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 $meta->add_method('meta' => sub {
49 # re-initialize so it inherits properly
50 Moose::Meta::Class->initialize($class);
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 #(scalar keys %options == 1 && exists $options{default})
86 # || confess "Inherited slot specifications can only alter the 'default' option";
87 my $new_attr = $inherited_attr->clone(%options);
88 $meta->add_attribute($new_attr);
91 if ($options{metaclass}) {
92 _load_all_classes($options{metaclass});
93 $meta->add_attribute($options{metaclass}->new($name, %options));
96 $meta->add_attribute($name, %options);
102 my $meta = _find_meta();
103 return subname 'Moose::before' => sub {
105 $meta->add_before_method_modifier($_, $code) for @_;
109 my $meta = _find_meta();
110 return subname 'Moose::after' => sub {
112 $meta->add_after_method_modifier($_, $code) for @_;
116 my $meta = _find_meta();
117 return subname 'Moose::around' => sub {
119 $meta->add_around_method_modifier($_, $code) for @_;
123 my $meta = _find_meta();
124 return subname 'Moose::super' => sub {};
127 my $meta = _find_meta();
128 return subname 'Moose::override' => sub {
129 my ($name, $method) = @_;
130 $meta->add_override_method_modifier($name => $method);
134 my $meta = _find_meta();
135 return subname 'Moose::inner' => sub {};
138 my $meta = _find_meta();
139 return subname 'Moose::augment' => sub {
140 my ($name, $method) = @_;
141 $meta->add_augment_method_modifier($name => $method);
145 return \&Carp::confess;
148 return \&Scalar::Util::blessed;
152 my $exporter = Sub::Exporter::build_exporter({
153 exports => \%exports,
162 # we should never export to main
163 return if $CALLER eq 'main';
171 sub _load_all_classes {
172 foreach my $super (@_) {
173 # see if this is already
174 # loaded in the symbol table
175 next if _is_class_already_loaded($super);
176 # otherwise require it ...
178 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
182 sub _is_class_already_loaded {
185 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
186 foreach (keys %{"${name}::"}) {
187 next if substr($_, -2, 2) eq '::';
188 return 1 if defined &{"${name}::$_"};
201 Moose - Moose, it's the new Camel
208 has 'x' => (isa => 'Int', is => 'rw');
209 has 'y' => (isa => 'Int', is => 'rw');
222 has 'z' => (isa => 'Int');
224 after 'clear' => sub {
231 This is an early release of this module, it still needs
232 some fine tuning and B<lots> more documentation. I am adopting
233 the I<release early and release often> approach with this module,
234 so keep an eye on your favorite CPAN mirror!
238 Moose is an extension of the Perl 5 object system.
240 =head2 Another object system!?!?
242 Yes, I know there has been an explosion recently of new ways to
243 build object's in Perl 5, most of them based on inside-out objects,
244 and other such things. Moose is different because it is not a new
245 object system for Perl 5, but instead an extension of the existing
248 Moose is built on top of L<Class::MOP>, which is a metaclass system
249 for Perl 5. This means that Moose not only makes building normal
250 Perl 5 objects better, but it also provides the power of metaclass
253 =head2 What does Moose stand for??
255 Moose doesn't stand for one thing in particular, however, if you
256 want, here are a few of my favorites, feel free to contribute
261 =item Make Other Object Systems Envious
263 =item Makes Object Orientation So Easy
265 =item Makes Object Orientation Spiffy- Er (sorry ingy)
267 =item Most Other Object Systems Emasculate
269 =item My Overcraft Overfilled (with) Some Eels
271 =item Moose Often Ovulate Sorta Early
273 =item Many Overloaded Object Systems Exists
275 =item Moose Offers Often Super Extensions
277 =item Meta Object Orientation Syntax Extensions
281 =head1 BUILDING CLASSES WITH MOOSE
283 Moose makes every attempt to provide as much convience during class
284 construction/definition, but still stay out of your way if you want
285 it to. Here are some of the features Moose provides:
287 Unless specified with C<extends>, any class which uses Moose will
288 inherit from L<Moose::Object>.
290 Moose will also manage all attributes (including inherited ones) that
291 are defined with C<has>. And assuming that you call C<new> which is
292 inherited from L<Moose::Object>, then this includes properly initializing
293 all instance slots, setting defaults where approprtiate and performing any
294 type constraint checking or coercion.
296 For more details, see the ever expanding L<Moose::Cookbook>.
298 =head1 EXPORTED FUNCTIONS
300 Moose will export a number of functions into the class's namespace, which
301 can then be used to set up the class. These functions all work directly
302 on the current class.
308 This is a method which provides access to the current class's metaclass.
310 =item B<extends (@superclasses)>
312 This function will set the superclass(es) for the current class.
314 This approach is recommended instead of C<use base>, because C<use base>
315 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
316 replace it. This is important to ensure that classes which do not have
317 superclasses properly inherit from L<Moose::Object>.
319 =item B<with ($role)>
321 This will apply a given C<$role> to the local class. Role support is
322 currently very experimental, see L<Moose::Role> for more details.
