8 our $AUTHORITY = 'cpan:STEVAN';
10 use Scalar::Util 'blessed', 'reftype';
12 use Sub::Name 'subname';
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;
24 use Moose::Meta::Role;
27 use Moose::Util::TypeConstraints;
33 my ( $class, $base_class, $metaclass ) = @_;
34 $base_class = $class unless defined $base_class;
35 $metaclass = 'Moose::Meta::Class' unless defined $metaclass;
38 "The Metaclass $metaclass must be a subclass of Moose::Meta::Class."
39 unless $metaclass->isa('Moose::Meta::Class');
41 # make a subtype for each Moose class
42 subtype $class => as 'Object' => where { $_->isa($class) } =>
43 optimize_as { blessed( $_[0] ) && $_[0]->isa($class) }
44 unless find_type_constraint($class);
47 if ( $class->can('meta') ) {
49 # this is the case where the metaclass pragma
50 # was used before the 'use Moose' statement to
51 # override a specific class
52 $meta = $class->meta();
53 ( blessed($meta) && $meta->isa('Moose::Meta::Class') )
54 || confess "You already have a &meta function, but it does not return a Moose::Meta::Class";
58 # this is broken currently, we actually need
59 # to allow the possiblity of an inherited
60 # meta, which will not be visible until the
61 # user 'extends' first. This needs to have
62 # more intelligence to it
63 $meta = $metaclass->initialize($class);
67 # re-initialize so it inherits properly
68 $metaclass->initialize( blessed( $_[0] ) || $_[0] );
73 # make sure they inherit from Moose::Object
74 $meta->superclasses($base_class)
75 unless $meta->superclasses();
81 return subname 'Moose::extends' => sub (@) {
82 confess "Must derive at least one class" unless @_;
83 Class::MOP::load_class($_) for @_;
85 # this checks the metaclass to make sure
86 # it is correct, sometimes it can get out
87 # of sync when the classes are being built
88 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
89 $meta->superclasses(@_);
94 return subname 'Moose::with' => sub (@) {
96 confess "Must specify at least one role" unless @args;
98 my $roles = Data::OptList::mkopt(\@args);
103 Class::MOP::load_class($_->[0]) for @$roles;
105 ($_->[0]->can('meta') && $_->[0]->meta->isa('Moose::Meta::Role'))
106 || confess "You can only consume roles, " . $_->[0] . " is not a Moose role"
109 my $meta = $class->meta;
111 if (scalar @$roles == 1) {
112 my ($role, $params) = @{$roles->[0]};
113 $role->meta->apply($meta, (defined $params ? %$params : ()));
116 Moose::Meta::Role->combine(
117 map { $_->[0]->meta } @$roles
121 #$class->meta->_apply_all_roles(@roles);
126 return subname 'Moose::has' => sub ($;%) {
127 my ( $name, %options ) = @_;
128 my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
129 $class->meta->_process_attribute( $_, %options ) for @$attrs;
134 return subname 'Moose::before' => sub (@&) {
136 my $meta = $class->meta;
137 $meta->add_before_method_modifier( $_, $code ) for @_;
142 return subname 'Moose::after' => sub (@&) {
144 my $meta = $class->meta;
145 $meta->add_after_method_modifier( $_, $code ) for @_;
150 return subname 'Moose::around' => sub (@&) {
152 my $meta = $class->meta;
153 $meta->add_around_method_modifier( $_, $code ) for @_;
160 $SUPER_SLOT{$CALLER} = \*{"${CALLER}::super"};
162 return subname 'Moose::super' => sub { };
166 return subname 'Moose::override' => sub ($&) {
167 my ( $name, $method ) = @_;
168 $class->meta->add_override_method_modifier( $name => $method );
175 $INNER_SLOT{$CALLER} = \*{"${CALLER}::inner"};
177 return subname 'Moose::inner' => sub { };
181 return subname 'Moose::augment' => sub (@&) {
182 my ( $name, $method ) = @_;
183 $class->meta->add_augment_method_modifier( $name => $method );
187 return \&Carp::confess;
190 return \&Scalar::Util::blessed;
194 my $exporter = Sub::Exporter::build_exporter(
196 exports => \%exports,
197 groups => { default => [':all'] }
201 # 1 extra level because it's called by import so there's a layer of indirection
205 ref $_[1] && defined $_[1]->{into}
207 : ref $_[1] && defined $_[1]->{into_level}
208 ? caller($offset + $_[1]->{into_level})
213 $CALLER = _get_caller(@_);
218 # we should never export to main
219 return if $CALLER eq 'main';
221 init_meta( $CALLER, 'Moose::Object' );
228 my $class = _get_caller(@_);
230 # loop through the exports ...
