8 our $AUTHORITY = 'cpan:STEVAN';
10 use Scalar::Util 'blessed', 'reftype';
12 use Sub::Name 'subname';
13 use B 'svref_2object';
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 => optimize_as { blessed($_[0]) && $_[0]->isa($class) }
39 unless find_type_constraint($class);
42 if ($class->can('meta')) {
44 # this is the case where the metaclass pragma
45 # was used before the 'use Moose' statement to
46 # override a specific class
47 $meta = $class->meta();
48 (blessed($meta) && $meta->isa('Moose::Meta::Class'))
49 || confess "You already have a &meta function, but it does not return a Moose::Meta::Class";
53 # this is broken currently, we actually need
54 # to allow the possiblity of an inherited
55 # meta, which will not be visible until the
56 # user 'extends' first. This needs to have
57 # more intelligence to it
58 $meta = Moose::Meta::Class->initialize($class);
59 $meta->add_method('meta' => sub {
60 # re-initialize so it inherits properly
61 Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
65 # make sure they inherit from Moose::Object
66 $meta->superclasses('Moose::Object')
67 unless $meta->superclasses();
73 return subname 'Moose::extends' => sub (@) {
74 confess "Must derive at least one class" unless @_;
75 Class::MOP::load_class($_) for @_;
76 # this checks the metaclass to make sure
77 # it is correct, sometimes it can get out
78 # of sync when the classes are being built
79 my $meta = $class->meta->_fix_metaclass_incompatability(@_);
80 $meta->superclasses(@_);
85 return subname 'Moose::with' => sub (@) {
87 confess "Must specify at least one role" unless @roles;
88 Class::MOP::load_class($_) for @roles;
89 $class->meta->_apply_all_roles(@roles);
94 return subname 'Moose::has' => sub ($;%) {
95 my ($name, %options) = @_;
96 $class->meta->_process_attribute($name, %options);
101 return subname 'Moose::before' => sub (@&) {
103 my $meta = $class->meta;
104 $meta->add_before_method_modifier($_, $code) for @_;
109 return subname 'Moose::after' => sub (@&) {
111 my $meta = $class->meta;
112 $meta->add_after_method_modifier($_, $code) for @_;
117 return subname 'Moose::around' => sub (@&) {
119 my $meta = $class->meta;
120 $meta->add_around_method_modifier($_, $code) for @_;
124 return subname 'Moose::super' => sub {};
128 return subname 'Moose::override' => sub ($&) {
129 my ($name, $method) = @_;
130 $class->meta->add_override_method_modifier($name => $method);
134 return subname 'Moose::inner' => sub {};
138 return subname 'Moose::augment' => sub (@&) {
139 my ($name, $method) = @_;
140 $class->meta->add_augment_method_modifier($name => $method);
145 # this is experimental, but I am not
146 # happy with it. If you want to try
147 # it, you will have to uncomment it
149 # There is a really good chance that
150 # this will be deprecated, dont get
153 # return subname 'Moose::self' => sub {};
156 # my $class = $CALLER;
157 # return subname 'Moose::method' => sub {
158 # my ($name, $method) = @_;
159 # $class->meta->add_method($name, sub {
162 # no warnings 'redefine';
163 # local *{$class->meta->name . '::self'} = sub { $self };
170 return \&Carp::confess;
173 return \&Scalar::Util::blessed;
177 my $exporter = Sub::Exporter::build_exporter({
178 exports => \%exports,
190 # we should never export to main
191 return if $CALLER eq 'main';
200 my $class = caller();
201 # loop through the exports ...
202 foreach my $name (keys %exports) {
203 next if $name =~ /inner|super|self/;
206 if (defined &{$class . '::' . $name}) {
207 my $keyword = \&{$class . '::' . $name};
209 # make sure it is from Moose
210 my $pkg_name = eval { svref_2object($keyword)->GV->STASH->NAME };
212 next if $pkg_name ne 'Moose';
214 # and if it is from Moose then undef the slot
215 delete ${$class . '::'}{$name};
223 ## make 'em all immutable
225 $_->meta->make_immutable(
226 inline_constructor => 0,
227 inline_accessors => 0,
229 'Moose::Meta::Attribute',
230 'Moose::Meta::Class',
231 'Moose::Meta::Instance',
233 'Moose::Meta::TypeConstraint',
234 'Moose::Meta::TypeConstraint::Union',
235 'Moose::Meta::TypeCoercion',
237 'Moose::Meta::Method',
238 'Moose::Meta::Method::Accessor',
239 'Moose::Meta::Method::Constructor',
240 'Moose::Meta::Method::Overriden',
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 an extension of the Perl 5 object system.
