8 our $VERSION = '0.091007'; # 0.91.7
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 $class->new(@_)'.";\n"
144 ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
155 Moo - Minimalist Object Orientation (with Moose compatiblity)
166 my $amount = shift || 1;
168 $self->pounds( $self->pounds - $amount );
178 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
184 isa => quote_sub q{ die "$_[0] is too much cat food!" unless $_[0] < 15 },
191 my $full = Cat::Food->new(
192 taste => 'DELICIOUS.',
193 brand => 'SWEET-TREATZ',
203 This module is an extremely light-weight, high-performance L<Moose> replacement.
204 It also avoids depending on any XS modules to allow simple deployments. The
205 name C<Moo> is based on the idea that it provides almost -but not quite- two
208 Unlike C<Mouse> this module does not aim at full L<Moose> compatibility. See
209 L</INCOMPATIBILITIES> for more details.
211 =head1 WHY MOO EXISTS
213 If you want a full object system with a rich Metaprotocol, L<Moose> is
216 I've tried several times to use L<Mouse> but it's 3x the size of Moo and
217 takes longer to load than most of my Moo based CGI scripts take to run.
219 If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
220 you want "as little as possible" - which means "no metaprotocol", which is
223 By Moo 1.0 I intend to have Moo's equivalent of L<Any::Moose> built in -
224 if Moose gets loaded, any Moo class or role will act as a Moose equivalent
227 Hence - Moo exists as its name - Minimal Object Orientation - with a pledge
228 to make it smooth to upgrade to L<Moose> when you need more than minimal
231 =head1 Moo and Moose - NEW, EXPERIMENTAL
233 If L<Moo> detects L<Moose> being loaded, it will automatically register
234 metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
235 to use them in L<Moose> code without it ever realising you aren't using
238 Extending a L<Moose> class or consuming a L<Moose::Role> should also work.
240 So should extending a L<Mouse> class or consuming a L<Mouse::Role>.
242 This means that there is no need for anything like L<Any::Moose> for Moo
243 code - Moo and Moose code should simply interoperate without problem. To
244 handle L<Mouse> code, you'll likely need an empty Moo role or class consuming
245 or extending the L<Mouse> stuff since it doesn't register true L<Moose>
246 metaclasses like we do.
248 However, these features are new as of 0.91.0 (0.091000) so while serviceable,
249 they are absolutely certain to not be 100% yet; please do report bugs.
251 If you need to disable the metaclass creation, add:
255 to your code before Moose is loaded, but bear in mind that this switch is
256 currently global and turns the mechanism off entirely, so don't put this
257 in library code, only in a top level script as a temporary measure while
258 you send a bug report.
260 =head1 IMPORTED METHODS
264 Foo::Bar->new( attr1 => 3 );
268 Foo::Bar->new({ attr1 => 3 });
273 my ( $class, @args ) = @_;
275 unshift @args, "attr1" if @args % 2 == 1;
282 The default implementation of this method accepts a hash or hash reference of
283 named parameters. If it receives a single argument that isn't a hash reference
286 You can override this method in your class to handle other types of options
287 passed to the constructor.
289 This method should always return a hash reference of named options.
293 Define a C<BUILD> method on your class and the constructor will automatically
294 call the C<BUILD> method from parent down to child after the object has
295 been instantiated. Typically this is used for object validation or possibly
300 If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
301 a C<DESTROY> method is created on first object construction which will call
302 C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
303 method from child upwards to parents.
305 Note that the C<DESTROY> method is created on first construction of an object
306 of your class in order to not add overhead to classes without C<DEMOLISH>
307 methods; this may prove slightly surprising if you try and define your own.
311 if ($foo->does('Some::Role1')) {
315 Returns true if the object composes in the passed role.
317 =head1 IMPORTED SUBROUTINES
321 extends 'Parent::Class';
323 Declares base class. Multiple superclasses can be passed for multiple
324 inheritance (but please use roles instead).
326 Calling extends more than once will REPLACE your superclasses, not add to
327 them like 'use base' would.
335 with 'Some::Role1', 'Some::Role2';
337 Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
338 class. An error will be raised if these roles have conflicting methods.
