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 $meta->superclasses(@_);
109 return subname 'Moose::with' => sub {
111 _load_all_classes(@roles);
112 ($_->can('meta') && $_->meta->isa('Moose::Meta::Role'))
113 || confess "You can only consume roles, $_ is not a Moose role"
115 if (scalar @roles == 1) {
116 $roles[0]->meta->apply($class->meta);
119 Moose::Meta::Role->combine(
120 map { $_->meta } @roles
121 )->apply($class->meta);
127 return subname 'Moose::has' => sub {
128 my ($name, %options) = @_;
129 my $meta = $class->meta;
130 if ($name =~ /^\+(.*)/) {
131 my $inherited_attr = $meta->find_attribute_by_name($1);
132 (defined $inherited_attr)
133 || confess "Could not find an attribute by the name of '$1' to inherit from";
135 if ($inherited_attr->isa('Moose::Meta::Attribute')) {
136 $new_attr = $inherited_attr->clone_and_inherit_options(%options);
140 # kind of a kludge to handle Class::MOP::Attributes
141 $new_attr = Moose::Meta::Attribute::clone_and_inherit_options(
142 $inherited_attr, %options
145 $meta->add_attribute($new_attr);
148 if ($options{metaclass}) {
149 _load_all_classes($options{metaclass});
150 $meta->add_attribute($options{metaclass}->new($name, %options));
153 $meta->add_attribute($name, %options);
160 return subname 'Moose::before' => sub {
162 my $meta = $class->meta;
163 $meta->add_before_method_modifier($_, $code) for @_;
168 return subname 'Moose::after' => sub {
170 my $meta = $class->meta;
171 $meta->add_after_method_modifier($_, $code) for @_;
176 return subname 'Moose::around' => sub {
178 my $meta = $class->meta;
179 $meta->add_around_method_modifier($_, $code) for @_;
183 return subname 'Moose::super' => sub {};
187 return subname 'Moose::override' => sub {
188 my ($name, $method) = @_;
189 $class->meta->add_override_method_modifier($name => $method);
193 return subname 'Moose::inner' => sub {};
197 return subname 'Moose::augment' => sub {
198 my ($name, $method) = @_;
199 $class->meta->add_augment_method_modifier($name => $method);
203 return \&Carp::confess;
206 return \&Scalar::Util::blessed;
210 my $exporter = Sub::Exporter::build_exporter({
211 exports => \%exports,
220 # we should never export to main
221 return if $CALLER eq 'main';
231 sub _load_all_classes {
232 foreach my $super (@_) {
233 # see if this is already
234 # loaded in the symbol table
235 next if _is_class_already_loaded($super);
236 # otherwise require it ...
238 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
242 sub _is_class_already_loaded {
245 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
246 foreach (keys %{"${name}::"}) {
247 next if substr($_, -2, 2) eq '::';
248 return 1 if defined &{"${name}::$_"};
261 Moose - Moose, it's the new Camel
268 has 'x' => (isa => 'Int', is => 'rw');
269 has 'y' => (isa => 'Int', is => 'rw');
282 has 'z' => (isa => 'Int');
284 after 'clear' => sub {
291 This is an early release of this module, it still needs
292 some fine tuning and B<lots> more documentation. I am adopting
293 the I<release early and release often> approach with this module,
294 so keep an eye on your favorite CPAN mirror!
298 Moose is an extension of the Perl 5 object system.
300 =head2 Another object system!?!?
302 Yes, I know there has been an explosion recently of new ways to
303 build object's in Perl 5, most of them based on inside-out objects,
304 and other such things. Moose is different because it is not a new
305 object system for Perl 5, but instead an extension of the existing
308 Moose is built on top of L<Class::MOP>, which is a metaclass system
309 for Perl 5. This means that Moose not only makes building normal
310 Perl 5 objects better, but it also provides the power of metaclass
313 =head2 What does Moose stand for??
315 Moose doesn't stand for one thing in particular, however, if you
316 want, here are a few of my favorites, feel free to contribute
321 =item Make Other Object Systems Envious
323 =item Makes Object Orientation So Easy
325 =item Makes Object Orientation Spiffy- Er (sorry ingy)
327 =item Most Other Object Systems Emasculate
329 =item My Overcraft Overfilled (with) Some Eels
331 =item Moose Often Ovulate Sorta Early
333 =item Many Overloaded Object Systems Exists
335 =item Moose Offers Often Super Extensions
337 =item Meta Object Orientation Syntax Extensions
341 =head1 BUILDING CLASSES WITH MOOSE
343 Moose makes every attempt to provide as much convience during class
344 construction/definition, but still stay out of your way if you want
345 it to. Here are some of the features Moose provides:
347 Unless specified with C<extends>, any class which uses Moose will
348 inherit from L<Moose::Object>.
350 Moose will also manage all attributes (including inherited ones) that
351 are defined with C<has>. And assuming that you call C<new> which is
352 inherited from L<Moose::Object>, then this includes properly initializing
353 all instance slots, setting defaults where approprtiate and performing any
354 type constraint checking or coercion.
356 For more details, see the ever expanding L<Moose::Cookbook>.
358 =head1 EXPORTED FUNCTIONS
360 Moose will export a number of functions into the class's namespace, which
361 can then be used to set up the class. These functions all work directly
362 on the current class.
368 This is a method which provides access to the current class's metaclass.
370 =item B<extends (@superclasses)>
372 This function will set the superclass(es) for the current class.
374 This approach is recommended instead of C<use base>, because C<use base>
375 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
376 replace it. This is important to ensure that classes which do not have
377 superclasses properly inherit from L<Moose::Object>.
