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For fastest.pl
  Run on Fri Jan 31 20:48:16 2014
Reported on Fri Jan 31 20:49:41 2014

Filename/opt/perl-5.18.1/lib/site_perl/5.18.1/Moo.pm
StatementsExecuted 220 statements in 3.28ms
Subroutines
Calls P F Exclusive
Time
Inclusive
Time
Subroutine
5215.14ms5.67msMoo::::_accessor_maker_forMoo::_accessor_maker_for
3221.82ms10.4msMoo::::_constructor_maker_forMoo::_constructor_maker_for (recurses: max depth 1, inclusive time 5.76ms)
1111.34ms1.91msMoo::::BEGIN@4Moo::BEGIN@4
332917µs4.37msMoo::::importMoo::import
111739µs974µsMoo::::BEGIN@3Moo::BEGIN@3
111736µs1.04msMoo::::BEGIN@6Moo::BEGIN@6
184189µs333µsMoo::::_install_trackedMoo::_install_tracked
21112µs17µsMoo::::_maybe_reset_handlemooseMoo::_maybe_reset_handlemoose
11111µs23µsMoo::::BEGIN@105Moo::BEGIN@105
11110µs752µsMoo::::BEGIN@5Moo::BEGIN@5
1119µs24µsMoo::::BEGIN@70Moo::BEGIN@70
0000s0sMoo::::__ANON__[:33]Moo::__ANON__[:33]
0000s0sMoo::::__ANON__[:38]Moo::__ANON__[:38]
0000s0sMoo::::__ANON__[:59]Moo::__ANON__[:59]
0000s0sMoo::::__ANON__[:65]Moo::__ANON__[:65]
0000s0sMoo::::_set_superclassesMoo::_set_superclasses
0000s0sMoo::::unimportMoo::unimport
Call graph for these subroutines as a Graphviz dot language file.
Line State
ments
Time
on line
Calls Time
in subs
Code
1package Moo;
2
33132µs31.04ms
# spent 974µs (739+235) within Moo::BEGIN@3 which was called: # once (739µs+235µs) by Foo::Moo::BEGIN@116 at line 3
use strictures 1;
# spent 974µs making 1 call to Moo::BEGIN@3 # spent 47µs making 1 call to strictures::import # spent 22µs making 1 call to strictures::VERSION
42139µs21.98ms
# spent 1.91ms (1.34+572µs) within Moo::BEGIN@4 which was called: # once (1.34ms+572µs) by Foo::Moo::BEGIN@116 at line 4
use Moo::_Utils;
# spent 1.91ms making 1 call to Moo::BEGIN@4 # spent 69µs making 1 call to Exporter::import
5243µs21.49ms
# spent 752µs (10+742) within Moo::BEGIN@5 which was called: # once (10µs+742µs) by Foo::Moo::BEGIN@116 at line 5
use B 'perlstring';
# spent 752µs making 1 call to Moo::BEGIN@5 # spent 742µs making 1 call to Exporter::import
62655µs11.04ms
# spent 1.04ms (736µs+306µs) within Moo::BEGIN@6 which was called: # once (736µs+306µs) by Foo::Moo::BEGIN@116 at line 6
use Sub::Defer ();
# spent 1.04ms making 1 call to Moo::BEGIN@6
7
81900nsour $VERSION = '1.003001';
9120µs$VERSION = eval $VERSION;
# spent 3µs executing statements in string eval
10
11184µsrequire Moo::sification;
12
131200nsour %MAKERS;
14
15
# spent 333µs (89+244) within Moo::_install_tracked which was called 18 times, avg 18µs/call: # 9 times (39µs+120µs) by Moo::import at line 65, avg 18µs/call # 3 times (23µs+54µs) by Moo::import at line 33, avg 26µs/call # 3 times (14µs+35µs) by Moo::import at line 38, avg 16µs/call # 3 times (12µs+35µs) by Moo::import at line 59, avg 16µs/call
sub _install_tracked {
16188µs my ($target, $name, $code) = @_;
171815µs $MAKERS{$target}{exports}{$name} = $code;
181860µs18244µs _install_coderef "${target}::${name}" => "Moo::${name}" => $code;
# spent 244µs making 18 calls to Moo::_Utils::_install_coderef, avg 14µs/call
19}
20
21
# spent 4.37ms (917µs+3.46) within Moo::import which was called 3 times, avg 1.46ms/call: # once (812µs+1.57ms) by Foo::Moo::BEGIN@116 at line 116 of fastest.pl # once (52µs+1.01ms) by Method::Generate::Constructor::BEGIN@186 at line 186 of Method/Generate/Constructor.pm # once (53µs+875µs) by Foo::Moo::QS::BEGIN@129 at line 129 of fastest.pl
sub import {
2233µs my $target = caller;
2332µs my $class = shift;
2434µs3133µs strictures->import;
# spent 133µs making 3 calls to strictures::import, avg 44µs/call
2531µs if ($Role::Tiny::INFO{$target} and $Role::Tiny::INFO{$target}{is_role}) {
26 die "Cannot import Moo into a role";
27 }
2833µs $MAKERS{$target} ||= {};
