7 our $VERSION = '0.55_01';
8 $VERSION = eval $VERSION;
9 our $AUTHORITY = 'cpan:STEVAN';
11 use Scalar::Util 'blessed';
12 use Carp 'confess', 'croak', 'cluck';
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;
33 use Moose::Meta::Role::Application::ToMetaclassInstance;
35 use Moose::Util::TypeConstraints;
41 croak "Must derive at least one class" unless @_;
44 foreach my $super (@supers) {
45 Class::MOP::load_class($super);
46 croak "You cannot inherit from a Moose Role ($super)"
47 if $super->can('meta') &&
48 blessed $super->meta &&
49 $super->meta->isa('Moose::Meta::Role')
54 # this checks the metaclass to make sure
55 # it is correct, sometimes it can get out
56 # of sync when the classes are being built
57 my $meta = Moose::Meta::Class->initialize($class)->_fix_metaclass_incompatability(@supers);
58 $meta->superclasses(@supers);
63 Moose::Util::apply_all_roles(Class::MOP::Class->initialize($class), @_);
69 croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1;
71 my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
72 Class::MOP::Class->initialize($class)->add_attribute( $_, %options ) for @$attrs;
77 Moose::Util::add_method_modifier($class, 'before', \@_);
82 Moose::Util::add_method_modifier($class, 'after', \@_);
87 Moose::Util::add_method_modifier($class, 'around', \@_);
91 return unless our $SUPER_BODY; $SUPER_BODY->(our @SUPER_ARGS);
96 my ( $name, $method ) = @_;
97 Class::MOP::Class->initialize($class)->add_override_method_modifier( $name => $method );
102 our ( %INNER_BODY, %INNER_ARGS );
104 if ( my $body = $INNER_BODY{$pkg} ) {
105 my @args = @{ $INNER_ARGS{$pkg} };
106 local $INNER_ARGS{$pkg};
107 local $INNER_BODY{$pkg};
108 return $body->(@args);
116 my ( $name, $method ) = @_;
117 Class::MOP::Class->initialize($class)->add_augment_method_modifier( $name => $method );
122 cluck "The make_immutable keyword has been deprecated, " .
123 "please go back to __PACKAGE__->meta->make_immutable\n";
124 Class::MOP::Class->initialize($class)->make_immutable(@_);
127 Moose::Exporter->setup_import_methods(
129 qw( extends with has before after around override augment make_immutable )
134 \&Scalar::Util::blessed,
139 # This used to be called as a function. This hack preserves
140 # backwards compatibility.
141 if ( $_[0] ne __PACKAGE__ ) {
142 return __PACKAGE__->init_meta(
152 my $class = $args{for_class}
153 or confess "Cannot call init_meta without specifying a for_class";
154 my $base_class = $args{base_class} || 'Moose::Object';
155 my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
158 "The Metaclass $metaclass must be a subclass of Moose::Meta::Class."
159 unless $metaclass->isa('Moose::Meta::Class');
161 # make a subtype for each Moose class
163 unless find_type_constraint($class);
167 if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
168 unless ( $meta->isa("Moose::Meta::Class") ) {
169 confess "$class already has a metaclass, but it does not inherit $metaclass ($meta)";
172 # no metaclass, no 'meta' method
174 # now we check whether our ancestors have metaclass, and if so borrow that
175 my ( undef, @isa ) = @{ $class->mro::get_linear_isa };
177 foreach my $ancestor ( @isa ) {
178 my $ancestor_meta = Class::MOP::get_metaclass_by_name($ancestor) || next;
180 my $ancestor_meta_class = ($ancestor_meta->is_immutable
181 ? $ancestor_meta->get_mutable_metaclass_name
182 : ref($ancestor_meta));
184 # if we have an ancestor metaclass that inherits $metaclass, we use
185 # that. This is like _fix_metaclass_incompatability, but we can do it now.
