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 () { qr/.*/ }
195 my $exporter = Sub::Exporter::build_exporter({
196 exports => \%exports,
205 # we should never export to main
206 return if $CALLER eq 'main';
216 sub _load_all_classes {
217 foreach my $super (@_) {
218 # see if this is already
219 # loaded in the symbol table
220 next if _is_class_already_loaded($super);
221 # otherwise require it ...
223 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
227 sub _is_class_already_loaded {
230 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
231 foreach (keys %{"${name}::"}) {
232 next if substr($_, -2, 2) eq '::';
233 return 1 if defined &{"${name}::$_"};
246 Moose - Moose, it's the new Camel
253 has 'x' => (isa => 'Int', is => 'rw');
254 has 'y' => (isa => 'Int', is => 'rw');
267 has 'z' => (isa => 'Int');
269 after 'clear' => sub {
276 This is an early release of this module, it still needs
277 some fine tuning and B<lots> more documentation. I am adopting
278 the I<release early and release often> approach with this module,
279 so keep an eye on your favorite CPAN mirror!
283 Moose is an extension of the Perl 5 object system.
285 =head2 Another object system!?!?
287 Yes, I know there has been an explosion recently of new ways to
288 build object's in Perl 5, most of them based on inside-out objects,
289 and other such things. Moose is different because it is not a new
290 object system for Perl 5, but instead an extension of the existing
293 Moose is built on top of L<Class::MOP>, which is a metaclass system
294 for Perl 5. This means that Moose not only makes building normal
295 Perl 5 objects better, but it also provides the power of metaclass
298 =head2 What does Moose stand for??
300 Moose doesn't stand for one thing in particular, however, if you
301 want, here are a few of my favorites, feel free to contribute
306 =item Make Other Object Systems Envious
308 =item Makes Object Orientation So Easy
310 =item Makes Object Orientation Spiffy- Er (sorry ingy)
312 =item Most Other Object Systems Emasculate
314 =item My Overcraft Overfilled (with) Some Eels
316 =item Moose Often Ovulate Sorta Early
318 =item Many Overloaded Object Systems Exists
320 =item Moose Offers Often Super Extensions
322 =item Meta Object Orientation Syntax Extensions
326 =head1 BUILDING CLASSES WITH MOOSE
328 Moose makes every attempt to provide as much convience during class
329 construction/definition, but still stay out of your way if you want
330 it to. Here are some of the features Moose provides:
332 Unless specified with C<extends>, any class which uses Moose will
333 inherit from L<Moose::Object>.
335 Moose will also manage all attributes (including inherited ones) that
336 are defined with C<has>. And assuming that you call C<new> which is
337 inherited from L<Moose::Object>, then this includes properly initializing
338 all instance slots, setting defaults where approprtiate and performing any
339 type constraint checking or coercion.
341 For more details, see the ever expanding L<Moose::Cookbook>.
343 =head1 EXPORTED FUNCTIONS
345 Moose will export a number of functions into the class's namespace, which
346 can then be used to set up the class. These functions all work directly
347 on the current class.
353 This is a method which provides access to the current class's metaclass.
355 =item B<extends (@superclasses)>
357 This function will set the superclass(es) for the current class.
359 This approach is recommended instead of C<use base>, because C<use base>
360 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
361 replace it. This is important to ensure that classes which do not have
362 superclasses properly inherit from L<Moose::Object>.
364 =item B<with ($role)>
366 This will apply a given C<$role> to the local class. Role support is
367 currently very experimental, see L<Moose::Role> for more details.
369 =item B<has ($name, %options)>
371 This will install an attribute of a given C<$name> into the current class.
372 The list of C<%options> are the same as those provided by both
373 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
374 few convience ones provided by Moose which are listed below:
378 =item I<is =E<gt> 'rw'|'ro'>
380 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
381 only). These will create either a read/write accessor or a read-only
382 accessor respectively, using the same name as the C<$name> of the attribute.
384 If you need more control over how your accessors are named, you can use the
385 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
387 =item I<isa =E<gt> $type_name>
389 The I<isa> option uses Moose's type constraint facilities to set up runtime
390 type checking for this attribute. Moose will perform the checks during class
391 construction, and within any accessors. The C<$type_name> argument must be a
392 string. The string can be either a class name, or a type defined using
393 Moose's type defintion features.
395 =item I<coerce =E<gt> (1|0)>
397 This will attempt to use coercion with the supplied type constraint to change
398 the value passed into any accessors of constructors. You B<must> have supplied
399 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
400 for an example usage.
