, not just the class metaclass. That includes the instance
959 metaclass, attribute metaclass, as well as its constructor class and
960 destructor class. However, for simplicity this discussion will just
961 refer to "metaclass", meaning the class metaclass, most of the time.
963 Moose has two algorithms for fixing metaclass incompatibility.
965 The first algorithm is very simple. If all the metaclass for the
966 parent is a I<subclass> of the child's metaclass, then we simply
967 replace the child's metaclass with the parent's.
969 The second algorithm is more complicated. It tries to determine if the
970 metaclasses only "differ by roles". This means that the parent and
971 child's metaclass share a common ancestor in their respective
972 hierarchies, and that the subclasses under the common ancestor are
973 only different because of role applications. This case is actually
974 fairly common when you mix and match various C<MooseX::*> modules,
975 many of which apply roles to the metaclass.
977 If the parent and child do differ by roles, Moose replaces the
978 metaclass in the child with a newly created metaclass. This metaclass
979 is a subclass of the parent's metaclass, does all of the roles that
980 the child's metaclass did before being replaced. Effectively, this
981 means the new metaclass does all of the roles done by both the
982 parent's and child's original metaclasses.
984 Ultimately, this is all transparent to you except in the case of an
985 unresolvable conflict.
987 =head2 The MooseX:: namespace
989 Generally if you're writing an extension I<for> Moose itself you'll want
990 to put your extension in the C<MooseX::> namespace. This namespace is
991 specifically for extensions that make Moose better or different in some
992 fundamental way. It is traditionally B<not> for a package that just happens
993 to use Moose. This namespace follows from the examples of the C<LWPx::>
994 and C<DBIx::> namespaces that perform the same function for C<LWP> and C<DBI>
1003 It should be noted that C<super> and C<inner> B<cannot> be used in the same
1004 method. However, they may be combined within the same class hierarchy; see
1005 F<t/014_override_augment_inner_super.t> for an example.
1007 The reason for this is that C<super> is only valid within a method
1008 with the C<override> modifier, and C<inner> will never be valid within an
1009 C<override> method. In fact, C<augment> will skip over any C<override> methods
1010 when searching for its appropriate C<inner>.
1012 This might seem like a restriction, but I am of the opinion that keeping these
1013 two features separate (yet interoperable) actually makes them easy to use, since
1014 their behavior is then easier to predict. Time will tell whether I am right or
1015 not (UPDATE: so far so good).
1021 We offer both a mailing list and a very active IRC channel.
1023 The mailing list is L<moose@perl.org>. You must be subscribed to send
1024 a message. To subscribe, send an empty message to
1025 L<moose-subscribe@perl.org>
1027 You can also visit us at C<#moose> on L<irc://irc.perl.org/#moose>
1028 This channel is quite active, and questions at all levels (on Moose-related
1029 topics ;) are welcome.
1031 =head1 ACKNOWLEDGEMENTS
1035 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
1037 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
1039 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
1040 and it certainly wouldn't have this name ;P
1042 =item The basis of the TypeContraints module was Rob Kinyon's idea
1043 originally, I just ran with it.
1045 =item Thanks to mst & chansen and the whole #moose posse for all the
1046 early ideas/feature-requests/encouragement/bug-finding.
1048 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
1056 =item L<http://www.iinteractive.com/moose>
1058 This is the official web home of Moose, it contains links to our public SVN repository
1059 as well as links to a number of talks and articles on Moose and Moose related
1062 =item The Moose is flying, a tutorial by Randal Schwartz
1064 Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
1066 Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
1068 =item Several Moose extension modules in the C<MooseX::> namespace.
1070 See L<http://search.cpan.org/search?query=MooseX::> for extensions.
1072 =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose>
1080 =item The Art of the MetaObject Protocol
1082 I mention this in the L<Class::MOP> docs too, this book was critical in
1083 the development of both modules and is highly recommended.
1091 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
1093 This paper (suggested by lbr on #moose) was what lead to the implementation
1094 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
1095 want to understand them, I suggest you read this.
1101 All complex software has bugs lurking in it, and this module is no
1104 Please report any bugs to C<bug-moose@rt.cpan.org>, or through the web
1105 interface at L<http://rt.cpan.org>.
1107 =head1 FEATURE REQUESTS
1109 We are very strict about what features we add to the Moose core, especially
1110 the user-visible features. Instead we have made sure that the underlying
1111 meta-system of Moose is as extensible as possible so that you can add your
1112 own features easily.
1114 That said, occasionally there is a feature needed in the meta-system
1115 to support your planned extension, in which case you should either
1116 email the mailing list (moose@perl.org) or join us on IRC at
1117 L<irc://irc.perl.org/#moose> to discuss. The
1118 L<Moose::Manual::Contributing> has more detail about how and when you
1123 Moose is an open project, there are at this point dozens of people who have
1124 contributed, and can contribute. If you have added anything to the Moose
1125 project you have a commit bit on this file and can add your name to the list.
1129 However there are only a few people with the rights to release a new version
1130 of Moose. The Moose Cabal are the people to go to with questions regarding
1131 the wider purview of Moose, and help out maintaining not just the code
1132 but the community as well.
1134 Stevan (stevan) Little E<lt>stevan@iinteractive.comE<gt>
1136 Yuval (nothingmuch) Kogman
1138 Shawn (sartak) Moore E<lt>sartak@bestpractical.comE<gt>
1140 Dave (autarch) Rolsky E<lt>autarch@urth.orgE<gt>
1142 Jesse (doy) Luehrs E<lt>doy at tozt dot netE<gt>
1144 Hans Dieter (confound) Pearcey E<lt>hdp@pobox.comE<gt>
1146 Chris (perigrin) Prather
1148 Florian Ragwitz E<lt>rafl@debian.orgE<gt>
1150 =head2 OTHER CONTRIBUTORS
1154 Adam (Alias) Kennedy
1156 Anders (Debolaz) Nor Berle
1158 Nathan (kolibrie) Gray
1160 Christian (chansen) Hansen
1162 Eric (ewilhelm) Wilhelm
1164 Guillermo (groditi) Roditi
1166 Jess (castaway) Robinson
1170 Robert (phaylon) Sedlacek
1174 Scott (konobi) McWhirter
1176 Shlomi (rindolf) Fish
1178 Wallace (wreis) Reis
1180 Jonathan (jrockway) Rockway
1182 Piotr (dexter) Roszatycki
1184 Sam (mugwump) Vilain
1188 Dylan Hardison (doc fixes)
1190 ... and many other #moose folks
1192 =head1 COPYRIGHT AND LICENSE
1194 Copyright 2006-2009 by Infinity Interactive, Inc.
1196 L<http://www.iinteractive.com>
1198 This library is free software; you can redistribute it and/or modify
1199 it under the same terms as Perl itself.