187 # the case of having an ancestry is not very common, but arises in
189 unless ( $metaclass->isa( $ancestor_meta_class ) ) {
190 if ( $ancestor_meta_class->isa($metaclass) ) {
191 $metaclass = $ancestor_meta_class;
196 $meta = $metaclass->initialize($class);
199 if ( $class->can('meta') ) {
200 # check 'meta' method
202 # it may be inherited
205 # this is the case where the metaclass pragma
206 # was used before the 'use Moose' statement to
207 # override a specific class
208 my $method_meta = $class->meta;
210 ( blessed($method_meta) && $method_meta->isa('Moose::Meta::Class') )
211 || confess "$class already has a &meta function, but it does not return a Moose::Meta::Class ($meta)";
213 $meta = $method_meta;
216 unless ( $meta->has_method("meta") ) { # don't overwrite
217 # also check for inherited non moose 'meta' method?
218 # FIXME also skip this if the user requested by passing an option
221 # re-initialize so it inherits properly
222 $metaclass->initialize( ref($_[0]) || $_[0] );
227 # make sure they inherit from Moose::Object
228 $meta->superclasses($base_class)
229 unless $meta->superclasses();
234 # This may be used in some older MooseX extensions.
236 goto &Moose::Exporter::_get_caller;
239 ## make 'em all immutable
241 $_->meta->make_immutable(
242 inline_constructor => 1,
243 constructor_name => "_new",
244 inline_accessors => 1, # these are Class::MOP accessors, so they need inlining
247 Moose::Meta::Attribute
249 Moose::Meta::Instance
251 Moose::Meta::TypeConstraint
252 Moose::Meta::TypeConstraint::Union
253 Moose::Meta::TypeConstraint::Parameterized
254 Moose::Meta::TypeConstraint::Parameterizable
255 Moose::Meta::TypeConstraint::Enum
256 Moose::Meta::TypeConstraint::Class
257 Moose::Meta::TypeConstraint::Role
258 Moose::Meta::TypeConstraint::Registry
259 Moose::Meta::TypeCoercion
260 Moose::Meta::TypeCoercion::Union
263 Moose::Meta::Method::Accessor
264 Moose::Meta::Method::Constructor
265 Moose::Meta::Method::Destructor
266 Moose::Meta::Method::Overriden
267 Moose::Meta::Method::Augmented
270 Moose::Meta::Role::Method
271 Moose::Meta::Role::Method::Required
273 Moose::Meta::Role::Composite
275 Moose::Meta::Role::Application
276 Moose::Meta::Role::Application::RoleSummation
277 Moose::Meta::Role::Application::ToClass
278 Moose::Meta::Role::Application::ToRole
279 Moose::Meta::Role::Application::ToInstance
280 Moose::Meta::Role::Application::ToMetaclassInstance
291 Moose - A postmodern object system for Perl 5
296 use Moose; # automatically turns on strict and warnings
298 has 'x' => (is => 'rw', isa => 'Int');
299 has 'y' => (is => 'rw', isa => 'Int');
312 has 'z' => (is => 'rw', isa => 'Int');
314 after 'clear' => sub {
321 Moose is an extension of the Perl 5 object system.
323 The main goal of Moose is to make Perl 5 Object Oriented programming
324 easier, more consistent and less tedious. With Moose you can to think
325 more about what you want to do and less about the mechanics of OOP.
327 Additionally, Moose is built on top of L<Class::MOP>, which is a
328 metaclass system for Perl 5. This means that Moose not only makes
329 building normal Perl 5 objects better, but it provides the power of
330 metaclass programming as well.
334 If you're new to Moose, the best place to start is the
335 L<Moose::Cookbook>. The recipes on Moose basics will get you up to
336 speed with many of Moose's features quickly. Once you have an idea of
337 what Moose can do, you can use the API documentation to get more
338 detail on features which interest you.
340 =head2 Moose Extensions
342 The C<MooseX::> namespace is the official place to find Moose extensions.
343 These extensions can be found on the CPAN. The easiest way to find them
344 is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
345 or to examine L<Task::Moose> which aims to keep an up-to-date, easily
346 installable list of Moose extensions.
348 =head1 BUILDING CLASSES WITH MOOSE
350 Moose makes every attempt to provide as much convenience as possible during
351 class construction/definition, but still stay out of your way if you want it
352 to. Here are a few items to note when building classes with Moose.