324 =item B<has ($name, %options)>
326 This will install an attribute of a given C<$name> into the current class.
327 The list of C<%options> are the same as those provided by both
328 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
329 few convience ones provided by Moose which are listed below:
333 =item I<is =E<gt> 'rw'|'ro'>
335 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
336 only). These will create either a read/write accessor or a read-only
337 accessor respectively, using the same name as the C<$name> of the attribute.
339 If you need more control over how your accessors are named, you can use the
340 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
342 =item I<isa =E<gt> $type_name>
344 The I<isa> option uses Moose's type constraint facilities to set up runtime
345 type checking for this attribute. Moose will perform the checks during class
346 construction, and within any accessors. The C<$type_name> argument must be a
347 string. The string can be either a class name, or a type defined using
348 Moose's type defintion features.
350 =item I<coerce =E<gt> (1|0)>
352 This will attempt to use coercion with the supplied type constraint to change
353 the value passed into any accessors of constructors. You B<must> have supplied
354 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
355 for an example usage.
357 =item I<does =E<gt> $role_name>
359 This will accept the name of a role which the value stored in this attribute
360 is expected to have consumed.
362 =item I<required =E<gt> (1|0)>
364 This marks the attribute as being required. This means a value must be supplied
365 during class construction, and the attribute can never be set to C<undef> with
368 =item I<weak_ref =E<gt> (1|0)>
370 This will tell the class to strore the value of this attribute as a weakened
371 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
373 =item I<lazy =E<gt> (1|0)>
375 This will tell the class to not create this slot until absolutely nessecary.
376 If an attribute is marked as lazy it B<must> have a default supplied.
378 =item I<trigger =E<gt> $code>
380 The trigger option is a CODE reference which will be called after the value of
381 the attribute is set. The CODE ref will be passed the instance itself, the
382 updated value and the attribute meta-object (this is for more advanced fiddling
383 and can typically be ignored in most cases). You can B<not> have a trigger on
384 a read-only attribute.
388 =item B<before $name|@names =E<gt> sub { ... }>
390 =item B<after $name|@names =E<gt> sub { ... }>
392 =item B<around $name|@names =E<gt> sub { ... }>
394 This three items are syntactic sugar for the before, after and around method
395 modifier features that L<Class::MOP> provides. More information on these can
396 be found in the L<Class::MOP> documentation for now.
400 The keyword C<super> is a noop when called outside of an C<override> method. In
401 the context of an C<override> method, it will call the next most appropriate
402 superclass method with the same arguments as the original method.
404 =item B<override ($name, &sub)>
406 An C<override> method, is a way of explictly saying "I am overriding this
407 method from my superclass". You can call C<super> within this method, and
408 it will work as expected. The same thing I<can> be accomplished with a normal
409 method call and the C<SUPER::> pseudo-package, it is really your choice.
413 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
414 an C<augment> method. You can think of C<inner> as being the inverse of
415 C<super>, the details of how C<inner> and C<augment> work is best described in
416 the L<Moose::Cookbook>.
418 =item B<augment ($name, &sub)>
420 An C<augment> method, is a way of explictly saying "I am augmenting this
421 method from my superclass". Once again, the details of how C<inner> and
422 C<augment> work is best described in the L<Moose::Cookbook>.
426 This is the C<Carp::confess> function, and exported here beause I use it
427 all the time. This feature may change in the future, so you have been warned.
431 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
432 use it all the time. It is highly recommended that this is used instead of
433 C<ref> anywhere you need to test for an object's class name.
443 It should be noted that C<super> and C<inner> can B<not> be used in the same
444 method. However, they can be combined together with the same class hierarchy,
445 see F<t/014_override_augment_inner_super.t> for an example.
447 The reason that this is so is because C<super> is only valid within a method
448 with the C<override> modifier, and C<inner> will never be valid within an
449 C<override> method. In fact, C<augment> will skip over any C<override> methods
450 when searching for it's appropriate C<inner>.
452 This might seem like a restriction, but I am of the opinion that keeping these
453 two features seperate (but interoperable) actually makes them easy to use since
454 their behavior is then easier to predict. Time will tell if I am right or not.
458 =head1 ACKNOWLEDGEMENTS
462 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
464 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
466 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
467 and it certainly wouldn't have this name ;P
469 =item The basis of the TypeContraints module was Rob Kinyon's idea
470 originally, I just ran with it.
472 =item Thanks to mst & chansen and the whole #moose poose for all the
473 ideas/feature-requests/encouragement
481 =item L<Class::MOP> documentation
483 =item The #moose channel on irc.perl.org
485 =item L<http://forum2.org/moose/>
487 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
489 This paper (suggested by lbr on #moose) was what lead to the implementation
490 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
491 want to understand this feature, I suggest you read this.
497 All complex software has bugs lurking in it, and this module is no
498 exception. If you find a bug please either email me, or add the bug
503 Stevan Little E<lt>stevan@iinteractive.comE<gt>
505 =head1 COPYRIGHT AND LICENSE
507 Copyright 2006 by Infinity Interactive, Inc.
509 L<http://www.iinteractive.com>
511 This library is free software; you can redistribute it and/or modify
512 it under the same terms as Perl itself.