7 our $VERSION = '0.09_02';
9 use Scalar::Util 'blessed', 'reftype';
11 use Sub::Name 'subname';
13 use UNIVERSAL::require;
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;
25 use Moose::Util::TypeConstraints;
33 # make a subtype for each Moose class
36 => where { $_->isa($class) }
37 unless find_type_constraint($class);
40 if ($class->can('meta')) {
42 # this is the case where the metaclass pragma
43 # was used before the 'use Moose' statement to
44 # override a specific class
45 $meta = $class->meta();
46 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
47 || confess "Whoops, not møøsey enough";
51 # this is broken currently, we actually need
52 # to allow the possiblity of an inherited
53 # meta, which will not be visible until the
54 # user 'extends' first. This needs to have
55 # more intelligence to it
56 $meta = Moose::Meta::Class->initialize($class);
57 $meta->add_method('meta' => sub {
58 # re-initialize so it inherits properly
59 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
63 # make sure they inherit from Moose::Object
64 $meta->superclasses('Moose::Object')
65 unless $meta->superclasses();
71 return subname 'Moose::extends' => sub ($;@) {
72 _load_all_classes(@_);
73 my $meta = $class->meta;
74 foreach my $super (@_) {
75 # don't bother if it does not have a meta.
76 next unless $super->can('meta');
77 # if it's meta is a vanilla Moose,
78 # then we can safely ignore it.
79 next if blessed($super->meta) eq 'Moose::Meta::Class';
80 # but if we have anything else,
81 # we need to check it out ...
82 unless (# see if of our metaclass is incompatible
83 ($meta->isa(blessed($super->meta)) &&
84 # and see if our instance metaclass is incompatible
85 $meta->instance_metaclass->isa($super->meta->instance_metaclass)) &&
86 # ... and if we are just a vanilla Moose
87 $meta->isa('Moose::Meta::Class')) {
88 # re-initialize the meta ...
89 my $super_meta = $super->meta;
91 # We might want to consider actually
92 # transfering any attributes from the
93 # original meta into this one, but in
94 # general you should not have any there
95 # at this point anyway, so it's very
96 # much an obscure edge case anyway
97 $meta = $super_meta->reinitialize($class => (
98 ':attribute_metaclass' => $super_meta->attribute_metaclass,
99 ':method_metaclass' => $super_meta->method_metaclass,
100 ':instance_metaclass' => $super_meta->instance_metaclass,
104 $meta->superclasses(@_);
109 return subname 'Moose::with' => sub ($;@) {
111 _load_all_classes(@roles);
112 ($_->can('meta') && $_->meta->isa('Moose::Meta::Role'))
113 || confess "You can only consume roles, $_ is not a Moose role"
115 if (scalar @roles == 1) {
116 $roles[0]->meta->apply($class->meta);
119 Moose::Meta::Role->combine(
120 map { $_->meta } @roles
121 )->apply($class->meta);
127 return subname 'Moose::has' => sub ($;%) {
128 my ($name, %options) = @_;
129 my $meta = $class->meta;
130 if ($name =~ /^\+(.*)/) {
131 my $inherited_attr = $meta->find_attribute_by_name($1);
132 (defined $inherited_attr)
133 || confess "Could not find an attribute by the name of '$1' to inherit from";
135 if ($inherited_attr->isa('Moose::Meta::Attribute')) {
136 $new_attr = $inherited_attr->clone_and_inherit_options(%options);
140 # kind of a kludge to handle Class::MOP::Attributes
141 $new_attr = Moose::Meta::Attribute::clone_and_inherit_options(
142 $inherited_attr, %options
145 $meta->add_attribute($new_attr);
148 if ($options{metaclass}) {
149 _load_all_classes($options{metaclass});
150 $meta->add_attribute($options{metaclass}->new($name, %options));
153 $meta->add_attribute($name, %options);
160 return subname 'Moose::before' => sub (@&) {
162 my $meta = $class->meta;
163 $meta->add_before_method_modifier($_, $code) for @_;
168 return subname 'Moose::after' => sub (@&) {
170 my $meta = $class->meta;
171 $meta->add_after_method_modifier($_, $code) for @_;
176 return subname 'Moose::around' => sub (@&) {
178 my $meta = $class->meta;
179 $meta->add_around_method_modifier($_, $code) for @_;
183 return subname 'Moose::super' => sub {};
187 return subname 'Moose::override' => sub ($&) {
188 my ($name, $method) = @_;
189 $class->meta->add_override_method_modifier($name => $method);
193 return subname 'Moose::inner' => sub {};
197 return subname 'Moose::augment' => sub (@&) {
198 my ($name, $method) = @_;
199 $class->meta->add_augment_method_modifier($name => $method);
203 return \&Carp::confess;
206 return \&Scalar::Util::blessed;
210 my $exporter = Sub::Exporter::build_exporter({
211 exports => \%exports,
220 # we should never export to main
221 return if $CALLER eq 'main';
231 sub _load_all_classes {
232 foreach my $super (@_) {
233 # see if this is already
234 # loaded in the symbol table
235 next if _is_class_already_loaded($super);
236 # otherwise require it ...
