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;
24 use Moose::Util::TypeConstraints;
27 my ( $CALLER, %METAS );
32 return $METAS{$class} if exists $METAS{$class};
34 # make a subtype for each Moose class
37 => where { $_->isa($class) }
38 unless find_type_constraint($class);
41 if ($class->can('meta')) {
42 $meta = $class->meta();
43 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
44 || confess "Whoops, not møøsey enough";
47 $meta = Moose::Meta::Class->initialize($class);
48 $meta->add_method('meta' => sub {
49 # re-initialize so it inherits properly
50 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
54 # make sure they inherit from Moose::Object
55 $meta->superclasses('Moose::Object')
56 unless $meta->superclasses();
58 return $METAS{$class} = $meta;
63 my $meta = _find_meta();
64 return subname 'Moose::extends' => sub {
65 _load_all_classes(@_);
66 $meta->superclasses(@_)
70 my $meta = _find_meta();
71 return subname 'Moose::with' => sub {
73 _load_all_classes($role);
74 $role->meta->apply($meta);
78 my $meta = _find_meta();
79 return subname 'Moose::has' => sub {
80 my ($name, %options) = @_;
81 if ($name =~ /^\+(.*)/) {
82 my $inherited_attr = $meta->find_attribute_by_name($1);
83 (defined $inherited_attr)
84 || confess "Could not find an attribute by the name of '$1' to inherit from";
85 my $new_attr = $inherited_attr->clone_and_inherit_options(%options);
86 $meta->add_attribute($new_attr);
89 if ($options{metaclass}) {
90 _load_all_classes($options{metaclass});
91 $meta->add_attribute($options{metaclass}->new($name, %options));
94 $meta->add_attribute($name, %options);
100 my $meta = _find_meta();
101 return subname 'Moose::before' => sub {
103 $meta->add_before_method_modifier($_, $code) for @_;
107 my $meta = _find_meta();
108 return subname 'Moose::after' => sub {
110 $meta->add_after_method_modifier($_, $code) for @_;
114 my $meta = _find_meta();
115 return subname 'Moose::around' => sub {
117 $meta->add_around_method_modifier($_, $code) for @_;
121 my $meta = _find_meta();
122 return subname 'Moose::super' => sub {};
125 my $meta = _find_meta();
126 return subname 'Moose::override' => sub {
127 my ($name, $method) = @_;
128 $meta->add_override_method_modifier($name => $method);
132 my $meta = _find_meta();
133 return subname 'Moose::inner' => sub {};
136 my $meta = _find_meta();
137 return subname 'Moose::augment' => sub {
138 my ($name, $method) = @_;
139 $meta->add_augment_method_modifier($name => $method);
143 return \&Carp::confess;
146 return \&Scalar::Util::blessed;
150 my $exporter = Sub::Exporter::build_exporter({
151 exports => \%exports,
160 # we should never export to main
161 return if $CALLER eq 'main';
169 sub _load_all_classes {
170 foreach my $super (@_) {
171 # see if this is already
172 # loaded in the symbol table
173 next if _is_class_already_loaded($super);
174 # otherwise require it ...
176 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
180 sub _is_class_already_loaded {
183 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
184 foreach (keys %{"${name}::"}) {
185 next if substr($_, -2, 2) eq '::';
186 return 1 if defined &{"${name}::$_"};
199 Moose - Moose, it's the new Camel
206 has 'x' => (isa => 'Int', is => 'rw');
207 has 'y' => (isa => 'Int', is => 'rw');
220 has 'z' => (isa => 'Int');
222 after 'clear' => sub {
229 This is an early release of this module, it still needs
230 some fine tuning and B<lots> more documentation. I am adopting
231 the I<release early and release often> approach with this module,
232 so keep an eye on your favorite CPAN mirror!
236 Moose is an extension of the Perl 5 object system.
238 =head2 Another object system!?!?
240 Yes, I know there has been an explosion recently of new ways to
241 build object's in Perl 5, most of them based on inside-out objects,
242 and other such things. Moose is different because it is not a new
243 object system for Perl 5, but instead an extension of the existing
246 Moose is built on top of L<Class::MOP>, which is a metaclass system
247 for Perl 5. This means that Moose not only makes building normal
248 Perl 5 objects better, but it also provides the power of metaclass
251 =head2 What does Moose stand for??
253 Moose doesn't stand for one thing in particular, however, if you
254 want, here are a few of my favorites, feel free to contribute
259 =item Make Other Object Systems Envious
261 =item Makes Object Orientation So Easy
263 =item Makes Object Orientation Spiffy- Er (sorry ingy)
265 =item Most Other Object Systems Emasculate
267 =item My Overcraft Overfilled (with) Some Eels
269 =item Moose Often Ovulate Sorta Early
271 =item Many Overloaded Object Systems Exists
273 =item Moose Offers Often Super Extensions
275 =item Meta Object Orientation Syntax Extensions
279 =head1 BUILDING CLASSES WITH MOOSE
281 Moose makes every attempt to provide as much convience during class
282 construction/definition, but still stay out of your way if you want
283 it to. Here are some of the features Moose provides:
285 Unless specified with C<extends>, any class which uses Moose will
286 inherit from L<Moose::Object>.
288 Moose will also manage all attributes (including inherited ones) that
289 are defined with C<has>. And assuming that you call C<new> which is
290 inherited from L<Moose::Object>, then this includes properly initializing
291 all instance slots, setting defaults where approprtiate and performing any
292 type constraint checking or coercion.
294 For more details, see the ever expanding L<Moose::Cookbook>.
296 =head1 EXPORTED FUNCTIONS
298 Moose will export a number of functions into the class's namespace, which
299 can then be used to set up the class. These functions all work directly
300 on the current class.
