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::Attribute
263 Moose::Meta::Role::Method
264 Moose::Meta::Role::Method::Required
265 Moose::Meta::Role::Method::Conflicting
267 Moose::Meta::Role::Composite
269 Moose::Meta::Role::Application
270 Moose::Meta::Role::Application::RoleSummation
271 Moose::Meta::Role::Application::ToClass
272 Moose::Meta::Role::Application::ToRole
273 Moose::Meta::Role::Application::ToInstance
276 Moose::Meta::Mixin::AttributeCore->meta->make_immutable(
277 inline_constructor => 0,
278 constructor_name => undef,
289 Moose - A postmodern object system for Perl 5
294 use Moose; # automatically turns on strict and warnings
296 has 'x' => (is => 'rw', isa => 'Int');
297 has 'y' => (is => 'rw', isa => 'Int');
310 has 'z' => (is => 'rw', isa => 'Int');
312 after 'clear' => sub {
319 Moose is an extension of the Perl 5 object system.
321 The main goal of Moose is to make Perl 5 Object Oriented programming
322 easier, more consistent and less tedious. With Moose you can to think
323 more about what you want to do and less about the mechanics of OOP.
325 Additionally, Moose is built on top of L<Class::MOP>, which is a
326 metaclass system for Perl 5. This means that Moose not only makes
327 building normal Perl 5 objects better, but it provides the power of
328 metaclass programming as well.
332 If you're new to Moose, the best place to start is the
333 L<Moose::Manual> docs, followed by the L<Moose::Cookbook>. The intro
334 will show you what Moose is, and how it makes Perl 5 OO better.
336 The cookbook recipes on Moose basics will get you up to speed with
337 many of Moose's features quickly. Once you have an idea of what Moose
338 can do, you can use the API documentation to get more detail on
339 features which interest you.
341 =head2 Moose Extensions
343 The C<MooseX::> namespace is the official place to find Moose extensions.
344 These extensions can be found on the CPAN. The easiest way to find them
345 is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
346 or to examine L<Task::Moose> which aims to keep an up-to-date, easily
347 installable list of Moose extensions.
351 Much of the Moose documentation has been translated into other languages.
357 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>
361 =head1 BUILDING CLASSES WITH MOOSE
363 Moose makes every attempt to provide as much convenience as possible during
364 class construction/definition, but still stay out of your way if you want it
365 to. Here are a few items to note when building classes with Moose.
367 Unless specified with C<extends>, any class which uses Moose will
368 inherit from L<Moose::Object>.
370 Moose will also manage all attributes (including inherited ones) that are
371 defined with C<has>. And (assuming you call C<new>, which is inherited from
372 L<Moose::Object>) this includes properly initializing all instance slots,
373 setting defaults where appropriate, and performing any type constraint checking
376 =head1 PROVIDED METHODS
378 Moose provides a number of methods to all your classes, mostly through the
379 inheritance of L<Moose::Object>. There is however, one exception.
385 This is a method which provides access to the current class's metaclass.
389 =head1 EXPORTED FUNCTIONS
391 Moose will export a number of functions into the class's namespace which
392 may then be used to set up the class. These functions all work directly
393 on the current class.
397 =item B<extends (@superclasses)>
399 This function will set the superclass(es) for the current class.
401 This approach is recommended instead of C<use base>, because C<use base>
402 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
403 replace it. This is important to ensure that classes which do not have
404 superclasses still properly inherit from L<Moose::Object>.
406 =item B<with (@roles)>
408 This will apply a given set of C<@roles> to the local class.
410 =item B<has $name|@$names =E<gt> %options>
412 This will install an attribute of a given C<$name> into the current class. If
413 the first parameter is an array reference, it will create an attribute for
414 every C<$name> in the list. The C<%options> are the same as those provided by
415 L<Class::MOP::Attribute>, in addition to the list below which are provided by
416 Moose (L<Moose::Meta::Attribute> to be more specific):
420 =item I<is =E<gt> 'rw'|'ro'>
422 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
423 only). These will create either a read/write accessor or a read-only
424 accessor respectively, using the same name as the C<$name> of the attribute.
426 If you need more control over how your accessors are named, you can
427 use the L<reader|Class::MOP::Attribute/reader>,
428 L<writer|Class::MOP::Attribute/writer> and
429 L<accessor|Class::MOP::Attribute/accessor> options inherited from
430 L<Class::MOP::Attribute>, however if you use those, you won't need the
433 =item I<isa =E<gt> $type_name>
435 The I<isa> option uses Moose's type constraint facilities to set up runtime
436 type checking for this attribute. Moose will perform the checks during class
437 construction, and within any accessors. The C<$type_name> argument must be a
438 string. The string may be either a class name or a type defined using
439 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
440 for information on how to define a new type, and how to retrieve type meta-data).
