9 use Scalar::Util 'blessed', 'reftype';
11 use Sub::Name 'subname';
13 use UNIVERSAL::require;
17 use Moose::Meta::Class;
18 use Moose::Meta::Attribute;
19 use Moose::Meta::TypeConstraint;
20 use Moose::Meta::TypeCoercion;
23 use Moose::Util::TypeConstraints;
29 # we should never export to main
30 return if $pkg eq 'main';
32 Moose::Util::TypeConstraints->import($pkg);
34 # make a subtype for each Moose class
37 => where { $_->isa($pkg) };
40 if ($pkg->can('meta')) {
42 (blessed($meta) && $meta->isa('Class::MOP::Class'))
43 || confess "Whoops, not møøsey enough";
46 $meta = Moose::Meta::Class->initialize($pkg => (
47 ':attribute_metaclass' => 'Moose::Meta::Attribute'
49 $meta->add_method('meta' => sub {
50 # re-initialize so it inherits properly
51 Moose::Meta::Class->initialize($pkg => (
52 ':attribute_metaclass' => 'Moose::Meta::Attribute'
58 # &alias_method will install the method, but it
59 # will not name it with
62 $meta->alias_method('extends' => subname 'Moose::extends' => sub {
63 _load_all_superclasses(@_);
64 $meta->superclasses(@_)
68 $meta->alias_method('has' => subname 'Moose::has' => sub {
69 my ($name, %options) = @_;
70 _process_has_options($name, \%options);
71 $meta->add_attribute($name, %options)
74 # handle method modifers
75 $meta->alias_method('before' => subname 'Moose::before' => sub {
77 $meta->add_before_method_modifier($_, $code) for @_;
79 $meta->alias_method('after' => subname 'Moose::after' => sub {
81 $meta->add_after_method_modifier($_, $code) for @_;
83 $meta->alias_method('around' => subname 'Moose::around' => sub {
85 $meta->add_around_method_modifier($_, $code) for @_;
88 $meta->alias_method('super' => subname 'Moose::super' => sub {});
89 $meta->alias_method('override' => subname 'Moose::override' => sub {
90 my ($name, $method) = @_;
91 $meta->add_method($name => _create_override_sub($meta, $name, $method));
94 $meta->alias_method('inner' => subname 'Moose::inner' => sub {});
95 $meta->alias_method('augment' => subname 'Moose::augment' => sub {
96 my ($name, $method) = @_;
97 $meta->add_method($name => _create_augment_sub($meta, $name, $method));
100 # make sure they inherit from Moose::Object
101 $meta->superclasses('Moose::Object')
102 unless $meta->superclasses();
104 # we recommend using these things
105 # so export them for them
106 $meta->alias_method('confess' => \&Carp::confess);
107 $meta->alias_method('blessed' => \&Scalar::Util::blessed);
112 sub _process_has_options {
113 my ($attr_name, $options) = @_;
114 if (exists $options->{is}) {
115 if ($options->{is} eq 'ro') {
116 $options->{reader} = $attr_name;
118 elsif ($options->{is} eq 'rw') {
119 $options->{accessor} = $attr_name;
122 if (exists $options->{isa}) {
123 # allow for anon-subtypes here ...
124 if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) {
125 $options->{type_constraint} = $options->{isa};
128 # otherwise assume it is a constraint
129 my $constraint = find_type_constraint($options->{isa});
130 # if the constraing it not found ....
131 unless (defined $constraint) {
132 # assume it is a foreign class, and make
133 # an anon constraint for it
134 $constraint = subtype Object => where { $_->isa($options->{isa}) };
136 $options->{type_constraint} = $constraint;
141 sub _load_all_superclasses {
142 foreach my $super (@_) {
143 # see if this is already
144 # loaded in the symbol table
145 next if _is_class_already_loaded($super);
146 # otherwise require it ...
148 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
152 sub _is_class_already_loaded {
155 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
156 foreach (keys %{"${name}::"}) {
157 next if substr($_, -2, 2) eq '::';
158 return 1 if defined &{"${name}::$_"};
163 sub _create_override_sub {
164 my ($meta, $name, $method) = @_;
165 my $super = $meta->find_next_method_by_name($name);
167 || confess "You cannot override '$name' because it has no super method";
171 no warnings 'redefine';
172 local *{$meta->name . '::super'} = sub { $super->(@args) };
173 return $method->(@args);
177 sub _create_augment_sub {
178 my ($meta, $name, $method) = @_;
179 my $super = $meta->find_next_method_by_name($name);
181 || confess "You cannot augment '$name' because it has no super method";
185 no warnings 'redefine';
186 local *{$super->package_name . '::inner'} = sub { $method->(@args) };
187 return $super->(@args);
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 a B<very> 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
277 =head1 BUILDING CLASSES WITH MOOSE
279 Moose makes every attempt to provide as much convience during class
280 construction/definition, but still stay out of your way if you want
281 it to. Here are some of the features Moose provides:
283 Unless specified with C<extends>, any class which uses Moose will
284 inherit from L<Moose::Object>.