231 foreach my $name ( keys %exports ) {
234 if ( defined &{ $class . '::' . $name } ) {
235 my $keyword = \&{ $class . '::' . $name };
237 # make sure it is from Moose
238 my ($pkg_name) = Class::MOP::get_code_info($keyword);
240 next if $pkg_name ne 'Moose';
242 # and if it is from Moose then undef the slot
243 delete ${ $class . '::' }{$name};
250 ## make 'em all immutable
252 $_->meta->make_immutable(
253 inline_constructor => 0,
254 inline_accessors => 1, # these are Class::MOP accessors, so they need inlining
257 'Moose::Meta::Attribute',
258 'Moose::Meta::Class',
259 'Moose::Meta::Instance',
261 'Moose::Meta::TypeConstraint',
262 'Moose::Meta::TypeConstraint::Union',
263 'Moose::Meta::TypeConstraint::Parameterized',
264 'Moose::Meta::TypeCoercion',
266 'Moose::Meta::Method',
267 'Moose::Meta::Method::Accessor',
268 'Moose::Meta::Method::Constructor',
269 'Moose::Meta::Method::Destructor',
270 'Moose::Meta::Method::Overriden',
273 'Moose::Meta::Role::Method',
274 'Moose::Meta::Role::Method::Required',
285 Moose - A complete modern object system for Perl 5
290 use Moose; # automatically turns on strict and warnings
292 has 'x' => (is => 'rw', isa => 'Int');
293 has 'y' => (is => 'rw', isa => 'Int');
306 has 'z' => (is => 'rw', isa => 'Int');
308 after 'clear' => sub {
315 Moose is an extension of the Perl 5 object system.
317 =head2 Another object system!?!?
319 Yes, I know there has been an explosion recently of new ways to
320 build object's in Perl 5, most of them based on inside-out objects
321 and other such things. Moose is different because it is not a new
322 object system for Perl 5, but instead an extension of the existing
325 Moose is built on top of L<Class::MOP>, which is a metaclass system
326 for Perl 5. This means that Moose not only makes building normal
327 Perl 5 objects better, but it also provides the power of metaclass
330 =head2 Is this for real? Or is this just an experiment?
332 Moose is I<based> on the prototypes and experiments I did for the Perl 6
333 meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>.
335 =head2 Is this ready for use in production?
337 Yes, I believe that it is.
339 Moose has been used successfully in production environemnts by several people
340 and companies (including the one I work for). There are Moose applications
341 which have been in production with little or no issue now for over a year.
342 I consider it highly stable and we are commited to keeping it stable.
344 Of course, in the end, you need to make this call yourself. If you have
345 any questions or concerns, please feel free to email me, or even the list
346 or just stop by #moose and ask away.
348 =head2 Is Moose just Perl 6 in Perl 5?
350 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
351 Instead, it is an OO system for Perl 5. I built Moose because I was tired of
352 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
353 instead of switching to Ruby, I wrote Moose :)
355 =head2 Moose Extensions
357 The L<MooseX::> namespace is the official place to find Moose extensions.
358 There are a number of these modules out on CPAN right now the best way to
359 find them is to search for MooseX:: on search.cpan.org.
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 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.
386 This is a method which provides access to the current class's metaclass.
388 =item B<extends (@superclasses)>
390 This function will set the superclass(es) for the current class.
392 This approach is recommended instead of C<use base>, because C<use base>
393 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
394 replace it. This is important to ensure that classes which do not have
395 superclasses still properly inherit from L<Moose::Object>.
397 =item B<with (@roles)>
399 This will apply a given set of C<@roles> to the local class. Role support
400 is currently under heavy development; see L<Moose::Role> for more details.