346 Declares an attribute for the class.
348 The options for C<has> are as follows:
354 B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>.
356 C<ro> generates an accessor that dies if you attempt to write to it - i.e.
357 a getter only - by defaulting C<reader> to the name of the attribute.
359 C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
360 C<builder> to C<_build_${attribute_name}> to allow on-demand generated
361 attributes. This feature was my attempt to fix my incompetence when
362 originally designing C<lazy_build>, and is also implemented by
363 L<MooseX::AttributeShortcuts>.
365 C<rwp> generates a reader like C<ro>, but also sets C<writer> to
366 C<_set_${attribute_name}> for attributes that are designed to be written
367 from inside of the class, but read-only from outside.
368 This feature comes from L<MooseX::AttributeShortcuts>.
370 C<rw> generates a normal getter/setter by defaulting C<accessor> to the
371 name of the attribute.
375 Takes a coderef which is meant to validate the attribute. Unlike L<Moose> Moo
376 does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
380 die "$_[0] is not a number!" unless looks_like_number $_[0]
383 L<Sub::Quote aware|/SUB QUOTE AWARE>
385 Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
386 subroutine has been supplied, C<isa> checks are not structural to your code
387 and can, if desired, be omitted on non-debug builds (although if this results
388 in an uncaught bug causing your program to break, the L<Moo> authors guarantee
389 nothing except that you get to keep both halves).
391 If you want L<MooseX::Types> style named types, look at
392 L<MooX::Types::MooseLike>.
394 To cause your C<isa> entries to be automatically mapped to named
395 L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
396 of creating an anonymous type), set:
398 $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
399 require MooseX::Types::Something;
400 return MooseX::Types::Something::TypeName();
403 Note that this example is purely illustrative; anything that returns a
404 L<Moose::Meta::TypeConstraint> object or something similar enough to it to
405 make L<Moose> happy is fine.
409 Takes a coderef which is meant to coerce the attribute. The basic idea is to
410 do something like the following:
412 coerce => quote_sub q{
413 $_[0] + 1 unless $_[0] % 2
416 Note that L<Moo> will always fire your coercion - this is to permit
417 isa entries to be used purely for bug trapping, whereas coercions are
418 always structural to your code. We do, however, apply any supplied C<isa>
419 check after the coercion has run to ensure that it returned a valid value.
421 L<Sub::Quote aware|/SUB QUOTE AWARE>
427 handles => 'RobotRole'
429 Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
430 becomes the list of methods to handle.
432 Takes a list of methods
434 handles => [ qw( one two ) ]
444 Takes a coderef which will get called any time the attribute is set. This
445 includes the constructor. Coderef will be invoked against the object with the
446 new value as an argument.
448 If you set this to just C<1>, it generates a trigger which calls the
449 C<_trigger_${attr_name}> method on C<$self>. This feature comes from
450 L<MooseX::AttributeShortcuts>.
452 Note that Moose also passes the old value, if any; this feature is not yet
455 L<Sub::Quote aware|/SUB QUOTE AWARE>
459 Takes a coderef which will get called with $self as its only argument
460 to populate an attribute if no value is supplied to the constructor - or
461 if the attribute is lazy, when the attribute is first retrieved if no
462 value has yet been provided.
464 Note that if your default is fired during new() there is no guarantee that
465 other attributes have been populated yet so you should not rely on their
468 L<Sub::Quote aware|/SUB QUOTE AWARE>
472 Takes a method name which will return true if an attribute has a value.
474 If you set this to just C<1>, the predicate is automatically named
475 C<has_${attr_name}> if your attribute's name does not start with an
476 underscore, or <_has_${attr_name_without_the_underscore}> if it does.
477 This feature comes from L<MooseX::AttributeShortcuts>.
481 Takes a method name which will be called to create the attribute - functions
482 exactly like default except that instead of calling
490 If you set this to just C<1>, the predicate is automatically named
491 C<_build_${attr_name}>. This feature comes from L<MooseX::AttributeShortcuts>.
495 Takes a method name which will clear the attribute.
497 If you set this to just C<1>, the clearer is automatically named
498 C<clear_${attr_name}> if your attribute's name does not start with an
499 underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
500 This feature comes from L<MooseX::AttributeShortcuts>.
504 B<Boolean>. Set this if you want values for the attribute to be grabbed
505 lazily. This is usually a good idea if you have a L</builder> which requires
506 another attribute to be set.