442 =item I<coerce =E<gt> (1|0)>
444 This will attempt to use coercion with the supplied type constraint to change
445 the value passed into any accessors or constructors. You B<must> have supplied
446 a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5>
449 =item I<does =E<gt> $role_name>
451 This will accept the name of a role which the value stored in this attribute
452 is expected to have consumed.
454 =item I<required =E<gt> (1|0)>
456 This marks the attribute as being required. This means a value must be
457 supplied during class construction, I<or> the attribute must be lazy
458 and have either a default or a builder. Note that c<required> does not
459 say anything about the attribute's value, which can be C<undef>.
461 =item I<weak_ref =E<gt> (1|0)>
463 This will tell the class to store the value of this attribute as a weakened
464 reference. If an attribute is a weakened reference, it B<cannot> also be
467 =item I<lazy =E<gt> (1|0)>
469 This will tell the class to not create this slot until absolutely necessary.
470 If an attribute is marked as lazy it B<must> have a default supplied.
472 =item I<auto_deref =E<gt> (1|0)>
474 This tells the accessor to automatically dereference the value of this
475 attribute when called in list context. The accessor will still return a
476 reference when called in scalar context. If this behavior isn't desirable,
477 L<Moose::Meta::Attribute::Native::Trait::Array/elements> or
478 L<Moose::Meta::Attribute::Native::Trait::Hash/elements> may be a better
479 choice. The I<auto_deref> option is only legal if your I<isa> option is
480 either C<ArrayRef> or C<HashRef>.
482 =item I<trigger =E<gt> $code>
484 The I<trigger> option is a CODE reference which will be called after
485 the value of the attribute is set. The CODE ref will be passed the
486 instance itself and the updated value. If the attribute already had a
487 value, this will be passed as the third value to the trigger.
489 You B<can> have a trigger on a read-only attribute.
491 B<NOTE:> Triggers will only fire when you B<assign> to the attribute,
492 either in the constructor, or using the writer. Default and built values will
493 B<not> cause the trigger to be fired.
495 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | DUCKTYPE | CODE>
497 The I<handles> option provides Moose classes with automated delegation features.
498 This is a pretty complex and powerful option. It accepts many different option
499 formats, each with its own benefits and drawbacks.
501 B<NOTE:> The class being delegated to does not need to be a Moose based class,
502 which is why this feature is especially useful when wrapping non-Moose classes.
504 All I<handles> option formats share the following traits:
506 You cannot override a locally defined method with a delegated method; an
507 exception will be thrown if you try. That is to say, if you define C<foo> in
508 your class, you cannot override it with a delegated C<foo>. This is almost never
509 something you would want to do, and if it is, you should do it by hand and not
512 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
513 and C<DEMOLISH> methods. These will not throw an exception, but will silently
514 move on to the next method in the list. My reasoning for this is that you would
515 almost never want to do this, since it usually breaks your class. As with
516 overriding locally defined methods, if you do want to do this, you should do it
517 manually, not with Moose.
519 You do not I<need> to have a reader (or accessor) for the attribute in order
520 to delegate to it. Moose will create a means of accessing the value for you,
521 however this will be several times B<less> efficient then if you had given
522 the attribute a reader (or accessor) to use.
524 Below is the documentation for each option format:
530 This is the most common usage for I<handles>. You basically pass a list of
531 method names to be delegated, and Moose will install a delegation method
536 This is the second most common usage for I<handles>. Instead of a list of
537 method names, you pass a HASH ref where each key is the method name you
538 want installed locally, and its value is the name of the original method
539 in the class being delegated to.
541 This can be very useful for recursive classes like trees. Here is a
542 quick example (soon to be expanded into a Moose::Cookbook recipe):
547 has 'node' => (is => 'rw', isa => 'Any');
552 default => sub { [] }
560 parent_node => 'node',
561 siblings => 'children',
565 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
566 which delegate to the C<node> and C<children> methods (respectively) of the Tree
567 instance stored in the C<parent> slot.
569 You may also use an array reference to curry arguments to the original method.
573 handles => { set_foo => [ set => 'foo' ] },
576 # $self->set_foo(...) calls $self->thing->set('foo', ...)
