8 our $AUTHORITY = 'cpan:STEVAN';
10 use Scalar::Util 'blessed', 'reftype';
12 use Sub::Name 'subname';
13 use B 'svref_2object';
19 use Moose::Meta::Class;
20 use Moose::Meta::TypeConstraint;
21 use Moose::Meta::TypeCoercion;
22 use Moose::Meta::Attribute;
23 use Moose::Meta::Instance;
26 use Moose::Util::TypeConstraints;
34 # make a subtype for each Moose class
37 => where { $_->isa($class) }
38 => optimize_as { blessed($_[0]) && $_[0]->isa($class) }
39 unless find_type_constraint($class);
42 if ($class->can('meta')) {
44 # this is the case where the metaclass pragma
45 # was used before the 'use Moose' statement to
46 # override a specific class
47 $meta = $class->meta();
48 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
49 || confess "You already have a &meta function, but it does not return a Moose::Meta::Class";
53 # this is broken currently, we actually need
54 # to allow the possiblity of an inherited
55 # meta, which will not be visible until the
56 # user 'extends' first. This needs to have
57 # more intelligence to it
58 $meta = Moose::Meta::Class->initialize($class);
59 $meta->add_method('meta' => sub {
60 # re-initialize so it inherits properly
61 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
65 # make sure they inherit from Moose::Object
66 $meta->superclasses('Moose::Object')
67 unless $meta->superclasses();
73 return subname 'Moose::extends' => sub (@) {
74 confess "Must derive at least one class" unless @_;
75 Class::MOP::load_class($_) for @_;
76 # this checks the metaclass to make sure
77 # it is correct, sometimes it can get out
78 # of sync when the classes are being built
79 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
80 $meta->superclasses(@_);
85 return subname 'Moose::with' => sub (@) {
87 confess "Must specify at least one role" unless @roles;
88 Class::MOP::load_class($_) for @roles;
89 $class->meta->_apply_all_roles(@roles);
94 return subname 'Moose::has' => sub ($;%) {
95 my ($name, %options) = @_;
96 my $attrs = (ref($name) eq 'ARRAY') ? $name : [($name)];
97 $class->meta->_process_attribute($_, %options) for @$attrs;
102 return subname 'Moose::before' => sub (@&) {
104 my $meta = $class->meta;
105 $meta->add_before_method_modifier($_, $code) for @_;
110 return subname 'Moose::after' => sub (@&) {
112 my $meta = $class->meta;
113 $meta->add_after_method_modifier($_, $code) for @_;
118 return subname 'Moose::around' => sub (@&) {
120 my $meta = $class->meta;
121 $meta->add_around_method_modifier($_, $code) for @_;
128 $SUPER_SLOT{$CALLER} = \*{"${CALLER}::super"};
130 return subname 'Moose::super' => sub {};
134 return subname 'Moose::override' => sub ($&) {
135 my ($name, $method) = @_;
136 $class->meta->add_override_method_modifier($name => $method);
143 $INNER_SLOT{$CALLER} = \*{"${CALLER}::inner"};
145 return subname 'Moose::inner' => sub {};
149 return subname 'Moose::augment' => sub (@&) {
150 my ($name, $method) = @_;
151 $class->meta->add_augment_method_modifier($name => $method);
156 # this is experimental, but I am not
157 # happy with it. If you want to try
158 # it, you will have to uncomment it
160 # There is a really good chance that
161 # this will be deprecated, dont get
164 # return subname 'Moose::self' => sub {};
167 # my $class = $CALLER;
168 # return subname 'Moose::method' => sub {
169 # my ($name, $method) = @_;
170 # $class->meta->add_method($name, sub {
173 # no warnings 'redefine';
174 # local *{$class->meta->name . '::self'} = sub { $self };
181 return \&Carp::confess;
184 return \&Scalar::Util::blessed;
188 my $exporter = Sub::Exporter::build_exporter({
189 exports => \%exports,
201 # we should never export to main
202 return if $CALLER eq 'main';
211 my $class = caller();
212 # loop through the exports ...
213 foreach my $name (keys %exports) {
216 if (defined &{$class . '::' . $name}) {
217 my $keyword = \&{$class . '::' . $name};
219 # make sure it is from Moose
220 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
222 next if $pkg_name ne 'Moose';
224 # and if it is from Moose then undef the slot
225 delete ${$class . '::'}{$name};
233 ## make 'em all immutable
235 $_->meta->make_immutable(
236 inline_constructor => 0,
237 inline_accessors => 0,
239 'Moose::Meta::Attribute',
240 'Moose::Meta::Class',
241 'Moose::Meta::Instance',
243 'Moose::Meta::TypeConstraint',
244 'Moose::Meta::TypeConstraint::Union',
245 'Moose::Meta::TypeCoercion',
247 'Moose::Meta::Method',
248 'Moose::Meta::Method::Accessor',
249 'Moose::Meta::Method::Constructor',
250 'Moose::Meta::Method::Overriden',
261 Moose - A complete modern object system for Perl 5
270 has 'x' => (is => 'rw', isa => 'Int');
271 has 'y' => (is => 'rw', isa => 'Int');
286 has 'z' => (is => 'rw', isa => 'Int');
288 after 'clear' => sub {
295 Moose is an extension of the Perl 5 object system.
297 =head2 Another object system!?!?
