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 foreach my $super (@_) {
64 # see if this is already
65 # loaded in the symbol table
66 next if _is_class_already_loaded($super);
67 # otherwise require it ...
69 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
71 $meta->superclasses(@_)
75 $meta->alias_method('has' => subname 'Moose::has' => sub {
76 my ($name, %options) = @_;
77 if (exists $options{is}) {
78 if ($options{is} eq 'ro') {
79 $options{reader} = $name;
81 elsif ($options{is} eq 'rw') {
82 $options{accessor} = $name;
85 if (exists $options{isa}) {
86 # allow for anon-subtypes here ...
87 if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) {
88 $options{type_constraint} = $options{isa};
91 # otherwise assume it is a constraint
92 my $constraint = find_type_constraint($options{isa});
93 # if the constraing it not found ....
94 unless (defined $constraint) {
95 # assume it is a foreign class, and make
96 # an anon constraint for it
97 $constraint = subtype Object => where { $_->isa($options{isa}) };
99 $options{type_constraint} = $constraint;
102 $meta->add_attribute($name, %options)
105 # handle method modifers
106 $meta->alias_method('before' => subname 'Moose::before' => sub {
108 $meta->add_before_method_modifier($_, $code) for @_;
110 $meta->alias_method('after' => subname 'Moose::after' => sub {
112 $meta->add_after_method_modifier($_, $code) for @_;
114 $meta->alias_method('around' => subname 'Moose::around' => sub {
116 $meta->add_around_method_modifier($_, $code) for @_;
119 $meta->alias_method('super' => subname 'Moose::super' => sub {});
120 $meta->alias_method('override' => subname 'Moose::override' => sub {
121 my ($name, $method) = @_;
122 my $super = $meta->find_next_method_by_name($name);
124 || confess "You cannot override '$name' because it has no super method";
125 $meta->add_method($name => sub {
128 no warnings 'redefine';
129 local *{$meta->name . '::super'} = sub { $super->(@args) };
130 return $method->(@args);
134 $meta->alias_method('inner' => subname 'Moose::inner' => sub {});
135 $meta->alias_method('augment' => subname 'Moose::augment' => sub {
136 my ($name, $method) = @_;
137 my $super = $meta->find_next_method_by_name($name);
139 || confess "You cannot augment '$name' because it has no super method";
140 $meta->add_method($name => sub {
143 no warnings 'redefine';
144 local *{$super->package_name . '::inner'} = sub { $method->(@args) };
145 return $super->(@args);
149 # make sure they inherit from Moose::Object
150 $meta->superclasses('Moose::Object')
151 unless $meta->superclasses();
153 # we recommend using these things
154 # so export them for them
155 $meta->alias_method('confess' => \&Carp::confess);
156 $meta->alias_method('blessed' => \&Scalar::Util::blessed);
159 sub _is_class_already_loaded {
162 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
163 foreach (keys %{"${name}::"}) {
164 next if substr($_, -2, 2) eq '::';
165 return 1 if defined &{"${name}::$_"};
178 Moose - Moose, it's the new Camel
185 has 'x' => (isa => 'Int', is => 'rw');
186 has 'y' => (isa => 'Int', is => 'rw');
199 has 'z' => (isa => 'Int');
201 after 'clear' => sub {
208 This is a B<very> early release of this module, it still needs
209 some fine tuning and B<lots> more documentation. I am adopting
210 the I<release early and release often> approach with this module,
211 so keep an eye on your favorite CPAN mirror!
215 Moose is an extension of the Perl 5 object system.
217 =head2 Another object system!?!?
219 Yes, I know there has been an explosion recently of new ways to
220 build object's in Perl 5, most of them based on inside-out objects,
221 and other such things. Moose is different because it is not a new
222 object system for Perl 5, but instead an extension of the existing
225 Moose is built on top of L<Class::MOP>, which is a metaclass system
226 for Perl 5. This means that Moose not only makes building normal
227 Perl 5 objects better, but it also provides the power of metaclass
230 =head2 What does Moose stand for??
232 Moose doesn't stand for one thing in particular, however, if you
233 want, here are a few of my favorites, feel free to contribute
238 =item Make Other Object Systems Envious
240 =item Makes Object Orientation So Easy
242 =item Makes Object Orientation Spiffy- Er (sorry ingy)
244 =item Most Other Object Systems Emasculate
246 =item My Overcraft Overfilled (with) Some Eels
248 =item Moose Often Ovulate Sorta Early
250 =item Many Overloaded Object Systems Exists
252 =item Moose Offers Often Super Extensions
256 =head1 BUILDING CLASSES WITH MOOSE
258 Moose makes every attempt to provide as much convience during class
259 construction/definition, but still stay out of your way if you want
260 it to. Here are some of the features Moose provides:
262 Unless specified with C<extends>, any class which uses Moose will
263 inherit from L<Moose::Object>.
