4 use lib File::Spec->catdir(
19 our $VERSION = '0.18';
20 our $AUTHORITY = 'cpan:STEVAN';
22 use Scalar::Util 'blessed', 'reftype';
24 use Sub::Name 'subname';
25 use B 'svref_2object';
31 use Moose::Meta::Class;
32 use Moose::Meta::TypeConstraint;
33 use Moose::Meta::TypeCoercion;
34 use Moose::Meta::Attribute;
35 use Moose::Meta::Instance;
38 use Moose::Util::TypeConstraints;
46 # make a subtype for each Moose class
49 => where { $_->isa($class) }
50 => optimize_as { blessed($_[0]) && $_[0]->isa($class) }
51 unless find_type_constraint($class);
54 if ($class->can('meta')) {
56 # this is the case where the metaclass pragma
57 # was used before the 'use Moose' statement to
58 # override a specific class
59 $meta = $class->meta();
60 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
61 || confess "You already have a &meta function, but it does not return a Moose::Meta::Class";
65 # this is broken currently, we actually need
66 # to allow the possiblity of an inherited
67 # meta, which will not be visible until the
68 # user 'extends' first. This needs to have
69 # more intelligence to it
70 $meta = Moose::Meta::Class->initialize($class);
71 $meta->add_method('meta' => sub {
72 # re-initialize so it inherits properly
73 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
77 # make sure they inherit from Moose::Object
78 $meta->superclasses('Moose::Object')
79 unless $meta->superclasses();
85 return subname 'Moose::extends' => sub (@) {
86 confess "Must derive at least one class" unless @_;
87 Class::MOP::load_class($_) for @_;
88 # this checks the metaclass to make sure
89 # it is correct, sometimes it can get out
90 # of sync when the classes are being built
91 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
92 $meta->superclasses(@_);
97 return subname 'Moose::with' => sub (@) {
99 confess "Must specify at least one role" unless @roles;
100 Class::MOP::load_class($_) for @roles;
101 $class->meta->_apply_all_roles(@roles);
106 return subname 'Moose::has' => sub ($;%) {
107 my ($name, %options) = @_;
108 $class->meta->_process_attribute($name, %options);
113 return subname 'Moose::before' => sub (@&) {
115 my $meta = $class->meta;
116 $meta->add_before_method_modifier($_, $code) for @_;
121 return subname 'Moose::after' => sub (@&) {
123 my $meta = $class->meta;
124 $meta->add_after_method_modifier($_, $code) for @_;
129 return subname 'Moose::around' => sub (@&) {
131 my $meta = $class->meta;
132 $meta->add_around_method_modifier($_, $code) for @_;
136 return subname 'Moose::super' => sub {};
140 return subname 'Moose::override' => sub ($&) {
141 my ($name, $method) = @_;
142 $class->meta->add_override_method_modifier($name => $method);
146 return subname 'Moose::inner' => sub {};
150 return subname 'Moose::augment' => sub (@&) {
151 my ($name, $method) = @_;
152 $class->meta->add_augment_method_modifier($name => $method);
157 # this is experimental, but I am not
158 # happy with it. If you want to try
159 # it, you will have to uncomment it
161 # There is a really good chance that
162 # this will be deprecated, dont get
165 # return subname 'Moose::self' => sub {};
168 # my $class = $CALLER;
169 # return subname 'Moose::method' => sub {
170 # my ($name, $method) = @_;
171 # $class->meta->add_method($name, sub {
174 # no warnings 'redefine';
175 # local *{$class->meta->name . '::self'} = sub { $self };
182 return \&Carp::confess;
185 return \&Scalar::Util::blessed;
189 my $exporter = Sub::Exporter::build_exporter({
190 exports => \%exports,
202 # we should never export to main
203 return if $CALLER eq 'main';
212 my $class = caller();
213 # loop through the exports ...
