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};
211 # return a true value
212 # so that it can be used
220 sub _load_all_classes {
221 foreach my $class (@_) {
222 # see if this is already
223 # loaded in the symbol table
224 next if _is_class_already_loaded($class);
225 # otherwise require it ...
226 my $file = $class . '.pm';
228 eval { CORE::require($file) };
230 "Could not load module '$class' because : $@"
235 sub _is_class_already_loaded {
238 return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
239 foreach (keys %{"${name}::"}) {
240 next if substr($_, -2, 2) eq '::';
241 return 1 if defined &{"${name}::$_"};
254 Moose - A complete modern object system for Perl 5
263 has 'x' => (is => 'rw', isa => 'Int');
264 has 'y' => (is => 'rw', isa => 'Int');
279 has 'z' => (is => 'rw', isa => 'Int');
281 after 'clear' => sub {
288 Moose is a rapidly maturing module, and is already being used by
289 a number of people. It's test suite is growing larger by the day,
290 and the docs should soon follow.
292 This said, Moose is not yet finished, and should still be considered
293 to be evolving. Much of the outer API is stable, but the internals
294 are still subject to change (although not without serious thought
297 For more details, please refer to the L<FUTURE PLANS> section of
302 Moose is an extension of the Perl 5 object system.
304 =head2 Another object system!?!?
306 Yes, I know there has been an explosion recently of new ways to
307 build object's in Perl 5, most of them based on inside-out objects
308 and other such things. Moose is different because it is not a new
309 object system for Perl 5, but instead an extension of the existing
312 Moose is built on top of L<Class::MOP>, which is a metaclass system
313 for Perl 5. This means that Moose not only makes building normal
314 Perl 5 objects better, but it also provides the power of metaclass
317 =head2 Can I use this in production? Or is this just an experiment?
319 Moose is I<based> on the prototypes and experiments I did for the Perl 6
320 meta-model; however Moose is B<NOT> an experiment/prototype, it is
321 for B<real>. I will be deploying Moose into production environments later
322 this year, and I have every intentions of using it as my de facto class
325 =head2 Is Moose just Perl 6 in Perl 5?
327 No. While Moose is very much inspired by Perl 6, it is not itself Perl 6.
328 Instead, it is an OO system for Perl 5. I built Moose because I was tired or
329 writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So
330 instead of switching to Ruby, I wrote Moose :)
332 =head1 BUILDING CLASSES WITH MOOSE
334 Moose makes every attempt to provide as much convenience as possible during
335 class construction/definition, but still stay out of your way if you want it
336 to. Here are a few items to note when building classes with Moose.
338 Unless specified with C<extends>, any class which uses Moose will
339 inherit from L<Moose::Object>.
341 Moose will also manage all attributes (including inherited ones) that
342 are defined with C<has>. And assuming that you call C<new>, which is
343 inherited from L<Moose::Object>, then this includes properly initializing
344 all instance slots, setting defaults where appropriate, and performing any
345 type constraint checking or coercion.
347 =head1 EXPORTED FUNCTIONS
349 Moose will export a number of functions into the class's namespace which
350 can then be used to set up the class. These functions all work directly
351 on the current class.
357 This is a method which provides access to the current class's metaclass.
359 =item B<extends (@superclasses)>
361 This function will set the superclass(es) for the current class.
363 This approach is recommended instead of C<use base>, because C<use base>
364 actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
365 replace it. This is important to ensure that classes which do not have
366 superclasses still properly inherit from L<Moose::Object>.
368 =item B<with (@roles)>
370 This will apply a given set of C<@roles> to the local class. Role support
371 is currently under heavy development; see L<Moose::Role> for more details.
373 =item B<has ($name, %options)>
375 This will install an attribute of a given C<$name> into the current class.
376 The list of C<%options> are the same as those provided by
377 L<Class::MOP::Attribute>, in addition to the list below which are provided
378 by Moose (L<Moose::Meta::Attribute> to be more specific):
382 =item I<is =E<gt> 'rw'|'ro'>
384 The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
385 only). These will create either a read/write accessor or a read-only
386 accessor respectively, using the same name as the C<$name> of the attribute.
388 If you need more control over how your accessors are named, you can use the
389 I<reader>, I<writer> and I<accessor> options inherited from L<Class::MOP::Attribute>.
391 =item I<isa =E<gt> $type_name>
393 The I<isa> option uses Moose's type constraint facilities to set up runtime
394 type checking for this attribute. Moose will perform the checks during class
395 construction, and within any accessors. The C<$type_name> argument must be a
396 string. The string can be either a class name or a type defined using
397 Moose's type definition features.
399 =item I<coerce =E<gt> (1|0)>
401 This will attempt to use coercion with the supplied type constraint to change
402 the value passed into any accessors or constructors. You B<must> have supplied
403 a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
404 for an example usage.
406 =item I<does =E<gt> $role_name>
408 This will accept the name of a role which the value stored in this attribute
409 is expected to have consumed.
