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 # just in case the class we are
224 # loading has a locally defined
225 # &require, we make sure that we
226 # use the on in UNIVERSAL
227 ($super->UNIVERSAL::require)
228 || confess "Could not load module '$super' because : " . $UNIVERSAL::require::ERROR;
232 sub _is_class_already_loaded {
235 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
236 foreach (keys %{"${name}::"}) {
237 next if substr($_, -2, 2) eq '::';
238 return 1 if defined &{"${name}::$_"};
251 Moose - A complete modern object system for Perl 5
260 has 'x' => (is => 'rw', isa => 'Int');
261 has 'y' => (is => 'rw', isa => 'Int');
276 has 'z' => (is => 'rw', isa => 'Int');
278 after 'clear' => sub {
285 Moose is a rapidly maturing module, and is already being used by
286 a number of people. It's test suite is growing larger by the day,
287 and the docs should soon follow.
289 This said, Moose is not yet finished, and should still be considered
290 to be evolving. Much of the outer API is stable, but the internals
291 are still subject to change (although not without serious thought
294 For more details, please refer to the L<FUTURE PLANS> section of
299 Moose is an extension of the Perl 5 object system.
301 =head2 Another object system!?!?
303 Yes, I know there has been an explosion recently of new ways to
304 build object's in Perl 5, most of them based on inside-out objects
305 and other such things. Moose is different because it is not a new
306 object system for Perl 5, but instead an extension of the existing
309 Moose is built on top of L<Class::MOP>, which is a metaclass system
310 for Perl 5. This means that Moose not only makes building normal
311 Perl 5 objects better, but it also provides the power of metaclass
314 =head2 Can I use this in production? Or is this just an experiment?
316 Moose is I<based> on the prototypes and experiments I did for the Perl 6
317 meta-model; however Moose is B<NOT> an experiment/prototype, it is
318 for B<real>. I will be deploying Moose into production environments later
319 this year, and I have every intentions of using it as my de facto class
322 =head2 Is Moose just Perl 6 in Perl 5?
324 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
325 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
326 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
327 instead of switching to Ruby, I wrote Moose :)
329 =head1 BUILDING CLASSES WITH MOOSE
331 Moose makes every attempt to provide as much convenience as possible during
332 class construction/definition, but still stay out of your way if you want it
333 to. Here are a few items to note when building classes with Moose.
335 Unless specified with C<extends>, any class which uses Moose will
336 inherit from L<Moose::Object>.
338 Moose will also manage all attributes (including inherited ones) that
339 are defined with C<has>. And assuming that you call C<new>, which is
340 inherited from L<Moose::Object>, then this includes properly initializing
341 all instance slots, setting defaults where appropriate, and performing any
342 type constraint checking or coercion.
344 =head1 EXPORTED FUNCTIONS
346 Moose will export a number of functions into the class's namespace which
347 can then be used to set up the class. These functions all work directly
348 on the current class.
354 This is a method which provides access to the current class's metaclass.
356 =item B<extends (@superclasses)>
358 This function will set the superclass(es) for the current class.
360 This approach is recommended instead of C<use base>, because C<use base>
361 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
362 replace it. This is important to ensure that classes which do not have
363 superclasses still properly inherit from L<Moose::Object>.
365 =item B<with (@roles)>
367 This will apply a given set of C<@roles> to the local class. Role support
368 is currently under heavy development; see L<Moose::Role> for more details.
370 =item B<has ($name, %options)>
372 This will install an attribute of a given C<$name> into the current class.
373 The list of C<%options> are the same as those provided by
374 L<Class::MOP::Attribute>, in addition to the list below which are provided
375 by Moose (L<Moose::Meta::Attribute> to be more specific):
379 =item I<is =E<gt> 'rw'|'ro'>
381 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
382 only). These will create either a read/write accessor or a read-only
383 accessor respectively, using the same name as the C<$name> of the attribute.
385 If you need more control over how your accessors are named, you can use the
386 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
388 =item I<isa =E<gt> $type_name>
390 The I<isa> option uses Moose's type constraint facilities to set up runtime
391 type checking for this attribute. Moose will perform the checks during class
392 construction, and within any accessors. The C<$type_name> argument must be a
393 string. The string can be either a class name or a type defined using
394 Moose's type definition features.
396 =item I<coerce =E<gt> (1|0)>
398 This will attempt to use coercion with the supplied type constraint to change
399 the value passed into any accessors or constructors. You B<must> have supplied
400 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
401 for an example usage.
403 =item I<does =E<gt> $role_name>
405 This will accept the name of a role which the value stored in this attribute
406 is expected to have consumed.