29 _install_tracked $target => extends => sub {
30 $class->_set_superclasses($target, @_);
31 $class->_maybe_reset_handlemoose($target);
32 return;
33315µs378µs };
# spent 78µs making 3 calls to Moo::_install_tracked, avg 26µs/call
34 _install_tracked $target => with => sub {
35 require Moo::Role;
36 Moo::Role->apply_roles_to_package($target, @_);
37 $class->_maybe_reset_handlemoose($target);
38311µs348µs };
# spent 48µs making 3 calls to Moo::_install_tracked, avg 16µs/call
39 _install_tracked $target => has => sub {
402900ns my $name_proto = shift;
4123µs my @name_proto = ref $name_proto eq 'ARRAY' ? @$name_proto : $name_proto;
4221µs if (@_ % 2 != 0) {
43 require Carp;
44 Carp::croak("Invalid options for " . join(', ', map "'$_'", @name_proto)
45 . " attribute(s): even number of arguments expected, got " . scalar @_)
46 }
4723µs my %spec = @_;
4822µs foreach my $name (@name_proto) {
49 # Note that when multiple attributes specified, each attribute
50 # needs a separate \%specs hashref
5122µs my $spec_ref = @name_proto > 1 ? +{%spec} : \%spec;
5229µs410.4ms $class->_constructor_maker_for($target)
# spent 10.4ms making 2 calls to Moo::_constructor_maker_for, avg 5.19ms/call # spent 19µs making 2 calls to Method::Generate::Constructor::register_attribute_specs, avg 10µs/call
53 ->register_attribute_specs($name, $spec_ref);
5427µs4437µs $class->_accessor_maker_for($target)
# spent 428µs making 2 calls to Method::Generate::Accessor::generate_method, avg 214µs/call # spent 8µs making 2 calls to Moo::_accessor_maker_for, avg 4µs/call
55 ->generate_method($target, $name, $spec_ref);
5626µs217µs $class->_maybe_reset_handlemoose($target);
# spent 17µs making 2 calls to Moo::_maybe_reset_handlemoose, avg 8µs/call
57 }
5828µs return;
59312µs348µs };
# spent 48µs making 3 calls to Moo::_install_tracked, avg 16µs/call
6032µs foreach my $type (qw(before after around)) {
61 _install_tracked $target => $type => sub {
62 require Class::Method::Modifiers;
63 _install_modifier($target, $type, @_);
64 return;
65936µs9159µs };
# spent 159µs making 9 calls to Moo::_install_tracked, avg 18µs/call
66 }
6732µs return if $MAKERS{$target}{is_class}; # already exported into this package
6832µs $MAKERS{$target}{is_class} = 1;
69 {
705334µs238µs
# spent 24µs (9+14) within Moo::BEGIN@70 which was called: # once (9µs+14µs) by Foo::Moo::BEGIN@116 at line 70
no strict 'refs';
# spent 24µs making 1 call to Moo::BEGIN@70 # spent 14µs making 1 call to strict::unimport
71 @{"${target}::ISA"} = do {
72492µs require Moo::Object; ('Moo::Object');
73326µs } unless @{"${target}::ISA"};
74 }
75318µs32.89ms if ($INC{'Moo/HandleMoose.pm'}) {
# spent 2.89ms making 3 calls to Moo::HandleMoose::inject_fake_metaclass_for, avg 964µs/call
76 Moo::HandleMoose::inject_fake_metaclass_for($target);
77 }
78}
79
80sub unimport {
81 my $target = caller;
82 _unimport_coderefs($target, $MAKERS{$target});
83}
84
85sub _set_superclasses {
86 my $class = shift;
87 my $target = shift;
88 foreach my $superclass (@_) {
89 _load_module($superclass);
90 if ($INC{"Role/Tiny.pm"} && $Role::Tiny::INFO{$superclass}) {
91 require Carp;
92 Carp::croak("Can't extend role '$superclass'");
93 }
94 }
95 # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA
96 @{*{_getglob("${target}::ISA")}{ARRAY}} = @_;
97 if (my $old = delete $Moo::MAKERS{$target}{constructor}) {
98 delete _getstash($target)->{new};
99 Moo->_constructor_maker_for($target)
100 ->register_attribute_specs(%{$old->all_attribute_specs});
101 }
102 elsif (!$target->isa('Moo::Object')) {
103 Moo->_constructor_maker_for($target);
104 }
10521.10ms234µs
# spent 23µs (11+11) within Moo::BEGIN@105 which was called: # once (11µs+11µs) by Foo::Moo::BEGIN@116 at line 105
no warnings 'once'; # piss off. -- mst
