9 use Scalar::Util 'blessed', 'reftype';
11 use Sub::Name 'subname';
12 use B 'svref_2object';
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 "You already have a &meta function, but it does not return a Moose::Meta::Class";
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 # this checks the metaclass to make sure
75 # it is correct, sometimes it can get out
76 # of sync when the classes are being built
77 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
78 $meta->superclasses(@_);
83 return subname 'Moose::with' => sub (@) {
85 confess "Must specify at least one role" unless @roles;
86 _load_all_classes(@roles);
87 $class->meta->_apply_all_roles(@roles);
92 return subname 'Moose::has' => sub ($;%) {
93 my ($name, %options) = @_;
94 $class->meta->_process_attribute($name, %options);
99 return subname 'Moose::before' => sub (@&) {
101 my $meta = $class->meta;
102 $meta->add_before_method_modifier($_, $code) for @_;
107 return subname 'Moose::after' => sub (@&) {
109 my $meta = $class->meta;
110 $meta->add_after_method_modifier($_, $code) for @_;
115 return subname 'Moose::around' => sub (@&) {
117 my $meta = $class->meta;
118 $meta->add_around_method_modifier($_, $code) for @_;
122 return subname 'Moose::super' => sub {};
126 return subname 'Moose::override' => sub ($&) {
127 my ($name, $method) = @_;
128 $class->meta->add_override_method_modifier($name => $method);
132 return subname 'Moose::inner' => sub {};
136 return subname 'Moose::augment' => sub (@&) {
137 my ($name, $method) = @_;
138 $class->meta->add_augment_method_modifier($name => $method);
143 # this is experimental for now ...
145 return subname 'Moose::self' => sub {};
149 return subname 'Moose::method' => sub {
150 my ($name, $method) = @_;
151 $class->meta->add_method($name, sub {
154 no warnings 'redefine';
155 local *{$class->meta->name . '::self'} = sub { $self };
162 return \&Carp::confess;
165 return \&Scalar::Util::blessed;
169 my $exporter = Sub::Exporter::build_exporter({
170 exports => \%exports,
182 # we should never export to main
183 return if $CALLER eq 'main';
192 my $class = caller();
193 # loop through the exports ...
194 foreach my $name (keys %exports) {
195 next if $name =~ /inner|super|self/;
198 if (defined &{$class . '::' . $name}) {
199 my $keyword = \&{$class . '::' . $name};
201 # make sure it is from Moose
202 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
204 next if $pkg_name ne 'Moose';
206 # and if it is from Moose then undef the slot
207 delete ${$class . '::'}{$name};
215 sub _load_all_classes {
216 foreach my $super (@_) {
217 # see if this is already
218 # loaded in the symbol table
219 next if _is_class_already_loaded($super);
220 # otherwise require it ...
221 my $file = $class . '.pm';
223 eval { CORE::require($file) };
225 "Could not load module '$super' because : $@"
230 sub _is_class_already_loaded {
233 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
234 foreach (keys %{"${name}::"}) {
235 next if substr($_, -2, 2) eq '::';
236 return 1 if defined &{"${name}::$_"};
249 Moose - A complete modern object system for Perl 5
258 has 'x' => (is => 'rw', isa => 'Int');
259 has 'y' => (is => 'rw', isa => 'Int');
274 has 'z' => (is => 'rw', isa => 'Int');
276 after 'clear' => sub {
283 Moose is a rapidly maturing module, and is already being used by
284 a number of people. It's test suite is growing larger by the day,
285 and the docs should soon follow.
287 This said, Moose is not yet finished, and should still be considered
288 to be evolving. Much of the outer API is stable, but the internals
289 are still subject to change (although not without serious thought
292 For more details, please refer to the L<FUTURE PLANS> section of
297 Moose is an extension of the Perl 5 object system.
299 =head2 Another object system!?!?
