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;
28 my ( $CALLER, %METAS );
33 return $METAS{$class} if exists $METAS{$class};
35 # make a subtype for each Moose class
38 => where { $_->isa($class) }
39 unless find_type_constraint($class);
42 if ($class->can('meta')) {
43 $meta = $class->meta();
44 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
45 || confess "Whoops, not møøsey enough";
48 $meta = Moose::Meta::Class->initialize($class);
49 $meta->add_method('meta' => sub {
50 # re-initialize so it inherits properly
51 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
55 # make sure they inherit from Moose::Object
56 $meta->superclasses('Moose::Object')
57 unless $meta->superclasses();
59 return $METAS{$class} = $meta;
64 my $meta = _find_meta();
65 return subname 'Moose::extends' => sub {
66 _load_all_classes(@_);
67 $meta->superclasses(@_)
71 my $meta = _find_meta();
72 return subname 'Moose::with' => sub {
74 _load_all_classes($role);
75 $role->meta->apply($meta);
79 my $meta = _find_meta();
80 return subname 'Moose::has' => sub {
81 my ($name, %options) = @_;
82 if ($name =~ /^\+(.*)/) {
83 my $inherited_attr = $meta->find_attribute_by_name($1);
84 (defined $inherited_attr)
85 || confess "Could not find an attribute by the name of '$1' to inherit from";
86 my $new_attr = $inherited_attr->clone_and_inherit_options(%options);
87 $meta->add_attribute($new_attr);
90 if ($options{metaclass}) {
91 _load_all_classes($options{metaclass});
92 $meta->add_attribute($options{metaclass}->new($name, %options));
95 $meta->add_attribute($name, %options);
101 my $meta = _find_meta();
102 return subname 'Moose::before' => sub {
104 $meta->add_before_method_modifier($_, $code) for @_;
108 my $meta = _find_meta();
109 return subname 'Moose::after' => sub {
111 $meta->add_after_method_modifier($_, $code) for @_;
115 my $meta = _find_meta();
116 return subname 'Moose::around' => sub {
118 $meta->add_around_method_modifier($_, $code) for @_;
122 my $meta = _find_meta();
123 return subname 'Moose::super' => sub {};
126 my $meta = _find_meta();
127 return subname 'Moose::override' => sub {
128 my ($name, $method) = @_;
129 $meta->add_override_method_modifier($name => $method);
133 my $meta = _find_meta();
134 return subname 'Moose::inner' => sub {};
137 my $meta = _find_meta();
138 return subname 'Moose::augment' => sub {
139 my ($name, $method) = @_;
140 $meta->add_augment_method_modifier($name => $method);
144 return \&Carp::confess;
147 return \&Scalar::Util::blessed;
150 subname 'Moose::all_methods' => sub () {
152 my ( $class, $delegate_class ) = @_;
153 $delegate_class->compute_all_applicable_methods();
159 my $exporter = Sub::Exporter::build_exporter({
160 exports => \%exports,
169 # we should never export to main
170 return if $CALLER eq 'main';
178 sub _load_all_classes {
179 foreach my $super (@_) {
180 # see if this is already
181 # loaded in the symbol table
182 next if _is_class_already_loaded($super);
183 # otherwise require it ...
185 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
189 sub _is_class_already_loaded {
192 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
193 foreach (keys %{"${name}::"}) {
194 next if substr($_, -2, 2) eq '::';
195 return 1 if defined &{"${name}::$_"};
208 Moose - Moose, it's the new Camel
215 has 'x' => (isa => 'Int', is => 'rw');
216 has 'y' => (isa => 'Int', is => 'rw');
229 has 'z' => (isa => 'Int');
231 after 'clear' => sub {
238 This is an early release of this module, it still needs
239 some fine tuning and B<lots> more documentation. I am adopting
240 the I<release early and release often> approach with this module,
241 so keep an eye on your favorite CPAN mirror!
245 Moose is an extension of the Perl 5 object system.
247 =head2 Another object system!?!?
249 Yes, I know there has been an explosion recently of new ways to
250 build object's in Perl 5, most of them based on inside-out objects,
251 and other such things. Moose is different because it is not a new
252 object system for Perl 5, but instead an extension of the existing
255 Moose is built on top of L<Class::MOP>, which is a metaclass system
256 for Perl 5. This means that Moose not only makes building normal
257 Perl 5 objects better, but it also provides the power of metaclass
260 =head2 What does Moose stand for??
262 Moose doesn't stand for one thing in particular, however, if you
263 want, here are a few of my favorites, feel free to contribute
268 =item Make Other Object Systems Envious
270 =item Makes Object Orientation So Easy
272 =item Makes Object Orientation Spiffy- Er (sorry ingy)
274 =item Most Other Object Systems Emasculate
276 =item My Overcraft Overfilled (with) Some Eels
278 =item Moose Often Ovulate Sorta Early
280 =item Many Overloaded Object Systems Exists
282 =item Moose Offers Often Super Extensions
284 =item Meta Object Orientation Syntax Extensions
288 =head1 BUILDING CLASSES WITH MOOSE
290 Moose makes every attempt to provide as much convience during class
291 construction/definition, but still stay out of your way if you want
292 it to. Here are some of the features Moose provides:
294 Unless specified with C<extends>, any class which uses Moose will
295 inherit from L<Moose::Object>.
297 Moose will also manage all attributes (including inherited ones) that
298 are defined with C<has>. And assuming that you call C<new> which is
299 inherited from L<Moose::Object>, then this includes properly initializing
300 all instance slots, setting defaults where approprtiate and performing any
301 type constraint checking or coercion.
303 For more details, see the ever expanding L<Moose::Cookbook>.
305 =head1 EXPORTED FUNCTIONS
307 Moose will export a number of functions into the class's namespace, which
308 can then be used to set up the class. These functions all work directly
309 on the current class.