411 =item I<required =E<gt> (1|0)>
413 This marks the attribute as being required. This means a value must be supplied
414 during class construction, and the attribute can never be set to C<undef> with
417 =item I<weak_ref =E<gt> (1|0)>
419 This will tell the class to store the value of this attribute as a weakened
420 reference. If an attribute is a weakened reference, it B<cannot> also be
423 =item I<lazy =E<gt> (1|0)>
425 This will tell the class to not create this slot until absolutely necessary.
426 If an attribute is marked as lazy it B<must> have a default supplied.
428 =item I<auto_deref =E<gt> (1|0)>
430 This tells the accessor whether to automatically dereference the value returned.
431 This is only legal if your C<isa> option is either an C<ArrayRef> or C<HashRef>.
433 =item I<trigger =E<gt> $code>
435 The trigger option is a CODE reference which will be called after the value of
436 the attribute is set. The CODE ref will be passed the instance itself, the
437 updated value and the attribute meta-object (this is for more advanced fiddling
438 and can typically be ignored in most cases). You B<cannot> have a trigger on
439 a read-only attribute.
441 =item I<handles =E<gt> [ @handles ]>
443 There is experimental support for attribute delegation using the C<handles>
444 option. More docs to come later.
448 =item B<before $name|@names =E<gt> sub { ... }>
450 =item B<after $name|@names =E<gt> sub { ... }>
452 =item B<around $name|@names =E<gt> sub { ... }>
454 This three items are syntactic sugar for the before, after, and around method
455 modifier features that L<Class::MOP> provides. More information on these can
456 be found in the L<Class::MOP> documentation for now.
460 The keyword C<super> is a no-op when called outside of an C<override> method. In
461 the context of an C<override> method, it will call the next most appropriate
462 superclass method with the same arguments as the original method.
464 =item B<override ($name, &sub)>
466 An C<override> method is a way of explicitly saying "I am overriding this
467 method from my superclass". You can call C<super> within this method, and
468 it will work as expected. The same thing I<can> be accomplished with a normal
469 method call and the C<SUPER::> pseudo-package; it is really your choice.
473 The keyword C<inner>, much like C<super>, is a no-op outside of the context of
474 an C<augment> method. You can think of C<inner> as being the inverse of
475 C<super>; the details of how C<inner> and C<augment> work is best described in
476 the L<Moose::Cookbook>.
478 =item B<augment ($name, &sub)>
480 An C<augment> method, is a way of explicitly saying "I am augmenting this
481 method from my superclass". Once again, the details of how C<inner> and
482 C<augment> work is best described in the L<Moose::Cookbook>.
486 This is the C<Carp::confess> function, and exported here because I use it
487 all the time. This feature may change in the future, so you have been warned.
491 This is the C<Scalar::Uti::blessed> function, it is exported here because I
492 use it all the time. It is highly recommended that this is used instead of
493 C<ref> anywhere you need to test for an object's class name.
497 =head1 UNEXPORTING FUNCTIONS
501 Moose offers a way of removing the keywords it exports though the C<unimport>
502 method. You simply have to say C<no Moose> at the bottom of your code for this
503 to work. Here is an example:
508 has 'first_name' => (is => 'rw', isa => 'Str');
509 has 'last_name' => (is => 'rw', isa => 'Str');
513 $self->first_name . ' ' . $self->last_name
516 no Moose; # keywords are removed from the Person package
520 =head2 What does Moose stand for??
522 Moose doesn't stand for one thing in particular, however, if you
523 want, here are a few of my favorites; feel free to contribute
528 =item Make Other Object Systems Envious
530 =item Makes Object Orientation So Easy
532 =item Makes Object Orientation Spiffy- Er (sorry ingy)
534 =item Most Other Object Systems Emasculate
536 =item Moose Often Ovulate Sorta Early
538 =item Moose Offers Often Super Extensions
540 =item Meta Object Orientation Syntax Extensions
550 It should be noted that C<super> and C<inner> C<cannot> be used in the same
551 method. However, they can be combined together with the same class hierarchy;
552 see F<t/014_override_augment_inner_super.t> for an example.
554 The reason for this is that C<super> is only valid within a method
555 with the C<override> modifier, and C<inner> will never be valid within an
556 C<override> method. In fact, C<augment> will skip over any C<override> methods
557 when searching for its appropriate C<inner>.
559 This might seem like a restriction, but I am of the opinion that keeping these
560 two features separate (but interoperable) actually makes them easy to use, since
561 their behavior is then easier to predict. Time will tell if I am right or not.
565 =head1 ACKNOWLEDGEMENTS
569 =item I blame Sam Vilain for introducing me to the insanity that is meta-models.
571 =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
573 =item Without Yuval "nothingmuch" Kogman this module would not be possible,
574 and it certainly wouldn't have this name ;P
576 =item The basis of the TypeContraints module was Rob Kinyon's idea
577 originally, I just ran with it.
579 =item Thanks to mst & chansen and the whole #moose poose for all the
580 ideas/feature-requests/encouragement
582 =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
590 =item L<Class::MOP> documentation
592 =item The #moose channel on irc.perl.org
594 =item The Moose mailing list - moose@perl.org
596 =item L<http://forum2.org/moose/>
598 =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
600 This paper (suggested by lbr on #moose) was what lead to the implementation
601 of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
602 want to understand this feature, I suggest you read this.
608 All complex software has bugs lurking in it, and this module is no
609 exception. If you find a bug please either email me, or add the bug
614 Stevan Little E<lt>stevan@iinteractive.comE<gt>
616 Christian Hansen E<lt>chansen@cpan.orgE<gt>
618 Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
620 =head1 COPYRIGHT AND LICENSE
622 Copyright 2006 by Infinity Interactive, Inc.
624 L<http://www.iinteractive.com>
626 This library is free software; you can redistribute it and/or modify
627 it under the same terms as Perl itself.