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')) {
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 "Whoops, not møøsey enough";
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();
69 return $METAS{$class} = $meta;
74 my $meta = _find_meta();
75 return subname 'Moose::extends' => sub {
76 _load_all_classes(@_);
77 $meta->superclasses(@_)
81 my $meta = _find_meta();
82 return subname 'Moose::with' => sub {
84 _load_all_classes($role);
85 $role->meta->apply($meta);
89 my $meta = _find_meta();
90 return subname 'Moose::has' => sub {
91 my ($name, %options) = @_;
92 if ($name =~ /^\+(.*)/) {
93 my $inherited_attr = $meta->find_attribute_by_name($1);
94 (defined $inherited_attr)
95 || confess "Could not find an attribute by the name of '$1' to inherit from";
96 my $new_attr = $inherited_attr->clone_and_inherit_options(%options);
97 $meta->add_attribute($new_attr);
100 if ($options{metaclass}) {
101 _load_all_classes($options{metaclass});
102 $meta->add_attribute($options{metaclass}->new($name, %options));
105 $meta->add_attribute($name, %options);
111 my $meta = _find_meta();
112 return subname 'Moose::before' => sub {
114 $meta->add_before_method_modifier($_, $code) for @_;
118 my $meta = _find_meta();
119 return subname 'Moose::after' => sub {
121 $meta->add_after_method_modifier($_, $code) for @_;
125 my $meta = _find_meta();
126 return subname 'Moose::around' => sub {
128 $meta->add_around_method_modifier($_, $code) for @_;
132 my $meta = _find_meta();
133 return subname 'Moose::super' => sub {};
136 my $meta = _find_meta();
137 return subname 'Moose::override' => sub {
138 my ($name, $method) = @_;
139 $meta->add_override_method_modifier($name => $method);
143 my $meta = _find_meta();
144 return subname 'Moose::inner' => sub {};
147 my $meta = _find_meta();
148 return subname 'Moose::augment' => sub {
149 my ($name, $method) = @_;
150 $meta->add_augment_method_modifier($name => $method);
154 return \&Carp::confess;
157 return \&Scalar::Util::blessed;
160 subname 'Moose::all_methods' => sub () {
162 my ( $class, $delegate_class ) = @_;
163 $delegate_class->compute_all_applicable_methods();
169 my $exporter = Sub::Exporter::build_exporter({
170 exports => \%exports,
179 # we should never export to main
180 return if $CALLER eq 'main';
188 sub _load_all_classes {
189 foreach my $super (@_) {
190 # see if this is already
191 # loaded in the symbol table
192 next if _is_class_already_loaded($super);
193 # otherwise require it ...
195 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
199 sub _is_class_already_loaded {
202 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
203 foreach (keys %{"${name}::"}) {
204 next if substr($_, -2, 2) eq '::';
205 return 1 if defined &{"${name}::$_"};
218 Moose - Moose, it's the new Camel
225 has 'x' => (isa => 'Int', is => 'rw');
226 has 'y' => (isa => 'Int', is => 'rw');
239 has 'z' => (isa => 'Int');
241 after 'clear' => sub {
248 This is an early release of this module, it still needs
249 some fine tuning and B<lots> more documentation. I am adopting
250 the I<release early and release often> approach with this module,
251 so keep an eye on your favorite CPAN mirror!
255 Moose is an extension of the Perl 5 object system.
257 =head2 Another object system!?!?
259 Yes, I know there has been an explosion recently of new ways to
260 build object's in Perl 5, most of them based on inside-out objects,
261 and other such things. Moose is different because it is not a new
262 object system for Perl 5, but instead an extension of the existing
265 Moose is built on top of L<Class::MOP>, which is a metaclass system
266 for Perl 5. This means that Moose not only makes building normal
267 Perl 5 objects better, but it also provides the power of metaclass
270 =head2 What does Moose stand for??
272 Moose doesn't stand for one thing in particular, however, if you
273 want, here are a few of my favorites, feel free to contribute
278 =item Make Other Object Systems Envious
280 =item Makes Object Orientation So Easy
282 =item Makes Object Orientation Spiffy- Er (sorry ingy)
284 =item Most Other Object Systems Emasculate
286 =item My Overcraft Overfilled (with) Some Eels
288 =item Moose Often Ovulate Sorta Early
290 =item Many Overloaded Object Systems Exists
292 =item Moose Offers Often Super Extensions
294 =item Meta Object Orientation Syntax Extensions
298 =head1 BUILDING CLASSES WITH MOOSE
300 Moose makes every attempt to provide as much convience during class
301 construction/definition, but still stay out of your way if you want
302 it to. Here are some of the features Moose provides:
304 Unless specified with C<extends>, any class which uses Moose will
305 inherit from L<Moose::Object>.
307 Moose will also manage all attributes (including inherited ones) that
308 are defined with C<has>. And assuming that you call C<new> which is
309 inherited from L<Moose::Object>, then this includes properly initializing
310 all instance slots, setting defaults where approprtiate and performing any
311 type constraint checking or coercion.
313 For more details, see the ever expanding L<Moose::Cookbook>.
315 =head1 EXPORTED FUNCTIONS
317 Moose will export a number of functions into the class's namespace, which
318 can then be used to set up the class. These functions all work directly
319 on the current class.
325 This is a method which provides access to the current class's metaclass.
327 =item B<extends (@superclasses)>
329 This function will set the superclass(es) for the current class.
331 This approach is recommended instead of C<use base>, because C<use base>
332 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
333 replace it. This is important to ensure that classes which do not have
334 superclasses properly inherit from L<Moose::Object>.
