7 our $VERSION = '0.09_02';
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
270 has 'x' => (is => 'rw', isa => 'Int');
271 has 'y' => (is => 'rw', isa => 'Int');
286 has 'z' => (is => 'rw', isa => 'Int');
288 after 'clear' => sub {
295 Moose is a rapidly maturing module, and is already being used by
296 a number of people. It's test suite is growing larger by the day,
297 and the docs should soon follow.
299 This said, Moose is not yet finished, and should still be considered
300 to be evolving. Much of the outer API is stable, but the internals
301 are still subject to change (although not without serious thought
304 For more details, please refer to the L<FUTURE PLANS> section of
309 Moose is an extension of the Perl 5 object system.
311 =head2 Another object system!?!?
313 Yes, I know there has been an explosion recently of new ways to
314 build object's in Perl 5, most of them based on inside-out objects,
315 and other such things. Moose is different because it is not a new
316 object system for Perl 5, but instead an extension of the existing
319 Moose is built on top of L<Class::MOP>, which is a metaclass system
320 for Perl 5. This means that Moose not only makes building normal
321 Perl 5 objects better, but it also provides the power of metaclass
324 =head2 Can I use this in production? Or is this just an experiment?
326 Moose is I<based> on the prototypes and experiments I did for the Perl 6
327 meta-model, however Moose is B<NOT> an experiment/prototype, it is
328 for B<real>. I will be deploying Moose into production environments later
329 this year, and I have all intentions of using it as my de-facto class
332 =head2 Is Moose just Perl 6 in Perl 5?
334 No. While Moose is very much inspired by Perl 6, it is not. Instead, it
335 is an OO system for Perl 5. I built Moose because I was tired or writing
336 the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
337 instead of switching to Ruby, I wrote Moose :)
339 =head1 BUILDING CLASSES WITH MOOSE
341 Moose makes every attempt to provide as much convience during class
342 construction/definition, but still stay out of your way if you want
343 it to. Here are a few items to note when building classes with Moose.
345 Unless specified with C<extends>, any class which uses Moose will
346 inherit from L<Moose::Object>.
348 Moose will also manage all attributes (including inherited ones) that
349 are defined with C<has>. And assuming that you call C<new> which is
350 inherited from L<Moose::Object>, then this includes properly initializing
351 all instance slots, setting defaults where approprtiate and performing any
352 type constraint checking or coercion.
354 =head1 EXPORTED FUNCTIONS
356 Moose will export a number of functions into the class's namespace, which
357 can then be used to set up the class. These functions all work directly
358 on the current class.
364 This is a method which provides access to the current class's metaclass.
366 =item B<extends (@superclasses)>
368 This function will set the superclass(es) for the current class.
370 This approach is recommended instead of C<use base>, because C<use base>
371 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
372 replace it. This is important to ensure that classes which do not have
373 superclasses properly inherit from L<Moose::Object>.
375 =item B<with (@roles)>
377 This will apply a given set of C<@roles> to the local class. Role support
378 is currently under heavy development, see L<Moose::Role> for more details.
380 =item B<has ($name, %options)>
382 This will install an attribute of a given C<$name> into the current class.
383 The list of C<%options> are the same as those provided by
384 L<Class::MOP::Attribute>, in addition to the list below which are provided
385 by Moose (L<Moose::Meta::Attribute> to be more specific):
389 =item I<is =E<gt> 'rw'|'ro'>
391 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
392 only). These will create either a read/write accessor or a read-only
393 accessor respectively, using the same name as the C<$name> of the attribute.
395 If you need more control over how your accessors are named, you can use the
396 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
398 =item I<isa =E<gt> $type_name>
400 The I<isa> option uses Moose's type constraint facilities to set up runtime
401 type checking for this attribute. Moose will perform the checks during class
402 construction, and within any accessors. The C<$type_name> argument must be a
403 string. The string can be either a class name, or a type defined using
404 Moose's type defintion features.
406 =item I<coerce =E<gt> (1|0)>
408 This will attempt to use coercion with the supplied type constraint to change
409 the value passed into any accessors of constructors. You B<must> have supplied
410 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
411 for an example usage.
413 =item I<does =E<gt> $role_name>
415 This will accept the name of a role which the value stored in this attribute
416 is expected to have consumed.