402 =item B<has $name =E<gt> %options>
404 This will install an attribute of a given C<$name> into the current class.
405 The C<%options> are the same as those provided by
406 L<Class::MOP::Attribute>, in addition to the list below which are provided
407 by Moose (L<Moose::Meta::Attribute> to be more specific):
411 =item I<is =E<gt> 'rw'|'ro'>
413 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
414 only). These will create either a read/write accessor or a read-only
415 accessor respectively, using the same name as the C<$name> of the attribute.
417 If you need more control over how your accessors are named, you can use the
418 I<reader>, I<writer> and I<accessor> options inherited from
419 L<Class::MOP::Attribute>.
421 =item I<isa =E<gt> $type_name>
423 The I<isa> option uses Moose's type constraint facilities to set up runtime
424 type checking for this attribute. Moose will perform the checks during class
425 construction, and within any accessors. The C<$type_name> argument must be a
426 string. The string may be either a class name or a type defined using
427 Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
428 for information on how to define a new type, and how to retrieve type meta-data).
430 =item I<coerce =E<gt> (1|0)>
432 This will attempt to use coercion with the supplied type constraint to change
433 the value passed into any accessors or constructors. You B<must> have supplied
434 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
437 =item I<does =E<gt> $role_name>
439 This will accept the name of a role which the value stored in this attribute
440 is expected to have consumed.
442 =item I<required =E<gt> (1|0)>
444 This marks the attribute as being required. This means a I<defined> value must be
445 supplied during class construction, and the attribute may never be set to
446 C<undef> with an accessor.
448 =item I<weak_ref =E<gt> (1|0)>
450 This will tell the class to store the value of this attribute as a weakened
451 reference. If an attribute is a weakened reference, it B<cannot> also be
454 =item I<lazy =E<gt> (1|0)>
456 This will tell the class to not create this slot until absolutely necessary.
457 If an attribute is marked as lazy it B<must> have a default supplied.
459 =item I<auto_deref =E<gt> (1|0)>
461 This tells the accessor whether to automatically dereference the value returned.
462 This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>.
464 =item I<metaclass =E<gt> $metaclass_name>
466 This tells the class to use a custom attribute metaclass for this particular
467 attribute. Custom attribute metaclasses are useful for extending the
468 capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
469 but they are still a fairly advanced topic and too much to cover here. I will
470 try and write a recipe on them soon.
472 The default behavior here is to just load C<$metaclass_name>; however, we also
473 have a way to alias to a shorter name. This will first look to see if
474 B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose
475 will then check to see if that has the method C<register_implementation>, which
476 should return the actual name of the custom attribute metaclass. If there is no
477 C<register_implementation> method, it will fall back to using
478 B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name.
480 =item I<trigger =E<gt> $code>
482 The I<trigger> option is a CODE reference which will be called after the value of
483 the attribute is set. The CODE ref will be passed the instance itself, the
484 updated value and the attribute meta-object (this is for more advanced fiddling
485 and can typically be ignored). You B<cannot> have a trigger on a read-only
488 =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE>
490 The I<handles> option provides Moose classes with automated delegation features.
491 This is a pretty complex and powerful option. It accepts many different option
492 formats, each with its own benefits and drawbacks.
494 B<NOTE:> This feature is no longer experimental, but it may still have subtle
495 bugs lurking in the deeper corners. If you think you have found a bug, you
496 probably have, so please report it to me right away.
498 B<NOTE:> The class being delegated to does not need to be a Moose based class,
499 which is why this feature is especially useful when wrapping non-Moose classes.
501 All I<handles> option formats share the following traits:
503 You cannot override a locally defined method with a delegated method; an
504 exception will be thrown if you try. That is to say, if you define C<foo> in
505 your class, you cannot override it with a delegated C<foo>. This is almost never
506 something you would want to do, and if it is, you should do it by hand and not
509 You cannot override any of the methods found in Moose::Object, or the C<BUILD>
510 and C<DEMOLISH> methods. These will not throw an exception, but will silently
511 move on to the next method in the list. My reasoning for this is that you would
512 almost never want to do this, since it usually breaks your class. As with
513 overriding locally defined methods, if you do want to do this, you should do it
514 manually, not with Moose.
516 You do not I<need> to have a reader (or accessor) for the attribute in order
517 to delegate to it. Moose will create a means of accessing the value for you,
518 however this will be several times B<less> efficient then if you had given
519 the attribute a reader (or accessor) to use.