578 The first element of the array reference is the original method name, and the
579 rest is a list of curried arguments.
583 The regexp option works very similar to the ARRAY option, except that it builds
584 the list of methods for you. It starts by collecting all possible methods of the
585 class being delegated to, then filters that list using the regexp supplied here.
587 B<NOTE:> An I<isa> option is required when using the regexp option format. This
588 is so that we can determine (at compile time) the method list from the class.
589 Without an I<isa> this is just not possible.
593 With the role option, you specify the name of a role whose "interface" then
594 becomes the list of methods to handle. The "interface" can be defined as; the
595 methods of the role and any required methods of the role. It should be noted
596 that this does B<not> include any method modifiers or generated attribute
597 methods (which is consistent with role composition).
601 With the duck type option, you pass a duck type object whose "interface" then
602 becomes the list of methods to handle. The "interface" can be defined as; the
603 list of methods passed to C<duck_type> to create a duck type object. For more
604 information on C<duck_type> please check
605 L<Moose::Util::TypeConstraints>.
609 This is the option to use when you really want to do something funky. You should
610 only use it if you really know what you are doing, as it involves manual
613 This takes a code reference, which should expect two arguments. The first is the
614 attribute meta-object this I<handles> is attached to. The second is the
615 metaclass of the class being delegated to. It expects you to return a hash (not
616 a HASH ref) of the methods you want mapped.
620 =item I<metaclass =E<gt> $metaclass_name>
622 This tells the class to use a custom attribute metaclass for this particular
623 attribute. Custom attribute metaclasses are useful for extending the
624 capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
625 but they are still a fairly advanced topic and too much to cover here, see
626 L<Moose::Cookbook::Meta::Recipe1> for more information.
628 See L<Metaclass and Trait Name Resolution> for details on how a metaclass name
629 is resolved to a class name.
631 =item I<traits =E<gt> [ @role_names ]>
633 This tells Moose to take the list of C<@role_names> and apply them to the
634 attribute meta-object. This is very similar to the I<metaclass> option, but
635 allows you to use more than one extension at a time.
637 See L<Metaclass and Trait Name Resolution> for details on how a trait name is
638 resolved to a role name.
640 Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
643 =item I<builder> => Str
645 The value of this key is the name of the method that will be called to
646 obtain the value used to initialize the attribute. See the L<builder
647 option docs in Class::MOP::Attribute|Class::MOP::Attribute/builder>
648 and/or L<Moose::Cookbook::Basics::Recipe8> for more information.
650 =item I<default> => SCALAR | CODE
652 The value of this key is the default value which will initialize the attribute.
654 NOTE: If the value is a simple scalar (string or number), then it can
655 be just passed as is. However, if you wish to initialize it with a
656 HASH or ARRAY ref, then you need to wrap that inside a CODE reference.
657 See the L<default option docs in
658 Class::MOP::Attribute|Class::MOP::Attribute/default> for more
661 =item I<clearer> => Str
663 Creates a method allowing you to clear the value, see the L<clearer option
664 docs in Class::MOP::Attribute|Class::MOP::Attribute/clearer> for more
667 =item I<predicate> => Str
669 Creates a method to perform a basic test to see if a value has been set in the
670 attribute, see the L<predicate option docs in
671 Class::MOP::Attribute|Class::MOP::Attribute/predicate> for more information.
673 =item I<lazy_build> => (0|1)
675 Automatically define lazy => 1 as well as builder => "_build_$attr", clearer =>
676 "clear_$attr', predicate => 'has_$attr' unless they are already defined.
678 =item I<initializer> => Str
680 This may be a method name (referring to a method on the class with
681 this attribute) or a CODE ref. The initializer is used to set the
682 attribute value on an instance when the attribute is set during
683 instance initialization (but not when the value is being assigned
684 to). See the L<initializer option docs in
685 Class::MOP::Attribute|Class::MOP::Attribute/initializer> for more
688 =item I<documentation> => $string
690 An arbitrary string that can be retrieved later by calling C<<
691 $attr->documentation >>.
697 =item B<has +$name =E<gt> %options>
699 This is variation on the normal attribute creator C<has> which allows you to
700 clone and extend an attribute from a superclass or from a role. Here is an
701 example of the superclass usage:
709 default => 'Hello, I am a Foo'
717 has '+message' => (default => 'Hello I am My::Foo');
719 What is happening here is that B<My::Foo> is cloning the C<message> attribute
720 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
721 'Str'> characteristics, but changing the value in C<default>.