354 Unless specified with C<extends>, any class which uses Moose will
355 inherit from L<Moose::Object>.
357 Moose will also manage all attributes (including inherited ones) that are
358 defined with C<has>. And (assuming you call C<new>, which is inherited from
359 L<Moose::Object>) this includes properly initializing all instance slots,
360 setting defaults where appropriate, and performing any type constraint checking
363 =head1 PROVIDED METHODS
365 Moose provides a number of methods to all your classes, mostly through the
366 inheritance of L<Moose::Object>. There is however, one exception.
372 This is a method which provides access to the current class's metaclass.
376 =head1 EXPORTED FUNCTIONS
378 Moose will export a number of functions into the class's namespace which
379 may then be used to set up the class. These functions all work directly
380 on the current class.
384 =item B<extends (@superclasses)>
386 This function will set the superclass(es) for the current class.
388 This approach is recommended instead of C<use base>, because C<use base>
389 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
390 replace it. This is important to ensure that classes which do not have
391 superclasses still properly inherit from L<Moose::Object>.
393 =item B<with (@roles)>
395 This will apply a given set of C<@roles> to the local class.
397 =item B<has $name =E<gt> %options>
399 This will install an attribute of a given C<$name> into the current class.
400 The C<%options> are the same as those provided by
401 L<Class::MOP::Attribute>, in addition to the list below which are provided
402 by Moose (L<Moose::Meta::Attribute> to be more specific):
406 =item I<is =E<gt> 'rw'|'ro'>
408 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
409 only). These will create either a read/write accessor or a read-only
410 accessor respectively, using the same name as the C<$name> of the attribute.
412 If you need more control over how your accessors are named, you can use the
413 I<reader>, I<writer> and I<accessor> options inherited from
414 L<Class::MOP::Attribute>, however if you use those, you won't need the I<is>
417 =item I<isa =E<gt> $type_name>
419 The I<isa> option uses Moose's type constraint facilities to set up runtime
420 type checking for this attribute. Moose will perform the checks during class
421 construction, and within any accessors. The C<$type_name> argument must be a
422 string. The string may be either a class name or a type defined using
423 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
424 for information on how to define a new type, and how to retrieve type meta-data).
426 =item I<coerce =E<gt> (1|0)>
428 This will attempt to use coercion with the supplied type constraint to change
429 the value passed into any accessors or constructors. You B<must> have supplied
430 a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5>
433 =item I<does =E<gt> $role_name>
435 This will accept the name of a role which the value stored in this attribute
436 is expected to have consumed.
438 =item I<required =E<gt> (1|0)>
440 This marks the attribute as being required. This means a I<defined> value must be
441 supplied during class construction, and the attribute may never be set to
442 C<undef> with an accessor.
444 =item I<weak_ref =E<gt> (1|0)>
446 This will tell the class to store the value of this attribute as a weakened
447 reference. If an attribute is a weakened reference, it B<cannot> also be
450 =item I<lazy =E<gt> (1|0)>
452 This will tell the class to not create this slot until absolutely necessary.
453 If an attribute is marked as lazy it B<must> have a default supplied.
455 =item I<auto_deref =E<gt> (1|0)>
457 This tells the accessor whether to automatically dereference the value returned.
458 This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>.
460 =item I<trigger =E<gt> $code>
462 The I<trigger> option is a CODE reference which will be called after the value of
463 the attribute is set. The CODE ref will be passed the instance itself, the
464 updated value and the attribute meta-object (this is for more advanced fiddling
465 and can typically be ignored). You B<cannot> have a trigger on a read-only
468 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE>
470 The I<handles> option provides Moose classes with automated delegation features.
471 This is a pretty complex and powerful option. It accepts many different option
472 formats, each with its own benefits and drawbacks.
474 B<NOTE:> The class being delegated to does not need to be a Moose based class,
475 which is why this feature is especially useful when wrapping non-Moose classes.