379 =item B<with ($role)>
381 This will apply a given C<$role> to the local class. Role support is
382 currently very experimental, see L<Moose::Role> for more details.
384 =item B<has ($name, %options)>
386 This will install an attribute of a given C<$name> into the current class.
387 The list of C<%options> are the same as those provided by both
388 L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
389 few convience ones provided by Moose which are listed below:
393 =item I<is =E<gt> 'rw'|'ro'>
395 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
396 only). These will create either a read/write accessor or a read-only
397 accessor respectively, using the same name as the C<$name> of the attribute.
399 If you need more control over how your accessors are named, you can use the
400 I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
402 =item I<isa =E<gt> $type_name>
404 The I<isa> option uses Moose's type constraint facilities to set up runtime
405 type checking for this attribute. Moose will perform the checks during class
406 construction, and within any accessors. The C<$type_name> argument must be a
407 string. The string can be either a class name, or a type defined using
408 Moose's type defintion features.
410 =item I<coerce =E<gt> (1|0)>
412 This will attempt to use coercion with the supplied type constraint to change
413 the value passed into any accessors of constructors. You B<must> have supplied
414 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
415 for an example usage.
417 =item I<does =E<gt> $role_name>
419 This will accept the name of a role which the value stored in this attribute
420 is expected to have consumed.
422 =item I<required =E<gt> (1|0)>
424 This marks the attribute as being required. This means a value must be supplied
425 during class construction, and the attribute can never be set to C<undef> with
428 =item I<weak_ref =E<gt> (1|0)>
430 This will tell the class to strore the value of this attribute as a weakened
431 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
433 =item I<lazy =E<gt> (1|0)>
435 This will tell the class to not create this slot until absolutely nessecary.
436 If an attribute is marked as lazy it B<must> have a default supplied.
438 =item I<trigger =E<gt> $code>
440 The trigger option is a CODE reference which will be called after the value of
441 the attribute is set. The CODE ref will be passed the instance itself, the
442 updated value and the attribute meta-object (this is for more advanced fiddling
443 and can typically be ignored in most cases). You can B<not> have a trigger on
444 a read-only attribute.
448 =item B<before $name|@names =E<gt> sub { ... }>
450 =item B<after $name|@names =E<gt> sub { ... }>
452 =item B<around $name|@names =E<gt> sub { ... }>
454 This three items are syntactic sugar for the before, after and around method
455 modifier features that L<Class::MOP> provides. More information on these can
456 be found in the L<Class::MOP> documentation for now.
460 The keyword C<super> is a noop when called outside of an C<override> method. In
461 the context of an C<override> method, it will call the next most appropriate
462 superclass method with the same arguments as the original method.
464 =item B<override ($name, &sub)>
466 An C<override> method, is a way of explictly saying "I am overriding this
467 method from my superclass". You can call C<super> within this method, and
468 it will work as expected. The same thing I<can> be accomplished with a normal
469 method call and the C<SUPER::> pseudo-package, it is really your choice.
473 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
474 an C<augment> method. You can think of C<inner> as being the inverse of
475 C<super>, the details of how C<inner> and C<augment> work is best described in
476 the L<Moose::Cookbook>.
478 =item B<augment ($name, &sub)>
480 An C<augment> method, is a way of explictly saying "I am augmenting this
481 method from my superclass". Once again, the details of how C<inner> and
482 C<augment> work is best described in the L<Moose::Cookbook>.
486 This is the C<Carp::confess> function, and exported here beause I use it
487 all the time. This feature may change in the future, so you have been warned.
491 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
492 use it all the time. It is highly recommended that this is used instead of
493 C<ref> anywhere you need to test for an object's class name.
503 It should be noted that C<super> and C<inner> can B<not> be used in the same
504 method. However, they can be combined together with the same class hierarchy,
505 see F<t/014_override_augment_inner_super.t> for an example.
507 The reason that this is so is because C<super> is only valid within a method
508 with the C<override> modifier, and C<inner> will never be valid within an
509 C<override> method. In fact, C<augment> will skip over any C<override> methods
510 when searching for it's appropriate C<inner>.
512 This might seem like a restriction, but I am of the opinion that keeping these
513 two features seperate (but interoperable) actually makes them easy to use since
514 their behavior is then easier to predict. Time will tell if I am right or not.
518 =head1 ACKNOWLEDGEMENTS
522 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
524 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
526 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
527 and it certainly wouldn't have this name ;P
529 =item The basis of the TypeContraints module was Rob Kinyon's idea
530 originally, I just ran with it.
532 =item Thanks to mst & chansen and the whole #moose poose for all the
533 ideas/feature-requests/encouragement
541 =item L<Class::MOP> documentation
543 =item The #moose channel on irc.perl.org
545 =item L<http://forum2.org/moose/>
547 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
549 This paper (suggested by lbr on #moose) was what lead to the implementation
550 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
551 want to understand this feature, I suggest you read this.
557 All complex software has bugs lurking in it, and this module is no
558 exception. If you find a bug please either email me, or add the bug
563 Stevan Little E<lt>stevan@iinteractive.comE<gt>
565 Christian Hansen E<lt>chansen@cpan.orgE<gt>
567 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
569 =head1 COPYRIGHT AND LICENSE
571 Copyright 2006 by Infinity Interactive, Inc.
573 L<http://www.iinteractive.com>
575 This library is free software; you can redistribute it and/or modify
576 it under the same terms as Perl itself.