723 Here is another example, but within the context of a role:
731 default => 'Hello, I am a Foo'
739 has '+message' => (default => 'Hello I am My::Foo');
741 In this case, we are basically taking the attribute which the role supplied
742 and altering it within the bounds of this feature.
744 Note that you can only extend an attribute from either a superclass or a role,
745 you cannot extend an attribute in a role that composes over an attribute from
748 Aside from where the attributes come from (one from superclass, the other
749 from a role), this feature works exactly the same. This feature is restricted
750 somewhat, so as to try and force at least I<some> sanity into it. You are only
751 allowed to change the following attributes:
757 Change the default value of an attribute.
761 Change whether the attribute attempts to coerce a value passed to it.
765 Change if the attribute is required to have a value.
767 =item I<documentation>
769 Change the documentation string associated with the attribute.
773 Change if the attribute lazily initializes the slot.
777 You I<are> allowed to change the type without restriction.
779 It is recommended that you use this freedom with caution. We used to
780 only allow for extension only if the type was a subtype of the parent's
781 type, but we felt that was too restrictive and is better left as a
786 You are allowed to B<add> a new C<handles> definition, but you are B<not>
787 allowed to I<change> one.
791 You are allowed to B<add> a new C<builder> definition, but you are B<not>
792 allowed to I<change> one.
796 You are allowed to B<add> a new C<metaclass> definition, but you are
797 B<not> allowed to I<change> one.
801 You are allowed to B<add> additional traits to the C<traits> definition.
802 These traits will be composed into the attribute, but preexisting traits
803 B<are not> overridden, or removed.
807 =item B<before $name|@names =E<gt> sub { ... }>
809 =item B<after $name|@names =E<gt> sub { ... }>
811 =item B<around $name|@names =E<gt> sub { ... }>
813 These three items are syntactic sugar for the before, after, and around method
814 modifier features that L<Class::MOP> provides. More information on these may be
815 found in L<Moose::Manual::MethodModifiers> and the
816 L<Class::MOP::Class documentation|Class::MOP::Class/"Method Modifiers">.
820 The keyword C<super> is a no-op when called outside of an C<override> method. In
821 the context of an C<override> method, it will call the next most appropriate
822 superclass method with the same arguments as the original method.
824 =item B<override ($name, &sub)>
826 An C<override> method is a way of explicitly saying "I am overriding this
827 method from my superclass". You can call C<super> within this method, and
828 it will work as expected. The same thing I<can> be accomplished with a normal
829 method call and the C<SUPER::> pseudo-package; it is really your choice.
833 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
834 an C<augment> method. You can think of C<inner> as being the inverse of
835 C<super>; the details of how C<inner> and C<augment> work is best described in
836 the L<Moose::Cookbook::Basics::Recipe6>.
838 =item B<augment ($name, &sub)>
840 An C<augment> method, is a way of explicitly saying "I am augmenting this
841 method from my superclass". Once again, the details of how C<inner> and
842 C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
846 This is the C<Carp::confess> function, and exported here because I use it
851 This is the C<Scalar::Util::blessed> function, it is exported here because I
852 use it all the time. It is highly recommended that this is used instead of
853 C<ref> anywhere you need to test for an object's class name.
859 When you use Moose, you can specify which metaclass to use:
861 use Moose -metaclass => 'My::Meta::Class';
863 You can also specify traits which will be applied to your metaclass:
865 use Moose -traits => 'My::Trait';
867 This is very similar to the attribute traits feature. When you do
868 this, your class's C<meta> object will have the specified traits
869 applied to it. See L<Metaclass and Trait Name Resolution> for more
872 =head2 Metaclass and Trait Name Resolution
874 By default, when given a trait name, Moose simply tries to load a
875 class of the same name. If such a class does not exist, it then looks
876 for for a class matching
877 B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
878 variable here will be one of B<Attribute> or B<Class>, depending on
879 what the trait is being applied to.
881 If a class with this long name exists, Moose checks to see if it has
882 the method C<register_implementation>. This method is expected to
883 return the I<real> class name of the trait. If there is no
884 C<register_implementation> method, it will fall back to using
885 B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
887 The lookup method for metaclasses is the same, except that it looks
888 for a class matching B<Moose::Meta::$type::Custom::$metaclass_name>.