418 =item I<required =E<gt> (1|0)>
420 This marks the attribute as being required. This means a value must be supplied
421 during class construction, and the attribute can never be set to C<undef> with
424 =item I<weak_ref =E<gt> (1|0)>
426 This will tell the class to strore the value of this attribute as a weakened
427 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
429 =item I<lazy =E<gt> (1|0)>
431 This will tell the class to not create this slot until absolutely nessecary.
432 If an attribute is marked as lazy it B<must> have a default supplied.
434 =item I<auto_deref =E<gt> (1|0)>
436 This tells the accessor whether to automatically de-reference the value returned.
437 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
439 =item I<trigger =E<gt> $code>
441 The trigger option is a CODE reference which will be called after the value of
442 the attribute is set. The CODE ref will be passed the instance itself, the
443 updated value and the attribute meta-object (this is for more advanced fiddling
444 and can typically be ignored in most cases). You can B<not> have a trigger on
445 a read-only attribute.
447 =item I<handles =E<gt> [ @handles ]>
449 There is experimental support for attribute delegation using the C<handles>
450 option. More docs to come later.
454 =item B<before $name|@names =E<gt> sub { ... }>
456 =item B<after $name|@names =E<gt> sub { ... }>
458 =item B<around $name|@names =E<gt> sub { ... }>
460 This three items are syntactic sugar for the before, after and around method
461 modifier features that L<Class::MOP> provides. More information on these can
462 be found in the L<Class::MOP> documentation for now.
466 The keyword C<super> is a noop when called outside of an C<override> method. In
467 the context of an C<override> method, it will call the next most appropriate
468 superclass method with the same arguments as the original method.
470 =item B<override ($name, &sub)>
472 An C<override> method, is a way of explictly saying "I am overriding this
473 method from my superclass". You can call C<super> within this method, and
474 it will work as expected. The same thing I<can> be accomplished with a normal
475 method call and the C<SUPER::> pseudo-package, it is really your choice.
479 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
480 an C<augment> method. You can think of C<inner> as being the inverse of
481 C<super>, the details of how C<inner> and C<augment> work is best described in
482 the L<Moose::Cookbook>.
484 =item B<augment ($name, &sub)>
486 An C<augment> method, is a way of explictly saying "I am augmenting this
487 method from my superclass". Once again, the details of how C<inner> and
488 C<augment> work is best described in the L<Moose::Cookbook>.
492 This is the C<Carp::confess> function, and exported here beause I use it
493 all the time. This feature may change in the future, so you have been warned.
497 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
498 use it all the time. It is highly recommended that this is used instead of
499 C<ref> anywhere you need to test for an object's class name.
505 Here is just a sampling of the plans we have in store for Moose:
511 Compiling Moose classes/roles into C<.pmc> files for faster loading and execution.
515 Supporting sealed and finalized classes in Moose. This will allow greater control
516 of the extensions of frameworks and such.
522 =head2 What does Moose stand for??
524 Moose doesn't stand for one thing in particular, however, if you
525 want, here are a few of my favorites, feel free to contribute
530 =item Make Other Object Systems Envious
532 =item Makes Object Orientation So Easy
534 =item Makes Object Orientation Spiffy- Er (sorry ingy)
536 =item Most Other Object Systems Emasculate
538 =item Moose Often Ovulate Sorta Early
540 =item Moose Offers Often Super Extensions
542 =item Meta Object Orientation Syntax Extensions
552 It should be noted that C<super> and C<inner> can B<not> be used in the same
553 method. However, they can be combined together with the same class hierarchy,
554 see F<t/014_override_augment_inner_super.t> for an example.
556 The reason that this is so is because C<super> is only valid within a method
557 with the C<override> modifier, and C<inner> will never be valid within an
558 C<override> method. In fact, C<augment> will skip over any C<override> methods
559 when searching for it's appropriate C<inner>.
561 This might seem like a restriction, but I am of the opinion that keeping these
562 two features seperate (but interoperable) actually makes them easy to use since
563 their behavior is then easier to predict. Time will tell if I am right or not.
567 =head1 ACKNOWLEDGEMENTS
571 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
573 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
575 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
576 and it certainly wouldn't have this name ;P
578 =item The basis of the TypeContraints module was Rob Kinyon's idea
579 originally, I just ran with it.
581 =item Thanks to mst & chansen and the whole #moose poose for all the
582 ideas/feature-requests/encouragement
590 =item L<Class::MOP> documentation
592 =item The #moose channel on irc.perl.org
594 =item L<http://forum2.org/moose/>
596 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
598 This paper (suggested by lbr on #moose) was what lead to the implementation
599 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
600 want to understand this feature, I suggest you read this.
606 All complex software has bugs lurking in it, and this module is no
607 exception. If you find a bug please either email me, or add the bug
612 Stevan Little E<lt>stevan@iinteractive.comE<gt>
614 Christian Hansen E<lt>chansen@cpan.orgE<gt>
616 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
618 =head1 COPYRIGHT AND LICENSE
620 Copyright 2006 by Infinity Interactive, Inc.
622 L<http://www.iinteractive.com>
624 This library is free software; you can redistribute it and/or modify
625 it under the same terms as Perl itself.