402 =item I<does =E<gt> $role_name>
404 This will accept the name of a role which the value stored in this attribute
405 is expected to have consumed.
407 =item I<required =E<gt> (1|0)>
409 This marks the attribute as being required. This means a value must be supplied
410 during class construction, and the attribute can never be set to C<undef> with
413 =item I<weak_ref =E<gt> (1|0)>
415 This will tell the class to strore the value of this attribute as a weakened
416 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
418 =item I<lazy =E<gt> (1|0)>
420 This will tell the class to not create this slot until absolutely nessecary.
421 If an attribute is marked as lazy it B<must> have a default supplied.
423 =item I<trigger =E<gt> $code>
425 The trigger option is a CODE reference which will be called after the value of
426 the attribute is set. The CODE ref will be passed the instance itself, the
427 updated value and the attribute meta-object (this is for more advanced fiddling
428 and can typically be ignored in most cases). You can B<not> have a trigger on
429 a read-only attribute.
433 =item B<before $name|@names =E<gt> sub { ... }>
435 =item B<after $name|@names =E<gt> sub { ... }>
437 =item B<around $name|@names =E<gt> sub { ... }>
439 This three items are syntactic sugar for the before, after and around method
440 modifier features that L<Class::MOP> provides. More information on these can
441 be found in the L<Class::MOP> documentation for now.
445 The keyword C<super> is a noop when called outside of an C<override> method. In
446 the context of an C<override> method, it will call the next most appropriate
447 superclass method with the same arguments as the original method.
449 =item B<override ($name, &sub)>
451 An C<override> method, is a way of explictly saying "I am overriding this
452 method from my superclass". You can call C<super> within this method, and
453 it will work as expected. The same thing I<can> be accomplished with a normal
454 method call and the C<SUPER::> pseudo-package, it is really your choice.
458 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
459 an C<augment> method. You can think of C<inner> as being the inverse of
460 C<super>, the details of how C<inner> and C<augment> work is best described in
461 the L<Moose::Cookbook>.
463 =item B<augment ($name, &sub)>
465 An C<augment> method, is a way of explictly saying "I am augmenting this
466 method from my superclass". Once again, the details of how C<inner> and
467 C<augment> work is best described in the L<Moose::Cookbook>.
471 This is the C<Carp::confess> function, and exported here beause I use it
472 all the time. This feature may change in the future, so you have been warned.
476 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
477 use it all the time. It is highly recommended that this is used instead of
478 C<ref> anywhere you need to test for an object's class name.
488 It should be noted that C<super> and C<inner> can B<not> be used in the same
489 method. However, they can be combined together with the same class hierarchy,
490 see F<t/014_override_augment_inner_super.t> for an example.
492 The reason that this is so is because C<super> is only valid within a method
493 with the C<override> modifier, and C<inner> will never be valid within an
494 C<override> method. In fact, C<augment> will skip over any C<override> methods
495 when searching for it's appropriate C<inner>.
497 This might seem like a restriction, but I am of the opinion that keeping these
498 two features seperate (but interoperable) actually makes them easy to use since
499 their behavior is then easier to predict. Time will tell if I am right or not.
503 =head1 ACKNOWLEDGEMENTS
507 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
509 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
511 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
512 and it certainly wouldn't have this name ;P
514 =item The basis of the TypeContraints module was Rob Kinyon's idea
515 originally, I just ran with it.
517 =item Thanks to mst & chansen and the whole #moose poose for all the
518 ideas/feature-requests/encouragement
526 =item L<Class::MOP> documentation
528 =item The #moose channel on irc.perl.org
530 =item L<http://forum2.org/moose/>
532 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
534 This paper (suggested by lbr on #moose) was what lead to the implementation
535 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
536 want to understand this feature, I suggest you read this.
542 All complex software has bugs lurking in it, and this module is no
543 exception. If you find a bug please either email me, or add the bug
548 Stevan Little E<lt>stevan@iinteractive.comE<gt>
550 =head1 COPYRIGHT AND LICENSE
552 Copyright 2006 by Infinity Interactive, Inc.
554 L<http://www.iinteractive.com>
556 This library is free software; you can redistribute it and/or modify
557 it under the same terms as Perl itself.