8 our $VERSION = '0.091003'; # 0.91.3
9 $VERSION = eval $VERSION;
11 require Moo::sification;
19 return if $MAKERS{$target}; # already exported into this package
20 _install_coderef "${target}::extends" => "Moo::extends" => sub {
21 _load_module($_) 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});
29 $class->_maybe_reset_handlemoose($target);
31 _install_coderef "${target}::with" => "Moo::with" => sub {
33 Moo::Role->apply_roles_to_package($target, $_[0]);
34 $class->_maybe_reset_handlemoose($target);
36 $MAKERS{$target} = {};
37 _install_coderef "${target}::has" => "Moo::has" => sub {
38 my ($name, %spec) = @_;
39 $class->_constructor_maker_for($target)
40 ->register_attribute_specs($name, \%spec);
41 $class->_accessor_maker_for($target)
42 ->generate_method($target, $name, \%spec);
43 $class->_maybe_reset_handlemoose($target);
45 foreach my $type (qw(before after around)) {
46 _install_coderef "${target}::${type}" => "Moo::${type}" => sub {
47 require Class::Method::Modifiers;
48 _install_modifier($target, $type, @_);
53 @{"${target}::ISA"} = do {
54 require Moo::Object; ('Moo::Object');
55 } unless @{"${target}::ISA"};
57 if ($INC{'Moo/HandleMoose.pm'}) {
58 Moo::HandleMoose::inject_fake_metaclass_for($target);
62 sub _maybe_reset_handlemoose {
63 my ($class, $target) = @_;
64 if ($INC{"Moo/HandleMoose.pm"}) {
65 Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target);
69 sub _accessor_maker_for {
70 my ($class, $target) = @_;
71 return unless $MAKERS{$target};
72 $MAKERS{$target}{accessor} ||= do {
73 my $maker_class = do {
75 if (my $defer_target =
76 (Sub::Defer::defer_info($target->can('new'))||[])->[0]
78 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
79 $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
86 require Method::Generate::Accessor;
87 'Method::Generate::Accessor'
94 sub _constructor_maker_for {
95 my ($class, $target, $select_super) = @_;
96 return unless $MAKERS{$target};
97 $MAKERS{$target}{constructor} ||= do {
98 require Method::Generate::Constructor;
100 my ($moo_constructor, $con);
102 if ($select_super && $MAKERS{$select_super}) {
103 $moo_constructor = 1;
104 $con = $MAKERS{$select_super}{constructor};
106 my $t_new = $target->can('new');
108 if ($t_new == Moo::Object->can('new')) {
109 $moo_constructor = 1;
110 } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) {
111 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
113 $moo_constructor = 1;
114 $con = $MAKERS{$pkg}{constructor};
118 $moo_constructor = 1; # no other constructor, make a Moo one
121 ($con ? ref($con) : 'Method::Generate::Constructor')
124 accessor_generator => $class->_accessor_maker_for($target),
125 construction_string => (
127 ? ($con ? $con->construction_string : undef)
128 : ('$class->'.$target.'::SUPER::new(@_)')
130 subconstructor_handler => (
131 ' if ($Moo::MAKERS{$class}) {'."\n"
132 .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
133 .' return $class->new(@_)'.";\n"
138 ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
149 Moo - Minimalist Object Orientation (with Moose compatiblity)
160 my $amount = shift || 1;
162 $self->pounds( $self->pounds - $amount );
172 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
178 isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
185 my $full = Cat::Food->new(
186 taste => 'DELICIOUS.',
187 brand => 'SWEET-TREATZ',
197 This module is an extremely light-weight, high-performance L<Moose> replacement.
198 It also avoids depending on any XS modules to allow simple deployments. The
199 name C<Moo> is based on the idea that it provides almost -but not quite- two
202 Unlike C<Mouse> this module does not aim at full L<Moose> compatibility. See
203 L</INCOMPATIBILITIES> for more details.
205 =head1 WHY MOO EXISTS
207 If you want a full object system with a rich Metaprotocol, L<Moose> is
210 I've tried several times to use L<Mouse> but it's 3x the size of Moo and
211 takes longer to load than most of my Moo based CGI scripts take to run.
213 If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
214 you want "as little as possible" - which means "no metaprotocol", which is
217 By Moo 1.0 I intend to have Moo's equivalent of L<Any::Moose> built in -
218 if Moose gets loaded, any Moo class or role will act as a Moose equivalent
221 Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
222 to make it smooth to upgrade to L<Moose> when you need more than minimal
225 =head1 Moo and Moose - NEW, EXPERIMENTAL
227 If L<Moo> detects L<Moose> being loaded, it will automatically register
228 metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
229 to use them in L<Moose> code without it ever realising you aren't using
232 Extending a L<Moose> class or consuming a L<Moose::Role> should also work.
234 This means that there is no need for anything like L<Any::Moose> for Moo
235 code - Moo and Moose code should simply interoperate without problem.