299 Yes, I know there has been an explosion recently of new ways to
300 build object's in Perl 5, most of them based on inside-out objects
301 and other such things. Moose is different because it is not a new
302 object system for Perl 5, but instead an extension of the existing
305 Moose is built on top of L<Class::MOP>, which is a metaclass system
306 for Perl 5. This means that Moose not only makes building normal
307 Perl 5 objects better, but it also provides the power of metaclass
310 =head2 Is this for real? Or is this just an experiment?
312 Moose is I<based> on the prototypes and experiments I did for the Perl 6
313 meta-model; however Moose is B<NOT> an experiment/prototype, it is
316 =head2 Is this ready for use in production?
318 Yes, I believe that it is.
320 I have two medium-to-large-ish web applications which use Moose heavily
321 and have been in production (without issue) for several months now. At
322 $work, we are re-writing our core offering in it. And several people on
323 #moose have been using it (in production) for several months now as well.
325 Of course, in the end, you need to make this call yourself. If you have
326 any questions or concerns, please feel free to email me, or even the list
327 or just stop by #moose and ask away.
329 =head2 Is Moose just Perl 6 in Perl 5?
331 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
332 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
333 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
334 instead of switching to Ruby, I wrote Moose :)
336 =head1 BUILDING CLASSES WITH MOOSE
338 Moose makes every attempt to provide as much convenience as possible during
339 class construction/definition, but still stay out of your way if you want it
340 to. Here are a few items to note when building classes with Moose.
342 Unless specified with C<extends>, any class which uses Moose will
343 inherit from L<Moose::Object>.
345 Moose will also manage all attributes (including inherited ones) that
346 are defined with C<has>. And assuming that you call C<new>, which is
347 inherited from L<Moose::Object>, then this includes properly initializing
348 all instance slots, setting defaults where appropriate, and performing any
349 type constraint checking or coercion.
351 =head1 EXPORTED FUNCTIONS
353 Moose will export a number of functions into the class's namespace which
354 can then be used to set up the class. These functions all work directly
355 on the current class.
361 This is a method which provides access to the current class's metaclass.
363 =item B<extends (@superclasses)>
365 This function will set the superclass(es) for the current class.
367 This approach is recommended instead of C<use base>, because C<use base>
368 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
369 replace it. This is important to ensure that classes which do not have
370 superclasses still properly inherit from L<Moose::Object>.
372 =item B<with (@roles)>
374 This will apply a given set of C<@roles> to the local class. Role support
375 is currently under heavy development; see L<Moose::Role> for more details.
377 =item B<has $name =E<gt> %options>
379 This will install an attribute of a given C<$name> into the current class.
380 The list of C<%options> are the same as those provided by
381 L<Class::MOP::Attribute>, in addition to the list below which are provided
382 by Moose (L<Moose::Meta::Attribute> to be more specific):
386 =item I<is =E<gt> 'rw'|'ro'>
388 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
389 only). These will create either a read/write accessor or a read-only
390 accessor respectively, using the same name as the C<$name> of the attribute.
392 If you need more control over how your accessors are named, you can use the
393 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
395 =item I<isa =E<gt> $type_name>
397 The I<isa> option uses Moose's type constraint facilities to set up runtime
398 type checking for this attribute. Moose will perform the checks during class
399 construction, and within any accessors. The C<$type_name> argument must be a
400 string. The string can be either a class name or a type defined using
401 Moose's type definition features.
403 =item I<coerce =E<gt> (1|0)>
405 This will attempt to use coercion with the supplied type constraint to change
406 the value passed into any accessors or constructors. You B<must> have supplied
407 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
408 for an example usage.
410 =item I<does =E<gt> $role_name>
412 This will accept the name of a role which the value stored in this attribute
413 is expected to have consumed.