287 =head2 Another object system!?!?
289 Yes, I know there has been an explosion recently of new ways to
290 build object's in Perl 5, most of them based on inside-out objects
291 and other such things. Moose is different because it is not a new
292 object system for Perl 5, but instead an extension of the existing
295 Moose is built on top of L<Class::MOP>, which is a metaclass system
296 for Perl 5. This means that Moose not only makes building normal
297 Perl 5 objects better, but it also provides the power of metaclass
300 =head2 Is this for real? Or is this just an experiment?
302 Moose is I<based> on the prototypes and experiments I did for the Perl 6
303 meta-model; however Moose is B<NOT> an experiment/prototype, it is
306 =head2 Is this ready for use in production?
308 Yes, I believe that it is.
310 I have two medium-to-large-ish web applications which use Moose heavily
311 and have been in production (without issue) for several months now. At
312 $work, we are re-writing our core offering in it. And several people on
313 #moose have been using it (in production) for several months now as well.
315 Of course, in the end, you need to make this call yourself. If you have
316 any questions or concerns, please feel free to email me, or even the list
317 or just stop by #moose and ask away.
319 =head2 Is Moose just Perl 6 in Perl 5?
321 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
322 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
323 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
324 instead of switching to Ruby, I wrote Moose :)
326 =head1 BUILDING CLASSES WITH MOOSE
328 Moose makes every attempt to provide as much convenience as possible during
329 class construction/definition, but still stay out of your way if you want it
330 to. Here are a few items to note when building classes with Moose.
332 Unless specified with C<extends>, any class which uses Moose will
333 inherit from L<Moose::Object>.
335 Moose will also manage all attributes (including inherited ones) that
336 are defined with C<has>. And assuming that you call C<new>, which is
337 inherited from L<Moose::Object>, then this includes properly initializing
338 all instance slots, setting defaults where appropriate, and performing any
339 type constraint checking or coercion.
341 =head1 EXPORTED FUNCTIONS
343 Moose will export a number of functions into the class's namespace which
344 can then be used to set up the class. These functions all work directly
345 on the current class.
351 This is a method which provides access to the current class's metaclass.
353 =item B<extends (@superclasses)>
355 This function will set the superclass(es) for the current class.
357 This approach is recommended instead of C<use base>, because C<use base>
358 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
359 replace it. This is important to ensure that classes which do not have
360 superclasses still properly inherit from L<Moose::Object>.
362 =item B<with (@roles)>
364 This will apply a given set of C<@roles> to the local class. Role support
365 is currently under heavy development; see L<Moose::Role> for more details.
367 =item B<has ($name, %options)>
369 This will install an attribute of a given C<$name> into the current class.
370 The list of C<%options> are the same as those provided by
371 L<Class::MOP::Attribute>, in addition to the list below which are provided
372 by Moose (L<Moose::Meta::Attribute> to be more specific):
376 =item I<is =E<gt> 'rw'|'ro'>
378 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
379 only). These will create either a read/write accessor or a read-only
380 accessor respectively, using the same name as the C<$name> of the attribute.
382 If you need more control over how your accessors are named, you can use the
383 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
385 =item I<isa =E<gt> $type_name>
387 The I<isa> option uses Moose's type constraint facilities to set up runtime
388 type checking for this attribute. Moose will perform the checks during class
389 construction, and within any accessors. The C<$type_name> argument must be a
390 string. The string can be either a class name or a type defined using
391 Moose's type definition features.
393 =item I<coerce =E<gt> (1|0)>
395 This will attempt to use coercion with the supplied type constraint to change
396 the value passed into any accessors or constructors. You B<must> have supplied
397 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
398 for an example usage.