238 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
242 sub _is_class_already_loaded {
245 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
246 foreach (keys %{"${name}::"}) {
247 next if substr($_, -2, 2) eq '::';
248 return 1 if defined &{"${name}::$_"};
261 Moose - Moose, it's the new Camel
268 has 'x' => (isa => 'Int', is => 'rw');
269 has 'y' => (isa => 'Int', is => 'rw');
282 has 'z' => (isa => 'Int');
284 after 'clear' => sub {
291 Moose is a rapidly maturing module, and is already being used by
292 a number of people. It's test suite is growing larger by the day,
293 and the docs should soon follow.
295 This said, Moose is not yet finished, and should still be considered
296 to be evolving. Much of the outer API is stable, but the internals
297 are still subject to change (although not without serious thought
300 For more details, please refer to the L<FUTURE PLANS> section of
305 Moose is an extension of the Perl 5 object system.
307 =head2 Another object system!?!?
309 Yes, I know there has been an explosion recently of new ways to
310 build object's in Perl 5, most of them based on inside-out objects,
311 and other such things. Moose is different because it is not a new
312 object system for Perl 5, but instead an extension of the existing
315 Moose is built on top of L<Class::MOP>, which is a metaclass system
316 for Perl 5. This means that Moose not only makes building normal
317 Perl 5 objects better, but it also provides the power of metaclass
320 =head2 Can I use this in production? Or is this just an experiment?
322 Moose is I<based> on the prototypes and experiments I did for the Perl 6
323 meta-model, however Moose is B<NOT> an experiment/prototype, it is
326 I will be deploying Moose into production environments later this
327 year, and I have all intentions of using it as my de-facto class builder
330 =head2 Is Moose just Perl 6 in perl 5?
332 No. While Moose is very much inspired by Perl 6, it is not. Instead, it
333 is an OO system for Perl 5.
335 I built Moose because I was tired or writing the same old boring Perl 5
336 OO code, and drooling over Perl 6 OO. So instead of switching to Ruby,
339 =head1 BUILDING CLASSES WITH MOOSE
341 Moose makes every attempt to provide as much convience during class
342 construction/definition, but still stay out of your way if you want
343 it to. Here are some of the features Moose provides:
345 Unless specified with C<extends>, any class which uses Moose will
346 inherit from L<Moose::Object>.
348 Moose will also manage all attributes (including inherited ones) that
349 are defined with C<has>. And assuming that you call C<new> which is
350 inherited from L<Moose::Object>, then this includes properly initializing
351 all instance slots, setting defaults where approprtiate and performing any
352 type constraint checking or coercion.
354 For more details, see the ever expanding L<Moose::Cookbook>.
356 =head1 EXPORTED FUNCTIONS
358 Moose will export a number of functions into the class's namespace, which
359 can then be used to set up the class. These functions all work directly
360 on the current class.
366 This is a method which provides access to the current class's metaclass.
368 =item B<extends (@superclasses)>
370 This function will set the superclass(es) for the current class.
372 This approach is recommended instead of C<use base>, because C<use base>
373 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
374 replace it. This is important to ensure that classes which do not have
375 superclasses properly inherit from L<Moose::Object>.
377 =item B<with (@role)>
379 This will apply a given set of C<@role> to the local class. Role support
380 is currently under heavy development, see L<Moose::Role> for more details.
382 =item B<has ($name, %options)>
384 This will install an attribute of a given C<$name> into the current class.
385 The list of C<%options> are the same as those provided by both
386 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
387 few convience ones provided by Moose which are listed below:
391 =item I<is =E<gt> 'rw'|'ro'>
393 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
394 only). These will create either a read/write accessor or a read-only
395 accessor respectively, using the same name as the C<$name> of the attribute.
397 If you need more control over how your accessors are named, you can use the
398 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
400 =item I<isa =E<gt> $type_name>
402 The I<isa> option uses Moose's type constraint facilities to set up runtime
403 type checking for this attribute. Moose will perform the checks during class
404 construction, and within any accessors. The C<$type_name> argument must be a
405 string. The string can be either a class name, or a type defined using
406 Moose's type defintion features.
408 =item I<coerce =E<gt> (1|0)>
410 This will attempt to use coercion with the supplied type constraint to change
411 the value passed into any accessors of constructors. You B<must> have supplied
412 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
413 for an example usage.
415 =item I<does =E<gt> $role_name>
417 This will accept the name of a role which the value stored in this attribute
418 is expected to have consumed.