510 B<Boolean>. Set this if the attribute must be passed on instantiation.
514 The value of this attribute will be the name of the method to get the value of
515 the attribute. If you like Java style methods, you might set this to
520 The value of this attribute will be the name of the method to set the value of
521 the attribute. If you like Java style methods, you might set this to
526 B<Boolean>. Set this if you want the reference that the attribute contains to
527 be weakened; use this when circular references are possible, which will cause
532 Takes the name of the key to look for at instantiation time of the object. A
533 common use of this is to make an underscored attribute have a non-underscored
534 initialization name. C<undef> means that passing the value in on instantiation
541 before foo => sub { ... };
543 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
548 around foo => sub { ... };
550 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
555 after foo => sub { ... };
557 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
560 =head1 SUB QUOTE AWARE
562 L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
563 giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
564 aware can take advantage of this.
566 =head1 INCOMPATIBILITIES WITH MOOSE
568 There is no built in type system. C<isa> is verified with a coderef, if you
569 need complex types, just make a library of coderefs, or better yet, functions
570 that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
571 to L<MooseX::Types::Moose> so that you can write
573 has days_to_live => (is => 'ro', isa => Int);
575 and have it work with both; it is hoped that providing only subrefs as an
576 API will encourage the use of other type systems as well, since it's
577 probably the weakest part of Moose design-wise.
579 C<initializer> is not supported in core since the author considers it to be a
580 bad idea but may be supported by an extension in future. Meanwhile C<trigger> or
581 C<coerce> are more likely to be able to fulfill your needs.
583 There is no meta object. If you need this level of complexity you wanted
584 L<Moose> - Moo succeeds at being small because it explicitly does not
585 provide a metaprotocol. However, if you load L<Moose>, then
587 Class::MOP::class_of($moo_class_or_role)
589 will return an appropriate metaclass pre-populated by L<Moo>.
591 No support for C<super>, C<override>, C<inner>, or C<augment> - the author
592 considers augment to be a bad idea, and override can be translated:
594 override foo => sub {
601 my ($orig, $self) = (shift, shift);
607 The C<dump> method is not provided by default. The author suggests loading
608 L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
609 using C<$obj-E<gt>$::Dwarn()> instead.
611 L</default> only supports coderefs, because doing otherwise is usually a
614 C<lazy_build> is not supported; you are instead encouraged to use the
615 C<is => 'lazy'> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
617 C<auto_deref> is not supported since the author considers it a bad idea.
619 C<documentation> will show up in a L<Moose> metaclass created from your class
620 but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
621 is arguably not an incompatibility.
623 Since C<coerce> does not require C<isa> to be defined but L<Moose> does
624 require it, the metaclass inflation for coerce-alone is a trifle insane
625 and if you attempt to subtype the result will almost certainly break.
627 Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
628 similar invocation for L<Moose> would be:
631 use warnings FATAL => "all";
633 Additionally, L<Moo> supports a set of attribute option shortcuts intended to
634 reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
635 module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
640 The nearest L<Moose> invocation would be:
645 use warnings FATAL => "all";
646 use MooseX::AttributeShortcuts;
648 or, if you're inheriting from a non-Moose class,
653 use MooseX::NonMoose;
654 use warnings FATAL => "all";
655 use MooseX::AttributeShortcuts;
657 Finally, Moose requires you to call
659 __PACKAGE__->meta->make_immutable;
661 at the end of your class to get an inlined (i.e. not horribly slow)
662 constructor. Moo does it automatically the first time ->new is called
667 IRC: #web-simple on irc.perl.org
671 mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
675 dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
677 frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
679 hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
681 jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
683 ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
685 chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
687 ajgb - Alex J. G. BurzyĆski (cpan:AJGB) <ajgb@cpan.org>
689 doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
691 perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
695 Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
700 This library is free software and may be distributed under the same terms