8 our $VERSION = '1.000000'; # 1.0.0
9 $VERSION = eval $VERSION;
11 require Moo::sification;
15 sub _install_tracked {
16 my ($target, $name, $code) = @_;
17 $MAKERS{$target}{exports}{$name} = $code;
18 _install_coderef "${target}::${name}" => "Moo::${name}" => $code;
25 return if $MAKERS{$target}; # already exported into this package
26 $MAKERS{$target} = {};
27 _install_tracked $target => extends => sub {
28 $class->_set_superclasses($target, @_);
29 $class->_maybe_reset_handlemoose($target);
32 _install_tracked $target => with => sub {
34 Moo::Role->apply_roles_to_package($target, @_);
35 $class->_maybe_reset_handlemoose($target);
37 _install_tracked $target => has => sub {
38 my ($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);
46 foreach my $type (qw(before after around)) {
47 _install_tracked $target => $type => sub {
48 require Class::Method::Modifiers;
49 _install_modifier($target, $type, @_);
55 @{"${target}::ISA"} = do {
56 require Moo::Object; ('Moo::Object');
57 } unless @{"${target}::ISA"};
59 if ($INC{'Moo/HandleMoose.pm'}) {
60 Moo::HandleMoose::inject_fake_metaclass_for($target);
66 _unimport_coderefs($target, $MAKERS{$target});
69 sub _set_superclasses {
74 if ($INC{"Role/Tiny.pm"} && $Role::Tiny::INFO{$_}) {
76 Carp::croak("Can't extend role '$_'");
79 # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA
80 @{*{_getglob("${target}::ISA")}{ARRAY}} = @_;
81 if (my $old = delete $Moo::MAKERS{$target}{constructor}) {
82 delete _getstash($target)->{new};
83 Moo->_constructor_maker_for($target)
84 ->register_attribute_specs(%{$old->all_attribute_specs});
86 no warnings 'once'; # piss off. -- mst
87 $Moo::HandleMoose::MOUSE{$target} = [
88 grep defined, map Mouse::Util::find_meta($_), @_
89 ] if $INC{"Mouse.pm"};
92 sub _maybe_reset_handlemoose {
93 my ($class, $target) = @_;
94 if ($INC{"Moo/HandleMoose.pm"}) {
95 Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target);
99 sub _accessor_maker_for {
100 my ($class, $target) = @_;
101 return unless $MAKERS{$target};
102 $MAKERS{$target}{accessor} ||= do {
103 my $maker_class = do {
105 if (my $defer_target =
106 (Sub::Defer::defer_info($target->can('new'))||[])->[0]
108 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
109 $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
116 require Method::Generate::Accessor;
117 'Method::Generate::Accessor'
124 sub _constructor_maker_for {
125 my ($class, $target, $select_super) = @_;
126 return unless $MAKERS{$target};
127 $MAKERS{$target}{constructor} ||= do {
128 require Method::Generate::Constructor;
130 my ($moo_constructor, $con);
132 if ($select_super && $MAKERS{$select_super}) {
133 $moo_constructor = 1;
134 $con = $MAKERS{$select_super}{constructor};
136 my $t_new = $target->can('new');
138 if ($t_new == Moo::Object->can('new')) {
139 $moo_constructor = 1;
140 } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) {
141 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
143 $moo_constructor = 1;
144 $con = $MAKERS{$pkg}{constructor};
148 $moo_constructor = 1; # no other constructor, make a Moo one
151 ($con ? ref($con) : 'Method::Generate::Constructor')
154 accessor_generator => $class->_accessor_maker_for($target),
155 construction_string => (
157 ? ($con ? $con->construction_string : undef)
158 : ('$class->'.$target.'::SUPER::new(@_)')
160 subconstructor_handler => (
161 ' if ($Moo::MAKERS{$class}) {'."\n"
162 .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
163 .' return $class->new(@_)'.";\n"
164 .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n"
165 .' return $meta->new_object(@_);'."\n"
170 ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
181 Moo - Minimalist Object Orientation (with Moose compatiblity)
192 my $amount = shift || 1;
194 $self->pounds( $self->pounds - $amount );
204 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
210 isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
217 my $full = Cat::Food->new(
218 taste => 'DELICIOUS.',
219 brand => 'SWEET-TREATZ',
229 This module is an extremely light-weight subset of L<Moose> optimised for
230 rapid startup and pay for what you use.
