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 $meta->superclasses(@_);
109 return subname 'Moose::with' => sub {
111 _load_all_classes($role);
112 ($role->can('meta') && $role->meta->isa('Moose::Meta::Role'))
113 || confess "You can only consume roles, $role is not a Moose role";
114 $role->meta->apply($class->meta);
119 return subname 'Moose::has' => sub {
120 my ($name, %options) = @_;
121 my $meta = $class->meta;
122 if ($name =~ /^\+(.*)/) {
123 my $inherited_attr = $meta->find_attribute_by_name($1);
124 (defined $inherited_attr)
125 || confess "Could not find an attribute by the name of '$1' to inherit from";
126 my $new_attr = $inherited_attr->clone_and_inherit_options(%options);
127 $meta->add_attribute($new_attr);
130 if ($options{metaclass}) {
131 _load_all_classes($options{metaclass});
132 $meta->add_attribute($options{metaclass}->new($name, %options));
135 $meta->add_attribute($name, %options);
142 return subname 'Moose::before' => sub {
144 my $meta = $class->meta;
145 $meta->add_before_method_modifier($_, $code) for @_;
150 return subname 'Moose::after' => sub {
152 my $meta = $class->meta;
153 $meta->add_after_method_modifier($_, $code) for @_;
158 return subname 'Moose::around' => sub {
160 my $meta = $class->meta;
161 $meta->add_around_method_modifier($_, $code) for @_;
165 return subname 'Moose::super' => sub {};
169 return subname 'Moose::override' => sub {
170 my ($name, $method) = @_;
171 $class->meta->add_override_method_modifier($name => $method);
175 return subname 'Moose::inner' => sub {};
179 return subname 'Moose::augment' => sub {
180 my ($name, $method) = @_;
181 $class->meta->add_augment_method_modifier($name => $method);
185 return \&Carp::confess;
188 return \&Scalar::Util::blessed;
191 subname 'Moose::all_methods' => sub () {
193 my ($class, $delegate_class) = @_;
194 $delegate_class->compute_all_applicable_methods();
200 my $exporter = Sub::Exporter::build_exporter({
201 exports => \%exports,
210 # we should never export to main
211 return if $CALLER eq 'main';
221 sub _load_all_classes {
222 foreach my $super (@_) {
223 # see if this is already
224 # loaded in the symbol table
225 next if _is_class_already_loaded($super);
226 # otherwise require it ...
228 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
232 sub _is_class_already_loaded {
235 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
236 foreach (keys %{"${name}::"}) {
237 next if substr($_, -2, 2) eq '::';
238 return 1 if defined &{"${name}::$_"};
251 Moose - Moose, it's the new Camel
258 has 'x' => (isa => 'Int', is => 'rw');
259 has 'y' => (isa => 'Int', is => 'rw');
272 has 'z' => (isa => 'Int');
274 after 'clear' => sub {
281 This is an early release of this module, it still needs
282 some fine tuning and B<lots> more documentation. I am adopting
283 the I<release early and release often> approach with this module,
284 so keep an eye on your favorite CPAN mirror!
288 Moose is an extension of the Perl 5 object system.
290 =head2 Another object system!?!?
292 Yes, I know there has been an explosion recently of new ways to
293 build object's in Perl 5, most of them based on inside-out objects,
294 and other such things. Moose is different because it is not a new
295 object system for Perl 5, but instead an extension of the existing
298 Moose is built on top of L<Class::MOP>, which is a metaclass system
299 for Perl 5. This means that Moose not only makes building normal
300 Perl 5 objects better, but it also provides the power of metaclass
303 =head2 What does Moose stand for??
305 Moose doesn't stand for one thing in particular, however, if you
306 want, here are a few of my favorites, feel free to contribute
311 =item Make Other Object Systems Envious
313 =item Makes Object Orientation So Easy
315 =item Makes Object Orientation Spiffy- Er (sorry ingy)
317 =item Most Other Object Systems Emasculate
319 =item My Overcraft Overfilled (with) Some Eels
321 =item Moose Often Ovulate Sorta Early
323 =item Many Overloaded Object Systems Exists
325 =item Moose Offers Often Super Extensions
327 =item Meta Object Orientation Syntax Extensions
331 =head1 BUILDING CLASSES WITH MOOSE
333 Moose makes every attempt to provide as much convience during class
334 construction/definition, but still stay out of your way if you want
335 it to. Here are some of the features Moose provides:
337 Unless specified with C<extends>, any class which uses Moose will
338 inherit from L<Moose::Object>.
340 Moose will also manage all attributes (including inherited ones) that
341 are defined with C<has>. And assuming that you call C<new> which is
342 inherited from L<Moose::Object>, then this includes properly initializing
343 all instance slots, setting defaults where approprtiate and performing any
344 type constraint checking or coercion.
346 For more details, see the ever expanding L<Moose::Cookbook>.
348 =head1 EXPORTED FUNCTIONS
350 Moose will export a number of functions into the class's namespace, which
351 can then be used to set up the class. These functions all work directly
352 on the current class.
358 This is a method which provides access to the current class's metaclass.
360 =item B<extends (@superclasses)>
362 This function will set the superclass(es) for the current class.
364 This approach is recommended instead of C<use base>, because C<use base>
365 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
366 replace it. This is important to ensure that classes which do not have
367 superclasses properly inherit from L<Moose::Object>.
