8 our $VERSION = '0.091001'; # 0.91.1
9 $VERSION = eval $VERSION;
11 require Moo::sification;
19 return if $MAKERS{$target}; # already exported into this package
20 _install_coderef "${target}::extends" => sub {
21 _load_module($_) for @_;
22 # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA
23 @{*{_getglob("${target}::ISA")}{ARRAY}} = @_;
24 if (my $old = delete $Moo::MAKERS{$target}{constructor}) {
25 delete _getstash($target)->{new};
26 Moo->_constructor_maker_for($target)
27 ->register_attribute_specs(%{$old->all_attribute_specs});
30 _install_coderef "${target}::with" => sub {
32 Moo::Role->apply_roles_to_package($target, $_[0]);
34 $MAKERS{$target} = {};
35 _install_coderef "${target}::has" => sub {
36 my ($name, %spec) = @_;
37 $class->_constructor_maker_for($target)
38 ->register_attribute_specs($name, \%spec);
39 $class->_accessor_maker_for($target)
40 ->generate_method($target, $name, \%spec);
42 foreach my $type (qw(before after around)) {
43 _install_coderef "${target}::${type}" => sub {
44 require Class::Method::Modifiers;
45 _install_modifier($target, $type, @_);
50 @{"${target}::ISA"} = do {
51 require Moo::Object; ('Moo::Object');
52 } unless @{"${target}::ISA"};
54 if ($INC{'Moo/HandleMoose.pm'}) {
55 Moo::HandleMoose::inject_fake_metaclass_for($target);
59 sub _accessor_maker_for {
60 my ($class, $target) = @_;
61 return unless $MAKERS{$target};
62 $MAKERS{$target}{accessor} ||= do {
63 my $maker_class = do {
65 if (my $defer_target =
66 (Sub::Defer::defer_info($target->can('new'))||[])->[0]
68 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
69 $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
76 require Method::Generate::Accessor;
77 'Method::Generate::Accessor'
84 sub _constructor_maker_for {
85 my ($class, $target, $select_super) = @_;
86 return unless $MAKERS{$target};
87 $MAKERS{$target}{constructor} ||= do {
88 require Method::Generate::Constructor;
90 my ($moo_constructor, $con);
92 if ($select_super && $MAKERS{$select_super}) {
94 $con = $MAKERS{$select_super}{constructor};
96 my $t_new = $target->can('new');
98 if ($t_new == Moo::Object->can('new')) {
100 } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) {
101 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
103 $moo_constructor = 1;
104 $con = $MAKERS{$pkg}{constructor};
108 $moo_constructor = 1; # no other constructor, make a Moo one
111 ($con ? ref($con) : 'Method::Generate::Constructor')
114 accessor_generator => $class->_accessor_maker_for($target),
115 construction_string => (
117 ? ($con ? $con->construction_string : undef)
118 : ('$class->'.$target.'::SUPER::new(@_)')
120 subconstructor_handler => (
121 ' if ($Moo::MAKERS{$class}) {'."\n"
122 .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
123 .' return $class->new(@_)'.";\n"
128 ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
139 Moo - Minimalist Object Orientation (with Moose compatiblity)
150 my $amount = shift || 1;
152 $self->pounds( $self->pounds - $amount );
162 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
168 isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
175 my $full = Cat::Food->new(
176 taste => 'DELICIOUS.',
177 brand => 'SWEET-TREATZ',
187 This module is an extremely light-weight, high-performance L<Moose> replacement.
188 It also avoids depending on any XS modules to allow simple deployments. The
189 name C<Moo> is based on the idea that it provides almost -but not quite- two
192 Unlike C<Mouse> this module does not aim at full L<Moose> compatibility. See
193 L</INCOMPATIBILITIES> for more details.
195 =head1 WHY MOO EXISTS
197 If you want a full object system with a rich Metaprotocol, L<Moose> is
200 I've tried several times to use L<Mouse> but it's 3x the size of Moo and
201 takes longer to load than most of my Moo based CGI scripts take to run.