232 It also avoids depending on any XS modules to allow simple deployments. The
233 name C<Moo> is based on the idea that it provides almost -but not quite- two
236 Unlike C<Mouse> this module does not aim at full compatibility with
237 L<Moose>'s surface syntax, preferring instead of provide full interoperability
238 via the metaclass inflation capabilites described in L</MOO AND MOOSE>.
240 For a full list of the minor differences between L<Moose> and L<Moo>'s surface
241 syntax, see L</INCOMPATIBILITIES>.
243 =head1 WHY MOO EXISTS
245 If you want a full object system with a rich Metaprotocol, L<Moose> is
248 However, sometimes you're writing a command line script or a CGI script
249 where fast startup is essential, or code designed to be deployed as a single
250 file via L<App::FatPacker>, or you're writing a CPAN module and you want it
251 to be usable by people with those constraints.
253 I've tried several times to use L<Mouse> but it's 3x the size of Moo and
254 takes longer to load than most of my Moo based CGI scripts take to run.
256 If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
257 you want "as little as possible" - which means "no metaprotocol", which is
260 Better still, if you install and load L<Moose>, we set up metaclasses for your
261 L<Moo> classes and L<Moo::Role> roles, so you can use them in L<Moose> code
262 without ever noticing that some of your codebase is using L<Moo>.
264 Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
265 to make it smooth to upgrade to L<Moose> when you need more than minimal
270 If L<Moo> detects L<Moose> being loaded, it will automatically register
271 metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
272 to use them in L<Moose> code without anybody ever noticing you aren't using
275 Extending a L<Moose> class or consuming a L<Moose::Role> will also work.
277 So will extending a L<Mouse> class or consuming a L<Mouse::Role> - but note
278 that we don't provide L<Mouse> metaclasses or metaroles so the other way
279 around doesn't work. This feature exists for L<Any::Moose> users porting to
280 L<Moo>, enabling L<Mouse> users to use L<Moo> classes is not a priority for us.
282 This means that there is no need for anything like L<Any::Moose> for Moo
283 code - Moo and Moose code should simply interoperate without problem. To
284 handle L<Mouse> code, you'll likely need an empty Moo role or class consuming
285 or extending the L<Mouse> stuff since it doesn't register true L<Moose>
286 metaclasses like L<Moo> does.
288 If you want types to be upgraded to the L<Moose> types, use
289 L<MooX::Types::MooseLike> and install the L<MooseX::Types> library to
290 match the L<MooX::Types::MooseLike> library you're using - L<Moo> will
291 load the L<MooseX::Types> library and use that type for the newly created
294 If you need to disable the metaclass creation, add:
298 to your code before Moose is loaded, but bear in mind that this switch is
299 currently global and turns the mechanism off entirely so don't put this
302 =head1 IMPORTED METHODS
306 Foo::Bar->new( attr1 => 3 );
310 Foo::Bar->new({ attr1 => 3 });
315 my ( $class, @args ) = @_;
317 unshift @args, "attr1" if @args % 2 == 1;
324 The default implementation of this method accepts a hash or hash reference of
325 named parameters. If it receives a single argument that isn't a hash reference
328 You can override this method in your class to handle other types of options
329 passed to the constructor.
331 This method should always return a hash reference of named options.
335 Define a C<BUILD> method on your class and the constructor will automatically
336 call the C<BUILD> method from parent down to child after the object has
337 been instantiated. Typically this is used for object validation or possibly
342 If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
343 a C<DESTROY> method is created on first object construction which will call
344 C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
345 method from child upwards to parents.
347 Note that the C<DESTROY> method is created on first construction of an object
348 of your class in order to not add overhead to classes without C<DEMOLISH>
349 methods; this may prove slightly surprising if you try and define your own.
353 if ($foo->does('Some::Role1')) {
357 Returns true if the object composes in the passed role.
359 =head1 IMPORTED SUBROUTINES
363 extends 'Parent::Class';
365 Declares base class. Multiple superclasses can be passed for multiple
366 inheritance (but please use roles instead).