890 If all this is confusing, take a look at
891 L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
894 =head1 UNIMPORTING FUNCTIONS
898 Moose offers a way to remove the keywords it exports, through the C<unimport>
899 method. You simply have to say C<no Moose> at the bottom of your code for this
900 to work. Here is an example:
905 has 'first_name' => (is => 'rw', isa => 'Str');
906 has 'last_name' => (is => 'rw', isa => 'Str');
910 $self->first_name . ' ' . $self->last_name
913 no Moose; # keywords are removed from the Person package
915 =head1 EXTENDING AND EMBEDDING MOOSE
917 To learn more about extending Moose, we recommend checking out the
918 "Extending" recipes in the L<Moose::Cookbook>, starting with
919 L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
920 all the different ways you might extend Moose.
922 =head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
924 The C<init_meta> method sets up the metaclass object for the class
925 specified by C<for_class>. This method injects a a C<meta> accessor
926 into the class so you can get at this object. It also sets the class's
927 superclass to C<base_class>, with L<Moose::Object> as the default.
929 C<init_meta> returns the metaclass object for C<$class>.
931 You can specify an alternate metaclass with the C<metaclass> option.
933 For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>.
935 This method used to be documented as a function which accepted
936 positional parameters. This calling style will still work for
937 backwards compatibility, but is deprecated.
941 Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
942 and C<{into_level =E<gt> 1}>.
944 B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter>
945 instead, which lets you stack multiple C<Moose.pm>-alike modules
946 sanely. It handles getting the exported functions into the right place
949 =head2 B<throw_error>
951 An alias for C<confess>, used by internally by Moose.
953 =head1 METACLASS COMPATIBILITY AND MOOSE
955 Metaclass compatibility is a thorny subject. You should start by
956 reading the "About Metaclass compatibility" section in the
959 Moose will attempt to resolve a few cases of metaclass incompatibility
960 when you set the superclasses for a class, unlike C<Class::MOP>, which
961 simply dies if the metaclasses are incompatible.
963 In actuality, Moose fixes incompatibility for I<all> of a class's
964 metaclasses, not just the class metaclass. That includes the instance
965 metaclass, attribute metaclass, as well as its constructor class and
966 destructor class. However, for simplicity this discussion will just
967 refer to "metaclass", meaning the class metaclass, most of the time.
969 Moose has two algorithms for fixing metaclass incompatibility.
971 The first algorithm is very simple. If all the metaclass for the
972 parent is a I<subclass> of the child's metaclass, then we simply
973 replace the child's metaclass with the parent's.
975 The second algorithm is more complicated. It tries to determine if the
976 metaclasses only "differ by roles". This means that the parent and
977 child's metaclass share a common ancestor in their respective
978 hierarchies, and that the subclasses under the common ancestor are
979 only different because of role applications. This case is actually
980 fairly common when you mix and match various C<MooseX::*> modules,
981 many of which apply roles to the metaclass.
983 If the parent and child do differ by roles, Moose replaces the
984 metaclass in the child with a newly created metaclass. This metaclass
985 is a subclass of the parent's metaclass, does all of the roles that
986 the child's metaclass did before being replaced. Effectively, this
987 means the new metaclass does all of the roles done by both the
988 parent's and child's original metaclasses.
990 Ultimately, this is all transparent to you except in the case of an
991 unresolvable conflict.
993 =head2 The MooseX:: namespace
995 Generally if you're writing an extension I<for> Moose itself you'll want
996 to put your extension in the C<MooseX::> namespace. This namespace is
997 specifically for extensions that make Moose better or different in some
998 fundamental way. It is traditionally B<not> for a package that just happens
999 to use Moose. This namespace follows from the examples of the C<LWPx::>
1000 and C<DBIx::> namespaces that perform the same function for C<LWP> and C<DBI>
1009 It should be noted that C<super> and C<inner> B<cannot> be used in the same
1010 method. However, they may be combined within the same class hierarchy; see
1011 F<t/014_override_augment_inner_super.t> for an example.
1013 The reason for this is that C<super> is only valid within a method
1014 with the C<override> modifier, and C<inner> will never be valid within an
1015 C<override> method. In fact, C<augment> will skip over any C<override> methods
1016 when searching for its appropriate C<inner>.
1018 This might seem like a restriction, but I am of the opinion that keeping these
1019 two features separate (yet interoperable) actually makes them easy to use, since
1020 their behavior is then easier to predict. Time will tell whether I am right or
1021 not (UPDATE: so far so good).
