7 our $VERSION = '0.09_03';
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,
223 # we should never export to main
224 return if $CALLER eq 'main';
234 sub _load_all_classes {
235 foreach my $super (@_) {
236 # see if this is already
237 # loaded in the symbol table
238 next if _is_class_already_loaded($super);
239 # otherwise require it ...
241 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
245 sub _is_class_already_loaded {
248 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
249 foreach (keys %{"${name}::"}) {
250 next if substr($_, -2, 2) eq '::';
251 return 1 if defined &{"${name}::$_"};
264 Moose - Moose, it's the new Camel
273 has 'x' => (is => 'rw', isa => 'Int');
274 has 'y' => (is => 'rw', isa => 'Int');
289 has 'z' => (is => 'rw', isa => 'Int');
291 after 'clear' => sub {
298 Moose is a rapidly maturing module, and is already being used by
299 a number of people. It's test suite is growing larger by the day,
300 and the docs should soon follow.
302 This said, Moose is not yet finished, and should still be considered
303 to be evolving. Much of the outer API is stable, but the internals
304 are still subject to change (although not without serious thought
307 For more details, please refer to the L<FUTURE PLANS> section of
312 Moose is an extension of the Perl 5 object system.
314 =head2 Another object system!?!?
316 Yes, I know there has been an explosion recently of new ways to
317 build object's in Perl 5, most of them based on inside-out objects,
318 and other such things. Moose is different because it is not a new
319 object system for Perl 5, but instead an extension of the existing
322 Moose is built on top of L<Class::MOP>, which is a metaclass system
323 for Perl 5. This means that Moose not only makes building normal
324 Perl 5 objects better, but it also provides the power of metaclass
327 =head2 Can I use this in production? Or is this just an experiment?
329 Moose is I<based> on the prototypes and experiments I did for the Perl 6
330 meta-model, however Moose is B<NOT> an experiment/prototype, it is
331 for B<real>. I will be deploying Moose into production environments later
332 this year, and I have all intentions of using it as my de-facto class
335 =head2 Is Moose just Perl 6 in Perl 5?
337 No. While Moose is very much inspired by Perl 6, it is not. Instead, it
338 is an OO system for Perl 5. I built Moose because I was tired or writing
339 the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
340 instead of switching to Ruby, I wrote Moose :)
342 =head1 BUILDING CLASSES WITH MOOSE
344 Moose makes every attempt to provide as much convience during class
345 construction/definition, but still stay out of your way if you want
346 it to. Here are a few items to note when building classes with Moose.
348 Unless specified with C<extends>, any class which uses Moose will
349 inherit from L<Moose::Object>.
351 Moose will also manage all attributes (including inherited ones) that
352 are defined with C<has>. And assuming that you call C<new> which is
353 inherited from L<Moose::Object>, then this includes properly initializing
354 all instance slots, setting defaults where approprtiate and performing any
355 type constraint checking or coercion.
357 =head1 EXPORTED FUNCTIONS
359 Moose will export a number of functions into the class's namespace, which
360 can then be used to set up the class. These functions all work directly
361 on the current class.
367 This is a method which provides access to the current class's metaclass.
369 =item B<extends (@superclasses)>
371 This function will set the superclass(es) for the current class.
373 This approach is recommended instead of C<use base>, because C<use base>
374 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
375 replace it. This is important to ensure that classes which do not have
376 superclasses properly inherit from L<Moose::Object>.
378 =item B<with (@roles)>
380 This will apply a given set of C<@roles> to the local class. Role support
381 is currently under heavy development, see L<Moose::Role> for more details.
383 =item B<has ($name, %options)>
385 This will install an attribute of a given C<$name> into the current class.
386 The list of C<%options> are the same as those provided by
387 L<Class::MOP::Attribute>, in addition to the list below which are provided
388 by Moose (L<Moose::Meta::Attribute> to be more specific):
392 =item I<is =E<gt> 'rw'|'ro'>
394 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
395 only). These will create either a read/write accessor or a read-only
396 accessor respectively, using the same name as the C<$name> of the attribute.
398 If you need more control over how your accessors are named, you can use the
399 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
401 =item I<isa =E<gt> $type_name>
403 The I<isa> option uses Moose's type constraint facilities to set up runtime
404 type checking for this attribute. Moose will perform the checks during class
405 construction, and within any accessors. The C<$type_name> argument must be a
406 string. The string can be either a class name, or a type defined using
407 Moose's type defintion features.
409 =item I<coerce =E<gt> (1|0)>
411 This will attempt to use coercion with the supplied type constraint to change
412 the value passed into any accessors of constructors. You B<must> have supplied
413 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
414 for an example usage.
416 =item I<does =E<gt> $role_name>
418 This will accept the name of a role which the value stored in this attribute
419 is expected to have consumed.