415 =item I<required =E<gt> (1|0)>
417 This marks the attribute as being required. This means a value must be supplied
418 during class construction, and the attribute can never be set to C<undef> with
421 =item I<weak_ref =E<gt> (1|0)>
423 This will tell the class to store the value of this attribute as a weakened
424 reference. If an attribute is a weakened reference, it B<cannot> also be
427 =item I<lazy =E<gt> (1|0)>
429 This will tell the class to not create this slot until absolutely necessary.
430 If an attribute is marked as lazy it B<must> have a default supplied.
432 =item I<auto_deref =E<gt> (1|0)>
434 This tells the accessor whether to automatically dereference the value returned.
435 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
437 =item I<metaclass =E<gt> $metaclass_name>
439 This tells the class to use a custom attribute metaclass for this particular
440 attribute. Custom attribute metaclasses are useful for extending the capabilities
441 of the I<has> keyword, they are the simplest way to extend the MOP, but they are
442 still a fairly advanced topic and too much to cover here. I will try and write a
445 The default behavior here is to just load C<$metaclass_name>, however, we also
446 have a way to alias to a shorter name. This will first look to see if
447 B<Moose::Meta::Attribute::Custom::$metaclass_name> exists, if it does it will
448 then check to see if that has the method C<register_implemenetation> which
449 should return the actual name of the custom attribute metaclass. If there is
450 no C<register_implemenetation> method, it will just default to using
451 B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name.
453 =item I<trigger =E<gt> $code>
455 The trigger option is a CODE reference which will be called after the value of
456 the attribute is set. The CODE ref will be passed the instance itself, the
457 updated value and the attribute meta-object (this is for more advanced fiddling
458 and can typically be ignored in most cases). You B<cannot> have a trigger on
459 a read-only attribute.
461 =item I<handles =E<gt> ARRAY | HASH | REGEXP | CODE>
463 The handles option provides Moose classes with automated delegation features.
464 This is a pretty complex and powerful option, it accepts many different option
465 formats, each with it's own benefits and drawbacks.
467 B<NOTE:> This features is no longer experimental, but it still may have subtle
468 bugs lurking in the deeper corners. So if you think you have found a bug, you
469 probably have, so please report it to me right away.
471 B<NOTE:> The class being delegated to does not need to be a Moose based class.
472 Which is why this feature is especially useful when wrapping non-Moose classes.
474 All handles option formats share the following traits.
476 You cannot override a locally defined method with a delegated method, an
477 exception will be thrown if you try. Meaning, if you define C<foo> in your
478 class, you cannot override it with a delegated C<foo>. This is almost never
479 something you would want to do, and if it is, you should do it by hand and
482 You cannot override any of the methods found in Moose::Object as well as
483 C<BUILD> or C<DEMOLISH> methods. These will not throw an exception, but will
484 silently move on to the next method in the list. My reasoning for this is that
485 you would almost never want to do this because it usually tends to break your
486 class. And as with overriding locally defined methods, if you do want to do this,
487 you should do it manually and not with Moose.
489 Below is the documentation for each option format:
495 This is the most common usage for handles. You basically pass a list of
496 method names to be delegated, and Moose will install a delegation method
497 for each one in the list.
501 This is the second most common usage for handles. Instead of a list of
502 method names, you pass a HASH ref where the key is the method name you
503 want installed locally, and the value is the name of the original method
504 in the class being delegated to.
506 This can be very useful for recursive classes like trees, here is a
507 quick example (soon to be expanded into a Moose::Cookbook::Recipe):
512 has 'node' => (is => 'rw', isa => 'Any');
517 default => sub { [] }
525 parent_node => 'node',
526 siblings => 'children',
530 In this example, the Tree package gets the C<parent_node> and C<siblings> methods
531 which delegate to the C<node> and C<children> methods of the Tree instance stored
536 The regexp option works very similar to the ARRAY option, except that it builds
537 the list of methods for you. It starts by collecting all possible methods of the
538 class being delegated to, then filters that list using the regexp supplied here.
540 B<NOTE:> An I<isa> option is required when using the regexp option format. This
541 is so that we can determine (at compile time) the method list from the class.
542 Without an I<isa> this is just not possible.
546 This is the option to use when you really want to do something funky. You should
547 only use it if you really know what you are doing as it involves manual metaclass
550 This takes a code reference, which should expect two arguments. The first is
551 the attribute meta-object this I<handles> is attached to. The second is the metaclass
552 of the class being delegated to. It expects you to return a hash (not a HASH ref)
553 of the methods you want mapped.
559 =item B<has +$name =E<gt> %options>
561 This is variation on the normal attibute creator C<has>, which allows you to
562 clone and extend an attribute from a superclass. Here is a quick example:
570 default => 'Hello, I am a Foo'
578 has '+message' => (default => 'Hello I am My::Foo');
580 What is happening here is that B<My::Foo> is cloning the C<message> attribute
581 from it's parent class B<Foo>, retaining the is =E<gt> 'rw' and isa =E<gt> 'Str'
582 characteristics, but changing the value in C<default>.