203 If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
204 you want "as little as possible" - which means "no metaprotocol", which is
207 By Moo 1.0 I intend to have Moo's equivalent of L<Any::Moose> built in -
208 if Moose gets loaded, any Moo class or role will act as a Moose equivalent
211 Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
212 to make it smooth to upgrade to L<Moose> when you need more than minimal
215 =head1 Moo and Moose - NEW, EXPERIMENTAL
217 If L<Moo> detects L<Moose> being loaded, it will automatically register
218 metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
219 to use them in L<Moose> code without it ever realising you aren't using
222 Extending a L<Moose> class or consuming a L<Moose::Role> should also work.
224 This means that there is no need for anything like L<Any::Moose> for Moo
225 code - Moo and Moose code should simply interoperate without problem.
227 However, these features are new as of 0.91.0 (0.091000) so while serviceable,
228 they are absolutely certain to not be 100% yet; please do report bugs.
230 If you need to disable the metaclass creation, add:
234 to your code before Moose is loaded, but bear in mind that this switch is
235 currently global and turns the mechanism off entirely, so don't put this
236 in library code, only in a top level script as a temporary measure while
237 you send a bug report.
239 =head1 IMPORTED METHODS
243 Foo::Bar->new( attr1 => 3 );
247 Foo::Bar->new({ attr1 => 3 });
252 my ( $class, @args ) = @_;
254 unshift @args, "attr1" if @args % 2 == 1;
261 The default implementation of this method accepts a hash or hash reference of
262 named parameters. If it receives a single argument that isn't a hash reference
265 You can override this method in your class to handle other types of options
266 passed to the constructor.
268 This method should always return a hash reference of named options.
272 Define a C<BUILD> method on your class and the constructor will automatically
273 call the C<BUILD> method from parent down to child after the object has
274 been instantiated. Typically this is used for object validation or possibly
279 If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
280 a C<DESTROY> method is created on first object construction which will call
281 C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
282 method from child upwards to parents.
284 Note that the C<DESTROY> method is created on first construction of an object
285 of your class in order to not add overhead to classes without C<DEMOLISH>
286 methods; this may prove slightly surprising if you try and define your own.
290 if ($foo->does('Some::Role1')) {
294 Returns true if the object composes in the passed role.
296 =head1 IMPORTED SUBROUTINES
300 extends 'Parent::Class';
302 Declares base class. Multiple superclasses can be passed for multiple
303 inheritance (but please use roles instead).
305 Calling extends more than once will REPLACE your superclasses, not add to
306 them like 'use base' would.
313 Composes a L<Role::Tiny> into current class. Only one role may be composed in
314 at a time to allow the code to remain as simple as possible.
322 Declares an attribute for the class.
324 The options for C<has> are as follows:
330 B<required>, must be C<ro> or C<rw>. Unsurprisingly, C<ro> generates an
331 accessor that will not respond to arguments; to be clear: a getter only. C<rw>
332 will create a perlish getter/setter.
336 Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
337 does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
341 die "$_[0] is not a number!" unless looks_like_number $_[0]
344 L<Sub::Quote aware|/SUB QUOTE AWARE>
348 Takes a coderef which is meant to coerce the attribute. The basic idea is to
349 do something like the following:
351 coerce => quote_sub q{
352 $_[0] + 1 unless $_[0] % 2
355 Coerce does not require C<isa> to be defined.
357 L<Sub::Quote aware|/SUB QUOTE AWARE>
363 handles => 'RobotRole'
365 Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
366 becomes the list of methods to handle.
368 Takes a list of methods
370 handles => [ qw( one two ) ]
380 Takes a coderef which will get called any time the attribute is set. This
381 includes the constructor. Coderef will be invoked against the object with the
382 new value as an argument.
384 Note that Moose also passes the old value, if any; this feature is not yet
387 L<Sub::Quote aware|/SUB QUOTE AWARE>
391 Takes a coderef which will get called with $self as its only argument
392 to populate an attribute if no value is supplied to the constructor - or
393 if the attribute is lazy, when the attribute is first retrieved if no
394 value has yet been provided.