408 =item I<required =E<gt> (1|0)>
410 This marks the attribute as being required. This means a value must be supplied
411 during class construction, and the attribute can never be set to C<undef> with
414 =item I<weak_ref =E<gt> (1|0)>
416 This will tell the class to store the value of this attribute as a weakened
417 reference. If an attribute is a weakened reference, it B<cannot> also be
420 =item I<lazy =E<gt> (1|0)>
422 This will tell the class to not create this slot until absolutely necessary.
423 If an attribute is marked as lazy it B<must> have a default supplied.
425 =item I<auto_deref =E<gt> (1|0)>
427 This tells the accessor whether to automatically dereference the value returned.
428 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
430 =item I<trigger =E<gt> $code>
432 The trigger option is a CODE reference which will be called after the value of
433 the attribute is set. The CODE ref will be passed the instance itself, the
434 updated value and the attribute meta-object (this is for more advanced fiddling
435 and can typically be ignored in most cases). You B<cannot> have a trigger on
436 a read-only attribute.
438 =item I<handles =E<gt> [ @handles ]>
440 There is experimental support for attribute delegation using the C<handles>
441 option. More docs to come later.
445 =item B<before $name|@names =E<gt> sub { ... }>
447 =item B<after $name|@names =E<gt> sub { ... }>
449 =item B<around $name|@names =E<gt> sub { ... }>
451 This three items are syntactic sugar for the before, after, and around method
452 modifier features that L<Class::MOP> provides. More information on these can
453 be found in the L<Class::MOP> documentation for now.
457 The keyword C<super> is a no-op when called outside of an C<override> method. In
458 the context of an C<override> method, it will call the next most appropriate
459 superclass method with the same arguments as the original method.
461 =item B<override ($name, &sub)>
463 An C<override> method is a way of explicitly saying "I am overriding this
464 method from my superclass". You can call C<super> within this method, and
465 it will work as expected. The same thing I<can> be accomplished with a normal
466 method call and the C<SUPER::> pseudo-package; it is really your choice.
470 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
471 an C<augment> method. You can think of C<inner> as being the inverse of
472 C<super>; the details of how C<inner> and C<augment> work is best described in
473 the L<Moose::Cookbook>.
475 =item B<augment ($name, &sub)>
477 An C<augment> method, is a way of explicitly saying "I am augmenting this
478 method from my superclass". Once again, the details of how C<inner> and
479 C<augment> work is best described in the L<Moose::Cookbook>.
483 This is the C<Carp::confess> function, and exported here because I use it
484 all the time. This feature may change in the future, so you have been warned.
488 This is the C<Scalar::Uti::blessed> function, it is exported here because I
489 use it all the time. It is highly recommended that this is used instead of
490 C<ref> anywhere you need to test for an object's class name.
494 =head1 UNEXPORTING FUNCTIONS
498 Moose offers a way of removing the keywords it exports though the C<unimport>
499 method. You simply have to say C<no Moose> at the bottom of your code for this
500 to work. Here is an example:
505 has 'first_name' => (is => 'rw', isa => 'Str');
506 has 'last_name' => (is => 'rw', isa => 'Str');
510 $self->first_name . ' ' . $self->last_name
513 no Moose; # keywords are removed from the Person package
517 =head2 What does Moose stand for??
519 Moose doesn't stand for one thing in particular, however, if you
520 want, here are a few of my favorites; feel free to contribute
525 =item Make Other Object Systems Envious
527 =item Makes Object Orientation So Easy
529 =item Makes Object Orientation Spiffy- Er (sorry ingy)
531 =item Most Other Object Systems Emasculate
533 =item Moose Often Ovulate Sorta Early
535 =item Moose Offers Often Super Extensions
537 =item Meta Object Orientation Syntax Extensions
547 It should be noted that C<super> and C<inner> C<cannot> be used in the same
548 method. However, they can be combined together with the same class hierarchy;
549 see F<t/014_override_augment_inner_super.t> for an example.
551 The reason for this is that C<super> is only valid within a method
552 with the C<override> modifier, and C<inner> will never be valid within an
553 C<override> method. In fact, C<augment> will skip over any C<override> methods
554 when searching for its appropriate C<inner>.
556 This might seem like a restriction, but I am of the opinion that keeping these
557 two features separate (but interoperable) actually makes them easy to use, since
558 their behavior is then easier to predict. Time will tell if I am right or not.
562 =head1 ACKNOWLEDGEMENTS
566 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
568 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
570 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
571 and it certainly wouldn't have this name ;P
573 =item The basis of the TypeContraints module was Rob Kinyon's idea
574 originally, I just ran with it.
576 =item Thanks to mst & chansen and the whole #moose poose for all the
577 ideas/feature-requests/encouragement
579 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
587 =item L<Class::MOP> documentation
589 =item The #moose channel on irc.perl.org
591 =item L<http://forum2.org/moose/>
593 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
595 This paper (suggested by lbr on #moose) was what lead to the implementation
596 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
597 want to understand this feature, I suggest you read this.
603 All complex software has bugs lurking in it, and this module is no
604 exception. If you find a bug please either email me, or add the bug
609 Stevan Little E<lt>stevan@iinteractive.comE<gt>
611 Christian Hansen E<lt>chansen@cpan.orgE<gt>
613 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
615 =head1 COPYRIGHT AND LICENSE
617 Copyright 2006 by Infinity Interactive, Inc.
619 L<http://www.iinteractive.com>
621 This library is free software; you can redistribute it and/or modify
622 it under the same terms as Perl itself.