214 foreach my $name (keys %exports) {
215 next if $name =~ /inner|super|self/;
218 if (defined &{$class . '::' . $name}) {
219 my $keyword = \&{$class . '::' . $name};
221 # make sure it is from Moose
222 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
224 next if $pkg_name ne 'Moose';
226 # and if it is from Moose then undef the slot
227 delete ${$class . '::'}{$name};
235 ## make 'em all immutable
237 $_->meta->make_immutable(
238 inline_constructor => 0,
239 inline_accessors => 0,
241 'Moose::Meta::Attribute',
242 'Moose::Meta::Class',
243 'Moose::Meta::Instance',
245 'Moose::Meta::TypeConstraint',
246 'Moose::Meta::TypeConstraint::Union',
247 'Moose::Meta::TypeCoercion',
249 'Moose::Meta::Method',
250 'Moose::Meta::Method::Accessor',
251 'Moose::Meta::Method::Constructor',
252 'Moose::Meta::Method::Overriden',
263 Moose - A complete modern object system for Perl 5
272 has 'x' => (is => 'rw', isa => 'Int');
273 has 'y' => (is => 'rw', isa => 'Int');
288 has 'z' => (is => 'rw', isa => 'Int');
290 after 'clear' => sub {
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 Is this for real? 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
318 =head2 Is this ready for use in production?
320 Yes, I believe that it is.
322 I have two medium-to-large-ish web applications which use Moose heavily
323 and have been in production (without issue) for several months now. At
324 $work, we are re-writing our core offering in it. And several people on
325 #moose have been using it (in production) for several months now as well.
327 Of course, in the end, you need to make this call yourself. If you have
328 any questions or concerns, please feel free to email me, or even the list
329 or just stop by #moose and ask away.
331 =head2 Is Moose just Perl 6 in Perl 5?
333 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
334 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
335 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
336 instead of switching to Ruby, I wrote Moose :)
338 =head1 BUILDING CLASSES WITH MOOSE
340 Moose makes every attempt to provide as much convenience as possible during
341 class construction/definition, but still stay out of your way if you want it
342 to. Here are a few items to note when building classes with Moose.
344 Unless specified with C<extends>, any class which uses Moose will
345 inherit from L<Moose::Object>.
347 Moose will also manage all attributes (including inherited ones) that
348 are defined with C<has>. And assuming that you call C<new>, which is
349 inherited from L<Moose::Object>, then this includes properly initializing
350 all instance slots, setting defaults where appropriate, and performing any
351 type constraint checking or coercion.
353 =head1 EXPORTED FUNCTIONS
355 Moose will export a number of functions into the class's namespace which
356 can then be used to set up the class. These functions all work directly
357 on the current class.
363 This is a method which provides access to the current class's metaclass.
365 =item B<extends (@superclasses)>
367 This function will set the superclass(es) for the current class.
369 This approach is recommended instead of C<use base>, because C<use base>
370 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
371 replace it. This is important to ensure that classes which do not have
372 superclasses still properly inherit from L<Moose::Object>.
374 =item B<with (@roles)>
376 This will apply a given set of C<@roles> to the local class. Role support
377 is currently under heavy development; see L<Moose::Role> for more details.
379 =item B<has ($name, %options)>
381 This will install an attribute of a given C<$name> into the current class.
382 The list of C<%options> are the same as those provided by
383 L<Class::MOP::Attribute>, in addition to the list below which are provided
384 by Moose (L<Moose::Meta::Attribute> to be more specific):
388 =item I<is =E<gt> 'rw'|'ro'>
390 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
391 only). These will create either a read/write accessor or a read-only
392 accessor respectively, using the same name as the C<$name> of the attribute.
394 If you need more control over how your accessors are named, you can use the
395 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
397 =item I<isa =E<gt> $type_name>
399 The I<isa> option uses Moose's type constraint facilities to set up runtime
400 type checking for this attribute. Moose will perform the checks during class
401 construction, and within any accessors. The C<$type_name> argument must be a
402 string. The string can be either a class name or a type defined using
403 Moose's type definition features.
405 =item I<coerce =E<gt> (1|0)>
407 This will attempt to use coercion with the supplied type constraint to change
408 the value passed into any accessors or constructors. You B<must> have supplied
409 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
410 for an example usage.
