Commit | Line | Data |
b1eebd55 |
1 | package Moo; |
6c74d087 |
2 | |
3 | use strictures 1; |
b1eebd55 |
4 | use Moo::_Utils; |
e0e12d16 |
5 | use B 'perlstring'; |
a41e15c3 |
6 | use Sub::Defer (); |
6c74d087 |
7 | |
6d98aee2 |
8 | our $VERSION = '1.002000'; # 1.2.0 |
6d71fae7 |
9 | $VERSION = eval $VERSION; |
10 | |
c2cb1fed |
11 | require Moo::sification; |
8c46a8f6 |
12 | |
14f32032 |
13 | our %MAKERS; |
14 | |
108f8ddc |
15 | sub _install_tracked { |
16 | my ($target, $name, $code) = @_; |
17 | $MAKERS{$target}{exports}{$name} = $code; |
18 | _install_coderef "${target}::${name}" => "Moo::${name}" => $code; |
19 | } |
20 | |
6c74d087 |
21 | sub import { |
22 | my $target = caller; |
a16d301e |
23 | my $class = shift; |
de3d4906 |
24 | strictures->import; |
1791ba32 |
25 | if ($Moo::Role::INFO{$target} and $Moo::Role::INFO{$target}{is_role}) { |
26 | die "Cannot import Moo into a role"; |
27 | } |
fa93bfb2 |
28 | $MAKERS{$target} ||= {}; |
108f8ddc |
29 | _install_tracked $target => extends => sub { |
48a51428 |
30 | $class->_set_superclasses($target, @_); |
6c49212f |
31 | $class->_maybe_reset_handlemoose($target); |
3d49ee27 |
32 | return; |
6c74d087 |
33 | }; |
108f8ddc |
34 | _install_tracked $target => with => sub { |
faa9ce11 |
35 | require Moo::Role; |
6067158c |
36 | Moo::Role->apply_roles_to_package($target, @_); |
6c49212f |
37 | $class->_maybe_reset_handlemoose($target); |
6c74d087 |
38 | }; |
108f8ddc |
39 | _install_tracked $target => has => sub { |
1d17c7c1 |
40 | my ($name_proto, %spec) = @_; |
41 | my $name_isref = ref $name_proto eq 'ARRAY'; |
42 | foreach my $name ($name_isref ? @$name_proto : $name_proto) { |
43 | # Note that when $name_proto is an arrayref, each attribute |
44 | # needs a separate \%specs hashref |
45 | my $spec_ref = $name_isref ? +{%spec} : \%spec; |
46 | $class->_constructor_maker_for($target) |
47 | ->register_attribute_specs($name, $spec_ref); |
48 | $class->_accessor_maker_for($target) |
49 | ->generate_method($target, $name, $spec_ref); |
50 | $class->_maybe_reset_handlemoose($target); |
51 | } |
3d49ee27 |
52 | return; |
14f32032 |
53 | }; |
6c74d087 |
54 | foreach my $type (qw(before after around)) { |
108f8ddc |
55 | _install_tracked $target => $type => sub { |
faa9ce11 |
56 | require Class::Method::Modifiers; |
6c74d087 |
57 | _install_modifier($target, $type, @_); |
3d49ee27 |
58 | return; |
6c74d087 |
59 | }; |
60 | } |
fa93bfb2 |
61 | return if $MAKERS{$target}{is_class}; # already exported into this package |
62 | $MAKERS{$target}{is_class} = 1; |
6c74d087 |
63 | { |
64 | no strict 'refs'; |
65 | @{"${target}::ISA"} = do { |
faa9ce11 |
66 | require Moo::Object; ('Moo::Object'); |
6c74d087 |
67 | } unless @{"${target}::ISA"}; |
68 | } |
3362e41c |
69 | if ($INC{'Moo/HandleMoose.pm'}) { |
70 | Moo::HandleMoose::inject_fake_metaclass_for($target); |
71 | } |
6c74d087 |
72 | } |
73 | |
108f8ddc |
74 | sub unimport { |
75 | my $target = caller; |
76 | _unimport_coderefs($target, $MAKERS{$target}); |
77 | } |
78 | |
48a51428 |
79 | sub _set_superclasses { |
88aaa04a |
80 | my $class = shift; |
81 | my $target = shift; |
141b507a |
82 | foreach my $superclass (@_) { |
83 | _load_module($superclass); |
84 | if ($INC{"Role/Tiny.pm"} && $Role::Tiny::INFO{$superclass}) { |
88aaa04a |
85 | require Carp; |
141b507a |
86 | Carp::croak("Can't extend role '$superclass'"); |
48a51428 |
87 | } |
88aaa04a |
88 | } |