301 Yes, I know there has been an explosion recently of new ways to
302 build object's in Perl 5, most of them based on inside-out objects
303 and other such things. Moose is different because it is not a new
304 object system for Perl 5, but instead an extension of the existing
307 Moose is built on top of L<Class::MOP>, which is a metaclass system
308 for Perl 5. This means that Moose not only makes building normal
309 Perl 5 objects better, but it also provides the power of metaclass
312 =head2 Can I use this in production? Or is this just an experiment?
314 Moose is I<based> on the prototypes and experiments I did for the Perl 6
315 meta-model; however Moose is B<NOT> an experiment/prototype, it is
316 for B<real>. I will be deploying Moose into production environments later
317 this year, and I have every intentions of using it as my de facto class
320 =head2 Is Moose just Perl 6 in Perl 5?
322 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
323 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
324 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
325 instead of switching to Ruby, I wrote Moose :)
327 =head1 BUILDING CLASSES WITH MOOSE
329 Moose makes every attempt to provide as much convenience as possible during
330 class construction/definition, but still stay out of your way if you want it
331 to. Here are a few items to note when building classes with Moose.
333 Unless specified with C<extends>, any class which uses Moose will
334 inherit from L<Moose::Object>.
336 Moose will also manage all attributes (including inherited ones) that
337 are defined with C<has>. And assuming that you call C<new>, which is
338 inherited from L<Moose::Object>, then this includes properly initializing
339 all instance slots, setting defaults where appropriate, and performing any
340 type constraint checking or coercion.
342 =head1 EXPORTED FUNCTIONS
344 Moose will export a number of functions into the class's namespace which
345 can then be used to set up the class. These functions all work directly
346 on the current class.
352 This is a method which provides access to the current class's metaclass.
354 =item B<extends (@superclasses)>
356 This function will set the superclass(es) for the current class.
358 This approach is recommended instead of C<use base>, because C<use base>
359 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
360 replace it. This is important to ensure that classes which do not have
361 superclasses still properly inherit from L<Moose::Object>.
363 =item B<with (@roles)>
365 This will apply a given set of C<@roles> to the local class. Role support
366 is currently under heavy development; see L<Moose::Role> for more details.
368 =item B<has ($name, %options)>
370 This will install an attribute of a given C<$name> into the current class.
371 The list of C<%options> are the same as those provided by
372 L<Class::MOP::Attribute>, in addition to the list below which are provided
373 by Moose (L<Moose::Meta::Attribute> to be more specific):
377 =item I<is =E<gt> 'rw'|'ro'>
379 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
380 only). These will create either a read/write accessor or a read-only
381 accessor respectively, using the same name as the C<$name> of the attribute.
383 If you need more control over how your accessors are named, you can use the
384 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
386 =item I<isa =E<gt> $type_name>
388 The I<isa> option uses Moose's type constraint facilities to set up runtime
389 type checking for this attribute. Moose will perform the checks during class
390 construction, and within any accessors. The C<$type_name> argument must be a
391 string. The string can be either a class name or a type defined using
392 Moose's type definition features.
394 =item I<coerce =E<gt> (1|0)>
396 This will attempt to use coercion with the supplied type constraint to change
397 the value passed into any accessors or constructors. You B<must> have supplied
398 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
399 for an example usage.
401 =item I<does =E<gt> $role_name>
403 This will accept the name of a role which the value stored in this attribute
404 is expected to have consumed.
406 =item I<required =E<gt> (1|0)>
408 This marks the attribute as being required. This means a value must be supplied
409 during class construction, and the attribute can never be set to C<undef> with
412 =item I<weak_ref =E<gt> (1|0)>
414 This will tell the class to store the value of this attribute as a weakened
415 reference. If an attribute is a weakened reference, it B<cannot> also be
418 =item I<lazy =E<gt> (1|0)>
420 This will tell the class to not create this slot until absolutely necessary.
421 If an attribute is marked as lazy it B<must> have a default supplied.
423 =item I<auto_deref =E<gt> (1|0)>
425 This tells the accessor whether to automatically dereference the value returned.
426 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
428 =item I<trigger =E<gt> $code>
430 The trigger option is a CODE reference which will be called after the value of
431 the attribute is set. The CODE ref will be passed the instance itself, the
432 updated value and the attribute meta-object (this is for more advanced fiddling
433 and can typically be ignored in most cases). You B<cannot> have a trigger on
434 a read-only attribute.
