8 our $VERSION = '0.091009'; # 0.91.9
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 $Moo::HandleMoose::MOUSE{$target} = [
30 grep defined, map Mouse::Util::find_meta($_), @_
31 ] if $INC{"Mouse.pm"};
32 $class->_maybe_reset_handlemoose($target);
35 _install_coderef "${target}::with" => "Moo::with" => sub {
37 Moo::Role->apply_roles_to_package($target, @_);
38 $class->_maybe_reset_handlemoose($target);
40 $MAKERS{$target} = {};
41 _install_coderef "${target}::has" => "Moo::has" => sub {
42 my ($name, %spec) = @_;
43 $class->_constructor_maker_for($target)
44 ->register_attribute_specs($name, \%spec);
45 $class->_accessor_maker_for($target)
46 ->generate_method($target, $name, \%spec);
47 $class->_maybe_reset_handlemoose($target);
50 foreach my $type (qw(before after around)) {
51 _install_coderef "${target}::${type}" => "Moo::${type}" => sub {
52 require Class::Method::Modifiers;
53 _install_modifier($target, $type, @_);
59 @{"${target}::ISA"} = do {
60 require Moo::Object; ('Moo::Object');
61 } unless @{"${target}::ISA"};
63 if ($INC{'Moo/HandleMoose.pm'}) {
64 Moo::HandleMoose::inject_fake_metaclass_for($target);
68 sub _maybe_reset_handlemoose {
69 my ($class, $target) = @_;
70 if ($INC{"Moo/HandleMoose.pm"}) {
71 Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target);
75 sub _accessor_maker_for {
76 my ($class, $target) = @_;
77 return unless $MAKERS{$target};
78 $MAKERS{$target}{accessor} ||= do {
79 my $maker_class = do {
81 if (my $defer_target =
82 (Sub::Defer::defer_info($target->can('new'))||[])->[0]
84 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
85 $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
92 require Method::Generate::Accessor;
93 'Method::Generate::Accessor'
100 sub _constructor_maker_for {
101 my ($class, $target, $select_super) = @_;
102 return unless $MAKERS{$target};
103 $MAKERS{$target}{constructor} ||= do {
104 require Method::Generate::Constructor;
106 my ($moo_constructor, $con);
108 if ($select_super && $MAKERS{$select_super}) {
109 $moo_constructor = 1;
110 $con = $MAKERS{$select_super}{constructor};
112 my $t_new = $target->can('new');
114 if ($t_new == Moo::Object->can('new')) {
115 $moo_constructor = 1;
116 } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) {
117 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
119 $moo_constructor = 1;
120 $con = $MAKERS{$pkg}{constructor};
124 $moo_constructor = 1; # no other constructor, make a Moo one
127 ($con ? ref($con) : 'Method::Generate::Constructor')
130 accessor_generator => $class->_accessor_maker_for($target),
131 construction_string => (
133 ? ($con ? $con->construction_string : undef)
134 : ('$class->'.$target.'::SUPER::new(@_)')
136 subconstructor_handler => (
137 ' if ($Moo::MAKERS{$class}) {'."\n"
138 .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
139 .' return $class->new(@_)'.";\n"
140 .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n"
141 .' return $meta->new_object(@_);'."\n"
146 ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
157 Moo - Minimalist Object Orientation (with Moose compatiblity)
168 my $amount = shift || 1;
170 $self->pounds( $self->pounds - $amount );
180 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
186 isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
193 my $full = Cat::Food->new(
194 taste => 'DELICIOUS.',
195 brand => 'SWEET-TREATZ',
205 This module is an extremely light-weight, high-performance L<Moose> replacement.
206 It also avoids depending on any XS modules to allow simple deployments. The
207 name C<Moo> is based on the idea that it provides almost -but not quite- two
210 Unlike C<Mouse> this module does not aim at full L<Moose> compatibility. See
211 L</INCOMPATIBILITIES> for more details.
213 =head1 WHY MOO EXISTS
215 If you want a full object system with a rich Metaprotocol, L<Moose> is
218 I've tried several times to use L<Mouse> but it's 3x the size of Moo and
219 takes longer to load than most of my Moo based CGI scripts take to run.
221 If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
222 you want "as little as possible" - which means "no metaprotocol", which is
225 By Moo 1.0 I intend to have Moo's equivalent of L<Any::Moose> built in -
226 if Moose gets loaded, any Moo class or role will act as a Moose equivalent
229 Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
230 to make it smooth to upgrade to L<Moose> when you need more than minimal
233 =head1 Moo and Moose - NEW, EXPERIMENTAL
235 If L<Moo> detects L<Moose> being loaded, it will automatically register
236 metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
237 to use them in L<Moose> code without it ever realising you aren't using
240 Extending a L<Moose> class or consuming a L<Moose::Role> should also work.
242 So should extending a L<Mouse> class or consuming a L<Mouse::Role>.
244 This means that there is no need for anything like L<Any::Moose> for Moo
245 code - Moo and Moose code should simply interoperate without problem. To
246 handle L<Mouse> code, you'll likely need an empty Moo role or class consuming
247 or extending the L<Mouse> stuff since it doesn't register true L<Moose>
248 metaclasses like we do.