89 | # Can't do *{...} = \@_ or 5.10.0's mro.pm stops seeing @ISA |
90 | @{*{_getglob("${target}::ISA")}{ARRAY}} = @_; |
91 | if (my $old = delete $Moo::MAKERS{$target}{constructor}) { |
92 | delete _getstash($target)->{new}; |
93 | Moo->_constructor_maker_for($target) |
94 | ->register_attribute_specs(%{$old->all_attribute_specs}); |
95 | } |
85de1ef9 |
96 | elsif (!$target->isa('Moo::Object')) { |
97 | Moo->_constructor_maker_for($target); |
98 | } |
88aaa04a |
99 | no warnings 'once'; # piss off. -- mst |
100 | $Moo::HandleMoose::MOUSE{$target} = [ |
101 | grep defined, map Mouse::Util::find_meta($_), @_ |
96b09f21 |
102 | ] if Mouse::Util->can('find_meta'); |
48a51428 |
103 | } |
104 | |
6c49212f |
105 | sub _maybe_reset_handlemoose { |
106 | my ($class, $target) = @_; |
107 | if ($INC{"Moo/HandleMoose.pm"}) { |
108 | Moo::HandleMoose::maybe_reinject_fake_metaclass_for($target); |
109 | } |
110 | } |
111 | |
02e9ef74 |
112 | sub _accessor_maker_for { |
113 | my ($class, $target) = @_; |
114 | return unless $MAKERS{$target}; |
115 | $MAKERS{$target}{accessor} ||= do { |
116 | my $maker_class = do { |
117 | if (my $m = do { |
118 | if (my $defer_target = |
119 | (Sub::Defer::defer_info($target->can('new'))||[])->[0] |
120 | ) { |
121 | my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/); |
122 | $MAKERS{$pkg} && $MAKERS{$pkg}{accessor}; |
123 | } else { |
124 | undef; |
125 | } |
126 | }) { |
127 | ref($m); |
128 | } else { |
129 | require Method::Generate::Accessor; |
130 | 'Method::Generate::Accessor' |
131 | } |
132 | }; |
133 | $maker_class->new; |
134 | } |
135 | } |
136 | |
a16d301e |
137 | sub _constructor_maker_for { |
c4570291 |
138 | my ($class, $target, $select_super) = @_; |
a16d301e |
139 | return unless $MAKERS{$target}; |
140 | $MAKERS{$target}{constructor} ||= do { |
faa9ce11 |
141 | require Method::Generate::Constructor; |
142 | require Sub::Defer; |
c4570291 |
143 | my ($moo_constructor, $con); |
de5c0e53 |
144 | |
c4570291 |
145 | if ($select_super && $MAKERS{$select_super}) { |
146 | $moo_constructor = 1; |
147 | $con = $MAKERS{$select_super}{constructor}; |
148 | } else { |
de5c0e53 |
149 | my $t_new = $target->can('new'); |
c4570291 |
150 | if ($t_new) { |
151 | if ($t_new == Moo::Object->can('new')) { |
152 | $moo_constructor = 1; |
153 | } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) { |
154 | my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/); |
155 | if ($MAKERS{$pkg}) { |
156 | $moo_constructor = 1; |
157 | $con = $MAKERS{$pkg}{constructor}; |
158 | } |
159 | } |
160 | } else { |
161 | $moo_constructor = 1; # no other constructor, make a Moo one |
162 | } |
de5c0e53 |
163 | }; |
02e9ef74 |
164 | ($con ? ref($con) : 'Method::Generate::Constructor') |
a16d301e |
165 | ->new( |
166 | package => $target, |
02e9ef74 |
167 | accessor_generator => $class->_accessor_maker_for($target), |
53875e2c |
168 | construction_string => ( |
169 | $moo_constructor |
170 | ? ($con ? $con->construction_string : undef) |
e963cc96 |
171 | : ('$class->'.$target.'::SUPER::new($class->can(q[FOREIGNBUILDARGS]) ? $class->FOREIGNBUILDARGS(@_) : @_)') |
e0e12d16 |
172 | ), |
76ab3977 |
173 | subconstructor_handler => ( |
174 | ' if ($Moo::MAKERS{$class}) {'."\n" |
175 | .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n" |
176 | .' return $class->new(@_)'.";\n" |
346177ba |
177 | .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n" |