436 =item I<handles =E<gt> [ @handles ]>
438 There is experimental support for attribute delegation using the C<handles>
439 option. More docs to come later.
443 =item B<before $name|@names =E<gt> sub { ... }>
445 =item B<after $name|@names =E<gt> sub { ... }>
447 =item B<around $name|@names =E<gt> sub { ... }>
449 This three items are syntactic sugar for the before, after, and around method
450 modifier features that L<Class::MOP> provides. More information on these can
451 be found in the L<Class::MOP> documentation for now.
455 The keyword C<super> is a no-op when called outside of an C<override> method. In
456 the context of an C<override> method, it will call the next most appropriate
457 superclass method with the same arguments as the original method.
459 =item B<override ($name, &sub)>
461 An C<override> method is a way of explicitly saying "I am overriding this
462 method from my superclass". You can call C<super> within this method, and
463 it will work as expected. The same thing I<can> be accomplished with a normal
464 method call and the C<SUPER::> pseudo-package; it is really your choice.
468 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
469 an C<augment> method. You can think of C<inner> as being the inverse of
470 C<super>; the details of how C<inner> and C<augment> work is best described in
471 the L<Moose::Cookbook>.
473 =item B<augment ($name, &sub)>
475 An C<augment> method, is a way of explicitly saying "I am augmenting this
476 method from my superclass". Once again, the details of how C<inner> and
477 C<augment> work is best described in the L<Moose::Cookbook>.
481 This is the C<Carp::confess> function, and exported here because I use it
482 all the time. This feature may change in the future, so you have been warned.
486 This is the C<Scalar::Uti::blessed> function, it is exported here because I
487 use it all the time. It is highly recommended that this is used instead of
488 C<ref> anywhere you need to test for an object's class name.
492 =head1 UNEXPORTING FUNCTIONS
496 Moose offers a way of removing the keywords it exports though the C<unimport>
497 method. You simply have to say C<no Moose> at the bottom of your code for this
498 to work. Here is an example:
503 has 'first_name' => (is => 'rw', isa => 'Str');
504 has 'last_name' => (is => 'rw', isa => 'Str');
508 $self->first_name . ' ' . $self->last_name
511 no Moose; # keywords are removed from the Person package
515 =head2 What does Moose stand for??
517 Moose doesn't stand for one thing in particular, however, if you
518 want, here are a few of my favorites; feel free to contribute
523 =item Make Other Object Systems Envious
525 =item Makes Object Orientation So Easy
527 =item Makes Object Orientation Spiffy- Er (sorry ingy)
529 =item Most Other Object Systems Emasculate
531 =item Moose Often Ovulate Sorta Early
533 =item Moose Offers Often Super Extensions
535 =item Meta Object Orientation Syntax Extensions
545 It should be noted that C<super> and C<inner> C<cannot> be used in the same
546 method. However, they can be combined together with the same class hierarchy;
547 see F<t/014_override_augment_inner_super.t> for an example.
549 The reason for this is that C<super> is only valid within a method
550 with the C<override> modifier, and C<inner> will never be valid within an
551 C<override> method. In fact, C<augment> will skip over any C<override> methods
552 when searching for its appropriate C<inner>.
554 This might seem like a restriction, but I am of the opinion that keeping these
555 two features separate (but interoperable) actually makes them easy to use, since
556 their behavior is then easier to predict. Time will tell if I am right or not.
560 =head1 ACKNOWLEDGEMENTS
564 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
566 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
568 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
569 and it certainly wouldn't have this name ;P
571 =item The basis of the TypeContraints module was Rob Kinyon's idea
572 originally, I just ran with it.
574 =item Thanks to mst & chansen and the whole #moose poose for all the
575 ideas/feature-requests/encouragement
577 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
585 =item L<Class::MOP> documentation
587 =item The #moose channel on irc.perl.org
589 =item The Moose mailing list - moose@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.