286 Moose will also manage all attributes (including inherited ones) that
287 are defined with C<has>. And assuming that you call C<new> which is
288 inherited from L<Moose::Object>, then this includes properly initializing
289 all instance slots, setting defaults where approprtiate and performing any
290 type constraint checking or coercion.
292 =head1 EXPORTED FUNCTIONS
294 Moose will export a number of functions into the class's namespace, which
295 can then be used to set up the class. These functions all work directly
296 on the current class.
302 This is a method which provides access to the current class's metaclass.
304 =item B<extends (@superclasses)>
306 This function will set the superclass(es) for the current class.
308 This approach is recommended instead of C<use base>, because C<use base>
309 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
310 replace it. This is important to ensure that classes which do not have
311 superclasses properly inherit from L<Moose::Object>.
313 =item B<has ($name, %options)>
315 This will install an attribute of a given C<$name> into the current class.
316 The list of C<%options> are the same as those provided by both
317 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
318 few convience ones provided by Moose which are listed below:
322 =item I<is =E<gt> 'rw'|'ro'>
324 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
325 only). These will create either a read/write accessor or a read-only
326 accessor respectively, using the same name as the C<$name> of the attribute.
328 If you need more control over how your accessors are named, you can use the
329 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
331 =item I<isa =E<gt> $type_name>
333 The I<isa> option uses Moose's type constraint facilities to set up runtime
334 type checking for this attribute. Moose will perform the checks during class
335 construction, and within any accessors. The C<$type_name> argument must be a
336 string. The string can be either a class name, or a type defined using
337 Moose's type defintion features.
341 =item B<before $name|@names =E<gt> sub { ... }>
343 =item B<after $name|@names =E<gt> sub { ... }>
345 =item B<around $name|@names =E<gt> sub { ... }>
347 This three items are syntactic sugar for the before, after and around method
348 modifier features that L<Class::MOP> provides. More information on these can
349 be found in the L<Class::MOP> documentation for now.
353 The keyword C<super> is a noop when called outside of an C<override> method. In
354 the context of an C<override> method, it will call the next most appropriate
355 superclass method with the same arguments as the original method.
357 =item B<override ($name, &sub)>
359 An C<override> method, is a way of explictly saying "I am overriding this
360 method from my superclass". You can call C<super> within this method, and
361 it will work as expected. The same thing I<can> be accomplished with a normal
362 method call and the C<SUPER::> pseudo-package, it is really your choice.
366 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
367 an C<augment> method. You can think of C<inner> as being the inverse of
368 C<super>, the details of how C<inner> and C<augment> work is best described in
369 the L<Moose::Cookbook>.
371 =item B<augment ($name, &sub)>
373 An C<augment> method, is a way of explictly saying "I am augmenting this
374 method from my superclass". Once again, the details of how C<inner> and
375 C<augment> work is best described in the L<Moose::Cookbook>.
379 This is the C<Carp::confess> function, and exported here beause I use it
380 all the time. This feature may change in the future, so you have been warned.
384 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
385 use it all the time. It is highly recommended that this is used instead of
386 C<ref> anywhere you need to test for an object's class name.
390 =head1 ACKNOWLEDGEMENTS
394 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
396 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
398 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
399 and it certainly wouldn't have this name ;P
401 =item The basis of the TypeContraints module was Rob Kinyon's idea
402 originally, I just ran with it.
404 =item Thanks to mst & chansen and the whole #moose poose for all the
405 ideas/feature-requests/encouragement
413 =item L<Class::MOP> documentation
415 =item The #moose channel on irc.perl.org
417 =item L<http://forum2.org/moose/>
419 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
421 This paper (suggested by lbr on #moose) was what lead to the implementation
422 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
423 want to understand this feature, I suggest you read this.
429 All complex software has bugs lurking in it, and this module is no
430 exception. If you find a bug please either email me, or add the bug
435 Stevan Little E<lt>stevan@iinteractive.comE<gt>
437 =head1 COPYRIGHT AND LICENSE
439 Copyright 2006 by Infinity Interactive, Inc.
441 L<http://www.iinteractive.com>
443 This library is free software; you can redistribute it and/or modify
444 it under the same terms as Perl itself.