eea41fb2 |
178 | .' return $meta->new_object($class->BUILDARGS(@_));'."\n" |
76ab3977 |
179 | .' }'."\n" |
e0e12d16 |
180 | ), |
a16d301e |
181 | ) |
182 | ->install_delayed |
de5c0e53 |
183 | ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}}) |
a16d301e |
184 | } |
185 | } |
186 | |
6c74d087 |
187 | 1; |
a17be455 |
188 | =pod |
189 | |
190 | =encoding utf-8 |
8146585e |
191 | |
505f8b7a |
192 | =head1 NAME |
193 | |
c1c6bd6d |
194 | Moo - Minimalist Object Orientation (with Moose compatibility) |
505f8b7a |
195 | |
8146585e |
196 | =head1 SYNOPSIS |
197 | |
198 | package Cat::Food; |
199 | |
200 | use Moo; |
8146585e |
201 | |
202 | sub feed_lion { |
203 | my $self = shift; |
204 | my $amount = shift || 1; |
205 | |
206 | $self->pounds( $self->pounds - $amount ); |
207 | } |
208 | |
209 | has taste => ( |
210 | is => 'ro', |
211 | ); |
212 | |
213 | has brand => ( |
214 | is => 'ro', |
215 | isa => sub { |
216 | die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ' |
217 | }, |
16382e05 |
218 | ); |
8146585e |
219 | |
220 | has pounds => ( |
221 | is => 'rw', |
c9f73a63 |
222 | isa => sub { die "$_[0] is too much cat food!" unless $_[0] < 15 }, |
8146585e |
223 | ); |
224 | |
225 | 1; |
226 | |
52e8f144 |
227 | And elsewhere: |
8146585e |
228 | |
229 | my $full = Cat::Food->new( |
230 | taste => 'DELICIOUS.', |
231 | brand => 'SWEET-TREATZ', |
232 | pounds => 10, |
233 | ); |
234 | |
235 | $full->feed_lion; |
236 | |
237 | say $full->pounds; |
238 | |
239 | =head1 DESCRIPTION |
240 | |
71bd6a81 |
241 | This module is an extremely light-weight subset of L<Moose> optimised for |
52e8f144 |
242 | rapid startup and "pay only for what you use". |
71bd6a81 |
243 | |
8146585e |
244 | It also avoids depending on any XS modules to allow simple deployments. The |
52e8f144 |
245 | name C<Moo> is based on the idea that it provides almost -- but not quite -- two |
8146585e |
246 | thirds of L<Moose>. |
247 | |
52e8f144 |
248 | Unlike L<Mouse> this module does not aim at full compatibility with |
71bd6a81 |
249 | L<Moose>'s surface syntax, preferring instead of provide full interoperability |
5f0ba39b |
250 | via the metaclass inflation capabilities described in L</MOO AND MOOSE>. |
71bd6a81 |
251 | |
252 | For a full list of the minor differences between L<Moose> and L<Moo>'s surface |
21717718 |
253 | syntax, see L</INCOMPATIBILITIES WITH MOOSE>. |
8146585e |
254 | |
5d5bb71d |
255 | =head1 WHY MOO EXISTS |
256 | |
257 | If you want a full object system with a rich Metaprotocol, L<Moose> is |
258 | already wonderful. |
259 | |
71bd6a81 |
260 | However, sometimes you're writing a command line script or a CGI script |
261 | where fast startup is essential, or code designed to be deployed as a single |
262 | file via L<App::FatPacker>, or you're writing a CPAN module and you want it |
263 | to be usable by people with those constraints. |
264 | |
5d5bb71d |
265 | I've tried several times to use L<Mouse> but it's 3x the size of Moo and |
266 | takes longer to load than most of my Moo based CGI scripts take to run. |
267 | |
268 | If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>, |
52e8f144 |
269 | you want "as little as possible" -- which means "no metaprotocol", which is |
5d5bb71d |
270 | what Moo provides. |
271 | |
71bd6a81 |
272 | Better still, if you install and load L<Moose>, we set up metaclasses for your |
