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 confess "Must derive at least one class" unless @_;
73 _load_all_classes(@_);
74 my $meta = $class->meta;
75 foreach my $super (@_) {
76 # don't bother if it does not have a meta.
77 next unless $super->can('meta');
78 # if it's meta is a vanilla Moose,
79 # then we can safely ignore it.
80 next if blessed($super->meta) eq 'Moose::Meta::Class';
81 # but if we have anything else,
82 # we need to check it out ...
83 unless (# see if of our metaclass is incompatible
84 ($meta->isa(blessed($super->meta)) &&
85 # and see if our instance metaclass is incompatible
86 $meta->instance_metaclass->isa($super->meta->instance_metaclass)) &&
87 # ... and if we are just a vanilla Moose
88 $meta->isa('Moose::Meta::Class')) {
89 # re-initialize the meta ...
90 my $super_meta = $super->meta;
92 # We might want to consider actually
93 # transfering any attributes from the
94 # original meta into this one, but in
95 # general you should not have any there
96 # at this point anyway, so it's very
97 # much an obscure edge case anyway
98 $meta = $super_meta->reinitialize($class => (
99 ':attribute_metaclass' => $super_meta->attribute_metaclass,
100 ':method_metaclass' => $super_meta->method_metaclass,
101 ':instance_metaclass' => $super_meta->instance_metaclass,
105 $meta->superclasses(@_);
110 return subname 'Moose::with' => sub (@) {
112 confess "Must specify at least one role" unless @roles;
113 _load_all_classes(@roles);
114 ($_->can('meta') && $_->meta->isa('Moose::Meta::Role'))
115 || confess "You can only consume roles, $_ is not a Moose role"
117 if (scalar @roles == 1) {
118 $roles[0]->meta->apply($class->meta);
121 Moose::Meta::Role->combine(
122 map { $_->meta } @roles
123 )->apply($class->meta);
129 return subname 'Moose::has' => sub ($;%) {
130 my ($name, %options) = @_;
131 my $meta = $class->meta;
132 if ($name =~ /^\+(.*)/) {
133 my $inherited_attr = $meta->find_attribute_by_name($1);
134 (defined $inherited_attr)
135 || confess "Could not find an attribute by the name of '$1' to inherit from";
137 if ($inherited_attr->isa('Moose::Meta::Attribute')) {
138 $new_attr = $inherited_attr->clone_and_inherit_options(%options);
142 # kind of a kludge to handle Class::MOP::Attributes
143 $new_attr = Moose::Meta::Attribute::clone_and_inherit_options(
144 $inherited_attr, %options
147 $meta->add_attribute($new_attr);
150 if ($options{metaclass}) {
151 _load_all_classes($options{metaclass});
152 $meta->add_attribute($options{metaclass}->new($name, %options));
155 $meta->add_attribute($name, %options);
162 return subname 'Moose::before' => sub (@&) {
164 my $meta = $class->meta;
165 $meta->add_before_method_modifier($_, $code) for @_;
170 return subname 'Moose::after' => sub (@&) {
172 my $meta = $class->meta;
173 $meta->add_after_method_modifier($_, $code) for @_;
178 return subname 'Moose::around' => sub (@&) {
180 my $meta = $class->meta;
181 $meta->add_around_method_modifier($_, $code) for @_;
185 return subname 'Moose::super' => sub {};
189 return subname 'Moose::override' => sub ($&) {
190 my ($name, $method) = @_;
191 $class->meta->add_override_method_modifier($name => $method);
195 return subname 'Moose::inner' => sub {};
199 return subname 'Moose::augment' => sub (@&) {
200 my ($name, $method) = @_;
201 $class->meta->add_augment_method_modifier($name => $method);
205 return \&Carp::confess;
208 return \&Scalar::Util::blessed;
212 my $exporter = Sub::Exporter::build_exporter({
213 exports => \%exports,
225 # we should never export to main
226 return if $CALLER eq 'main';
236 sub _load_all_classes {
237 foreach my $super (@_) {
238 # see if this is already
239 # loaded in the symbol table
240 next if _is_class_already_loaded($super);
241 # otherwise require it ...
243 || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
247 sub _is_class_already_loaded {
250 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
251 foreach (keys %{"${name}::"}) {
252 next if substr($_, -2, 2) eq '::';
253 return 1 if defined &{"${name}::$_"};
266 Moose - Moose, it's the new Camel
275 has 'x' => (is => 'rw', isa => 'Int');
276 has 'y' => (is => 'rw', isa => 'Int');
291 has 'z' => (is => 'rw', isa => 'Int');
293 after 'clear' => sub {
300 Moose is a rapidly maturing module, and is already being used by
301 a number of people. It's test suite is growing larger by the day,
302 and the docs should soon follow.