250 However, these features are new as of 0.91.0 (0.091000) so while serviceable,
251 they are absolutely certain to not be 100% yet; please do report bugs.
253 If you need to disable the metaclass creation, add:
257 to your code before Moose is loaded, but bear in mind that this switch is
258 currently global and turns the mechanism off entirely, so don't put this
259 in library code, only in a top level script as a temporary measure while
260 you send a bug report.
262 =head1 IMPORTED METHODS
266 Foo::Bar->new( attr1 => 3 );
270 Foo::Bar->new({ attr1 => 3 });
275 my ( $class, @args ) = @_;
277 unshift @args, "attr1" if @args % 2 == 1;
284 The default implementation of this method accepts a hash or hash reference of
285 named parameters. If it receives a single argument that isn't a hash reference
288 You can override this method in your class to handle other types of options
289 passed to the constructor.
291 This method should always return a hash reference of named options.
295 Define a C<BUILD> method on your class and the constructor will automatically
296 call the C<BUILD> method from parent down to child after the object has
297 been instantiated. Typically this is used for object validation or possibly
302 If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
303 a C<DESTROY> method is created on first object construction which will call
304 C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
305 method from child upwards to parents.
307 Note that the C<DESTROY> method is created on first construction of an object
308 of your class in order to not add overhead to classes without C<DEMOLISH>
309 methods; this may prove slightly surprising if you try and define your own.
313 if ($foo->does('Some::Role1')) {
317 Returns true if the object composes in the passed role.
319 =head1 IMPORTED SUBROUTINES
323 extends 'Parent::Class';
325 Declares base class. Multiple superclasses can be passed for multiple
326 inheritance (but please use roles instead).
328 Calling extends more than once will REPLACE your superclasses, not add to
329 them like 'use base' would.
337 with 'Some::Role1', 'Some::Role2';
339 Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
340 class. An error will be raised if these roles have conflicting methods.
348 Declares an attribute for the class.
350 The options for C<has> are as follows:
356 B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>.
358 C<ro> generates an accessor that dies if you attempt to write to it - i.e.
359 a getter only - by defaulting C<reader> to the name of the attribute.
361 C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
362 C<builder> to C<_build_${attribute_name}> to allow on-demand generated
363 attributes. This feature was my attempt to fix my incompetence when
364 originally designing C<lazy_build>, and is also implemented by
365 L<MooseX::AttributeShortcuts>.
367 C<rwp> generates a reader like C<ro>, but also sets C<writer> to
368 C<_set_${attribute_name}> for attributes that are designed to be written
369 from inside of the class, but read-only from outside.
370 This feature comes from L<MooseX::AttributeShortcuts>.
372 C<rw> generates a normal getter/setter by defaulting C<accessor> to the
373 name of the attribute.
377 Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
378 does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
382 die "$_[0] is not a number!" unless looks_like_number $_[0]
385 L<Sub::Quote aware|/SUB QUOTE AWARE>
387 Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
388 subroutine has been supplied, C<isa> checks are not structural to your code
389 and can, if desired, be omitted on non-debug builds (although if this results
390 in an uncaught bug causing your program to break, the L<Moo> authors guarantee
391 nothing except that you get to keep both halves).
393 If you want L<MooseX::Types> style named types, look at
394 L<MooX::Types::MooseLike>.
396 To cause your C<isa> entries to be automatically mapped to named
397 L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
398 of creating an anonymous type), set:
400 $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
401 require MooseX::Types::Something;
402 return MooseX::Types::Something::TypeName();
405 Note that this example is purely illustrative; anything that returns a
406 L<Moose::Meta::TypeConstraint> object or something similar enough to it to
407 make L<Moose> happy is fine.
411 Takes a coderef which is meant to coerce the attribute. The basic idea is to
412 do something like the following:
414 coerce => quote_sub q{
415 $_[0] + 1 unless $_[0] % 2
418 Note that L<Moo> will always fire your coercion - this is to permit
419 isa entries to be used purely for bug trapping, whereas coercions are
420 always structural to your code. We do, however, apply any supplied C<isa>
421 check after the coercion has run to ensure that it returned a valid value.
423 L<Sub::Quote aware|/SUB QUOTE AWARE>
429 handles => 'RobotRole'
431 Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
432 becomes the list of methods to handle.
434 Takes a list of methods
436 handles => [ qw( one two ) ]
446 Takes a coderef which will get called any time the attribute is set. This
447 includes the constructor. Coderef will be invoked against the object with the
448 new value as an argument.
450 If you set this to just C<1>, it generates a trigger which calls the
451 C<_trigger_${attr_name}> method on C<$self>. This feature comes from
452 L<MooseX::AttributeShortcuts>.
454 Note that Moose also passes the old value, if any; this feature is not yet
457 L<Sub::Quote aware|/SUB QUOTE AWARE>
461 Takes a coderef which will get called with $self as its only argument
462 to populate an attribute if no value is supplied to the constructor - or
463 if the attribute is lazy, when the attribute is first retrieved if no
464 value has yet been provided.