273 | L<Moo> classes and L<Moo::Role> roles, so you can use them in L<Moose> code |
274 | without ever noticing that some of your codebase is using L<Moo>. |
5d5bb71d |
275 | |
52e8f144 |
276 | Hence, Moo exists as its name -- Minimal Object Orientation -- with a pledge |
5d5bb71d |
277 | to make it smooth to upgrade to L<Moose> when you need more than minimal |
278 | features. |
279 | |
71bd6a81 |
280 | =head1 MOO AND MOOSE |
1fce5bc9 |
281 | |
282 | If L<Moo> detects L<Moose> being loaded, it will automatically register |
283 | metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able |
a297a9ab |
284 | to use them in L<Moose> code without anybody ever noticing you aren't using |
1fce5bc9 |
285 | L<Moose> everywhere. |
286 | |
9a3fc505 |
287 | L<Moo> will also create L<Moose type constraints|Moose::Manual::Types> for |
288 | classes and roles, so that C<< isa => 'MyClass' >> and C<< isa => 'MyRole' >> |
289 | work the same as for L<Moose> classes and roles. |
290 | |
a297a9ab |
291 | Extending a L<Moose> class or consuming a L<Moose::Role> will also work. |
1fce5bc9 |
292 | |
a297a9ab |
293 | So will extending a L<Mouse> class or consuming a L<Mouse::Role> - but note |
294 | that we don't provide L<Mouse> metaclasses or metaroles so the other way |
295 | around doesn't work. This feature exists for L<Any::Moose> users porting to |
52e8f144 |
296 | L<Moo>; enabling L<Mouse> users to use L<Moo> classes is not a priority for us. |
c100c04c |
297 | |
660f3db2 |
298 | This means that there is no need for anything like L<Any::Moose> for Moo |
c100c04c |
299 | code - Moo and Moose code should simply interoperate without problem. To |
300 | handle L<Mouse> code, you'll likely need an empty Moo role or class consuming |
301 | or extending the L<Mouse> stuff since it doesn't register true L<Moose> |
71bd6a81 |
302 | metaclasses like L<Moo> does. |
303 | |
304 | If you want types to be upgraded to the L<Moose> types, use |
305 | L<MooX::Types::MooseLike> and install the L<MooseX::Types> library to |
306 | match the L<MooX::Types::MooseLike> library you're using - L<Moo> will |
307 | load the L<MooseX::Types> library and use that type for the newly created |
308 | metaclass. |
660f3db2 |
309 | |
1fce5bc9 |
310 | If you need to disable the metaclass creation, add: |
311 | |
312 | no Moo::sification; |
313 | |
314 | to your code before Moose is loaded, but bear in mind that this switch is |
a297a9ab |
315 | currently global and turns the mechanism off entirely so don't put this |
316 | in library code. |
1fce5bc9 |
317 | |
c687d016 |
318 | =head1 MOO VERSUS ANY::MOOSE |
319 | |
320 | L<Any::Moose> will load L<Mouse> normally, and L<Moose> in a program using |
321 | L<Moose> - which theoretically allows you to get the startup time of L<Mouse> |
322 | without disadvantaging L<Moose> users. |
323 | |
324 | Sadly, this doesn't entirely work, since the selection is load order dependent |
325 | - L<Moo>'s metaclass inflation system explained above in L</MOO AND MOOSE> is |
326 | significantly more reliable. |
327 | |
328 | So if you want to write a CPAN module that loads fast or has only pure perl |
329 | dependencies but is also fully usable by L<Moose> users, you should be using |
330 | L<Moo>. |
331 | |
332 | For a full explanation, see the article |
333 | L<http://shadow.cat/blog/matt-s-trout/moo-versus-any-moose> which explains |
334 | the differing strategies in more detail and provides a direct example of |