# spent 23µs making 1 call to Moo::BEGIN@105 # spent 11µs making 1 call to warnings::unimport
106 $Moo::HandleMoose::MOUSE{$target} = [
107 grep defined, map Mouse::Util::find_meta($_), @_
108 ] if Mouse::Util->can('find_meta');
109}
110
111
# spent 17µs (12+5) within Moo::_maybe_reset_handlemoose which was called 2 times, avg 8µs/call: # 2 times (12µs+5µs) by Moo::has at line 56, avg 8µs/call
sub _maybe_reset_handlemoose {
11221µs my ($class, $target) = @_;
11329µs25µs if ($INC{"Moo/HandleMoose.pm"}) {
# spent 5µs making 2 calls to Moo::HandleMoose::maybe_reinject_fake_metaclass_for, avg 2µs/call
114 Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target);
115 }
116}
117
118
# spent 5.67ms (5.14+531µs) within Moo::_accessor_maker_for which was called 5 times, avg 1.13ms/call: # 3 times (5.13ms+531µs) by Moo::_constructor_maker_for at line 189, avg 1.89ms/call # 2 times (8µs+0s) by Moo::has at line 54, avg 4µs/call
sub _accessor_maker_for {
11952µs my ($class, $target) = @_;
12055µs return unless $MAKERS{$target};
121517µs $MAKERS{$target}{accessor} ||= do {
12232µs my $maker_class = do {
12331µs if (my $m = do {
124317µs612µs if (my $defer_target =
# spent 8µs making 3 calls to Sub::Defer::defer_info, avg 3µs/call # spent 3µs making 3 calls to UNIVERSAL::can, avg 1µs/call
125 (Sub::Defer::defer_info($target->can('new'))||[])->[0]
126 ) {
127 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
128 $MAKERS{$pkg} && $MAKERS{$pkg}{accessor};
129 } else {
1303700ns undef;
131 }
132 }) {
133 ref($m);
134 } else {
135398µs require Method::Generate::Accessor;
1363400ns 'Method::Generate::Accessor'
137 }
138 };
13939µs343µs $maker_class->new;
# spent 43µs making 3 calls to Moo::Object::new, avg 14µs/call
140 }
141}
142
143
# spent 10.4ms (1.82+8.57) within Moo::_constructor_maker_for which was called 3 times, avg 3.46ms/call: # 2 times (1.76ms+8.62ms) by Moo::has at line 52, avg 5.19ms/call # once (56µs+-56µs) by Moo::_constructor_maker_for at line 187 of Method/Generate/Constructor.pm
sub _constructor_maker_for {
14432µs my ($class, $target, $select_super) = @_;
14532µs return unless $MAKERS{$target};
146317µs $MAKERS{$target}{constructor} ||= do {
1473135µs require Method::Generate::Constructor;
1483800ns require Sub::Defer;
1493300ns my ($moo_constructor, $con);
150
15131µs if ($select_super && $MAKERS{$select_super}) {
152 $moo_constructor = 1;
153 $con = $MAKERS{$select_super}{constructor};
154 } else {
155333µs39µs my $t_new = $target->can('new');
# spent 9µs making 3 calls to UNIVERSAL::can, avg 3µs/call
15632µs if ($t_new) {
157315µs33µs if ($t_new == Moo::Object->can('new')) {
# spent 3µs making 3 calls to UNIVERSAL::can, avg 967ns/call
158 $moo_constructor = 1;
159 } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) {
160 my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/);
161 if ($MAKERS{$pkg}) {
162 $moo_constructor = 1;
163 $con = $MAKERS{$pkg}{constructor};
164 }
165 }
166 } else {
167 $moo_constructor = 1; # no other constructor, make a Moo one
168 }
169 };
170 ($con ? ref($con) : 'Method::Generate::Constructor')
171 ->new(
172 package => $target,
173 accessor_generator => $class->_accessor_maker_for($target),
174 construction_string => (
175 $moo_constructor
176 ? ($con ? $con->construction_string : undef)
177 : ('$class->'.$target.'::SUPER::new($class->can(q[FOREIGNBUILDARGS]) ? $class->FOREIGNBUILDARGS(@_) : @_)')
178 ),
179 subconstructor_handler => (
180 ' if ($Moo::MAKERS{$class}) {'."\n"
181 .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n"
182 .' return $class->new(@_)'.";\n"
183 .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n"
184 .' return $meta->new_object($class->BUILDARGS(@_));'."\n"
185 .' }'."\n"
186 ),
187 )
188 ->install_delayed