369 =item B<with ($role)>
371 This will apply a given C<$role> to the local class. Role support is
372 currently very experimental, see L<Moose::Role> for more details.
374 =item B<has ($name, %options)>
376 This will install an attribute of a given C<$name> into the current class.
377 The list of C<%options> are the same as those provided by both
378 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
379 few convience ones provided by Moose which are listed below:
383 =item I<is =E<gt> 'rw'|'ro'>
385 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
386 only). These will create either a read/write accessor or a read-only
387 accessor respectively, using the same name as the C<$name> of the attribute.
389 If you need more control over how your accessors are named, you can use the
390 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
392 =item I<isa =E<gt> $type_name>
394 The I<isa> option uses Moose's type constraint facilities to set up runtime
395 type checking for this attribute. Moose will perform the checks during class
396 construction, and within any accessors. The C<$type_name> argument must be a
397 string. The string can be either a class name, or a type defined using
398 Moose's type defintion features.
400 =item I<coerce =E<gt> (1|0)>
402 This will attempt to use coercion with the supplied type constraint to change
403 the value passed into any accessors of constructors. You B<must> have supplied
404 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
405 for an example usage.
407 =item I<does =E<gt> $role_name>
409 This will accept the name of a role which the value stored in this attribute
410 is expected to have consumed.
412 =item I<required =E<gt> (1|0)>
414 This marks the attribute as being required. This means a value must be supplied
415 during class construction, and the attribute can never be set to C<undef> with
418 =item I<weak_ref =E<gt> (1|0)>
420 This will tell the class to strore the value of this attribute as a weakened
421 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
423 =item I<lazy =E<gt> (1|0)>
425 This will tell the class to not create this slot until absolutely nessecary.
426 If an attribute is marked as lazy it B<must> have a default supplied.
428 =item I<trigger =E<gt> $code>
430 The trigger option is a CODE reference which will be called after the value of
431 the attribute is set. The CODE ref will be passed the instance itself, the
432 updated value and the attribute meta-object (this is for more advanced fiddling
433 and can typically be ignored in most cases). You can B<not> have a trigger on
434 a read-only attribute.
438 =item B<before $name|@names =E<gt> sub { ... }>
440 =item B<after $name|@names =E<gt> sub { ... }>
442 =item B<around $name|@names =E<gt> sub { ... }>
444 This three items are syntactic sugar for the before, after and around method
445 modifier features that L<Class::MOP> provides. More information on these can
446 be found in the L<Class::MOP> documentation for now.
450 The keyword C<super> is a noop when called outside of an C<override> method. In
451 the context of an C<override> method, it will call the next most appropriate
452 superclass method with the same arguments as the original method.
454 =item B<override ($name, &sub)>
456 An C<override> method, is a way of explictly saying "I am overriding this
457 method from my superclass". You can call C<super> within this method, and
458 it will work as expected. The same thing I<can> be accomplished with a normal
459 method call and the C<SUPER::> pseudo-package, it is really your choice.
463 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
464 an C<augment> method. You can think of C<inner> as being the inverse of
465 C<super>, the details of how C<inner> and C<augment> work is best described in
466 the L<Moose::Cookbook>.
468 =item B<augment ($name, &sub)>
470 An C<augment> method, is a way of explictly saying "I am augmenting this
471 method from my superclass". Once again, the details of how C<inner> and
472 C<augment> work is best described in the L<Moose::Cookbook>.
476 This is the C<Carp::confess> function, and exported here beause I use it
477 all the time. This feature may change in the future, so you have been warned.
481 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
482 use it all the time. It is highly recommended that this is used instead of
483 C<ref> anywhere you need to test for an object's class name.
493 It should be noted that C<super> and C<inner> can B<not> be used in the same
494 method. However, they can be combined together with the same class hierarchy,
495 see F<t/014_override_augment_inner_super.t> for an example.
497 The reason that this is so is because C<super> is only valid within a method
498 with the C<override> modifier, and C<inner> will never be valid within an
499 C<override> method. In fact, C<augment> will skip over any C<override> methods
500 when searching for it's appropriate C<inner>.
502 This might seem like a restriction, but I am of the opinion that keeping these
503 two features seperate (but interoperable) actually makes them easy to use since
504 their behavior is then easier to predict. Time will tell if I am right or not.
508 =head1 ACKNOWLEDGEMENTS
512 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
514 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
516 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
517 and it certainly wouldn't have this name ;P
519 =item The basis of the TypeContraints module was Rob Kinyon's idea
520 originally, I just ran with it.
522 =item Thanks to mst & chansen and the whole #moose poose for all the
523 ideas/feature-requests/encouragement
531 =item L<Class::MOP> documentation
533 =item The #moose channel on irc.perl.org
535 =item L<http://forum2.org/moose/>
537 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
539 This paper (suggested by lbr on #moose) was what lead to the implementation
540 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
541 want to understand this feature, I suggest you read this.
547 All complex software has bugs lurking in it, and this module is no
548 exception. If you find a bug please either email me, or add the bug
553 Stevan Little E<lt>stevan@iinteractive.comE<gt>
555 =head1 COPYRIGHT AND LICENSE
557 Copyright 2006 by Infinity Interactive, Inc.
559 L<http://www.iinteractive.com>
561 This library is free software; you can redistribute it and/or modify
562 it under the same terms as Perl itself.