396 Note that if your default is fired during new() there is no guarantee that
397 other attributes have been populated yet so you should not rely on their
400 L<Sub::Quote aware|/SUB QUOTE AWARE>
404 Takes a method name which will return true if an attribute has a value.
406 A common example of this would be to call it C<has_$foo>, implying that the
407 object has a C<$foo> set.
411 Takes a method name which will be called to create the attribute - functions
412 exactly like default except that instead of calling
422 Takes a method name which will clear the attribute.
426 B<Boolean>. Set this if you want values for the attribute to be grabbed
427 lazily. This is usually a good idea if you have a L</builder> which requires
428 another attribute to be set.
432 B<Boolean>. Set this if the attribute must be passed on instantiation.
436 The value of this attribute will be the name of the method to get the value of
437 the attribute. If you like Java style methods, you might set this to
442 The value of this attribute will be the name of the method to set the value of
443 the attribute. If you like Java style methods, you might set this to
448 B<Boolean>. Set this if you want the reference that the attribute contains to
449 be weakened; use this when circular references are possible, which will cause
454 Takes the name of the key to look for at instantiation time of the object. A
455 common use of this is to make an underscored attribute have a non-underscored
456 initialization name. C<undef> means that passing the value in on instantiation
462 before foo => sub { ... };
464 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
469 around foo => sub { ... };
471 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
476 after foo => sub { ... };
478 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
481 =head1 SUB QUOTE AWARE
483 L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
484 giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
485 aware can take advantage of this.
487 =head1 INCOMPATIBILITIES WITH MOOSE
489 You can only compose one role at a time. If your application is large or
490 complex enough to warrant complex composition, you wanted L<Moose>. Note that
491 this does not mean you can only compose one role per class -
496 is absolutely fine, there's just currently no equivalent of Moose's
498 with 'FirstRole', 'SecondRole';
500 which composes the two roles together, and then applies them.
502 There is no built in type system. C<isa> is verified with a coderef, if you
503 need complex types, just make a library of coderefs, or better yet, functions
504 that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
505 to L<MooseX::Types::Moose> so that you can write
507 has days_to_live => (is => 'ro', isa => Int);
509 and have it work with both; it is hoped that providing only subrefs as an
510 API will encourage the use of other type systems as well, since it's
511 probably the weakest part of Moose design-wise.
513 C<initializer> is not supported in core since the author considers it to be a
514 bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
515 C<coerce> are more likely to be able to fulfill your needs.
517 There is no meta object. If you need this level of complexity you wanted
518 L<Moose> - Moo succeeds at being small because it explicitly does not
519 provide a metaprotocol.
521 No support for C<super>, C<override>, C<inner>, or C<augment> - override can
522 be handled by around albeit with a little more typing, and the author considers
523 augment to be a bad idea.
525 The C<dump> method is not provided by default. The author suggests loading
526 L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
527 using C<$obj-E<gt>$::Dwarn()> instead.
529 L</default> only supports coderefs, because doing otherwise is usually a
532 C<lazy_build> is not supported per se, but of course it will work if you
533 manually set all the options it implies.
535 C<auto_deref> is not supported since the author considers it a bad idea.
537 C<documentation> is not supported since it's a very poor replacement for POD.
539 Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
540 similar invocation for L<Moose> would be:
543 use warnings FATAL => "all";
545 Additionally, L<Moo> supports a set of attribute option shortcuts intended to
546 reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
547 module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
552 The nearest L<Moose> invocation would be:
557 use warnings FATAL => "all";
558 use MooseX::AttributeShortcuts;
560 or, if you're inheriting from a non-Moose class,
565 use MooseX::NonMoose;
566 use warnings FATAL => "all";
567 use MooseX::AttributeShortcuts;
569 Finally, Moose requires you to call
571 __PACKAGE__->meta->make_immutable;
573 at the end of your class to get an inlined (i.e. not horribly slow)
574 constructor. Moo does it automatically the first time ->new is called
579 IRC: #web-simple on irc.perl.org
583 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
587 dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
589 frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
591 hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
593 jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
595 ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
597 chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
599 ajgb - Alex J. G. BurzyĆski (cpan:AJGB) <ajgb@cpan.org>
601 doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
603 perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
607 Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
612 This library is free software and may be distributed under the same terms