477 All I<handles> option formats share the following traits:
479 You cannot override a locally defined method with a delegated method; an
480 exception will be thrown if you try. That is to say, if you define C<foo> in
481 your class, you cannot override it with a delegated C<foo>. This is almost never
482 something you would want to do, and if it is, you should do it by hand and not
485 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
486 and C<DEMOLISH> methods. These will not throw an exception, but will silently
487 move on to the next method in the list. My reasoning for this is that you would
488 almost never want to do this, since it usually breaks your class. As with
489 overriding locally defined methods, if you do want to do this, you should do it
490 manually, not with Moose.
492 You do not I<need> to have a reader (or accessor) for the attribute in order
493 to delegate to it. Moose will create a means of accessing the value for you,
494 however this will be several times B<less> efficient then if you had given
495 the attribute a reader (or accessor) to use.
497 Below is the documentation for each option format:
503 This is the most common usage for I<handles>. You basically pass a list of
504 method names to be delegated, and Moose will install a delegation method
509 This is the second most common usage for I<handles>. Instead of a list of
510 method names, you pass a HASH ref where each key is the method name you
511 want installed locally, and its value is the name of the original method
512 in the class being delegated to.
514 This can be very useful for recursive classes like trees. Here is a
515 quick example (soon to be expanded into a Moose::Cookbook recipe):
520 has 'node' => (is => 'rw', isa => 'Any');
525 default => sub { [] }
533 parent_node => 'node',
534 siblings => 'children',
538 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
539 which delegate to the C<node> and C<children> methods (respectively) of the Tree
540 instance stored in the C<parent> slot.
544 The regexp option works very similar to the ARRAY option, except that it builds
545 the list of methods for you. It starts by collecting all possible methods of the
546 class being delegated to, then filters that list using the regexp supplied here.
548 B<NOTE:> An I<isa> option is required when using the regexp option format. This
549 is so that we can determine (at compile time) the method list from the class.
550 Without an I<isa> this is just not possible.
554 With the role option, you specify the name of a role whose "interface" then
555 becomes the list of methods to handle. The "interface" can be defined as; the
556 methods of the role and any required methods of the role. It should be noted
557 that this does B<not> include any method modifiers or generated attribute
558 methods (which is consistent with role composition).
562 This is the option to use when you really want to do something funky. You should
563 only use it if you really know what you are doing, as it involves manual
566 This takes a code reference, which should expect two arguments. The first is the
567 attribute meta-object this I<handles> is attached to. The second is the
568 metaclass of the class being delegated to. It expects you to return a hash (not
569 a HASH ref) of the methods you want mapped.
573 =item I<metaclass =E<gt> $metaclass_name>
575 This tells the class to use a custom attribute metaclass for this particular
576 attribute. Custom attribute metaclasses are useful for extending the
577 capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
578 but they are still a fairly advanced topic and too much to cover here, see
579 L<Moose::Cookbook::Meta::Recipe1> for more information.
581 The default behavior here is to just load C<$metaclass_name>; however, we also
582 have a way to alias to a shorter name. This will first look to see if
583 B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose
584 will then check to see if that has the method C<register_implementation>, which
585 should return the actual name of the custom attribute metaclass. If there is no
586 C<register_implementation> method, it will fall back to using
587 B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name.
589 =item I<traits =E<gt> [ @role_names ]>
591 This tells Moose to take the list of C<@role_names> and apply them to the
592 attribute meta-object. This is very similar to the I<metaclass> option, but
593 allows you to use more than one extension at a time.
595 See L<TRAIT NAME RESOLUTION> for details on how a trait name is
596 resolved to a class name.
598 Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
603 =item B<has +$name =E<gt> %options>
605 This is variation on the normal attibute creator C<has> which allows you to
606 clone and extend an attribute from a superclass or from a role. Here is an
607 example of the superclass usage:
615 default => 'Hello, I am a Foo'
623 has '+message' => (default => 'Hello I am My::Foo');
625 What is happening here is that B<My::Foo> is cloning the C<message> attribute
626 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
627 'Str'> characteristics, but changing the value in C<default>.
629 Here is another example, but within the context of a role:
637 default => 'Hello, I am a Foo'
645 has '+message' => (default => 'Hello I am My::Foo');
647 In this case, we are basically taking the attribute which the role supplied
648 and altering it within the bounds of this feature.