368 Calling extends more than once will REPLACE your superclasses, not add to
369 them like 'use base' would.
377 with 'Some::Role1', 'Some::Role2';
379 Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
380 class. An error will be raised if these roles have conflicting methods.
388 Declares an attribute for the class.
390 The options for C<has> are as follows:
396 B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>.
398 C<ro> generates an accessor that dies if you attempt to write to it - i.e.
399 a getter only - by defaulting C<reader> to the name of the attribute.
401 C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
402 C<builder> to C<_build_${attribute_name}> to allow on-demand generated
403 attributes. This feature was my attempt to fix my incompetence when
404 originally designing C<lazy_build>, and is also implemented by
405 L<MooseX::AttributeShortcuts>.
407 C<rwp> generates a reader like C<ro>, but also sets C<writer> to
408 C<_set_${attribute_name}> for attributes that are designed to be written
409 from inside of the class, but read-only from outside.
410 This feature comes from L<MooseX::AttributeShortcuts>.
412 C<rw> generates a normal getter/setter by defaulting C<accessor> to the
413 name of the attribute.
417 Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
418 does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
422 die "$_[0] is not a number!" unless looks_like_number $_[0]
425 L<Sub::Quote aware|/SUB QUOTE AWARE>
427 Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
428 subroutine has been supplied, C<isa> checks are not structural to your code
429 and can, if desired, be omitted on non-debug builds (although if this results
430 in an uncaught bug causing your program to break, the L<Moo> authors guarantee
431 nothing except that you get to keep both halves).
433 If you want L<MooseX::Types> style named types, look at
434 L<MooX::Types::MooseLike>.
436 To cause your C<isa> entries to be automatically mapped to named
437 L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
438 of creating an anonymous type), set:
440 $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
441 require MooseX::Types::Something;
442 return MooseX::Types::Something::TypeName();
445 Note that this example is purely illustrative; anything that returns a
446 L<Moose::Meta::TypeConstraint> object or something similar enough to it to
447 make L<Moose> happy is fine.
451 Takes a coderef which is meant to coerce the attribute. The basic idea is to
452 do something like the following:
454 coerce => quote_sub q{
455 $_[0] + 1 unless $_[0] % 2
458 Note that L<Moo> will always fire your coercion - this is to permit
459 isa entries to be used purely for bug trapping, whereas coercions are
460 always structural to your code. We do, however, apply any supplied C<isa>
461 check after the coercion has run to ensure that it returned a valid value.
463 L<Sub::Quote aware|/SUB QUOTE AWARE>
469 handles => 'RobotRole'
471 Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
472 becomes the list of methods to handle.
474 Takes a list of methods
476 handles => [ qw( one two ) ]
486 Takes a coderef which will get called any time the attribute is set. This
487 includes the constructor. Coderef will be invoked against the object with the
488 new value as an argument.
490 If you set this to just C<1>, it generates a trigger which calls the
491 C<_trigger_${attr_name}> method on C<$self>. This feature comes from
492 L<MooseX::AttributeShortcuts>.
494 Note that Moose also passes the old value, if any; this feature is not yet
497 L<Sub::Quote aware|/SUB QUOTE AWARE>
501 Takes a coderef which will get called with $self as its only argument
502 to populate an attribute if no value is supplied to the constructor - or
503 if the attribute is lazy, when the attribute is first retrieved if no
504 value has yet been provided.
506 Note that if your default is fired during new() there is no guarantee that
507 other attributes have been populated yet so you should not rely on their
510 L<Sub::Quote aware|/SUB QUOTE AWARE>
514 Takes a method name which will return true if an attribute has a value.
516 If you set this to just C<1>, the predicate is automatically named
517 C<has_${attr_name}> if your attribute's name does not start with an
518 underscore, or <_has_${attr_name_without_the_underscore}> if it does.
519 This feature comes from L<MooseX::AttributeShortcuts>.
523 Takes a method name which will be called to create the attribute - functions
524 exactly like default except that instead of calling
532 If you set this to just C<1>, the predicate is automatically named
533 C<_build_${attr_name}>. This feature comes from L<MooseX::AttributeShortcuts>.
537 Takes a method name which will clear the attribute.
539 If you set this to just C<1>, the clearer is automatically named
540 C<clear_${attr_name}> if your attribute's name does not start with an
541 underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
542 This feature comes from L<MooseX::AttributeShortcuts>.
546 B<Boolean>. Set this if you want values for the attribute to be grabbed
547 lazily. This is usually a good idea if you have a L</builder> which requires
548 another attribute to be set.