412 =item I<does =E<gt> $role_name>
414 This will accept the name of a role which the value stored in this attribute
415 is expected to have consumed.
417 =item I<required =E<gt> (1|0)>
419 This marks the attribute as being required. This means a value must be supplied
420 during class construction, and the attribute can never be set to C<undef> with
423 =item I<weak_ref =E<gt> (1|0)>
425 This will tell the class to store the value of this attribute as a weakened
426 reference. If an attribute is a weakened reference, it B<cannot> also be
429 =item I<lazy =E<gt> (1|0)>
431 This will tell the class to not create this slot until absolutely necessary.
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 dereference 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 B<cannot> 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 $name|@names =E<gt> sub { ... }>
460 This three items are syntactic sugar for the before, after, and around method
461 modifier features that L<Class::MOP> provides. More information on these can
462 be found in the L<Class::MOP> documentation for now.
466 The keyword C<super> is a no-op when called outside of an C<override> method. In
467 the context of an C<override> method, it will call the next most appropriate
468 superclass method with the same arguments as the original method.
470 =item B<override ($name, &sub)>
472 An C<override> method is a way of explicitly 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 explicitly 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 because 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 because 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.
503 =head1 UNEXPORTING FUNCTIONS
507 Moose offers a way of removing the keywords it exports though the C<unimport>
508 method. You simply have to say C<no Moose> at the bottom of your code for this
509 to work. Here is an example:
514 has 'first_name' => (is => 'rw', isa => 'Str');
515 has 'last_name' => (is => 'rw', isa => 'Str');
519 $self->first_name . ' ' . $self->last_name
522 no Moose; # keywords are removed from the Person package
526 =head2 What does Moose stand for??
528 Moose doesn't stand for one thing in particular, however, if you
529 want, here are a few of my favorites; feel free to contribute
534 =item Make Other Object Systems Envious
536 =item Makes Object Orientation So Easy
538 =item Makes Object Orientation Spiffy- Er (sorry ingy)
540 =item Most Other Object Systems Emasculate
542 =item Moose Often Ovulate Sorta Early
544 =item Moose Offers Often Super Extensions
546 =item Meta Object Orientation Syntax Extensions
556 It should be noted that C<super> and C<inner> C<cannot> be used in the same
557 method. However, they can be combined together with the same class hierarchy;
558 see F<t/014_override_augment_inner_super.t> for an example.
560 The reason for this is that C<super> is only valid within a method
561 with the C<override> modifier, and C<inner> will never be valid within an
562 C<override> method. In fact, C<augment> will skip over any C<override> methods
563 when searching for its appropriate C<inner>.
565 This might seem like a restriction, but I am of the opinion that keeping these
566 two features separate (but interoperable) actually makes them easy to use, since
567 their behavior is then easier to predict. Time will tell if I am right or not.
571 =head1 ACKNOWLEDGEMENTS
575 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
577 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
579 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
580 and it certainly wouldn't have this name ;P
582 =item The basis of the TypeContraints module was Rob Kinyon's idea
583 originally, I just ran with it.
585 =item Thanks to mst & chansen and the whole #moose poose for all the
586 ideas/feature-requests/encouragement
588 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
596 =item L<Class::MOP> documentation
598 =item The #moose channel on irc.perl.org
600 =item The Moose mailing list - moose@perl.org
602 =item L<http://forum2.org/moose/>
604 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
606 This paper (suggested by lbr on #moose) was what lead to the implementation
607 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
608 want to understand this feature, I suggest you read this.
614 All complex software has bugs lurking in it, and this module is no
615 exception. If you find a bug please either email me, or add the bug
620 Stevan Little E<lt>stevan@iinteractive.comE<gt>
622 Christian Hansen E<lt>chansen@cpan.orgE<gt>
624 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
626 =head1 COPYRIGHT AND LICENSE
628 Copyright 2006, 2007 by Infinity Interactive, Inc.
630 L<http://www.iinteractive.com>
632 This library is free software; you can redistribute it and/or modify
633 it under the same terms as Perl itself.