335 | where L<Moo> succeeds and L<Any::Moose> fails. |
336 | |
8146585e |
337 | =head1 IMPORTED METHODS |
338 | |
339 | =head2 new |
340 | |
341 | Foo::Bar->new( attr1 => 3 ); |
342 | |
343 | or |
344 | |
345 | Foo::Bar->new({ attr1 => 3 }); |
346 | |
2e575bcd |
347 | =head2 BUILDARGS |
348 | |
f2eac33e |
349 | sub BUILDARGS { |
a17be455 |
350 | my ( $class, @args ) = @_; |
351 | |
352 | unshift @args, "attr1" if @args % 2 == 1; |
353 | |
f2eac33e |
354 | return { @args }; |
a17be455 |
355 | }; |
356 | |
357 | Foo::Bar->new( 3 ); |
358 | |
359 | The default implementation of this method accepts a hash or hash reference of |
360 | named parameters. If it receives a single argument that isn't a hash reference |
361 | it throws an error. |
362 | |
363 | You can override this method in your class to handle other types of options |
364 | passed to the constructor. |
365 | |
366 | This method should always return a hash reference of named options. |
2e575bcd |
367 | |
76a0beff |
368 | =head2 FOREIGNBUILDARGS |
369 | |
370 | If you are inheriting from a non-Moo class, the arguments passed to the parent |
371 | class constructor can be manipulated by defining a C<FOREIGNBUILDARGS> method. |
416bcb6c |
372 | It will receive the same arguments as C<BUILDARGS>, and should return a list |
76a0beff |
373 | of arguments to pass to the parent class constructor. |
374 | |
2d00f3d6 |
375 | =head2 BUILD |
8146585e |
376 | |
2d00f3d6 |
377 | Define a C<BUILD> method on your class and the constructor will automatically |
378 | call the C<BUILD> method from parent down to child after the object has |
379 | been instantiated. Typically this is used for object validation or possibly |
380 | logging. |
8146585e |
381 | |
2d00f3d6 |
382 | =head2 DEMOLISH |
c2cc003f |
383 | |
debb3fcd |
384 | If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy, |
385 | a C<DESTROY> method is created on first object construction which will call |
c2cc003f |
386 | C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH> |
debb3fcd |
387 | method from child upwards to parents. |
388 | |
389 | Note that the C<DESTROY> method is created on first construction of an object |
390 | of your class in order to not add overhead to classes without C<DEMOLISH> |
391 | methods; this may prove slightly surprising if you try and define your own. |
c2cc003f |
392 | |
8146585e |
393 | =head2 does |
394 | |
395 | if ($foo->does('Some::Role1')) { |
396 | ... |
397 | } |
398 | |
399 | Returns true if the object composes in the passed role. |
400 | |
401 | =head1 IMPORTED SUBROUTINES |
402 | |
403 | =head2 extends |
404 | |
405 | extends 'Parent::Class'; |
406 | |
2e575bcd |
407 | Declares base class. Multiple superclasses can be passed for multiple |
408 | inheritance (but please use roles instead). |
409 | |
410 | Calling extends more than once will REPLACE your superclasses, not add to |
411 | them like 'use base' would. |
8146585e |
412 | |
413 | =head2 with |
414 | |
415 | with 'Some::Role1'; |
8146585e |
416 | |
f9755246 |
417 | or |
418 | |
419 | with 'Some::Role1', 'Some::Role2'; |
420 | |
421 | Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current |
422 | class. An error will be raised if these roles have conflicting methods. |
8146585e |
423 | |
424 | =head2 has |
425 | |
426 | has attr => ( |
427 | is => 'ro', |
428 | ); |
429 | |
430 | Declares an attribute for the class. |