584 This feature is restricted somewhat, so as to try and enfore at least I<some>
585 sanity into it. You are only allowed to change the following attributes:
591 Change the default value of an attribute.
595 Change whether the attribute attempts to coerce a value passed to it.
599 Change if the attribute is required to have a value.
601 =item I<documentation>
603 Change the documentation string associated with the attribute.
607 You I<are> allowed to change the type, but if and B<only if> the new type is
608 a subtype of the old type.
612 =item B<before $name|@names =E<gt> sub { ... }>
614 =item B<after $name|@names =E<gt> sub { ... }>
616 =item B<around $name|@names =E<gt> sub { ... }>
618 This three items are syntactic sugar for the before, after, and around method
619 modifier features that L<Class::MOP> provides. More information on these can
620 be found in the L<Class::MOP> documentation for now.
624 The keyword C<super> is a no-op when called outside of an C<override> method. In
625 the context of an C<override> method, it will call the next most appropriate
626 superclass method with the same arguments as the original method.
628 =item B<override ($name, &sub)>
630 An C<override> method is a way of explicitly saying "I am overriding this
631 method from my superclass". You can call C<super> within this method, and
632 it will work as expected. The same thing I<can> be accomplished with a normal
633 method call and the C<SUPER::> pseudo-package; it is really your choice.
637 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
638 an C<augment> method. You can think of C<inner> as being the inverse of
639 C<super>; the details of how C<inner> and C<augment> work is best described in
640 the L<Moose::Cookbook>.
642 =item B<augment ($name, &sub)>
644 An C<augment> method, is a way of explicitly saying "I am augmenting this
645 method from my superclass". Once again, the details of how C<inner> and
646 C<augment> work is best described in the L<Moose::Cookbook>.
650 This is the C<Carp::confess> function, and exported here because I use it
651 all the time. This feature may change in the future, so you have been warned.
655 This is the C<Scalar::Uti::blessed> function, it is exported here because I
656 use it all the time. It is highly recommended that this is used instead of
657 C<ref> anywhere you need to test for an object's class name.
661 =head1 UNEXPORTING FUNCTIONS
665 Moose offers a way of removing the keywords it exports though the C<unimport>
666 method. You simply have to say C<no Moose> at the bottom of your code for this
667 to work. Here is an example:
672 has 'first_name' => (is => 'rw', isa => 'Str');
673 has 'last_name' => (is => 'rw', isa => 'Str');
677 $self->first_name . ' ' . $self->last_name
680 no Moose; # keywords are removed from the Person package
684 =head2 What does Moose stand for??
686 Moose doesn't stand for one thing in particular, however, if you
687 want, here are a few of my favorites; feel free to contribute
692 =item Make Other Object Systems Envious
694 =item Makes Object Orientation So Easy
696 =item Makes Object Orientation Spiffy- Er (sorry ingy)
698 =item Most Other Object Systems Emasculate
700 =item Moose Often Ovulate Sorta Early
702 =item Moose Offers Often Super Extensions
704 =item Meta Object Orientation Syntax Extensions
714 It should be noted that C<super> and C<inner> C<cannot> be used in the same
715 method. However, they can be combined together with the same class hierarchy;
716 see F<t/014_override_augment_inner_super.t> for an example.
718 The reason for this is that C<super> is only valid within a method
719 with the C<override> modifier, and C<inner> will never be valid within an
720 C<override> method. In fact, C<augment> will skip over any C<override> methods
721 when searching for its appropriate C<inner>.
723 This might seem like a restriction, but I am of the opinion that keeping these
724 two features separate (but interoperable) actually makes them easy to use, since
725 their behavior is then easier to predict. Time will tell if I am right or not.
729 =head1 ACKNOWLEDGEMENTS
733 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
735 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
737 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
738 and it certainly wouldn't have this name ;P
740 =item The basis of the TypeContraints module was Rob Kinyon's idea
741 originally, I just ran with it.
743 =item Thanks to mst & chansen and the whole #moose poose for all the
744 ideas/feature-requests/encouragement/bug-finding.
746 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
754 =item L<Class::MOP> documentation
756 =item The #moose channel on irc.perl.org
758 =item The Moose mailing list - moose@perl.org
760 =item L<http://forum2.org/moose/>
762 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
764 This paper (suggested by lbr on #moose) was what lead to the implementation
765 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
766 want to understand this feature, I suggest you read this.
772 All complex software has bugs lurking in it, and this module is no
773 exception. If you find a bug please either email me, or add the bug
778 Stevan Little E<lt>stevan@iinteractive.comE<gt>
780 Christian Hansen E<lt>chansen@cpan.orgE<gt>
782 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
784 =head1 COPYRIGHT AND LICENSE
786 Copyright 2006, 2007 by Infinity Interactive, Inc.
788 L<http://www.iinteractive.com>
790 This library is free software; you can redistribute it and/or modify
791 it under the same terms as Perl itself.