400 =item I<does =E<gt> $role_name>
402 This will accept the name of a role which the value stored in this attribute
403 is expected to have consumed.
405 =item I<required =E<gt> (1|0)>
407 This marks the attribute as being required. This means a value must be supplied
408 during class construction, and the attribute can never be set to C<undef> with
411 =item I<weak_ref =E<gt> (1|0)>
413 This will tell the class to store the value of this attribute as a weakened
414 reference. If an attribute is a weakened reference, it B<cannot> also be
417 =item I<lazy =E<gt> (1|0)>
419 This will tell the class to not create this slot until absolutely necessary.
420 If an attribute is marked as lazy it B<must> have a default supplied.
422 =item I<auto_deref =E<gt> (1|0)>
424 This tells the accessor whether to automatically dereference the value returned.
425 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
427 =item I<trigger =E<gt> $code>
429 The trigger option is a CODE reference which will be called after the value of
430 the attribute is set. The CODE ref will be passed the instance itself, the
431 updated value and the attribute meta-object (this is for more advanced fiddling
432 and can typically be ignored in most cases). You B<cannot> have a trigger on
433 a read-only attribute.
435 =item I<handles =E<gt> ARRAY | HASH | REGEXP | CODE>
437 The handles option provides Moose classes with automated delegation features.
438 This is a pretty complex and powerful option, it accepts many different option
439 formats, each with it's own benefits and drawbacks.
441 B<NOTE:> This features is no longer experimental, but it still may have subtle
442 bugs lurking in the deeper corners. So if you think you have found a bug, you
443 probably have, so please report it to me right away.
445 B<NOTE:> The class being delegated too does not need to be a Moose based class.
446 Which is why this feature is especially useful when wrapping non-Moose classes.
448 All handles option formats share the following traits.
450 You cannot override a locally defined method with a delegated method, an
451 exception will be thrown if you try. Meaning, if you define C<foo> in your
452 class, you cannot override it with a delegated C<foo>. This is almost never
453 something you would want to do, and if it is, you should do it by hand and
456 You cannot override any of the methods found in Moose::Object as well as
457 C<BUILD> or C<DEMOLISH> methods. These will not throw an exception, but will
458 silently move on to the next method in the list. My reasoning for this is that
459 you would almost never want to do this because it usually tends to break your
460 class. And as with overriding locally defined methods, if you do want to do this,
461 you should do it manually and not with Moose.
463 Below is the documentation for each option format:
469 This is the most common usage for handles. You basically pass a list of
470 method names to be delegated, and Moose will install a delegation method
471 for each one in the list.
475 This is the second most common usage for handles. Instead of a list of
476 method names, you pass a HASH ref where the key is the method name you
477 want installed locally, and the value is the name of the original method
478 in the class being delegated too.
480 This can be very useful for recursive classes like trees, here is a
481 quick example (soon to be expanded into a Moose::Cookbook::Recipe):
486 has 'node' => (is => 'rw', isa => 'Any');
491 default => sub { [] }
499 parent_node => 'node',
500 siblings => 'children',
504 In this example, the Tree package gets the C<parent_node> and C<siblings> methods
505 which delegate to the C<node> and C<children> methods of the Tree instance stored
510 The regexp option works very similar to the ARRAY option, except that it builds
511 the list of methods for you. It starts by collecting all possible methods of the
512 class being delegated too, then filters that list using the regexp supplied here.
514 B<NOTE:> An I<isa> option is required when using the regexp option format. This
515 is so that we can determine (at compile time) the method list from the class.
516 Without an I<isa> this is just not possible.
520 This is the option to use when you really want to do something funky. You should
521 only use it if you really know what you are doing as it involves manual metaclass
524 This takes a code reference, which should expect two arguments. The first is
525 the attribute meta-object this I<handles> is attached too. The second is the metaclass
526 of the class being delegated too. It expects you to return a hash (not a HASH ref)
527 of the methods you want mapped.
533 =item B<before $name|@names =E<gt> sub { ... }>
535 =item B<after $name|@names =E<gt> sub { ... }>
537 =item B<around $name|@names =E<gt> sub { ... }>
539 This three items are syntactic sugar for the before, after, and around method
540 modifier features that L<Class::MOP> provides. More information on these can
541 be found in the L<Class::MOP> documentation for now.