265 Moose will also manage all attributes (including inherited ones) that
266 are defined with C<has>. And assuming that you call C<new> which is
267 inherited from L<Moose::Object>, then this includes properly initializing
268 all instance slots, setting defaults where approprtiate and performing any
269 type constraint checking or coercion.
271 =head1 EXPORTED FUNCTIONS
273 Moose will export a number of functions into the class's namespace, which
274 can then be used to set up the class. These functions all work directly
275 on the current class.
281 This is a method which provides access to the current class's metaclass.
283 =item B<extends (@superclasses)>
285 This function will set the superclass(es) for the current class.
287 This approach is recommended instead of C<use base>, because C<use base>
288 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
289 replace it. This is important to ensure that classes which do not have
290 superclasses properly inherit from L<Moose::Object>.
292 =item B<has ($name, %options)>
294 This will install an attribute of a given C<$name> into the current class.
295 The list of C<%options> are the same as those provided by both
296 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
297 few convience ones provided by Moose which are listed below:
301 =item I<is =E<gt> 'rw'|'ro'>
303 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
304 only). These will create either a read/write accessor or a read-only
305 accessor respectively, using the same name as the C<$name> of the attribute.
307 If you need more control over how your accessors are named, you can use the
308 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
310 =item I<isa =E<gt> $type_name>
312 The I<isa> option uses Moose's type constraint facilities to set up runtime
313 type checking for this attribute. Moose will perform the checks during class
314 construction, and within any accessors. The C<$type_name> argument must be a
315 string. The string can be either a class name, or a type defined using
316 Moose's type defintion features.
320 =item B<before $name|@names =E<gt> sub { ... }>
322 =item B<after $name|@names =E<gt> sub { ... }>
324 =item B<around $name|@names =E<gt> sub { ... }>
326 This three items are syntactic sugar for the before, after and around method
327 modifier features that L<Class::MOP> provides. More information on these can
328 be found in the L<Class::MOP> documentation for now.
332 The keyword C<super> is a noop when called outside of an C<override> method. In
333 the context of an C<override> method, it will call the next most appropriate
334 superclass method with the same arguments as the original method.
336 =item B<override ($name, &sub)>
338 An C<override> method, is a way of explictly saying "I am overriding this
339 method from my superclass". You can call C<super> within this method, and
340 it will work as expected. The same thing I<can> be accomplished with a normal
341 method call and the C<SUPER::> pseudo-package, it is really your choice.
345 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
346 an C<augment> method. You can think of C<inner> as being the inverse of
347 C<super>, the details of how C<inner> and C<augment> work is best described in
348 the L<Moose::Cookbook>.
350 =item B<augment ($name, &sub)>
352 An C<augment> method, is a way of explictly saying "I am augmenting this
353 method from my superclass". Once again, the details of how C<inner> and
354 C<augment> work is best described in the L<Moose::Cookbook>.
358 This is the C<Carp::confess> function, and exported here beause I use it
359 all the time. This feature may change in the future, so you have been warned.
363 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
364 use it all the time. It is highly recommended that this is used instead of
365 C<ref> anywhere you need to test for an object's class name.
369 =head1 ACKNOWLEDGEMENTS
373 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
375 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
377 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
378 and it certainly wouldn't have this name ;P
380 =item The basis of the TypeContraints module was Rob Kinyon's idea
381 originally, I just ran with it.
383 =item Thanks to mst & chansen and the whole #moose poose for all the
384 ideas/feature-requests/encouragement
392 =item L<Class::MOP> documentation
394 =item The #moose channel on irc.perl.org
396 =item L<http://forum2.org/moose/>
398 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
400 This paper (suggested by lbr on #moose) was what lead to the implementation
401 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
402 want to understand this feature, I suggest you read this.
408 All complex software has bugs lurking in it, and this module is no
409 exception. If you find a bug please either email me, or add the bug
414 Stevan Little E<lt>stevan@iinteractive.comE<gt>
416 =head1 COPYRIGHT AND LICENSE
418 Copyright 2006 by Infinity Interactive, Inc.
420 L<http://www.iinteractive.com>
422 This library is free software; you can redistribute it and/or modify
423 it under the same terms as Perl itself.