650 Aside from where the attributes come from (one from superclass, the other
651 from a role), this feature works exactly the same. This feature is restricted
652 somewhat, so as to try and force at least I<some> sanity into it. You are only
653 allowed to change the following attributes:
659 Change the default value of an attribute.
663 Change whether the attribute attempts to coerce a value passed to it.
667 Change if the attribute is required to have a value.
669 =item I<documentation>
671 Change the documentation string associated with the attribute.
675 Change if the attribute lazily initializes the slot.
679 You I<are> allowed to change the type without restriction.
681 It is recommended that you use this freedom with caution. We used to
682 only allow for extension only if the type was a subtype of the parent's
683 type, but we felt that was too restrictive and is better left as a
688 You are allowed to B<add> a new C<handles> definition, but you are B<not>
689 allowed to I<change> one.
693 You are allowed to B<add> a new C<builder> definition, but you are B<not>
694 allowed to I<change> one.
698 You are allowed to B<add> a new C<metaclass> definition, but you are
699 B<not> allowed to I<change> one.
703 You are allowed to B<add> additional traits to the C<traits> definition.
704 These traits will be composed into the attribute, but pre-existing traits
705 B<are not> overridden, or removed.
709 =item B<before $name|@names =E<gt> sub { ... }>
711 =item B<after $name|@names =E<gt> sub { ... }>
713 =item B<around $name|@names =E<gt> sub { ... }>
715 This three items are syntactic sugar for the before, after, and around method
716 modifier features that L<Class::MOP> provides. More information on these may be
717 found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method
722 The keyword C<super> is a no-op when called outside of an C<override> method. In
723 the context of an C<override> method, it will call the next most appropriate
724 superclass method with the same arguments as the original method.
726 =item B<override ($name, &sub)>
728 An C<override> method is a way of explicitly saying "I am overriding this
729 method from my superclass". You can call C<super> within this method, and
730 it will work as expected. The same thing I<can> be accomplished with a normal
731 method call and the C<SUPER::> pseudo-package; it is really your choice.
735 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
736 an C<augment> method. You can think of C<inner> as being the inverse of
737 C<super>; the details of how C<inner> and C<augment> work is best described in
738 the L<Moose::Cookbook::Basics::Recipe6>.
740 =item B<augment ($name, &sub)>
742 An C<augment> method, is a way of explicitly saying "I am augmenting this
743 method from my superclass". Once again, the details of how C<inner> and
744 C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
748 This is the C<Carp::confess> function, and exported here because I use it
753 This is the C<Scalar::Util::blessed> function, it is exported here because I
754 use it all the time. It is highly recommended that this is used instead of
755 C<ref> anywhere you need to test for an object's class name.
759 =head1 METACLASS TRAITS
761 When you use Moose, you can also specify traits which will be applied
764 use Moose -traits => 'My::Trait';
766 This is very similar to the attribute traits feature. When you do
767 this, your class's C<meta> object will have the specified traits
768 applied to it. See L<TRAIT NAME RESOLUTION> for more details.
770 =head1 TRAIT NAME RESOLUTION
772 By default, when given a trait name, Moose simply tries to load a
773 class of the same name. If such a class does not exist, it then looks
774 for for a class matching
775 B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
776 variable here will be one of B<Attribute> or B<Class>, depending on
777 what the trait is being applied to.
779 If a class with this long name exists, Moose checks to see if it has
780 the method C<register_implementation>. This method is expected to
781 return the I<real> class name of the trait. If there is no
782 C<register_implementation> method, it will fall back to using
783 B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
785 If all this is confusing, take a look at
786 L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
789 =head1 UNIMPORTING FUNCTIONS
793 Moose offers a way to remove the keywords it exports, through the C<unimport>
794 method. You simply have to say C<no Moose> at the bottom of your code for this
795 to work. Here is an example:
800 has 'first_name' => (is => 'rw', isa => 'Str');
801 has 'last_name' => (is => 'rw', isa => 'Str');