545 The keyword C<super> is a no-op when called outside of an C<override> method. In
546 the context of an C<override> method, it will call the next most appropriate
547 superclass method with the same arguments as the original method.
549 =item B<override ($name, &sub)>
551 An C<override> method is a way of explicitly saying "I am overriding this
552 method from my superclass". You can call C<super> within this method, and
553 it will work as expected. The same thing I<can> be accomplished with a normal
554 method call and the C<SUPER::> pseudo-package; it is really your choice.
558 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
559 an C<augment> method. You can think of C<inner> as being the inverse of
560 C<super>; the details of how C<inner> and C<augment> work is best described in
561 the L<Moose::Cookbook>.
563 =item B<augment ($name, &sub)>
565 An C<augment> method, is a way of explicitly saying "I am augmenting this
566 method from my superclass". Once again, the details of how C<inner> and
567 C<augment> work is best described in the L<Moose::Cookbook>.
571 This is the C<Carp::confess> function, and exported here because I use it
572 all the time. This feature may change in the future, so you have been warned.
576 This is the C<Scalar::Uti::blessed> function, it is exported here because I
577 use it all the time. It is highly recommended that this is used instead of
578 C<ref> anywhere you need to test for an object's class name.
582 =head1 UNEXPORTING FUNCTIONS
586 Moose offers a way of removing the keywords it exports though the C<unimport>
587 method. You simply have to say C<no Moose> at the bottom of your code for this
588 to work. Here is an example:
593 has 'first_name' => (is => 'rw', isa => 'Str');
594 has 'last_name' => (is => 'rw', isa => 'Str');
598 $self->first_name . ' ' . $self->last_name
601 no Moose; # keywords are removed from the Person package
605 =head2 What does Moose stand for??
607 Moose doesn't stand for one thing in particular, however, if you
608 want, here are a few of my favorites; feel free to contribute
613 =item Make Other Object Systems Envious
615 =item Makes Object Orientation So Easy
617 =item Makes Object Orientation Spiffy- Er (sorry ingy)
619 =item Most Other Object Systems Emasculate
621 =item Moose Often Ovulate Sorta Early
623 =item Moose Offers Often Super Extensions
625 =item Meta Object Orientation Syntax Extensions
635 It should be noted that C<super> and C<inner> C<cannot> be used in the same
636 method. However, they can be combined together with the same class hierarchy;
637 see F<t/014_override_augment_inner_super.t> for an example.
639 The reason for this is that C<super> is only valid within a method
640 with the C<override> modifier, and C<inner> will never be valid within an
641 C<override> method. In fact, C<augment> will skip over any C<override> methods
642 when searching for its appropriate C<inner>.
644 This might seem like a restriction, but I am of the opinion that keeping these
645 two features separate (but interoperable) actually makes them easy to use, since
646 their behavior is then easier to predict. Time will tell if I am right or not.
650 =head1 ACKNOWLEDGEMENTS
654 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
656 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
658 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
659 and it certainly wouldn't have this name ;P
661 =item The basis of the TypeContraints module was Rob Kinyon's idea
662 originally, I just ran with it.
664 =item Thanks to mst & chansen and the whole #moose poose for all the
665 ideas/feature-requests/encouragement/bug-finding.
667 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
675 =item L<Class::MOP> documentation
677 =item The #moose channel on irc.perl.org
679 =item The Moose mailing list - moose@perl.org
681 =item L<http://forum2.org/moose/>
683 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
685 This paper (suggested by lbr on #moose) was what lead to the implementation
686 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
687 want to understand this feature, I suggest you read this.
693 All complex software has bugs lurking in it, and this module is no
694 exception. If you find a bug please either email me, or add the bug
699 Stevan Little E<lt>stevan@iinteractive.comE<gt>
701 Christian Hansen E<lt>chansen@cpan.orgE<gt>
703 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
705 =head1 COPYRIGHT AND LICENSE
707 Copyright 2006, 2007 by Infinity Interactive, Inc.
709 L<http://www.iinteractive.com>
711 This library is free software; you can redistribute it and/or modify
712 it under the same terms as Perl itself.