336 =item B<with ($role)>
338 This will apply a given C<$role> to the local class. Role support is
339 currently very experimental, see L<Moose::Role> for more details.
341 =item B<has ($name, %options)>
343 This will install an attribute of a given C<$name> into the current class.
344 The list of C<%options> are the same as those provided by both
345 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
346 few convience ones provided by Moose which are listed below:
350 =item I<is =E<gt> 'rw'|'ro'>
352 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
353 only). These will create either a read/write accessor or a read-only
354 accessor respectively, using the same name as the C<$name> of the attribute.
356 If you need more control over how your accessors are named, you can use the
357 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
359 =item I<isa =E<gt> $type_name>
361 The I<isa> option uses Moose's type constraint facilities to set up runtime
362 type checking for this attribute. Moose will perform the checks during class
363 construction, and within any accessors. The C<$type_name> argument must be a
364 string. The string can be either a class name, or a type defined using
365 Moose's type defintion features.
367 =item I<coerce =E<gt> (1|0)>
369 This will attempt to use coercion with the supplied type constraint to change
370 the value passed into any accessors of constructors. You B<must> have supplied
371 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
372 for an example usage.
374 =item I<does =E<gt> $role_name>
376 This will accept the name of a role which the value stored in this attribute
377 is expected to have consumed.
379 =item I<required =E<gt> (1|0)>
381 This marks the attribute as being required. This means a value must be supplied
382 during class construction, and the attribute can never be set to C<undef> with
385 =item I<weak_ref =E<gt> (1|0)>
387 This will tell the class to strore the value of this attribute as a weakened
388 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
390 =item I<lazy =E<gt> (1|0)>
392 This will tell the class to not create this slot until absolutely nessecary.
393 If an attribute is marked as lazy it B<must> have a default supplied.
395 =item I<trigger =E<gt> $code>
397 The trigger option is a CODE reference which will be called after the value of
398 the attribute is set. The CODE ref will be passed the instance itself, the
399 updated value and the attribute meta-object (this is for more advanced fiddling
400 and can typically be ignored in most cases). You can B<not> have a trigger on
401 a read-only attribute.
405 =item B<before $name|@names =E<gt> sub { ... }>
407 =item B<after $name|@names =E<gt> sub { ... }>
409 =item B<around $name|@names =E<gt> sub { ... }>
411 This three items are syntactic sugar for the before, after and around method
412 modifier features that L<Class::MOP> provides. More information on these can
413 be found in the L<Class::MOP> documentation for now.
417 The keyword C<super> is a noop when called outside of an C<override> method. In
418 the context of an C<override> method, it will call the next most appropriate
419 superclass method with the same arguments as the original method.
421 =item B<override ($name, &sub)>
423 An C<override> method, is a way of explictly saying "I am overriding this
424 method from my superclass". You can call C<super> within this method, and
425 it will work as expected. The same thing I<can> be accomplished with a normal
426 method call and the C<SUPER::> pseudo-package, it is really your choice.
430 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
431 an C<augment> method. You can think of C<inner> as being the inverse of
432 C<super>, the details of how C<inner> and C<augment> work is best described in
433 the L<Moose::Cookbook>.
435 =item B<augment ($name, &sub)>
437 An C<augment> method, is a way of explictly saying "I am augmenting this
438 method from my superclass". Once again, the details of how C<inner> and
439 C<augment> work is best described in the L<Moose::Cookbook>.
443 This is the C<Carp::confess> function, and exported here beause I use it
444 all the time. This feature may change in the future, so you have been warned.
448 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
449 use it all the time. It is highly recommended that this is used instead of
450 C<ref> anywhere you need to test for an object's class name.
460 It should be noted that C<super> and C<inner> can B<not> be used in the same
461 method. However, they can be combined together with the same class hierarchy,
462 see F<t/014_override_augment_inner_super.t> for an example.
464 The reason that this is so is because C<super> is only valid within a method
465 with the C<override> modifier, and C<inner> will never be valid within an
466 C<override> method. In fact, C<augment> will skip over any C<override> methods
467 when searching for it's appropriate C<inner>.
469 This might seem like a restriction, but I am of the opinion that keeping these
470 two features seperate (but interoperable) actually makes them easy to use since
471 their behavior is then easier to predict. Time will tell if I am right or not.
475 =head1 ACKNOWLEDGEMENTS
479 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
481 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
483 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
484 and it certainly wouldn't have this name ;P
486 =item The basis of the TypeContraints module was Rob Kinyon's idea
487 originally, I just ran with it.
489 =item Thanks to mst & chansen and the whole #moose poose for all the
490 ideas/feature-requests/encouragement
498 =item L<Class::MOP> documentation
500 =item The #moose channel on irc.perl.org
502 =item L<http://forum2.org/moose/>
504 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
506 This paper (suggested by lbr on #moose) was what lead to the implementation
507 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
508 want to understand this feature, I suggest you read this.
514 All complex software has bugs lurking in it, and this module is no
515 exception. If you find a bug please either email me, or add the bug
520 Stevan Little E<lt>stevan@iinteractive.comE<gt>
522 =head1 COPYRIGHT AND LICENSE
524 Copyright 2006 by Infinity Interactive, Inc.
526 L<http://www.iinteractive.com>
528 This library is free software; you can redistribute it and/or modify
529 it under the same terms as Perl itself.