189343µs157.01ms ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}})
# spent 5.67ms making 3 calls to Moo::_accessor_maker_for, avg 1.89ms/call # spent 1.18ms making 2 calls to Method::Generate::Constructor::new, avg 592µs/call # spent 120µs making 3 calls to Method::Generate::Constructor::install_delayed, avg 40µs/call # spent 20µs making 3 calls to Method::Generate::Constructor::register_attribute_specs, avg 7µs/call # spent 18µs making 1 call to Moo::Object::new # spent 5µs making 3 calls to B::perlstring, avg 2µs/call
190 }
191}
192
19314µs1;
194=pod
195
196=encoding utf-8
197
198=head1 NAME
199
200Moo - Minimalist Object Orientation (with Moose compatibility)
201
202=head1 SYNOPSIS
203
204 package Cat::Food;
205
206 use Moo;
207
208 sub feed_lion {
209 my $self = shift;
210 my $amount = shift || 1;
211
212 $self->pounds( $self->pounds - $amount );
213 }
214
215 has taste => (
216 is => 'ro',
217 );
218
219 has brand => (
220 is => 'ro',
221 isa => sub {
222 die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ'
223 },
224 );
225
226 has pounds => (
227 is => 'rw',
228 isa => sub { die "$_[0] is too much cat food!" unless $_[0] < 15 },
229 );
230
231 1;
232
233And elsewhere:
234
235 my $full = Cat::Food->new(
236 taste => 'DELICIOUS.',
237 brand => 'SWEET-TREATZ',
238 pounds => 10,
239 );
240
241 $full->feed_lion;
242
243 say $full->pounds;
244
245=head1 DESCRIPTION
246
247This module is an extremely light-weight subset of L<Moose> optimised for
248rapid startup and "pay only for what you use".
249
250It also avoids depending on any XS modules to allow simple deployments. The
251name C<Moo> is based on the idea that it provides almost -- but not quite -- two
252thirds of L<Moose>.
253
254Unlike L<Mouse> this module does not aim at full compatibility with
255L<Moose>'s surface syntax, preferring instead of provide full interoperability
256via the metaclass inflation capabilities described in L</MOO AND MOOSE>.
257
258For a full list of the minor differences between L<Moose> and L<Moo>'s surface
259syntax, see L</INCOMPATIBILITIES WITH MOOSE>.
260
261=head1 WHY MOO EXISTS
262
263If you want a full object system with a rich Metaprotocol, L<Moose> is
264already wonderful.
265
266However, sometimes you're writing a command line script or a CGI script
267where fast startup is essential, or code designed to be deployed as a single
268file via L<App::FatPacker>, or you're writing a CPAN module and you want it
269to be usable by people with those constraints.
270
271I've tried several times to use L<Mouse> but it's 3x the size of Moo and
272takes longer to load than most of my Moo based CGI scripts take to run.
273
274If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>,
275you want "as little as possible" -- which means "no metaprotocol", which is
276what Moo provides.
277
278Better still, if you install and load L<Moose>, we set up metaclasses for your
279L<Moo> classes and L<Moo::Role> roles, so you can use them in L<Moose> code
280without ever noticing that some of your codebase is using L<Moo>.
281
282Hence, Moo exists as its name -- Minimal Object Orientation -- with a pledge
283to make it smooth to upgrade to L<Moose> when you need more than minimal
284features.
285
286=head1 MOO AND MOOSE
287
288If L<Moo> detects L<Moose> being loaded, it will automatically register
289metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able
290to use them in L<Moose> code without anybody ever noticing you aren't using
291L<Moose> everywhere.
292
293L<Moo> will also create L<Moose type constraints|Moose::Manual::Types> for
294classes and roles, so that C<< isa => 'MyClass' >> and C<< isa => 'MyRole' >>
295work the same as for L<Moose> classes and roles.
296
297Extending a L<Moose> class or consuming a L<Moose::Role> will also work.