306 This is a method which provides access to the current class's metaclass.
308 =item B<extends (@superclasses)>
310 This function will set the superclass(es) for the current class.
312 This approach is recommended instead of C<use base>, because C<use base>
313 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
314 replace it. This is important to ensure that classes which do not have
315 superclasses properly inherit from L<Moose::Object>.
317 =item B<with ($role)>
319 This will apply a given C<$role> to the local class. Role support is
320 currently very experimental, see L<Moose::Role> for more details.
322 =item B<has ($name, %options)>
324 This will install an attribute of a given C<$name> into the current class.
325 The list of C<%options> are the same as those provided by both
326 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
327 few convience ones provided by Moose which are listed below:
331 =item I<is =E<gt> 'rw'|'ro'>
333 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
334 only). These will create either a read/write accessor or a read-only
335 accessor respectively, using the same name as the C<$name> of the attribute.
337 If you need more control over how your accessors are named, you can use the
338 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
340 =item I<isa =E<gt> $type_name>
342 The I<isa> option uses Moose's type constraint facilities to set up runtime
343 type checking for this attribute. Moose will perform the checks during class
344 construction, and within any accessors. The C<$type_name> argument must be a
345 string. The string can be either a class name, or a type defined using
346 Moose's type defintion features.
348 =item I<coerce =E<gt> (1|0)>
350 This will attempt to use coercion with the supplied type constraint to change
351 the value passed into any accessors of constructors. You B<must> have supplied
352 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
353 for an example usage.
355 =item I<does =E<gt> $role_name>
357 This will accept the name of a role which the value stored in this attribute
358 is expected to have consumed.
360 =item I<required =E<gt> (1|0)>
362 This marks the attribute as being required. This means a value must be supplied
363 during class construction, and the attribute can never be set to C<undef> with
366 =item I<weak_ref =E<gt> (1|0)>
368 This will tell the class to strore the value of this attribute as a weakened
369 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
371 =item I<lazy =E<gt> (1|0)>
373 This will tell the class to not create this slot until absolutely nessecary.
374 If an attribute is marked as lazy it B<must> have a default supplied.
376 =item I<trigger =E<gt> $code>
378 The trigger option is a CODE reference which will be called after the value of
379 the attribute is set. The CODE ref will be passed the instance itself, the
380 updated value and the attribute meta-object (this is for more advanced fiddling
381 and can typically be ignored in most cases). You can B<not> have a trigger on
382 a read-only attribute.
386 =item B<before $name|@names =E<gt> sub { ... }>
388 =item B<after $name|@names =E<gt> sub { ... }>
390 =item B<around $name|@names =E<gt> sub { ... }>
392 This three items are syntactic sugar for the before, after and around method
393 modifier features that L<Class::MOP> provides. More information on these can
394 be found in the L<Class::MOP> documentation for now.
398 The keyword C<super> is a noop when called outside of an C<override> method. In
399 the context of an C<override> method, it will call the next most appropriate
400 superclass method with the same arguments as the original method.
402 =item B<override ($name, &sub)>
404 An C<override> method, is a way of explictly saying "I am overriding this
405 method from my superclass". You can call C<super> within this method, and
406 it will work as expected. The same thing I<can> be accomplished with a normal
407 method call and the C<SUPER::> pseudo-package, it is really your choice.
411 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
412 an C<augment> method. You can think of C<inner> as being the inverse of
413 C<super>, the details of how C<inner> and C<augment> work is best described in
414 the L<Moose::Cookbook>.
416 =item B<augment ($name, &sub)>
418 An C<augment> method, is a way of explictly saying "I am augmenting this
419 method from my superclass". Once again, the details of how C<inner> and
420 C<augment> work is best described in the L<Moose::Cookbook>.
424 This is the C<Carp::confess> function, and exported here beause I use it
425 all the time. This feature may change in the future, so you have been warned.
429 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
430 use it all the time. It is highly recommended that this is used instead of
431 C<ref> anywhere you need to test for an object's class name.
441 It should be noted that C<super> and C<inner> can B<not> be used in the same
442 method. However, they can be combined together with the same class hierarchy,
443 see F<t/014_override_augment_inner_super.t> for an example.
445 The reason that this is so is because C<super> is only valid within a method
446 with the C<override> modifier, and C<inner> will never be valid within an
447 C<override> method. In fact, C<augment> will skip over any C<override> methods
448 when searching for it's appropriate C<inner>.
450 This might seem like a restriction, but I am of the opinion that keeping these
451 two features seperate (but interoperable) actually makes them easy to use since
452 their behavior is then easier to predict. Time will tell if I am right or not.
456 =head1 ACKNOWLEDGEMENTS
460 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
462 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
464 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
465 and it certainly wouldn't have this name ;P
467 =item The basis of the TypeContraints module was Rob Kinyon's idea
468 originally, I just ran with it.
470 =item Thanks to mst & chansen and the whole #moose poose for all the
471 ideas/feature-requests/encouragement
479 =item L<Class::MOP> documentation
481 =item The #moose channel on irc.perl.org
483 =item L<http://forum2.org/moose/>
485 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
487 This paper (suggested by lbr on #moose) was what lead to the implementation
488 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
489 want to understand this feature, I suggest you read this.
495 All complex software has bugs lurking in it, and this module is no
496 exception. If you find a bug please either email me, or add the bug
501 Stevan Little E<lt>stevan@iinteractive.comE<gt>
503 =head1 COPYRIGHT AND LICENSE
505 Copyright 2006 by Infinity Interactive, Inc.
507 L<http://www.iinteractive.com>
509 This library is free software; you can redistribute it and/or modify
510 it under the same terms as Perl itself.