421 =item I<required =E<gt> (1|0)>
423 This marks the attribute as being required. This means a value must be supplied
424 during class construction, and the attribute can never be set to C<undef> with
427 =item I<weak_ref =E<gt> (1|0)>
429 This will tell the class to strore the value of this attribute as a weakened
430 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
432 =item I<lazy =E<gt> (1|0)>
434 This will tell the class to not create this slot until absolutely nessecary.
435 If an attribute is marked as lazy it B<must> have a default supplied.
437 =item I<auto_deref =E<gt> (1|0)>
439 This tells the accessor whether to automatically de-reference the value returned.
440 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
442 =item I<trigger =E<gt> $code>
444 The trigger option is a CODE reference which will be called after the value of
445 the attribute is set. The CODE ref will be passed the instance itself, the
446 updated value and the attribute meta-object (this is for more advanced fiddling
447 and can typically be ignored in most cases). You can B<not> have a trigger on
448 a read-only attribute.
450 =item I<handles =E<gt> [ @handles ]>
452 There is experimental support for attribute delegation using the C<handles>
453 option. More docs to come later.
457 =item B<before $name|@names =E<gt> sub { ... }>
459 =item B<after $name|@names =E<gt> sub { ... }>
461 =item B<around $name|@names =E<gt> sub { ... }>
463 This three items are syntactic sugar for the before, after and around method
464 modifier features that L<Class::MOP> provides. More information on these can
465 be found in the L<Class::MOP> documentation for now.
469 The keyword C<super> is a noop when called outside of an C<override> method. In
470 the context of an C<override> method, it will call the next most appropriate
471 superclass method with the same arguments as the original method.
473 =item B<override ($name, &sub)>
475 An C<override> method, is a way of explictly saying "I am overriding this
476 method from my superclass". You can call C<super> within this method, and
477 it will work as expected. The same thing I<can> be accomplished with a normal
478 method call and the C<SUPER::> pseudo-package, it is really your choice.
482 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
483 an C<augment> method. You can think of C<inner> as being the inverse of
484 C<super>, the details of how C<inner> and C<augment> work is best described in
485 the L<Moose::Cookbook>.
487 =item B<augment ($name, &sub)>
489 An C<augment> method, is a way of explictly saying "I am augmenting this
490 method from my superclass". Once again, the details of how C<inner> and
491 C<augment> work is best described in the L<Moose::Cookbook>.
495 This is the C<Carp::confess> function, and exported here beause I use it
496 all the time. This feature may change in the future, so you have been warned.
500 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
501 use it all the time. It is highly recommended that this is used instead of
502 C<ref> anywhere you need to test for an object's class name.
508 Here is just a sampling of the plans we have in store for Moose:
514 Compiling Moose classes/roles into C<.pmc> files for faster loading and execution.
518 Supporting sealed and finalized classes in Moose. This will allow greater control
519 of the extensions of frameworks and such.
525 =head2 What does Moose stand for??
527 Moose doesn't stand for one thing in particular, however, if you
528 want, here are a few of my favorites, feel free to contribute
533 =item Make Other Object Systems Envious
535 =item Makes Object Orientation So Easy
537 =item Makes Object Orientation Spiffy- Er (sorry ingy)
539 =item Most Other Object Systems Emasculate
541 =item Moose Often Ovulate Sorta Early
543 =item Moose Offers Often Super Extensions
545 =item Meta Object Orientation Syntax Extensions
555 It should be noted that C<super> and C<inner> can B<not> be used in the same
556 method. However, they can be combined together with the same class hierarchy,
557 see F<t/014_override_augment_inner_super.t> for an example.
559 The reason that this is so is because C<super> is only valid within a method
560 with the C<override> modifier, and C<inner> will never be valid within an
561 C<override> method. In fact, C<augment> will skip over any C<override> methods
562 when searching for it's appropriate C<inner>.
564 This might seem like a restriction, but I am of the opinion that keeping these
565 two features seperate (but interoperable) actually makes them easy to use since
566 their behavior is then easier to predict. Time will tell if I am right or not.
570 =head1 ACKNOWLEDGEMENTS
574 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
576 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
578 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
579 and it certainly wouldn't have this name ;P
581 =item The basis of the TypeContraints module was Rob Kinyon's idea
582 originally, I just ran with it.
584 =item Thanks to mst & chansen and the whole #moose poose for all the
585 ideas/feature-requests/encouragement
593 =item L<Class::MOP> documentation
595 =item The #moose channel on irc.perl.org
597 =item L<http://forum2.org/moose/>
599 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
601 This paper (suggested by lbr on #moose) was what lead to the implementation
602 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
603 want to understand this feature, I suggest you read this.
609 All complex software has bugs lurking in it, and this module is no
610 exception. If you find a bug please either email me, or add the bug
615 Stevan Little E<lt>stevan@iinteractive.comE<gt>
617 Christian Hansen E<lt>chansen@cpan.orgE<gt>
619 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
621 =head1 COPYRIGHT AND LICENSE
623 Copyright 2006 by Infinity Interactive, Inc.
625 L<http://www.iinteractive.com>
627 This library is free software; you can redistribute it and/or modify
628 it under the same terms as Perl itself.