298
299So will extending a L<Mouse> class or consuming a L<Mouse::Role> - but note
300that we don't provide L<Mouse> metaclasses or metaroles so the other way
301around doesn't work. This feature exists for L<Any::Moose> users porting to
302L<Moo>; enabling L<Mouse> users to use L<Moo> classes is not a priority for us.
303
304This means that there is no need for anything like L<Any::Moose> for Moo
305code - Moo and Moose code should simply interoperate without problem. To
306handle L<Mouse> code, you'll likely need an empty Moo role or class consuming
307or extending the L<Mouse> stuff since it doesn't register true L<Moose>
308metaclasses like L<Moo> does.
309
310If you want types to be upgraded to the L<Moose> types, use
311L<MooX::Types::MooseLike> and install the L<MooseX::Types> library to
312match the L<MooX::Types::MooseLike> library you're using - L<Moo> will
313load the L<MooseX::Types> library and use that type for the newly created
314metaclass.
315
316If you need to disable the metaclass creation, add:
317
318 no Moo::sification;
319
320to your code before Moose is loaded, but bear in mind that this switch is
321currently global and turns the mechanism off entirely so don't put this
322in library code.
323
324=head1 MOO AND CLASS::XSACCESSOR
325
326If a new enough version of L<Class::XSAccessor> is available, it
327will be used to generate simple accessors, readers, and writers for
328a speed boost. Simple accessors are those without lazy defaults,
329type checks/coercions, or triggers. Readers and writers generated
330by L<Class::XSAccessor> will behave slightly differently: they will
331reject attempts to call them with the incorrect number of parameters.
332
333=head1 MOO VERSUS ANY::MOOSE
334
335L<Any::Moose> will load L<Mouse> normally, and L<Moose> in a program using
336L<Moose> - which theoretically allows you to get the startup time of L<Mouse>
337without disadvantaging L<Moose> users.
338
339Sadly, this doesn't entirely work, since the selection is load order dependent
340- L<Moo>'s metaclass inflation system explained above in L</MOO AND MOOSE> is
341significantly more reliable.
342
343So if you want to write a CPAN module that loads fast or has only pure perl
344dependencies but is also fully usable by L<Moose> users, you should be using
345L<Moo>.
346
347For a full explanation, see the article
348L<http://shadow.cat/blog/matt-s-trout/moo-versus-any-moose> which explains
349the differing strategies in more detail and provides a direct example of
350where L<Moo> succeeds and L<Any::Moose> fails.
351
352=head1 IMPORTED METHODS
353
354=head2 new
355
356 Foo::Bar->new( attr1 => 3 );
357
358or
359
360 Foo::Bar->new({ attr1 => 3 });
361
362=head2 BUILDARGS
363
364 sub BUILDARGS {
365 my ( $class, @args ) = @_;
366
367 unshift @args, "attr1" if @args % 2 == 1;
368
369 return { @args };
370 };
371
372 Foo::Bar->new( 3 );
373
374The default implementation of this method accepts a hash or hash reference of
375named parameters. If it receives a single argument that isn't a hash reference
376it throws an error.
377
378You can override this method in your class to handle other types of options
379passed to the constructor.
380
381This method should always return a hash reference of named options.
382
383=head2 FOREIGNBUILDARGS
384
385If you are inheriting from a non-Moo class, the arguments passed to the parent
386class constructor can be manipulated by defining a C<FOREIGNBUILDARGS> method.
387It will receive the same arguments as C<BUILDARGS>, and should return a list
388of arguments to pass to the parent class constructor.
389
390=head2 BUILD
391
392Define a C<BUILD> method on your class and the constructor will automatically
393call the C<BUILD> method from parent down to child after the object has
394been instantiated. Typically this is used for object validation or possibly
395logging.
396
397=head2 DEMOLISH
398
399If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy,
400a C<DESTROY> method is created on first object construction which will call
401C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH>
402method from child upwards to parents.
403
404Note that the C<DESTROY> method is created on first construction of an object
405of your class in order to not add overhead to classes without C<DEMOLISH>
406methods; this may prove slightly surprising if you try and define your own.
407
408=head2 does
409
410 if ($foo->does('Some::Role1')) {
411 ...
412 }
413
414Returns true if the object composes in the passed role.
415
416=head1 IMPORTED SUBROUTINES
417
418=head2 extends
419
420 extends 'Parent::Class';
421
422Declares base class. Multiple superclasses can be passed for multiple
423inheritance (but please use roles instead).
424
425Calling extends more than once will REPLACE your superclasses, not add to
426them like 'use base' would.
