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 "Whoops, not møøsey enough";
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);
143 return \&Carp::confess;
146 return \&Scalar::Util::blessed;
150 my $exporter = Sub::Exporter::build_exporter({
151 exports => \%exports,
163 # we should never export to main
164 return if $CALLER eq 'main';
173 my $class = caller();
174 # loop through the exports ...
175 foreach my $name (keys %exports) {
178 if (defined &{$class . '::' . $name}) {
179 my $keyword = \&{$class . '::' . $name};
181 # make sure it is from Moose
182 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
184 next if $pkg_name ne 'Moose';
186 # and if it is from Moose then undef the slot
187 delete ${$class . '::'}{$name};
195 sub _load_all_classes {
196 foreach my $super (@_) {
197 # see if this is already
198 # loaded in the symbol table
199 next if _is_class_already_loaded($super);
200 # otherwise require it ...
202 || confess "Could not load module '$super' because : " . $UNIVERSAL::require::ERROR;
206 sub _is_class_already_loaded {
209 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
210 foreach (keys %{"${name}::"}) {
211 next if substr($_, -2, 2) eq '::';
212 return 1 if defined &{"${name}::$_"};
225 Moose - A complete modern object system for Perl 5
234 has 'x' => (is => 'rw', isa => 'Int');
235 has 'y' => (is => 'rw', isa => 'Int');
250 has 'z' => (is => 'rw', isa => 'Int');
252 after 'clear' => sub {
259 Moose is a rapidly maturing module, and is already being used by
260 a number of people. It's test suite is growing larger by the day,
261 and the docs should soon follow.
263 This said, Moose is not yet finished, and should still be considered
264 to be evolving. Much of the outer API is stable, but the internals
265 are still subject to change (although not without serious thought
268 For more details, please refer to the L<FUTURE PLANS> section of
273 Moose is an extension of the Perl 5 object system.
275 =head2 Another object system!?!?
277 Yes, I know there has been an explosion recently of new ways to
278 build object's in Perl 5, most of them based on inside-out objects,
279 and other such things. Moose is different because it is not a new
280 object system for Perl 5, but instead an extension of the existing
283 Moose is built on top of L<Class::MOP>, which is a metaclass system
284 for Perl 5. This means that Moose not only makes building normal
285 Perl 5 objects better, but it also provides the power of metaclass
288 =head2 Can I use this in production? Or is this just an experiment?
290 Moose is I<based> on the prototypes and experiments I did for the Perl 6
291 meta-model, however Moose is B<NOT> an experiment/prototype, it is
292 for B<real>. I will be deploying Moose into production environments later
293 this year, and I have all intentions of using it as my de-facto class
296 =head2 Is Moose just Perl 6 in Perl 5?
298 No. While Moose is very much inspired by Perl 6, it is not. Instead, it
299 is an OO system for Perl 5. I built Moose because I was tired or writing
300 the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
301 instead of switching to Ruby, I wrote Moose :)
303 =head1 BUILDING CLASSES WITH MOOSE
305 Moose makes every attempt to provide as much convience during class
306 construction/definition, but still stay out of your way if you want
307 it to. Here are a few items to note when building classes with Moose.
309 Unless specified with C<extends>, any class which uses Moose will
310 inherit from L<Moose::Object>.
312 Moose will also manage all attributes (including inherited ones) that
313 are defined with C<has>. And assuming that you call C<new> which is
314 inherited from L<Moose::Object>, then this includes properly initializing
315 all instance slots, setting defaults where approprtiate and performing any
316 type constraint checking or coercion.
318 =head1 EXPORTED FUNCTIONS
320 Moose will export a number of functions into the class's namespace, which
321 can then be used to set up the class. These functions all work directly
322 on the current class.
328 This is a method which provides access to the current class's metaclass.
330 =item B<extends (@superclasses)>
332 This function will set the superclass(es) for the current class.
334 This approach is recommended instead of C<use base>, because C<use base>
335 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
336 replace it. This is important to ensure that classes which do not have
337 superclasses properly inherit from L<Moose::Object>.
339 =item B<with (@roles)>
341 This will apply a given set of C<@roles> to the local class. Role support
342 is currently under heavy development, see L<Moose::Role> for more details.
344 =item B<has ($name, %options)>
346 This will install an attribute of a given C<$name> into the current class.
347 The list of C<%options> are the same as those provided by
348 L<Class::MOP::Attribute>, in addition to the list below which are provided
349 by Moose (L<Moose::Meta::Attribute> to be more specific):
353 =item I<is =E<gt> 'rw'|'ro'>
355 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
356 only). These will create either a read/write accessor or a read-only
357 accessor respectively, using the same name as the C<$name> of the attribute.
359 If you need more control over how your accessors are named, you can use the
360 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
362 =item I<isa =E<gt> $type_name>
364 The I<isa> option uses Moose's type constraint facilities to set up runtime
365 type checking for this attribute. Moose will perform the checks during class
366 construction, and within any accessors. The C<$type_name> argument must be a
367 string. The string can be either a class name, or a type defined using
368 Moose's type defintion features.
370 =item I<coerce =E<gt> (1|0)>
372 This will attempt to use coercion with the supplied type constraint to change
373 the value passed into any accessors of constructors. You B<must> have supplied
374 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
375 for an example usage.
377 =item I<does =E<gt> $role_name>
379 This will accept the name of a role which the value stored in this attribute
380 is expected to have consumed.
382 =item I<required =E<gt> (1|0)>
384 This marks the attribute as being required. This means a value must be supplied
385 during class construction, and the attribute can never be set to C<undef> with
388 =item I<weak_ref =E<gt> (1|0)>
390 This will tell the class to strore the value of this attribute as a weakened
391 reference. If an attribute is a weakened reference, it can B<not> also be coerced.