431 | |
1c9916fa |
432 | package Foo; |
433 | use Moo; |
434 | has 'attr' => ( |
435 | is => 'ro' |
436 | ); |
d56136b9 |
437 | |
1c9916fa |
438 | package Bar; |
439 | use Moo; |
440 | extends 'Foo'; |
d56136b9 |
441 | has '+attr' => ( |
442 | default => sub { "blah" }, |
443 | ); |
444 | |
445 | Using the C<+> notation, it's possible to override an attribute. |
446 | |
8146585e |
447 | The options for C<has> are as follows: |
448 | |
449 | =over 2 |
450 | |
451 | =item * is |
452 | |
6577509a |
453 | B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>. |
71db76ce |
454 | |
455 | C<ro> generates an accessor that dies if you attempt to write to it - i.e. |
456 | a getter only - by defaulting C<reader> to the name of the attribute. |
457 | |
71db76ce |
458 | C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and |
459 | C<builder> to C<_build_${attribute_name}> to allow on-demand generated |
460 | attributes. This feature was my attempt to fix my incompetence when |
461 | originally designing C<lazy_build>, and is also implemented by |
876b1e94 |
462 | L<MooseX::AttributeShortcuts>. There is, however, nothing to stop you |
463 | using C<lazy> and C<builder> yourself with C<rwp> or C<rw> - it's just that |
464 | this isn't generally a good idea so we don't provide a shortcut for it. |
71db76ce |
465 | |
466 | C<rwp> generates a reader like C<ro>, but also sets C<writer> to |
467 | C<_set_${attribute_name}> for attributes that are designed to be written |
468 | from inside of the class, but read-only from outside. |
469 | This feature comes from L<MooseX::AttributeShortcuts>. |
8146585e |
470 | |
6577509a |
471 | C<rw> generates a normal getter/setter by defaulting C<accessor> to the |
472 | name of the attribute. |
473 | |
8146585e |
474 | =item * isa |
475 | |
52e8f144 |
476 | Takes a coderef which is meant to validate the attribute. Unlike L<Moose>, Moo |
8146585e |
477 | does not include a basic type system, so instead of doing C<< isa => 'Num' >>, |
478 | one should do |
479 | |
c9f73a63 |
480 | isa => sub { |
8146585e |
481 | die "$_[0] is not a number!" unless looks_like_number $_[0] |
482 | }, |
483 | |
9a3fc505 |
484 | Note that the return value is ignored, only whether the sub lives or |
485 | dies matters. |
486 | |
8146585e |
487 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
488 | |
c4074652 |
489 | Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion |
490 | subroutine has been supplied, C<isa> checks are not structural to your code |
491 | and can, if desired, be omitted on non-debug builds (although if this results |
492 | in an uncaught bug causing your program to break, the L<Moo> authors guarantee |
493 | nothing except that you get to keep both halves). |
494 | |
71db76ce |
495 | If you want L<MooseX::Types> style named types, look at |
496 | L<MooX::Types::MooseLike>. |
497 | |
498 | To cause your C<isa> entries to be automatically mapped to named |
499 | L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour |
500 | of creating an anonymous type), set: |
501 | |
502 | $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub { |
503 | require MooseX::Types::Something; |
504 | return MooseX::Types::Something::TypeName(); |
505 | }; |
506 | |
507 | Note that this example is purely illustrative; anything that returns a |
508 | L<Moose::Meta::TypeConstraint> object or something similar enough to it to |