237 However, these features are new as of 0.91.0 (0.091000) so while serviceable,
238 they are absolutely certain to not be 100% yet; please do report bugs.
240 If you need to disable the metaclass creation, add:
244 to your code before Moose is loaded, but bear in mind that this switch is
245 currently global and turns the mechanism off entirely, so don't put this
246 in library code, only in a top level script as a temporary measure while
247 you send a bug report.
249 =head1 IMPORTED METHODS
253 Foo::Bar->new( attr1 => 3 );
257 Foo::Bar->new({ attr1 => 3 });
262 my ( $class, @args ) = @_;
264 unshift @args, "attr1" if @args % 2 == 1;
271 The default implementation of this method accepts a hash or hash reference of
272 named parameters. If it receives a single argument that isn't a hash reference
275 You can override this method in your class to handle other types of options
276 passed to the constructor.
278 This method should always return a hash reference of named options.
282 Define a C<BUILD> method on your class and the constructor will automatically
283 call the C<BUILD> method from parent down to child after the object has
284 been instantiated. Typically this is used for object validation or possibly
289 If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
290 a C<DESTROY> method is created on first object construction which will call
291 C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
292 method from child upwards to parents.
294 Note that the C<DESTROY> method is created on first construction of an object
295 of your class in order to not add overhead to classes without C<DEMOLISH>
296 methods; this may prove slightly surprising if you try and define your own.
300 if ($foo->does('Some::Role1')) {
304 Returns true if the object composes in the passed role.
306 =head1 IMPORTED SUBROUTINES
310 extends 'Parent::Class';
312 Declares base class. Multiple superclasses can be passed for multiple
313 inheritance (but please use roles instead).
315 Calling extends more than once will REPLACE your superclasses, not add to
316 them like 'use base' would.
324 with 'Some::Role1', 'Some::Role2';
326 Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
327 class. An error will be raised if these roles have conflicting methods.
335 Declares an attribute for the class.
337 The options for C<has> are as follows:
343 B<required>, may be C<ro>, C<rw>, C<lazy> or C<rwp>.
345 C<ro> generates an accessor that dies if you attempt to write to it - i.e.
346 a getter only - by defaulting C<reader> to the name of the attribute.
348 C<rw> generates a normal getter/setter by defauting C<accessor> to the
349 name of the attribute.
351 C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
352 C<builder> to C<_build_${attribute_name}> to allow on-demand generated
353 attributes. This feature was my attempt to fix my incompetence when
354 originally designing C<lazy_build>, and is also implemented by
355 L<MooseX::AttributeShortcuts>.
357 C<rwp> generates a reader like C<ro>, but also sets C<writer> to
358 C<_set_${attribute_name}> for attributes that are designed to be written
359 from inside of the class, but read-only from outside.
360 This feature comes from L<MooseX::AttributeShortcuts>.
364 Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
365 does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
369 die "$_[0] is not a number!" unless looks_like_number $_[0]
372 L<Sub::Quote aware|/SUB QUOTE AWARE>
374 Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
375 subroutine has been supplied, C<isa> checks are not structural to your code
376 and can, if desired, be omitted on non-debug builds (although if this results
377 in an uncaught bug causing your program to break, the L<Moo> authors guarantee
378 nothing except that you get to keep both halves).
380 If you want L<MooseX::Types> style named types, look at
381 L<MooX::Types::MooseLike>.
383 To cause your C<isa> entries to be automatically mapped to named
384 L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
385 of creating an anonymous type), set:
387 $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
388 require MooseX::Types::Something;
389 return MooseX::Types::Something::TypeName();
392 Note that this example is purely illustrative; anything that returns a
393 L<Moose::Meta::TypeConstraint> object or something similar enough to it to
394 make L<Moose> happy is fine.
398 Takes a coderef which is meant to coerce the attribute. The basic idea is to
399 do something like the following:
401 coerce => quote_sub q{
402 $_[0] + 1 unless $_[0] % 2
405 Note that L<Moo> will always fire your coercion - this is to permit
406 isa entries to be used purely for bug trapping, whereas coercions are
407 always structural to your code. We do, however, apply any supplied C<isa>
408 check after the coercion has run to ensure that it returned a valid value.
410 L<Sub::Quote aware|/SUB QUOTE AWARE>
416 handles => 'RobotRole'
418 Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
419 becomes the list of methods to handle.
421 Takes a list of methods
423 handles => [ qw( one two ) ]
433 Takes a coderef which will get called any time the attribute is set. This
434 includes the constructor. Coderef will be invoked against the object with the
435 new value as an argument.
437 If you set this to just C<1>, it generates a trigger which calls the
438 C<_trigger_${attr_name}> method on C<$self>. This feature comes from
439 L<MooseX::AttributeShortcuts>.
441 Note that Moose also passes the old value, if any; this feature is not yet
444 L<Sub::Quote aware|/SUB QUOTE AWARE>
448 Takes a coderef which will get called with $self as its only argument
449 to populate an attribute if no value is supplied to the constructor - or
450 if the attribute is lazy, when the attribute is first retrieved if no
451 value has yet been provided.