466 Note that if your default is fired during new() there is no guarantee that
467 other attributes have been populated yet so you should not rely on their
470 L<Sub::Quote aware|/SUB QUOTE AWARE>
474 Takes a method name which will return true if an attribute has a value.
476 If you set this to just C<1>, the predicate is automatically named
477 C<has_${attr_name}> if your attribute's name does not start with an
478 underscore, or <_has_${attr_name_without_the_underscore}> if it does.
479 This feature comes from L<MooseX::AttributeShortcuts>.
483 Takes a method name which will be called to create the attribute - functions
484 exactly like default except that instead of calling
492 If you set this to just C<1>, the predicate is automatically named
493 C<_build_${attr_name}>. This feature comes from L<MooseX::AttributeShortcuts>.
497 Takes a method name which will clear the attribute.
499 If you set this to just C<1>, the clearer is automatically named
500 C<clear_${attr_name}> if your attribute's name does not start with an
501 underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
502 This feature comes from L<MooseX::AttributeShortcuts>.
506 B<Boolean>. Set this if you want values for the attribute to be grabbed
507 lazily. This is usually a good idea if you have a L</builder> which requires
508 another attribute to be set.
512 B<Boolean>. Set this if the attribute must be passed on instantiation.
516 The value of this attribute will be the name of the method to get the value of
517 the attribute. If you like Java style methods, you might set this to
522 The value of this attribute will be the name of the method to set the value of
523 the attribute. If you like Java style methods, you might set this to
528 B<Boolean>. Set this if you want the reference that the attribute contains to
529 be weakened; use this when circular references are possible, which will cause
534 Takes the name of the key to look for at instantiation time of the object. A
535 common use of this is to make an underscored attribute have a non-underscored
536 initialization name. C<undef> means that passing the value in on instantiation
543 before foo => sub { ... };
545 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
550 around foo => sub { ... };
552 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
557 after foo => sub { ... };
559 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
562 =head1 SUB QUOTE AWARE
564 L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
565 giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
566 aware can take advantage of this.
568 =head1 INCOMPATIBILITIES WITH MOOSE
570 There is no built in type system. C<isa> is verified with a coderef, if you
571 need complex types, just make a library of coderefs, or better yet, functions
572 that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
573 to L<MooseX::Types::Moose> so that you can write
575 has days_to_live => (is => 'ro', isa => Int);
577 and have it work with both; it is hoped that providing only subrefs as an
578 API will encourage the use of other type systems as well, since it's
579 probably the weakest part of Moose design-wise.
581 C<initializer> is not supported in core since the author considers it to be a
582 bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
583 C<coerce> are more likely to be able to fulfill your needs.
585 There is no meta object. If you need this level of complexity you wanted
586 L<Moose> - Moo succeeds at being small because it explicitly does not
587 provide a metaprotocol. However, if you load L<Moose>, then
589 Class::MOP::class_of($moo_class_or_role)
591 will return an appropriate metaclass pre-populated by L<Moo>.
593 No support for C<super>, C<override>, C<inner>, or C<augment> - the author
594 considers augment to be a bad idea, and override can be translated:
596 override foo => sub {
603 my ($orig, $self) = (shift, shift);
609 The C<dump> method is not provided by default. The author suggests loading
610 L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
611 using C<$obj-E<gt>$::Dwarn()> instead.
613 L</default> only supports coderefs, because doing otherwise is usually a
616 C<lazy_build> is not supported; you are instead encouraged to use the
617 C<is => 'lazy'> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
619 C<auto_deref> is not supported since the author considers it a bad idea.
621 C<documentation> will show up in a L<Moose> metaclass created from your class
622 but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
623 is arguably not an incompatibility.
625 Since C<coerce> does not require C<isa> to be defined but L<Moose> does
626 require it, the metaclass inflation for coerce-alone is a trifle insane
627 and if you attempt to subtype the result will almost certainly break.
629 Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
630 similar invocation for L<Moose> would be:
633 use warnings FATAL => "all";
635 Additionally, L<Moo> supports a set of attribute option shortcuts intended to
636 reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
637 module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
642 The nearest L<Moose> invocation would be:
647 use warnings FATAL => "all";
648 use MooseX::AttributeShortcuts;
650 or, if you're inheriting from a non-Moose class,
655 use MooseX::NonMoose;
656 use warnings FATAL => "all";
657 use MooseX::AttributeShortcuts;
659 Finally, Moose requires you to call
661 __PACKAGE__->meta->make_immutable;
663 at the end of your class to get an inlined (i.e. not horribly slow)
664 constructor. Moo does it automatically the first time ->new is called
669 IRC: #web-simple on irc.perl.org
673 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
677 dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
679 frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
681 hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
683 jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
685 ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
687 chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
689 ajgb - Alex J. G. BurzyĆski (cpan:AJGB) <ajgb@cpan.org>
691 doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
693 perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
697 Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
702 This library is free software and may be distributed under the same terms