304 This said, Moose is not yet finished, and should still be considered
305 to be evolving. Much of the outer API is stable, but the internals
306 are still subject to change (although not without serious thought
309 For more details, please refer to the L<FUTURE PLANS> section of
314 Moose is an extension of the Perl 5 object system.
316 =head2 Another object system!?!?
318 Yes, I know there has been an explosion recently of new ways to
319 build object's in Perl 5, most of them based on inside-out objects,
320 and other such things. Moose is different because it is not a new
321 object system for Perl 5, but instead an extension of the existing
324 Moose is built on top of L<Class::MOP>, which is a metaclass system
325 for Perl 5. This means that Moose not only makes building normal
326 Perl 5 objects better, but it also provides the power of metaclass
329 =head2 Can I use this in production? Or is this just an experiment?
331 Moose is I<based> on the prototypes and experiments I did for the Perl 6
332 meta-model, however Moose is B<NOT> an experiment/prototype, it is
333 for B<real>. I will be deploying Moose into production environments later
334 this year, and I have all intentions of using it as my de-facto class
337 =head2 Is Moose just Perl 6 in Perl 5?
339 No. While Moose is very much inspired by Perl 6, it is not. Instead, it
340 is an OO system for Perl 5. I built Moose because I was tired or writing
341 the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
342 instead of switching to Ruby, I wrote Moose :)
344 =head1 BUILDING CLASSES WITH MOOSE
346 Moose makes every attempt to provide as much convience during class
347 construction/definition, but still stay out of your way if you want
348 it to. Here are a few items to note when building classes with Moose.
350 Unless specified with C<extends>, any class which uses Moose will
351 inherit from L<Moose::Object>.
353 Moose will also manage all attributes (including inherited ones) that
354 are defined with C<has>. And assuming that you call C<new> which is
355 inherited from L<Moose::Object>, then this includes properly initializing
356 all instance slots, setting defaults where approprtiate and performing any
357 type constraint checking or coercion.
359 =head1 EXPORTED FUNCTIONS
361 Moose will export a number of functions into the class's namespace, which
362 can then be used to set up the class. These functions all work directly
363 on the current class.
369 This is a method which provides access to the current class's metaclass.
371 =item B<extends (@superclasses)>
373 This function will set the superclass(es) for the current class.
375 This approach is recommended instead of C<use base>, because C<use base>
376 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
377 replace it. This is important to ensure that classes which do not have
378 superclasses properly inherit from L<Moose::Object>.
380 =item B<with (@roles)>
382 This will apply a given set of C<@roles> to the local class. Role support
383 is currently under heavy development, see L<Moose::Role> for more details.
385 =item B<has ($name, %options)>
387 This will install an attribute of a given C<$name> into the current class.
388 The list of C<%options> are the same as those provided by
389 L<Class::MOP::Attribute>, in addition to the list below which are provided
390 by Moose (L<Moose::Meta::Attribute> to be more specific):
394 =item I<is =E<gt> 'rw'|'ro'>
396 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
397 only). These will create either a read/write accessor or a read-only
398 accessor respectively, using the same name as the C<$name> of the attribute.
400 If you need more control over how your accessors are named, you can use the
401 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
403 =item I<isa =E<gt> $type_name>
405 The I<isa> option uses Moose's type constraint facilities to set up runtime
406 type checking for this attribute. Moose will perform the checks during class
407 construction, and within any accessors. The C<$type_name> argument must be a
408 string. The string can be either a class name, or a type defined using
409 Moose's type defintion features.
411 =item I<coerce =E<gt> (1|0)>
413 This will attempt to use coercion with the supplied type constraint to change
414 the value passed into any accessors of constructors. You B<must> have supplied
415 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
416 for an example usage.
418 =item I<does =E<gt> $role_name>
420 This will accept the name of a role which the value stored in this attribute
421 is expected to have consumed.
423 =item I<required =E<gt> (1|0)>
425 This marks the attribute as being required. This means a value must be supplied
426 during class construction, and the attribute can never be set to C<undef> with
429 =item I<weak_ref =E<gt> (1|0)>
431 This will tell the class to strore the value of this attribute as a weakened
432 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
434 =item I<lazy =E<gt> (1|0)>
436 This will tell the class to not create this slot until absolutely nessecary.
437 If an attribute is marked as lazy it B<must> have a default supplied.
439 =item I<auto_deref =E<gt> (1|0)>
441 This tells the accessor whether to automatically de-reference the value returned.
442 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
444 =item I<trigger =E<gt> $code>
446 The trigger option is a CODE reference which will be called after the value of
447 the attribute is set. The CODE ref will be passed the instance itself, the
448 updated value and the attribute meta-object (this is for more advanced fiddling
449 and can typically be ignored in most cases). You can B<not> have a trigger on
450 a read-only attribute.