1027 We offer both a mailing list and a very active IRC channel.
1029 The mailing list is L<moose@perl.org>. You must be subscribed to send
1030 a message. To subscribe, send an empty message to
1031 L<moose-subscribe@perl.org>
1033 You can also visit us at C<#moose> on L<irc://irc.perl.org/#moose>
1034 This channel is quite active, and questions at all levels (on Moose-related
1035 topics ;) are welcome.
1037 =head1 ACKNOWLEDGEMENTS
1041 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
1043 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
1045 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
1046 and it certainly wouldn't have this name ;P
1048 =item The basis of the TypeContraints module was Rob Kinyon's idea
1049 originally, I just ran with it.
1051 =item Thanks to mst & chansen and the whole #moose posse for all the
1052 early ideas/feature-requests/encouragement/bug-finding.
1054 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
1062 =item L<http://www.iinteractive.com/moose>
1064 This is the official web home of Moose, it contains links to our public SVN repository
1065 as well as links to a number of talks and articles on Moose and Moose related
1068 =item The Moose is flying, a tutorial by Randal Schwartz
1070 Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
1072 Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
1074 =item Several Moose extension modules in the C<MooseX::> namespace.
1076 See L<http://search.cpan.org/search?query=MooseX::> for extensions.
1078 =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose>
1086 =item The Art of the MetaObject Protocol
1088 I mention this in the L<Class::MOP> docs too, this book was critical in
1089 the development of both modules and is highly recommended.
1097 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
1099 This paper (suggested by lbr on #moose) was what lead to the implementation
1100 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
1101 want to understand them, I suggest you read this.
1107 All complex software has bugs lurking in it, and this module is no
1110 Please report any bugs to C<bug-moose@rt.cpan.org>, or through the web
1111 interface at L<http://rt.cpan.org>.
1113 You can also discuss feature requests or possible bugs on the Moose mailing
1114 list (moose@perl.org) or on IRC at L<irc://irc.perl.org/#moose>.
1116 =head1 FEATURE REQUESTS
1118 We are very strict about what features we add to the Moose core, especially
1119 the user-visible features. Instead we have made sure that the underlying
1120 meta-system of Moose is as extensible as possible so that you can add your
1121 own features easily.
1123 That said, occasionally there is a feature needed in the meta-system
1124 to support your planned extension, in which case you should either
1125 email the mailing list (moose@perl.org) or join us on IRC at
1126 L<irc://irc.perl.org/#moose> to discuss. The
1127 L<Moose::Manual::Contributing> has more detail about how and when you
1132 Moose is an open project, there are at this point dozens of people who have
1133 contributed, and can contribute. If you have added anything to the Moose
1134 project you have a commit bit on this file and can add your name to the list.
1138 However there are only a few people with the rights to release a new version
1139 of Moose. The Moose Cabal are the people to go to with questions regarding
1140 the wider purview of Moose, and help out maintaining not just the code
1141 but the community as well.
1143 Stevan (stevan) Little E<lt>stevan@iinteractive.comE<gt>
1145 Jesse (doy) Luehrs E<lt>doy at tozt dot netE<gt>
1147 Yuval (nothingmuch) Kogman
1149 Shawn (sartak) Moore E<lt>sartak@bestpractical.comE<gt>
1151 Hans Dieter (confound) Pearcey E<lt>hdp@pobox.comE<gt>
1153 Chris (perigrin) Prather
1155 Florian Ragwitz E<lt>rafl@debian.orgE<gt>
1157 Dave (autarch) Rolsky E<lt>autarch@urth.orgE<gt>
1159 =head2 OTHER CONTRIBUTORS
1163 Adam (Alias) Kennedy
1165 Anders (Debolaz) Nor Berle
1167 Nathan (kolibrie) Gray
1169 Christian (chansen) Hansen
1171 Eric (ewilhelm) Wilhelm
1173 Guillermo (groditi) Roditi
1175 Jess (castaway) Robinson
1179 Robert (phaylon) Sedlacek
1183 Scott (konobi) McWhirter
1185 Shlomi (rindolf) Fish
1187 Wallace (wreis) Reis
1189 Jonathan (jrockway) Rockway
1191 Piotr (dexter) Roszatycki
1193 Sam (mugwump) Vilain
1197 Dylan Hardison (doc fixes)
1199 ... and many other #moose folks
1201 =head1 COPYRIGHT AND LICENSE
1203 Copyright 2006-2010 by Infinity Interactive, Inc.
1205 L<http://www.iinteractive.com>
1207 This library is free software; you can redistribute it and/or modify
1208 it under the same terms as Perl itself.