509 | make L<Moose> happy is fine. |
510 | |
8146585e |
511 | =item * coerce |
512 | |
513 | Takes a coderef which is meant to coerce the attribute. The basic idea is to |
514 | do something like the following: |
515 | |
c9f73a63 |
516 | coerce => sub { |
8146585e |
517 | $_[0] + 1 unless $_[0] % 2 |
518 | }, |
519 | |
52e8f144 |
520 | Note that L<Moo> will always fire your coercion: this is to permit |
521 | C<isa> entries to be used purely for bug trapping, whereas coercions are |
c4074652 |
522 | always structural to your code. We do, however, apply any supplied C<isa> |
523 | check after the coercion has run to ensure that it returned a valid value. |
8146585e |
524 | |
23a3e34e |
525 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
2e575bcd |
526 | |
e1efec09 |
527 | =item * handles |
528 | |
529 | Takes a string |
530 | |
69673ca7 |
531 | handles => 'RobotRole' |
532 | |
533 | Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which |
534 | becomes the list of methods to handle. |
e1efec09 |
535 | |
536 | Takes a list of methods |
537 | |
538 | handles => [ qw( one two ) ] |
539 | |
540 | Takes a hashref |
541 | |
542 | handles => { |
543 | un => 'one', |
544 | } |
545 | |
cc7ad717 |
546 | =item * C<trigger> |
8146585e |
547 | |
6fe5100d |
548 | Takes a coderef which will get called any time the attribute is set. This |
cc7ad717 |
549 | includes the constructor, but not default or built values. Coderef will be |
550 | invoked against the object with the new value as an argument. |
8146585e |
551 | |
71db76ce |
552 | If you set this to just C<1>, it generates a trigger which calls the |
553 | C<_trigger_${attr_name}> method on C<$self>. This feature comes from |
554 | L<MooseX::AttributeShortcuts>. |
555 | |
2e575bcd |
556 | Note that Moose also passes the old value, if any; this feature is not yet |
557 | supported. |
558 | |
8146585e |
559 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
560 | |
52e8f144 |
561 | =item * C<default> |
8146585e |
562 | |
2e575bcd |
563 | Takes a coderef which will get called with $self as its only argument |
564 | to populate an attribute if no value is supplied to the constructor - or |
565 | if the attribute is lazy, when the attribute is first retrieved if no |
566 | value has yet been provided. |
567 | |
0e43f98f |
568 | If a simple scalar is provided, it will be inlined as a string. Any non-code |
569 | reference (hash, array) will result in an error - for that case instead use |
570 | a code reference that returns the desired value. |
571 | |
2e575bcd |
572 | Note that if your default is fired during new() there is no guarantee that |
573 | other attributes have been populated yet so you should not rely on their |
574 | existence. |
8146585e |
575 | |
576 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
577 | |
52e8f144 |
578 | =item * C<predicate> |
8146585e |
579 | |
2e575bcd |
580 | Takes a method name which will return true if an attribute has a value. |
8146585e |
581 | |
71db76ce |
582 | If you set this to just C<1>, the predicate is automatically named |
583 | C<has_${attr_name}> if your attribute's name does not start with an |
157aa466 |
584 | underscore, or C<_has_${attr_name_without_the_underscore}> if it does. |
71db76ce |
585 | This feature comes from L<MooseX::AttributeShortcuts>. |
8146585e |
586 | |
52e8f144 |
587 | =item * C<builder> |
8146585e |
588 | |
2e575bcd |
589 | