9 use Scalar::Util 'blessed', 'reftype';
11 use Sub::Name 'subname';
12 use B 'svref_2object';
14 use UNIVERSAL::require;
19 use Moose::Meta::Class;
20 use Moose::Meta::TypeConstraint;
21 use Moose::Meta::TypeCoercion;
22 use Moose::Meta::Attribute;
23 use Moose::Meta::Instance;
26 use Moose::Util::TypeConstraints;
34 # make a subtype for each Moose class
37 => where { $_->isa($class) }
38 unless find_type_constraint($class);
41 if ($class->can('meta')) {
43 # this is the case where the metaclass pragma
44 # was used before the 'use Moose' statement to
45 # override a specific class
46 $meta = $class->meta();
47 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
48 || confess "You already have a &meta function, but it does not return a Moose::Meta::Class";
52 # this is broken currently, we actually need
53 # to allow the possiblity of an inherited
54 # meta, which will not be visible until the
55 # user 'extends' first. This needs to have
56 # more intelligence to it
57 $meta = Moose::Meta::Class->initialize($class);
58 $meta->add_method('meta' => sub {
59 # re-initialize so it inherits properly
60 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
64 # make sure they inherit from Moose::Object
65 $meta->superclasses('Moose::Object')
66 unless $meta->superclasses();
72 return subname 'Moose::extends' => sub (@) {
73 confess "Must derive at least one class" unless @_;
74 _load_all_classes(@_);
75 # this checks the metaclass to make sure
76 # it is correct, sometimes it can get out
77 # of sync when the classes are being built
78 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
79 $meta->superclasses(@_);
84 return subname 'Moose::with' => sub (@) {
86 confess "Must specify at least one role" unless @roles;
87 _load_all_classes(@roles);
88 $class->meta->_apply_all_roles(@roles);
93 return subname 'Moose::has' => sub ($;%) {
94 my ($name, %options) = @_;
95 $class->meta->_process_attribute($name, %options);
100 return subname 'Moose::before' => sub (@&) {
102 my $meta = $class->meta;
103 $meta->add_before_method_modifier($_, $code) for @_;
108 return subname 'Moose::after' => sub (@&) {
110 my $meta = $class->meta;
111 $meta->add_after_method_modifier($_, $code) for @_;
116 return subname 'Moose::around' => sub (@&) {
118 my $meta = $class->meta;
119 $meta->add_around_method_modifier($_, $code) for @_;
123 return subname 'Moose::super' => sub {};
127 return subname 'Moose::override' => sub ($&) {
128 my ($name, $method) = @_;
129 $class->meta->add_override_method_modifier($name => $method);
133 return subname 'Moose::inner' => sub {};
137 return subname 'Moose::augment' => sub (@&) {
138 my ($name, $method) = @_;
139 $class->meta->add_augment_method_modifier($name => $method);
144 # this is experimental for now ...
146 return subname 'Moose::self' => sub {};
150 return subname 'Moose::method' => sub {
151 my ($name, $method) = @_;
152 $class->meta->add_method($name, sub {
155 no warnings 'redefine';
156 local *{$class->meta->name . '::self'} = sub { $self };
163 return \&Carp::confess;
166 return \&Scalar::Util::blessed;
170 my $exporter = Sub::Exporter::build_exporter({
171 exports => \%exports,
183 # we should never export to main
184 return if $CALLER eq 'main';
193 my $class = caller();
194 # loop through the exports ...
195 foreach my $name (keys %exports) {
196 next if $name =~ /inner|super|self/;
199 if (defined &{$class . '::' . $name}) {
200 my $keyword = \&{$class . '::' . $name};
202 # make sure it is from Moose
203 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
205 next if $pkg_name ne 'Moose';
207 # and if it is from Moose then undef the slot
208 delete ${$class . '::'}{$name};
216 sub _load_all_classes {
217 foreach my $super (@_) {
218 # see if this is already
219 # loaded in the symbol table
220 next if _is_class_already_loaded($super);
221 # otherwise require it ...
223 || confess "Could not load module '$super' because : " . $UNIVERSAL::require::ERROR;
227 sub _is_class_already_loaded {
230 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
231 foreach (keys %{"${name}::"}) {
232 next if substr($_, -2, 2) eq '::';
233 return 1 if defined &{"${name}::$_"};
246 Moose - A complete modern object system for Perl 5
255 has 'x' => (is => 'rw', isa => 'Int');
256 has 'y' => (is => 'rw', isa => 'Int');
271 has 'z' => (is => 'rw', isa => 'Int');
273 after 'clear' => sub {
280 Moose is a rapidly maturing module, and is already being used by
281 a number of people. It's test suite is growing larger by the day,
282 and the docs should soon follow.
284 This said, Moose is not yet finished, and should still be considered
285 to be evolving. Much of the outer API is stable, but the internals
286 are still subject to change (although not without serious thought
289 For more details, please refer to the L<FUTURE PLANS> section of
294 Moose is an extension of the Perl 5 object system.
296 =head2 Another object system!?!?
298 Yes, I know there has been an explosion recently of new ways to
299 build object's in Perl 5, most of them based on inside-out objects
300 and other such things. Moose is different because it is not a new
301 object system for Perl 5, but instead an extension of the existing
304 Moose is built on top of L<Class::MOP>, which is a metaclass system
305 for Perl 5. This means that Moose not only makes building normal
306 Perl 5 objects better, but it also provides the power of metaclass
309 =head2 Can I use this in production? Or is this just an experiment?
311 Moose is I<based> on the prototypes and experiments I did for the Perl 6
312 meta-model; however Moose is B<NOT> an experiment/prototype, it is
313 for B<real>. I will be deploying Moose into production environments later
314 this year, and I have every intentions of using it as my de facto class
317 =head2 Is Moose just Perl 6 in Perl 5?
319 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
320 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
321 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
322 instead of switching to Ruby, I wrote Moose :)
324 =head1 BUILDING CLASSES WITH MOOSE
326 Moose makes every attempt to provide as much convenience as possible during
327 class construction/definition, but still stay out of your way if you want it
328 to. Here are a few items to note when building classes with Moose.
330 Unless specified with C<extends>, any class which uses Moose will
331 inherit from L<Moose::Object>.
333 Moose will also manage all attributes (including inherited ones) that
334 are defined with C<has>. And assuming that you call C<new>, which is
335 inherited from L<Moose::Object>, then this includes properly initializing
336 all instance slots, setting defaults where appropriate, and performing any
337 type constraint checking or coercion.
339 =head1 EXPORTED FUNCTIONS
341 Moose will export a number of functions into the class's namespace which
342 can then be used to set up the class. These functions all work directly
343 on the current class.
349 This is a method which provides access to the current class's metaclass.
351 =item B<extends (@superclasses)>
353 This function will set the superclass(es) for the current class.
355 This approach is recommended instead of C<use base>, because C<use base>
356 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
357 replace it. This is important to ensure that classes which do not have
358 superclasses still properly inherit from L<Moose::Object>.
360 =item B<with (@roles)>
362 This will apply a given set of C<@roles> to the local class. Role support
363 is currently under heavy development; see L<Moose::Role> for more details.
365 =item B<has ($name, %options)>
367 This will install an attribute of a given C<$name> into the current class.
368 The list of C<%options> are the same as those provided by
369 L<Class::MOP::Attribute>, in addition to the list below which are provided
370 by Moose (L<Moose::Meta::Attribute> to be more specific):
374 =item I<is =E<gt> 'rw'|'ro'>
376 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
377 only). These will create either a read/write accessor or a read-only
378 accessor respectively, using the same name as the C<$name> of the attribute.
380 If you need more control over how your accessors are named, you can use the
381 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
383 =item I<isa =E<gt> $type_name>
385 The I<isa> option uses Moose's type constraint facilities to set up runtime
386 type checking for this attribute. Moose will perform the checks during class
387 construction, and within any accessors. The C<$type_name> argument must be a
388 string. The string can be either a class name or a type defined using
389 Moose's type definition features.
391 =item I<coerce =E<gt> (1|0)>
393 This will attempt to use coercion with the supplied type constraint to change
394 the value passed into any accessors or constructors. You B<must> have supplied
395 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
396 for an example usage.
398 =item I<does =E<gt> $role_name>
400 This will accept the name of a role which the value stored in this attribute
401 is expected to have consumed.
403 =item I<required =E<gt> (1|0)>
405 This marks the attribute as being required. This means a value must be supplied
406 during class construction, and the attribute can never be set to C<undef> with
409 =item I<weak_ref =E<gt> (1|0)>
411 This will tell the class to store the value of this attribute as a weakened
412 reference. If an attribute is a weakened reference, it B<cannot> also be
415 =item I<lazy =E<gt> (1|0)>
417 This will tell the class to not create this slot until absolutely necessary.
418 If an attribute is marked as lazy it B<must> have a default supplied.
420 =item I<auto_deref =E<gt> (1|0)>
422 This tells the accessor whether to automatically dereference the value returned.
423 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
425 =item I<trigger =E<gt> $code>
427 The trigger option is a CODE reference which will be called after the value of
428 the attribute is set. The CODE ref will be passed the instance itself, the
429 updated value and the attribute meta-object (this is for more advanced fiddling
430 and can typically be ignored in most cases). You B<cannot> have a trigger on
431 a read-only attribute.
433 =item I<handles =E<gt> [ @handles ]>
435 There is experimental support for attribute delegation using the C<handles>
436 option. More docs to come later.
440 =item B<before $name|@names =E<gt> sub { ... }>
442 =item B<after $name|@names =E<gt> sub { ... }>
444 =item B<around $name|@names =E<gt> sub { ... }>
446 This three items are syntactic sugar for the before, after, and around method
447 modifier features that L<Class::MOP> provides. More information on these can
448 be found in the L<Class::MOP> documentation for now.
452 The keyword C<super> is a no-op when called outside of an C<override> method. In
453 the context of an C<override> method, it will call the next most appropriate
454 superclass method with the same arguments as the original method.
456 =item B<override ($name, &sub)>
458 An C<override> method is a way of explicitly saying "I am overriding this
459 method from my superclass". You can call C<super> within this method, and
460 it will work as expected. The same thing I<can> be accomplished with a normal
461 method call and the C<SUPER::> pseudo-package; it is really your choice.
465 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
466 an C<augment> method. You can think of C<inner> as being the inverse of
467 C<super>; the details of how C<inner> and C<augment> work is best described in
468 the L<Moose::Cookbook>.
470 =item B<augment ($name, &sub)>
472 An C<augment> method, is a way of explicitly saying "I am augmenting this
473 method from my superclass". Once again, the details of how C<inner> and
474 C<augment> work is best described in the L<Moose::Cookbook>.
478 This is the C<Carp::confess> function, and exported here because I use it
479 all the time. This feature may change in the future, so you have been warned.
483 This is the C<Scalar::Uti::blessed> function, it is exported here because I
484 use it all the time. It is highly recommended that this is used instead of
485 C<ref> anywhere you need to test for an object's class name.
489 =head1 UNEXPORTING FUNCTIONS
493 Moose offers a way of removing the keywords it exports though the C<unimport>
494 method. You simply have to say C<no Moose> at the bottom of your code for this
495 to work. Here is an example:
500 has 'first_name' => (is => 'rw', isa => 'Str');
501 has 'last_name' => (is => 'rw', isa => 'Str');
505 $self->first_name . ' ' . $self->last_name
508 no Moose; # keywords are removed from the Person package
512 =head2 What does Moose stand for??
514 Moose doesn't stand for one thing in particular, however, if you
515 want, here are a few of my favorites; feel free to contribute
520 =item Make Other Object Systems Envious
522 =item Makes Object Orientation So Easy
524 =item Makes Object Orientation Spiffy- Er (sorry ingy)
526 =item Most Other Object Systems Emasculate
528 =item Moose Often Ovulate Sorta Early
530 =item Moose Offers Often Super Extensions
532 =item Meta Object Orientation Syntax Extensions
542 It should be noted that C<super> and C<inner> C<cannot> be used in the same
543 method. However, they can be combined together with the same class hierarchy;
544 see F<t/014_override_augment_inner_super.t> for an example.
546 The reason for this is that C<super> is only valid within a method
547 with the C<override> modifier, and C<inner> will never be valid within an
548 C<override> method. In fact, C<augment> will skip over any C<override> methods
549 when searching for its appropriate C<inner>.
551 This might seem like a restriction, but I am of the opinion that keeping these
552 two features separate (but interoperable) actually makes them easy to use, since
553 their behavior is then easier to predict. Time will tell if I am right or not.
557 =head1 ACKNOWLEDGEMENTS
561 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
563 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
565 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
566 and it certainly wouldn't have this name ;P
568 =item The basis of the TypeContraints module was Rob Kinyon's idea
569 originally, I just ran with it.
571 =item Thanks to mst & chansen and the whole #moose poose for all the
572 ideas/feature-requests/encouragement
574 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
582 =item L<Class::MOP> documentation
584 =item The #moose channel on irc.perl.org
586 =item L<http://forum2.org/moose/>
588 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
590 This paper (suggested by lbr on #moose) was what lead to the implementation
591 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
592 want to understand this feature, I suggest you read this.
598 All complex software has bugs lurking in it, and this module is no
599 exception. If you find a bug please either email me, or add the bug
604 Stevan Little E<lt>stevan@iinteractive.comE<gt>
606 Christian Hansen E<lt>chansen@cpan.orgE<gt>
608 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
610 =head1 COPYRIGHT AND LICENSE
612 Copyright 2006 by Infinity Interactive, Inc.
614 L<http://www.iinteractive.com>
616 This library is free software; you can redistribute it and/or modify
617 it under the same terms as Perl itself.