452 =item I<handles =E<gt> [ @handles ]>
454 There is experimental support for attribute delegation using the C<handles>
455 option. More docs to come later.
459 =item B<before $name|@names =E<gt> sub { ... }>
461 =item B<after $name|@names =E<gt> sub { ... }>
463 =item B<around $name|@names =E<gt> sub { ... }>
465 This three items are syntactic sugar for the before, after and around method
466 modifier features that L<Class::MOP> provides. More information on these can
467 be found in the L<Class::MOP> documentation for now.
471 The keyword C<super> is a noop when called outside of an C<override> method. In
472 the context of an C<override> method, it will call the next most appropriate
473 superclass method with the same arguments as the original method.
475 =item B<override ($name, &sub)>
477 An C<override> method, is a way of explictly saying "I am overriding this
478 method from my superclass". You can call C<super> within this method, and
479 it will work as expected. The same thing I<can> be accomplished with a normal
480 method call and the C<SUPER::> pseudo-package, it is really your choice.
484 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
485 an C<augment> method. You can think of C<inner> as being the inverse of
486 C<super>, the details of how C<inner> and C<augment> work is best described in
487 the L<Moose::Cookbook>.
489 =item B<augment ($name, &sub)>
491 An C<augment> method, is a way of explictly saying "I am augmenting this
492 method from my superclass". Once again, the details of how C<inner> and
493 C<augment> work is best described in the L<Moose::Cookbook>.
497 This is the C<Carp::confess> function, and exported here beause I use it
498 all the time. This feature may change in the future, so you have been warned.
502 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
503 use it all the time. It is highly recommended that this is used instead of
504 C<ref> anywhere you need to test for an object's class name.
510 Here is just a sampling of the plans we have in store for Moose:
516 Compiling Moose classes/roles into C<.pmc> files for faster loading and execution.
520 Supporting sealed and finalized classes in Moose. This will allow greater control
521 of the extensions of frameworks and such.
527 =head2 What does Moose stand for??
529 Moose doesn't stand for one thing in particular, however, if you
530 want, here are a few of my favorites, feel free to contribute
535 =item Make Other Object Systems Envious
537 =item Makes Object Orientation So Easy
539 =item Makes Object Orientation Spiffy- Er (sorry ingy)
541 =item Most Other Object Systems Emasculate
543 =item Moose Often Ovulate Sorta Early
545 =item Moose Offers Often Super Extensions
547 =item Meta Object Orientation Syntax Extensions
557 It should be noted that C<super> and C<inner> can B<not> be used in the same
558 method. However, they can be combined together with the same class hierarchy,
559 see F<t/014_override_augment_inner_super.t> for an example.
561 The reason that this is so is because C<super> is only valid within a method
562 with the C<override> modifier, and C<inner> will never be valid within an
563 C<override> method. In fact, C<augment> will skip over any C<override> methods
564 when searching for it's appropriate C<inner>.
566 This might seem like a restriction, but I am of the opinion that keeping these
567 two features seperate (but interoperable) actually makes them easy to use since
568 their behavior is then easier to predict. Time will tell if I am right or not.
572 =head1 ACKNOWLEDGEMENTS
576 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
578 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
580 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
581 and it certainly wouldn't have this name ;P
583 =item The basis of the TypeContraints module was Rob Kinyon's idea
584 originally, I just ran with it.
586 =item Thanks to mst & chansen and the whole #moose poose for all the
587 ideas/feature-requests/encouragement
595 =item L<Class::MOP> documentation
597 =item The #moose channel on irc.perl.org
599 =item L<http://forum2.org/moose/>
601 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
603 This paper (suggested by lbr on #moose) was what lead to the implementation
604 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
605 want to understand this feature, I suggest you read this.
611 All complex software has bugs lurking in it, and this module is no
612 exception. If you find a bug please either email me, or add the bug
617 Stevan Little E<lt>stevan@iinteractive.comE<gt>
619 Christian Hansen E<lt>chansen@cpan.orgE<gt>
621 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
623 =head1 COPYRIGHT AND LICENSE
625 Copyright 2006 by Infinity Interactive, Inc.
627 L<http://www.iinteractive.com>
629 This library is free software; you can redistribute it and/or modify
630 it under the same terms as Perl itself.