552 B<Boolean>. Set this if the attribute must be passed on instantiation.
556 The value of this attribute will be the name of the method to get the value of
557 the attribute. If you like Java style methods, you might set this to
562 The value of this attribute will be the name of the method to set the value of
563 the attribute. If you like Java style methods, you might set this to
568 B<Boolean>. Set this if you want the reference that the attribute contains to
569 be weakened; use this when circular references are possible, which will cause
574 Takes the name of the key to look for at instantiation time of the object. A
575 common use of this is to make an underscored attribute have a non-underscored
576 initialization name. C<undef> means that passing the value in on instantiation
583 before foo => sub { ... };
585 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
590 around foo => sub { ... };
592 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
597 after foo => sub { ... };
599 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
602 =head1 SUB QUOTE AWARE
604 L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
605 giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
606 aware can take advantage of this.
608 =head1 INCOMPATIBILITIES WITH MOOSE
610 There is no built in type system. C<isa> is verified with a coderef, if you
611 need complex types, just make a library of coderefs, or better yet, functions
612 that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
613 to L<MooseX::Types::Moose> so that you can write
615 has days_to_live => (is => 'ro', isa => Int);
617 and have it work with both; it is hoped that providing only subrefs as an
618 API will encourage the use of other type systems as well, since it's
619 probably the weakest part of Moose design-wise.
621 C<initializer> is not supported in core since the author considers it to be a
622 bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
623 C<coerce> are more likely to be able to fulfill your needs.
625 There is no meta object. If you need this level of complexity you wanted
626 L<Moose> - Moo succeeds at being small because it explicitly does not
627 provide a metaprotocol. However, if you load L<Moose>, then
629 Class::MOP::class_of($moo_class_or_role)
631 will return an appropriate metaclass pre-populated by L<Moo>.
633 No support for C<super>, C<override>, C<inner>, or C<augment> - the author
634 considers augment to be a bad idea, and override can be translated:
636 override foo => sub {
643 my ($orig, $self) = (shift, shift);
649 The C<dump> method is not provided by default. The author suggests loading
650 L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
651 using C<$obj-E<gt>$::Dwarn()> instead.
653 L</default> only supports coderefs, because doing otherwise is usually a
656 C<lazy_build> is not supported; you are instead encouraged to use the
657 C<is => 'lazy'> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
659 C<auto_deref> is not supported since the author considers it a bad idea.
661 C<documentation> will show up in a L<Moose> metaclass created from your class
662 but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
663 is arguably not an incompatibility.
665 Since C<coerce> does not require C<isa> to be defined but L<Moose> does
666 require it, the metaclass inflation for coerce-alone is a trifle insane
667 and if you attempt to subtype the result will almost certainly break.
669 Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
670 similar invocation for L<Moose> would be:
673 use warnings FATAL => "all";
675 Additionally, L<Moo> supports a set of attribute option shortcuts intended to
676 reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
677 module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
682 The nearest L<Moose> invocation would be:
687 use warnings FATAL => "all";
688 use MooseX::AttributeShortcuts;
690 or, if you're inheriting from a non-Moose class,
695 use MooseX::NonMoose;
696 use warnings FATAL => "all";
697 use MooseX::AttributeShortcuts;
699 Finally, Moose requires you to call
701 __PACKAGE__->meta->make_immutable;
703 at the end of your class to get an inlined (i.e. not horribly slow)
704 constructor. Moo does it automatically the first time ->new is called
709 Users' IRC: #moose on irc.perl.org
711 Development and contribution IRC: #web-simple on irc.perl.org
715 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
719 dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
721 frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
723 hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
725 jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
727 ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
729 chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
731 ajgb - Alex J. G. Burzyński (cpan:AJGB) <ajgb@cpan.org>
733 doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
735 perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
737 Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com>
739 ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org>
743 Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
748 This library is free software and may be distributed under the same terms