393 =item I<lazy =E<gt> (1|0)>
395 This will tell the class to not create this slot until absolutely nessecary.
396 If an attribute is marked as lazy it B<must> have a default supplied.
398 =item I<auto_deref =E<gt> (1|0)>
400 This tells the accessor whether to automatically de-reference the value returned.
401 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
403 =item I<trigger =E<gt> $code>
405 The trigger option is a CODE reference which will be called after the value of
406 the attribute is set. The CODE ref will be passed the instance itself, the
407 updated value and the attribute meta-object (this is for more advanced fiddling
408 and can typically be ignored in most cases). You can B<not> have a trigger on
409 a read-only attribute.
411 =item I<handles =E<gt> [ @handles ]>
413 There is experimental support for attribute delegation using the C<handles>
414 option. More docs to come later.
418 =item B<before $name|@names =E<gt> sub { ... }>
420 =item B<after $name|@names =E<gt> sub { ... }>
422 =item B<around $name|@names =E<gt> sub { ... }>
424 This three items are syntactic sugar for the before, after and around method
425 modifier features that L<Class::MOP> provides. More information on these can
426 be found in the L<Class::MOP> documentation for now.
430 The keyword C<super> is a noop when called outside of an C<override> method. In
431 the context of an C<override> method, it will call the next most appropriate
432 superclass method with the same arguments as the original method.
434 =item B<override ($name, &sub)>
436 An C<override> method, is a way of explictly saying "I am overriding this
437 method from my superclass". You can call C<super> within this method, and
438 it will work as expected. The same thing I<can> be accomplished with a normal
439 method call and the C<SUPER::> pseudo-package, it is really your choice.
443 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
444 an C<augment> method. You can think of C<inner> as being the inverse of
445 C<super>, the details of how C<inner> and C<augment> work is best described in
446 the L<Moose::Cookbook>.
448 =item B<augment ($name, &sub)>
450 An C<augment> method, is a way of explictly saying "I am augmenting this
451 method from my superclass". Once again, the details of how C<inner> and
452 C<augment> work is best described in the L<Moose::Cookbook>.
456 This is the C<Carp::confess> function, and exported here beause I use it
457 all the time. This feature may change in the future, so you have been warned.
461 This is the C<Scalar::Uti::blessed> function, it is exported here beause I
462 use it all the time. It is highly recommended that this is used instead of
463 C<ref> anywhere you need to test for an object's class name.
467 =head1 UNEXPORTING FUNCTIONS
471 Moose offers a way of removing the keywords it exports though the C<unimport>
472 method. You simply have to say C<no Moose> at the bottom of your code for this
473 to work. Here is an example:
478 has 'first_name' => (is => 'rw', isa => 'Str');
479 has 'last_name' => (is => 'rw', isa => 'Str');
483 $self->first_name . ' ' . $self->last_name
486 no Moose; # keywords are removed from the Person package
490 Here is just a sampling of the plans we have in store for Moose:
496 Compiling Moose classes/roles into C<.pmc> files for faster loading and execution.
500 Supporting sealed and finalized classes in Moose. This will allow greater control
501 of the extensions of frameworks and such.
507 =head2 What does Moose stand for??
509 Moose doesn't stand for one thing in particular, however, if you
510 want, here are a few of my favorites, feel free to contribute
515 =item Make Other Object Systems Envious
517 =item Makes Object Orientation So Easy
519 =item Makes Object Orientation Spiffy- Er (sorry ingy)
521 =item Most Other Object Systems Emasculate
523 =item Moose Often Ovulate Sorta Early
525 =item Moose Offers Often Super Extensions
527 =item Meta Object Orientation Syntax Extensions
537 It should be noted that C<super> and C<inner> can B<not> be used in the same
538 method. However, they can be combined together with the same class hierarchy,
539 see F<t/014_override_augment_inner_super.t> for an example.
541 The reason that this is so is because C<super> is only valid within a method
542 with the C<override> modifier, and C<inner> will never be valid within an
543 C<override> method. In fact, C<augment> will skip over any C<override> methods
544 when searching for it's appropriate C<inner>.
546 This might seem like a restriction, but I am of the opinion that keeping these
547 two features seperate (but interoperable) actually makes them easy to use since
548 their behavior is then easier to predict. Time will tell if I am right or not.
552 =head1 ACKNOWLEDGEMENTS
556 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
558 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
560 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
561 and it certainly wouldn't have this name ;P
563 =item The basis of the TypeContraints module was Rob Kinyon's idea
564 originally, I just ran with it.
566 =item Thanks to mst & chansen and the whole #moose poose for all the
567 ideas/feature-requests/encouragement
575 =item L<Class::MOP> documentation
577 =item The #moose channel on irc.perl.org
579 =item L<http://forum2.org/moose/>
581 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
583 This paper (suggested by lbr on #moose) was what lead to the implementation
584 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
585 want to understand this feature, I suggest you read this.
591 All complex software has bugs lurking in it, and this module is no
592 exception. If you find a bug please either email me, or add the bug
597 Stevan Little E<lt>stevan@iinteractive.comE<gt>
599 Christian Hansen E<lt>chansen@cpan.orgE<gt>
601 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
603 =head1 COPYRIGHT AND LICENSE
605 Copyright 2006 by Infinity Interactive, Inc.
607 L<http://www.iinteractive.com>
609 This library is free software; you can redistribute it and/or modify
610 it under the same terms as Perl itself.