315 This is a method which provides access to the current class's metaclass.
317 =item B<extends (@superclasses)>
319 This function will set the superclass(es) for the current class.
321 This approach is recommended instead of C<use base>, because C<use base>
322 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
323 replace it. This is important to ensure that classes which do not have
324 superclasses properly inherit from L<Moose::Object>.
326 =item B<with ($role)>
328 This will apply a given C<$role> to the local class. Role support is
329 currently very experimental, see L<Moose::Role> for more details.
331 =item B<has ($name, %options)>
333 This will install an attribute of a given C<$name> into the current class.
334 The list of C<%options> are the same as those provided by both
335 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
336 few convience ones provided by Moose which are listed below:
340 =item I<is =E<gt> 'rw'|'ro'>
342 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
343 only). These will create either a read/write accessor or a read-only
344 accessor respectively, using the same name as the C<$name> of the attribute.
346 If you need more control over how your accessors are named, you can use the
347 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
349 =item I<isa =E<gt> $type_name>
351 The I<isa> option uses Moose's type constraint facilities to set up runtime
352 type checking for this attribute. Moose will perform the checks during class
353 construction, and within any accessors. The C<$type_name> argument must be a
354 string. The string can be either a class name, or a type defined using
355 Moose's type defintion features.
357 =item I<coerce =E<gt> (1|0)>
359 This will attempt to use coercion with the supplied type constraint to change
360 the value passed into any accessors of constructors. You B<must> have supplied
361 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
362 for an example usage.
364 =item I<does =E<gt> $role_name>
366 This will accept the name of a role which the value stored in this attribute
367 is expected to have consumed.
369 =item I<required =E<gt> (1|0)>
371 This marks the attribute as being required. This means a value must be supplied
372 during class construction, and the attribute can never be set to C<undef> with
375 =item I<weak_ref =E<gt> (1|0)>
377 This will tell the class to strore the value of this attribute as a weakened
378 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
380 =item I<lazy =E<gt> (1|0)>
382 This will tell the class to not create this slot until absolutely nessecary.
383 If an attribute is marked as lazy it B<must> have a default supplied.
385 =item I<trigger =E<gt> $code>
387 The trigger option is a CODE reference which will be called after the value of
388 the attribute is set. The CODE ref will be passed the instance itself, the
389 updated value and the attribute meta-object (this is for more advanced fiddling
390 and can typically be ignored in most cases). You can B<not> have a trigger on
391 a read-only attribute.
395 =item B<before $name|@names =E<gt> sub { ... }>
397 =item B<after $name|@names =E<gt> sub { ... }>
399 =item B<around $name|@names =E<gt> sub { ... }>
401 This three items are syntactic sugar for the before, after and around method
402 modifier features that L<Class::MOP> provides. More information on these can
403 be found in the L<Class::MOP> documentation for now.
407 The keyword C<super> is a noop when called outside of an C<override> method. In
408 the context of an C<override> method, it will call the next most appropriate
409 superclass method with the same arguments as the original method.
411 =item B<override ($name, &sub)>
413 An C<override> method, is a way of explictly saying "I am overriding this
414 method from my superclass". You can call C<super> within this method, and
415 it will work as expected. The same thing I<can> be accomplished with a normal
416 method call and the C<SUPER::> pseudo-package, it is really your choice.
420 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
421 an C<augment> method. You can think of C<inner> as being the inverse of
422 C<super>, the details of how C<inner> and C<augment> work is best described in
423 the L<Moose::Cookbook>.
425 =item B<augment ($name, &sub)>
427 An C<augment> method, is a way of explictly saying "I am augmenting this
428 method from my superclass". Once again, the details of how C<inner> and
429 C<augment> work is best described in the L<Moose::Cookbook>.
433 This is the C<Carp::confess> function, and exported here beause I use it
434 all the time. This feature may change in the future, so you have been warned.
438 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
439 use it all the time. It is highly recommended that this is used instead of
440 C<ref> anywhere you need to test for an object's class name.
450 It should be noted that C<super> and C<inner> can B<not> be used in the same
451 method. However, they can be combined together with the same class hierarchy,
452 see F<t/014_override_augment_inner_super.t> for an example.
454 The reason that this is so is because C<super> is only valid within a method
455 with the C<override> modifier, and C<inner> will never be valid within an
456 C<override> method. In fact, C<augment> will skip over any C<override> methods
457 when searching for it's appropriate C<inner>.
459 This might seem like a restriction, but I am of the opinion that keeping these
460 two features seperate (but interoperable) actually makes them easy to use since
461 their behavior is then easier to predict. Time will tell if I am right or not.
465 =head1 ACKNOWLEDGEMENTS
469 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
471 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
473 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
474 and it certainly wouldn't have this name ;P
476 =item The basis of the TypeContraints module was Rob Kinyon's idea
477 originally, I just ran with it.
479 =item Thanks to mst & chansen and the whole #moose poose for all the
480 ideas/feature-requests/encouragement
488 =item L<Class::MOP> documentation
490 =item The #moose channel on irc.perl.org
492 =item L<http://forum2.org/moose/>
494 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
496 This paper (suggested by lbr on #moose) was what lead to the implementation
497 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
498 want to understand this feature, I suggest you read this.
504 All complex software has bugs lurking in it, and this module is no
505 exception. If you find a bug please either email me, or add the bug
510 Stevan Little E<lt>stevan@iinteractive.comE<gt>
512 =head1 COPYRIGHT AND LICENSE
514 Copyright 2006 by Infinity Interactive, Inc.
516 L<http://www.iinteractive.com>
518 This library is free software; you can redistribute it and/or modify
519 it under the same terms as Perl itself.