427
428=head2 with
429
430 with 'Some::Role1';
431
432or
433
434 with 'Some::Role1', 'Some::Role2';
435
436Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current
437class. An error will be raised if these roles have conflicting methods.
438
439=head2 has
440
441 has attr => (
442 is => 'ro',
443 );
444
445Declares an attribute for the class.
446
447 package Foo;
448 use Moo;
449 has 'attr' => (
450 is => 'ro'
451 );
452
453 package Bar;
454 use Moo;
455 extends 'Foo';
456 has '+attr' => (
457 default => sub { "blah" },
458 );
459
460Using the C<+> notation, it's possible to override an attribute.
461
462The options for C<has> are as follows:
463
464=over 2
465
466=item * is
467
468B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>.
469
470C<ro> generates an accessor that dies if you attempt to write to it - i.e.
471a getter only - by defaulting C<reader> to the name of the attribute.
472
473C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and
474C<builder> to C<_build_${attribute_name}> to allow on-demand generated
475attributes. This feature was my attempt to fix my incompetence when
476originally designing C<lazy_build>, and is also implemented by
477L<MooseX::AttributeShortcuts>. There is, however, nothing to stop you
478using C<lazy> and C<builder> yourself with C<rwp> or C<rw> - it's just that
479this isn't generally a good idea so we don't provide a shortcut for it.
480
481C<rwp> generates a reader like C<ro>, but also sets C<writer> to
482C<_set_${attribute_name}> for attributes that are designed to be written
483from inside of the class, but read-only from outside.
484This feature comes from L<MooseX::AttributeShortcuts>.
485
486C<rw> generates a normal getter/setter by defaulting C<accessor> to the
487name of the attribute.
488
489=item * isa
490
491Takes a coderef which is meant to validate the attribute. Unlike L<Moose>, Moo
492does not include a basic type system, so instead of doing C<< isa => 'Num' >>,
493one should do
494
495 isa => sub {
496 die "$_[0] is not a number!" unless looks_like_number $_[0]
497 },
498
499Note that the return value is ignored, only whether the sub lives or
500dies matters.
501
502L<Sub::Quote aware|/SUB QUOTE AWARE>
503
504Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion
505subroutine has been supplied, C<isa> checks are not structural to your code
506and can, if desired, be omitted on non-debug builds (although if this results
507in an uncaught bug causing your program to break, the L<Moo> authors guarantee
508nothing except that you get to keep both halves).
509
510If you want L<MooseX::Types> style named types, look at
511L<MooX::Types::MooseLike>.
512
513To cause your C<isa> entries to be automatically mapped to named
514L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour
515of creating an anonymous type), set:
516
517 $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub {
518 require MooseX::Types::Something;
519 return MooseX::Types::Something::TypeName();
520 };
521
522Note that this example is purely illustrative; anything that returns a
523L<Moose::Meta::TypeConstraint> object or something similar enough to it to
524make L<Moose> happy is fine.
525
526=item * coerce
527
528Takes a coderef which is meant to coerce the attribute. The basic idea is to
529do something like the following:
530
531 coerce => sub {
532 $_[0] % 2 ? $_[0] : $_[0] + 1
533 },
534
535Note that L<Moo> will always fire your coercion: this is to permit
536C<isa> entries to be used purely for bug trapping, whereas coercions are
537always structural to your code. We do, however, apply any supplied C<isa>
538check after the coercion has run to ensure that it returned a valid value.
539
540L<Sub::Quote aware|/SUB QUOTE AWARE>
541
542=item * handles
543
544Takes a string
545
546 handles => 'RobotRole'
547
548Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which
549becomes the list of methods to handle.
550
551Takes a list of methods
552
553 handles => [ qw( one two ) ]
554
555Takes a hashref
556
557 handles => {
558 un => 'one',
559 }
560
561=item * C<trigger>
562
563Takes a coderef which will get called any time the attribute is set. This
564includes the constructor, but not default or built values. Coderef will be
565invoked against the object with the new value as an argument.
566
567If you set this to just C<1>, it generates a trigger which calls the
568C<_trigger_${attr_name}> method on C<$self>. This feature comes from
569L<MooseX::AttributeShortcuts>.
570
571Note that Moose also passes the old value, if any; this feature is not yet
572supported.
573
574L<Sub::Quote aware|/SUB QUOTE AWARE>
575
576=item * C<default>
577
578Takes a coderef which will get called with $self as its only argument
579to populate an attribute if no value is supplied to the constructor - or
580if the attribute is lazy, when the attribute is first retrieved if no
581value has yet been provided.