805 $self->first_name . ' ' . $self->last_name
808 no Moose; # keywords are removed from the Person package
810 =head1 EXTENDING AND EMBEDDING MOOSE
812 Moose also offers some options for extending or embedding it into your
813 own framework. There are several things you might want to do as part
814 of such a framework. First, you probably want to export Moose's sugar
815 functions (C<has>, C<extends>, etc) for users of the
816 framework. Second, you may want to provide additional sugar of your
817 own. Third, you may want to provide your own object base class instead
818 of L<Moose::Object>, and/or your own metaclass class instead of
819 L<Moose::Meta::Class>.
821 The exporting needs can be asily satisfied by using
822 L<Moose::Exporter>, which is what C<Moose.pm> itself uses for
823 exporting. L<Moose::Exporter> lets you "export like Moose".
825 If you define an C<init_meta> method in a module that uses
826 L<Moose::Exporter>, then this method will be called I<before>
827 C<Moose.pm>'s own C<init_meta>. This gives you a chance to provide an
828 alternate object base class or metaclass class.
830 Here is a simple example:
837 use Moose (); # no need to get Moose's exports
840 Moose::Exporter->setup_import_methods( also => 'Moose' );
844 return Moose->init_meta( @_, base_class => 'MyFramework::Base' );
847 In this example, any class that includes C<use MyFramework> will get
848 all of C<Moose.pm>'s sugar functions, and will have their superclass
849 set to C<MyFramework::Base>.
851 Additionally, that class can include C<no MyFramework> to unimport
853 =head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
855 The C<init_meta> method sets up the metaclass object for the class
856 specified by C<for_class>. This method injects a a C<meta> accessor
857 into the class so you can get at this object. It also sets the class's
858 superclass to C<base_class>, with L<Moose::Object> as the default.
860 You can specify an alternate metaclass with the C<metaclass> parameter.
862 For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>.
864 This method used to be documented as a function which accepted
865 positional parameters. This calling style will still work for
866 backwards compatibility, but is deprecated.
870 Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
871 and C<{into_level =E<gt> 1}>.
873 B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter>
874 instead, which lets you stack multiple C<Moose.pm>-alike modules
875 sanely. It handles getting the exported functions into the right place
884 It should be noted that C<super> and C<inner> B<cannot> be used in the same
885 method. However, they may be combined within the same class hierarchy; see
886 F<t/014_override_augment_inner_super.t> for an example.
888 The reason for this is that C<super> is only valid within a method
889 with the C<override> modifier, and C<inner> will never be valid within an
890 C<override> method. In fact, C<augment> will skip over any C<override> methods
891 when searching for its appropriate C<inner>.
893 This might seem like a restriction, but I am of the opinion that keeping these
894 two features separate (yet interoperable) actually makes them easy to use, since
895 their behavior is then easier to predict. Time will tell whether I am right or
896 not (UPDATE: so far so good).
900 It is important to note that we currently have no simple way of combining
901 multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above),
902 and that in many cases they will conflict with one another. We are working on
903 developing a way around this issue, but in the meantime, you have been warned.
909 In case you are still asking yourself "Why do I need this?", then this
910 section is for you. This used to be part of the main DESCRIPTION, but
911 I think Moose no longer actually needs justification, so it is included
912 (read: buried) here for those who are still not convinced.
916 =item Another object system!?!?
918 Yes, I know there has been an explosion recently of new ways to
919 build objects in Perl 5, most of them based on inside-out objects
920 and other such things. Moose is different because it is not a new
921 object system for Perl 5, but instead an extension of the existing
924 Moose is built on top of L<Class::MOP>, which is a metaclass system
925 for Perl 5. This means that Moose not only makes building normal
926 Perl 5 objects better, but it also provides the power of metaclass
929 =item Is this for real? Or is this just an experiment?
931 Moose is I<based> on the prototypes and experiments I did for the Perl 6
932 meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>.
934 =item Is this ready for use in production?
936 Yes, I believe that it is.
938 Moose has been used successfully in production environemnts by several people
939 and companies (including the one I work for). There are Moose applications
940 which have been in production with little or no issue now for well over two years.