521 Below is the documentation for each option format:
527 This is the most common usage for I<handles>. You basically pass a list of
528 method names to be delegated, and Moose will install a delegation method
533 This is the second most common usage for I<handles>. Instead of a list of
534 method names, you pass a HASH ref where each key is the method name you
535 want installed locally, and its value is the name of the original method
536 in the class being delegated to.
538 This can be very useful for recursive classes like trees. Here is a
539 quick example (soon to be expanded into a Moose::Cookbook::Recipe):
544 has 'node' => (is => 'rw', isa => 'Any');
549 default => sub { [] }
557 parent_node => 'node',
558 siblings => 'children',
562 In this example, the Tree package gets C<parent_node> and C<siblings> methods,
563 which delegate to the C<node> and C<children> methods (respectively) of the Tree
564 instance stored in the C<parent> slot.
568 The regexp option works very similar to the ARRAY option, except that it builds
569 the list of methods for you. It starts by collecting all possible methods of the
570 class being delegated to, then filters that list using the regexp supplied here.
572 B<NOTE:> An I<isa> option is required when using the regexp option format. This
573 is so that we can determine (at compile time) the method list from the class.
574 Without an I<isa> this is just not possible.
578 With the role option, you specify the name of a role whose "interface" then
579 becomes the list of methods to handle. The "interface" can be defined as; the
580 methods of the role and any required methods of the role. It should be noted
581 that this does B<not> include any method modifiers or generated attribute
582 methods (which is consistent with role composition).
586 This is the option to use when you really want to do something funky. You should
587 only use it if you really know what you are doing, as it involves manual
590 This takes a code reference, which should expect two arguments. The first is the
591 attribute meta-object this I<handles> is attached to. The second is the
592 metaclass of the class being delegated to. It expects you to return a hash (not
593 a HASH ref) of the methods you want mapped.
599 =item B<has +$name =E<gt> %options>
601 This is variation on the normal attibute creator C<has> which allows you to
602 clone and extend an attribute from a superclass. Here is a quick example:
610 default => 'Hello, I am a Foo'
618 has '+message' => (default => 'Hello I am My::Foo');
620 What is happening here is that B<My::Foo> is cloning the C<message> attribute
621 from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
622 'Str'> characteristics, but changing the value in C<default>.
624 This feature is restricted somewhat, so as to try and force at least I<some>
625 sanity into it. You are only allowed to change the following attributes:
631 Change the default value of an attribute.
635 Change whether the attribute attempts to coerce a value passed to it.
639 Change if the attribute is required to have a value.
641 =item I<documentation>
643 Change the documentation string associated with the attribute.
647 Change if the attribute lazily initializes the slot.
651 You I<are> allowed to change the type, B<if and only if> the new type is a
652 subtype of the old type.
656 You are allowed to B<add> a new C<handles> definition, but you are B<not>
657 allowed to I<change> one.
661 =item B<before $name|@names =E<gt> sub { ... }>
663 =item B<after $name|@names =E<gt> sub { ... }>
665 =item B<around $name|@names =E<gt> sub { ... }>
667 This three items are syntactic sugar for the before, after, and around method
668 modifier features that L<Class::MOP> provides. More information on these may be
669 found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method
674 The keyword C<super> is a no-op when called outside of an C<override> method. In
675 the context of an C<override> method, it will call the next most appropriate
676 superclass method with the same arguments as the original method.
678 =item B<override ($name, &sub)>
680 An C<override> method is a way of explicitly saying "I am overriding this
681 method from my superclass". You can call C<super> within this method, and
682 it will work as expected. The same thing I<can> be accomplished with a normal
683 method call and the C<SUPER::> pseudo-package; it is really your choice.
687 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
688 an C<augment> method. You can think of C<inner> as being the inverse of
689 C<super>; the details of how C<inner> and C<augment> work is best described in
690 the L<Moose::Cookbook>.
692 =item B<augment ($name, &sub)>
694 An C<augment> method, is a way of explicitly saying "I am augmenting this
695 method from my superclass". Once again, the details of how C<inner> and
696 C<augment> work is best described in the L<Moose::Cookbook>.
700 This is the C<Carp::confess> function, and exported here because I use it
701 all the time. This feature may change in the future, so you have been warned.