420 =item I<required =E<gt> (1|0)>
422 This marks the attribute as being required. This means a value must be supplied
423 during class construction, and the attribute can never be set to C<undef> with
426 =item I<weak_ref =E<gt> (1|0)>
428 This will tell the class to strore the value of this attribute as a weakened
429 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
431 =item I<lazy =E<gt> (1|0)>
433 This will tell the class to not create this slot until absolutely nessecary.
434 If an attribute is marked as lazy it B<must> have a default supplied.
436 =item I<trigger =E<gt> $code>
438 The trigger option is a CODE reference which will be called after the value of
439 the attribute is set. The CODE ref will be passed the instance itself, the
440 updated value and the attribute meta-object (this is for more advanced fiddling
441 and can typically be ignored in most cases). You can B<not> have a trigger on
442 a read-only attribute.
444 =item I<handles =E<gt> [ @handles ]>
446 There is experimental support for attribute delegation using the C<handles>
447 option. More docs to come later.
451 =item B<before $name|@names =E<gt> sub { ... }>
453 =item B<after $name|@names =E<gt> sub { ... }>
455 =item B<around $name|@names =E<gt> sub { ... }>
457 This three items are syntactic sugar for the before, after and around method
458 modifier features that L<Class::MOP> provides. More information on these can
459 be found in the L<Class::MOP> documentation for now.
463 The keyword C<super> is a noop when called outside of an C<override> method. In
464 the context of an C<override> method, it will call the next most appropriate
465 superclass method with the same arguments as the original method.
467 =item B<override ($name, &sub)>
469 An C<override> method, is a way of explictly saying "I am overriding this
470 method from my superclass". You can call C<super> within this method, and
471 it will work as expected. The same thing I<can> be accomplished with a normal
472 method call and the C<SUPER::> pseudo-package, it is really your choice.
476 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
477 an C<augment> method. You can think of C<inner> as being the inverse of
478 C<super>, the details of how C<inner> and C<augment> work is best described in
479 the L<Moose::Cookbook>.
481 =item B<augment ($name, &sub)>
483 An C<augment> method, is a way of explictly saying "I am augmenting this
484 method from my superclass". Once again, the details of how C<inner> and
485 C<augment> work is best described in the L<Moose::Cookbook>.
489 This is the C<Carp::confess> function, and exported here beause I use it
490 all the time. This feature may change in the future, so you have been warned.
494 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
495 use it all the time. It is highly recommended that this is used instead of
496 C<ref> anywhere you need to test for an object's class name.
502 Here is just a sampling of the plans we have in store for Moose:
508 Compiling Moose classes/roles into C<.pmc> files for faster loading and execution.
512 Supporting sealed and finalized classes in Moose. This will allow greater control
513 of the extensions of frameworks and such.
519 =head2 What does Moose stand for??
521 Moose doesn't stand for one thing in particular, however, if you
522 want, here are a few of my favorites, feel free to contribute
527 =item Make Other Object Systems Envious
529 =item Makes Object Orientation So Easy
531 =item Makes Object Orientation Spiffy- Er (sorry ingy)
533 =item Most Other Object Systems Emasculate
535 =item My Overcraft Overfilled (with) Some Eels
537 =item Moose Often Ovulate Sorta Early
539 =item Many Overloaded Object Systems Exists
541 =item Moose Offers Often Super Extensions
543 =item Meta Object Orientation Syntax Extensions
553 It should be noted that C<super> and C<inner> can B<not> be used in the same
554 method. However, they can be combined together with the same class hierarchy,
555 see F<t/014_override_augment_inner_super.t> for an example.
557 The reason that this is so is because C<super> is only valid within a method
558 with the C<override> modifier, and C<inner> will never be valid within an
559 C<override> method. In fact, C<augment> will skip over any C<override> methods
560 when searching for it's appropriate C<inner>.
562 This might seem like a restriction, but I am of the opinion that keeping these
563 two features seperate (but interoperable) actually makes them easy to use since
564 their behavior is then easier to predict. Time will tell if I am right or not.
568 =head1 ACKNOWLEDGEMENTS
572 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
574 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
576 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
577 and it certainly wouldn't have this name ;P
579 =item The basis of the TypeContraints module was Rob Kinyon's idea
580 originally, I just ran with it.
582 =item Thanks to mst & chansen and the whole #moose poose for all the
583 ideas/feature-requests/encouragement
591 =item L<Class::MOP> documentation
593 =item The #moose channel on irc.perl.org
595 =item L<http://forum2.org/moose/>
597 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
599 This paper (suggested by lbr on #moose) was what lead to the implementation
600 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
601 want to understand this feature, I suggest you read this.
607 All complex software has bugs lurking in it, and this module is no
608 exception. If you find a bug please either email me, or add the bug
613 Stevan Little E<lt>stevan@iinteractive.comE<gt>
615 Christian Hansen E<lt>chansen@cpan.orgE<gt>
617 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
619 =head1 COPYRIGHT AND LICENSE
621 Copyright 2006 by Infinity Interactive, Inc.
623 L<http://www.iinteractive.com>
625 This library is free software; you can redistribute it and/or modify
626 it under the same terms as Perl itself.