941 I consider it highly stable and we are commited to keeping it stable.
943 Of course, in the end, you need to make this call yourself. If you have
944 any questions or concerns, please feel free to email me, or even the list
945 or just stop by #moose and ask away.
947 =item Is Moose just Perl 6 in Perl 5?
949 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
950 Instead, it is an OO system for Perl 5. I built Moose because I was tired of
951 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
952 instead of switching to Ruby, I wrote Moose :)
954 =item Wait, I<post> modern, I thought it was just I<modern>?
956 So I was reading Larry Wall's talk from the 1999 Linux World entitled
957 "Perl, the first postmodern computer language" in which he talks about how
958 he picked the features for Perl because he thought they were cool and he
959 threw out the ones that he thought sucked. This got me thinking about how
960 we have done the same thing in Moose. For Moose, we have "borrowed" features
961 from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and
962 the bits we didn't like (cause they sucked) we tossed aside. So for this
963 reason (and a few others) I have re-dubbed Moose a I<postmodern> object system.
969 =head1 ACKNOWLEDGEMENTS
973 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
975 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
977 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
978 and it certainly wouldn't have this name ;P
980 =item The basis of the TypeContraints module was Rob Kinyon's idea
981 originally, I just ran with it.
983 =item Thanks to mst & chansen and the whole #moose posse for all the
984 early ideas/feature-requests/encouragement/bug-finding.
986 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
994 =item L<http://www.iinteractive.com/moose>
996 This is the official web home of Moose, it contains links to our public SVN repo
997 as well as links to a number of talks and articles on Moose and Moose related
1000 =item L<Moose::Cookbook> - How to cook a Moose
1002 =item The Moose is flying, a tutorial by Randal Schwartz
1004 Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
1006 Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
1008 =item L<Class::MOP> documentation
1010 =item The #moose channel on irc.perl.org
1012 =item The Moose mailing list - moose@perl.org
1014 =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose>
1016 =item Several Moose extension modules in the C<MooseX::> namespace.
1018 See L<http://search.cpan.org/search?query=MooseX::> for extensions.
1026 =item The Art of the MetaObject Protocol
1028 I mention this in the L<Class::MOP> docs too, this book was critical in
1029 the development of both modules and is highly recommended.
1037 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
1039 This paper (suggested by lbr on #moose) was what lead to the implementation
1040 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
1041 want to understand them, I suggest you read this.
1047 All complex software has bugs lurking in it, and this module is no
1048 exception. If you find a bug please either email me, or add the bug
1051 =head1 FEATURE REQUESTS
1053 We are very strict about what features we add to the Moose core, especially
1054 the user-visible features. Instead we have made sure that the underlying
1055 meta-system of Moose is as extensible as possible so that you can add your
1056 own features easily. That said, occasionally there is a feature needed in the
1057 meta-system to support your planned extension, in which case you should
1058 either email the mailing list or join us on irc at #moose to discuss.
1062 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1064 B<with contributions from:>
1068 Adam (Alias) Kennedy
1070 Anders (Debolaz) Nor Berle
1072 Nathan (kolibre) Gray
1074 Christian (chansen) Hansen
1076 Hans Dieter (confound) Pearcey
1078 Eric (ewilhelm) Wilhelm
1080 Guillermo (groditi) Roditi
1082 Jess (castaway) Robinson
1086 Robert (phaylon) Sedlacek
1090 Scott (konobi) McWhirter
1092 Shlomi (rindolf) Fish
1094 Yuval (nothingmuch) Kogman
1096 Chris (perigrin) Prather
1098 Wallace (wreis) Reis
1100 Jonathan (jrockway) Rockway
1102 Piotr (dexter) Roszatycki
1104 Sam (mugwump) Vilain
1106 Shawn (sartak) Moore
1108 ... and many other #moose folks
1110 =head1 COPYRIGHT AND LICENSE
1112 Copyright 2006-2008 by Infinity Interactive, Inc.
1114 L<http://www.iinteractive.com>
1116 This library is free software; you can redistribute it and/or modify
1117 it under the same terms as Perl itself.