453 Note that if your default is fired during new() there is no guarantee that
454 other attributes have been populated yet so you should not rely on their
457 L<Sub::Quote aware|/SUB QUOTE AWARE>
461 Takes a method name which will return true if an attribute has a value.
463 If you set this to just C<1>, the predicate is automatically named
464 C<has_${attr_name}> if your attribute's name does not start with an
465 underscore, or <_has_${attr_name_without_the_underscore}> if it does.
466 This feature comes from L<MooseX::AttributeShortcuts>.
470 Takes a method name which will be called to create the attribute - functions
471 exactly like default except that instead of calling
479 If you set this to just C<1>, the predicate is automatically named
480 C<_build_${attr_name}>. This feature comes from L<MooseX::AttributeShortcuts>.
484 Takes a method name which will clear the attribute.
486 If you set this to just C<1>, the clearer is automatically named
487 C<clear_${attr_name}> if your attribute's name does not start with an
488 underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
489 This feature comes from L<MooseX::AttributeShortcuts>.
493 B<Boolean>. Set this if you want values for the attribute to be grabbed
494 lazily. This is usually a good idea if you have a L</builder> which requires
495 another attribute to be set.
499 B<Boolean>. Set this if the attribute must be passed on instantiation.
503 The value of this attribute will be the name of the method to get the value of
504 the attribute. If you like Java style methods, you might set this to
509 The value of this attribute will be the name of the method to set the value of
510 the attribute. If you like Java style methods, you might set this to
515 B<Boolean>. Set this if you want the reference that the attribute contains to
516 be weakened; use this when circular references are possible, which will cause
521 Takes the name of the key to look for at instantiation time of the object. A
522 common use of this is to make an underscored attribute have a non-underscored
523 initialization name. C<undef> means that passing the value in on instantiation
530 before foo => sub { ... };
532 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
537 around foo => sub { ... };
539 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
544 after foo => sub { ... };
546 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
549 =head1 SUB QUOTE AWARE
551 L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
552 giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
553 aware can take advantage of this.
555 =head1 INCOMPATIBILITIES WITH MOOSE
557 There is no built in type system. C<isa> is verified with a coderef, if you
558 need complex types, just make a library of coderefs, or better yet, functions
559 that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
560 to L<MooseX::Types::Moose> so that you can write
562 has days_to_live => (is => 'ro', isa => Int);
564 and have it work with both; it is hoped that providing only subrefs as an
565 API will encourage the use of other type systems as well, since it's
566 probably the weakest part of Moose design-wise.
568 C<initializer> is not supported in core since the author considers it to be a
569 bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
570 C<coerce> are more likely to be able to fulfill your needs.
572 There is no meta object. If you need this level of complexity you wanted
573 L<Moose> - Moo succeeds at being small because it explicitly does not
574 provide a metaprotocol. However, if you load L<Moose>, then
576 Class::MOP::class_of($moo_class_or_role)
578 will return an appropriate metaclass pre-populated by L<Moo>.
580 No support for C<super>, C<override>, C<inner>, or C<augment> - override can
581 be handled by around albeit with a little more typing, and the author considers
582 augment to be a bad idea.
584 The C<dump> method is not provided by default. The author suggests loading
585 L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
586 using C<$obj-E<gt>$::Dwarn()> instead.
588 L</default> only supports coderefs, because doing otherwise is usually a
591 C<lazy_build> is not supported; you are instead encouraged to use the
592 C<is => 'lazy'> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
594 C<auto_deref> is not supported since the author considers it a bad idea.
596 C<documentation> will show up in a L<Moose> metaclass created from your class
597 but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
598 is arguably not an incompatibility.
600 Since C<coerce> does not require C<isa> to be defined but L<Moose> does
601 require it, the metaclass inflation for coerce-alone is a trifle insane
602 and if you attempt to subtype the result will almost certainly break.
604 Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
605 similar invocation for L<Moose> would be:
608 use warnings FATAL => "all";
610 Additionally, L<Moo> supports a set of attribute option shortcuts intended to
611 reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
612 module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
617 The nearest L<Moose> invocation would be:
622 use warnings FATAL => "all";
623 use MooseX::AttributeShortcuts;
625 or, if you're inheriting from a non-Moose class,
630 use MooseX::NonMoose;
631 use warnings FATAL => "all";
632 use MooseX::AttributeShortcuts;
634 Finally, Moose requires you to call
636 __PACKAGE__->meta->make_immutable;
638 at the end of your class to get an inlined (i.e. not horribly slow)
639 constructor. Moo does it automatically the first time ->new is called
644 IRC: #web-simple on irc.perl.org
648 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
652 dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
654 frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
656 hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
658 jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
660 ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
662 chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
664 ajgb - Alex J. G. BurzyĆski (cpan:AJGB) <ajgb@cpan.org>
666 doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
668 perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
672 Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
677 This library is free software and may be distributed under the same terms