705 This is the C<Scalar::Util::blessed> function, it is exported here because I
706 use it all the time. It is highly recommended that this is used instead of
707 C<ref> anywhere you need to test for an object's class name.
711 =head1 UNIMPORTING FUNCTIONS
715 Moose offers a way to remove the keywords it exports, through the C<unimport>
716 method. You simply have to say C<no Moose> at the bottom of your code for this
717 to work. Here is an example:
722 has 'first_name' => (is => 'rw', isa => 'Str');
723 has 'last_name' => (is => 'rw', isa => 'Str');
727 $self->first_name . ' ' . $self->last_name
730 no Moose; # keywords are removed from the Person package
732 =head1 EXTENDING AND EMBEDDING MOOSE
734 Moose also offers some options for extending or embedding it into your own
735 framework. The basic premise is to have something that sets up your class'
736 metaclass and export the moose declarators (C<has>, C<with>, C<extends>,...).
743 my $CALLER = caller();
748 # we should never export to main
749 return if $CALLER eq 'main';
750 Moose::init_meta( $CALLER, 'MyFramework::Base' );
751 Moose->import({into => $CALLER});
753 # Do my custom framework stuff
760 Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
761 and C<{into_level =E<gt> 1}>
763 =head2 B<init_meta ($class, $baseclass, $metaclass)>
765 Moose does some boot strapping: it creates a metaclass object for your class,
766 and then injects a C<meta> accessor into your class to retrieve it. Then it
767 sets your baseclass to Moose::Object or the value you pass in unless you already
768 have one. This is all done via C<init_meta> which takes the name of your class
769 and optionally a baseclass and a metaclass as arguments.
777 It should be noted that C<super> and C<inner> B<cannot> be used in the same
778 method. However, they may be combined within the same class hierarchy; see
779 F<t/014_override_augment_inner_super.t> for an example.
781 The reason for this is that C<super> is only valid within a method
782 with the C<override> modifier, and C<inner> will never be valid within an
783 C<override> method. In fact, C<augment> will skip over any C<override> methods
784 when searching for its appropriate C<inner>.
786 This might seem like a restriction, but I am of the opinion that keeping these
787 two features separate (yet interoperable) actually makes them easy to use, since
788 their behavior is then easier to predict. Time will tell whether I am right or
789 not (UPDATE: so far so good).
793 =head1 ACKNOWLEDGEMENTS
797 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
799 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
801 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
802 and it certainly wouldn't have this name ;P
804 =item The basis of the TypeContraints module was Rob Kinyon's idea
805 originally, I just ran with it.
807 =item Thanks to mst & chansen and the whole #moose poose for all the
808 early ideas/feature-requests/encouragement/bug-finding.
810 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
818 =item L<http://www.iinteractive.com/moose>
820 This is the official web home of Moose, it contains links to our public SVN repo
821 as well as links to a number of talks and articles on Moose and Moose related
824 =item L<Class::MOP> documentation
826 =item The #moose channel on irc.perl.org
828 =item The Moose mailing list - moose@perl.org
830 =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/5788>
832 =item Several Moose extension modules in the L<MooseX::> namespace.
840 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
842 This paper (suggested by lbr on #moose) was what lead to the implementation
843 of the C<super>/C<override> and C<inner>/C<augment> features. If you really
844 want to understand them, I suggest you read this.
850 All complex software has bugs lurking in it, and this module is no
851 exception. If you find a bug please either email me, or add the bug
856 Stevan Little E<lt>stevan@iinteractive.comE<gt>
858 B<with contributions from:>
864 Anders (Debolaz) Nor Berle
866 Nathan (kolibre) Gray
868 Christian (chansen) Hansen
870 Hans Dieter (confound) Pearcey
872 Eric (ewilhelm) Wilhelm
874 Guillermo (groditi) Roditi
876 Jess (castaway) Robinson
880 Robert (phaylon) Sedlacek
884 Scott (konobi) McWhirter
886 Shlomi (rindolf) Fish
888 Yuval (nothingmuch) Kogman
890 Chris (perigrin) Prather
892 Jonathan (jrockway) Rockway
894 Piotr (dexter) Roszatycki
900 ... and many other #moose folks
902 =head1 COPYRIGHT AND LICENSE
904 Copyright 2006-2008 by Infinity Interactive, Inc.
906 L<http://www.iinteractive.com>
908 This library is free software; you can redistribute it and/or modify
909 it under the same terms as Perl itself.