582
583If a simple scalar is provided, it will be inlined as a string. Any non-code
584reference (hash, array) will result in an error - for that case instead use
585a code reference that returns the desired value.
586
587Note that if your default is fired during new() there is no guarantee that
588other attributes have been populated yet so you should not rely on their
589existence.
590
591L<Sub::Quote aware|/SUB QUOTE AWARE>
592
593=item * C<predicate>
594
595Takes a method name which will return true if an attribute has a value.
596
597If you set this to just C<1>, the predicate is automatically named
598C<has_${attr_name}> if your attribute's name does not start with an
599underscore, or C<_has_${attr_name_without_the_underscore}> if it does.
600This feature comes from L<MooseX::AttributeShortcuts>.
601
602=item * C<builder>
603
604Takes a method name which will be called to create the attribute - functions
605exactly like default except that instead of calling
606
607 $default->($self);
608
609Moo will call
610
611 $self->$builder;
612
613The following features come from L<MooseX::AttributeShortcuts>:
614
615If you set this to just C<1>, the builder is automatically named
616C<_build_${attr_name}>.
617
618If you set this to a coderef or code-convertible object, that variable will be
619installed under C<$class::_build_${attr_name}> and the builder set to the same
620name.
621
622=item * C<clearer>
623
624Takes a method name which will clear the attribute.
625
626If you set this to just C<1>, the clearer is automatically named
627C<clear_${attr_name}> if your attribute's name does not start with an
628underscore, or <_clear_${attr_name_without_the_underscore}> if it does.
629This feature comes from L<MooseX::AttributeShortcuts>.
630
631=item * C<lazy>
632
633B<Boolean>. Set this if you want values for the attribute to be grabbed
634lazily. This is usually a good idea if you have a L</builder> which requires
635another attribute to be set.
636
637=item * C<required>
638
639B<Boolean>. Set this if the attribute must be passed on instantiation.
640
641=item * C<reader>
642
643The value of this attribute will be the name of the method to get the value of
644the attribute. If you like Java style methods, you might set this to
645C<get_foo>
646
647=item * C<writer>
648
649The value of this attribute will be the name of the method to set the value of
650the attribute. If you like Java style methods, you might set this to
651C<set_foo>.
652
653=item * C<weak_ref>
654
655B<Boolean>. Set this if you want the reference that the attribute contains to
656be weakened; use this when circular references are possible, which will cause
657leaks.
658
659=item * C<init_arg>
660
661Takes the name of the key to look for at instantiation time of the object. A
662common use of this is to make an underscored attribute have a non-underscored
663initialization name. C<undef> means that passing the value in on instantiation
664is ignored.
665
666=item * C<moosify>
667
668Takes either a coderef or array of coderefs which is meant to transform the
669given attributes specifications if necessary when upgrading to a Moose role or
670class. You shouldn't need this by default, but is provided as a means of
671possible extensibility.
672
673=back
674
675=head2 before
676
677 before foo => sub { ... };
678
679See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
680documentation.
681
682=head2 around
683
684 around foo => sub { ... };
685
686See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
687documentation.
688
689=head2 after
690
691 after foo => sub { ... };
692
693See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
694documentation.
695
696=head1 SUB QUOTE AWARE
697
698L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable,"
699giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote>
700aware can take advantage of this.
701
702To do this, you can write
703
704 use Moo;
705 use Sub::Quote;
706
707 has foo => (
708 is => 'ro',
709 isa => quote_sub(q{ die "Not <3" unless $_[0] < 3 })
710 );
711
712which will be inlined as
713
714 do {
715 local @_ = ($_[0]->{foo});
716 die "Not <3" unless $_[0] < 3;
717 }
718
719or to avoid localizing @_,
720
721 has foo => (
722 is => 'ro',
723 isa => quote_sub(q{ my ($val) = @_; die "Not <3" unless $val < 3 })
724 );
725
726which will be inlined as
727
728 do {
729 my ($val) = ($_[0]->{foo});
730 die "Not <3" unless $val < 3;
731 }
732
733See L<Sub::Quote> for more information, including how to pass lexical
734captures that will also be compiled into the subroutine.
735
736=head1 INCOMPATIBILITIES WITH MOOSE
737
738There is no built-in type system. C<isa> is verified with a coderef; if you
739need complex types, just make a library of coderefs, or better yet, functions
740that return quoted subs. L<MooX::Types::MooseLike> provides a similar API
741to L<MooseX::Types::Moose> so that you can write
742
743 has days_to_live => (is => 'ro', isa => Int);
744
745and have it work with both; it is hoped that providing only subrefs as an
746API will encourage the use of other type systems as well, since it's
747probably the weakest part of Moose design-wise.
748
749C<initializer> is not supported in core since the author considers it to be a
750bad idea and Moose best practices recommend avoiding it. Meanwhile C<trigger> or
751C<coerce> are more likely to be able to fulfill your needs.
752
753There is no meta object. If you need this level of complexity you wanted
754L<Moose> - Moo succeeds at being small because it explicitly does not
755provide a metaprotocol. However, if you load L<Moose>, then
756
757 Class::MOP::class_of($moo_class_or_role)
758
759will return an appropriate metaclass pre-populated by L<Moo>.
760
761No support for C<super>, C<override>, C<inner>, or C<augment> - the author
762considers augment to be a bad idea, and override can be translated:
763
764 override foo => sub {
765 ...
766 super();
767 ...
768 };
769
770 around foo => sub {
771 my ($orig, $self) = (shift, shift);
772 ...
773 $self->$orig(@_);
774 ...
775 };
776
777The C<dump> method is not provided by default. The author suggests loading
778L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and
779using C<$obj-E<gt>$::Dwarn()> instead.
780
781L</default> only supports coderefs and plain scalars, because passing a hash
782or array reference as a default is almost always incorrect since the value is
783then shared between all objects using that default.
784
785C<lazy_build> is not supported; you are instead encouraged to use the
786C<< is => 'lazy' >> option supported by L<Moo> and L<MooseX::AttributeShortcuts>.
787
788C<auto_deref> is not supported since the author considers it a bad idea and
789it has been considered best practice to avoid it for some time.
790
791C<documentation> will show up in a L<Moose> metaclass created from your class
792but is otherwise ignored. Then again, L<Moose> ignores it as well, so this
793is arguably not an incompatibility.
794
795Since C<coerce> does not require C<isa> to be defined but L<Moose> does
796require it, the metaclass inflation for coerce alone is a trifle insane
797and if you attempt to subtype the result will almost certainly break.
798
799Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest
800similar invocation for L<Moose> would be:
801
802 use Moose;
803 use warnings FATAL => "all";
804
805Additionally, L<Moo> supports a set of attribute option shortcuts intended to
806reduce common boilerplate. The set of shortcuts is the same as in the L<Moose>
807module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you:
808
809 package MyClass;
810 use Moo;
811
812The nearest L<Moose> invocation would be:
813
814 package MyClass;
815
816 use Moose;
817 use warnings FATAL => "all";
818 use MooseX::AttributeShortcuts;
819
820or, if you're inheriting from a non-Moose class,
821
822 package MyClass;
823
824 use Moose;
825 use MooseX::NonMoose;
826 use warnings FATAL => "all";
827 use MooseX::AttributeShortcuts;
828
829Finally, Moose requires you to call
830
831 __PACKAGE__->meta->make_immutable;
832
833at the end of your class to get an inlined (i.e. not horribly slow)
834constructor. Moo does it automatically the first time ->new is called
835on your class. (C<make_immutable> is a no-op in Moo to ease migration.)
836
837An extension L<MooX::late> exists to ease translating Moose packages
838to Moo by providing a more Moose-like interface.
839
840=head1 SUPPORT
841
842Users' IRC: #moose on irc.perl.org
843
844=for html <a href="http://chat.mibbit.com/#moose@irc.perl.org">(click for instant chatroom login)</a>
845
846Development and contribution IRC: #web-simple on irc.perl.org
847
848=for html <a href="http://chat.mibbit.com/#web-simple@irc.perl.org">(click for instant chatroom login)</a>
849
850Bugtracker: L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Moo>
851
852Git repository: L<git://git.shadowcat.co.uk/gitmo/Moo.git>
853
854Git web access: L<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo/Moo.git>
855
856=head1 AUTHOR
857
858mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
859
860=head1 CONTRIBUTORS
861
862dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
863
864frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
865
866hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
867
868jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
869
870ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
871
872chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
873
874ajgb - Alex J. G. Burzyński (cpan:AJGB) <ajgb@cpan.org>
875
876doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
877
878perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
879
880Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com>
881
882ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org>
883
884tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org>
885
886haarg - Graham Knop (cpan:HAARG) <haarg@cpan.org>
887
888mattp - Matt Phillips (cpan:MATTP) <mattp@cpan.org>
889
890=head1 COPYRIGHT
891
892Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS>
893as listed above.
894
895=head1 LICENSE
896
897This library is free software and may be distributed under the same terms
898as perl itself. See L<http://dev.perl.org/licenses/>.
899
900=cut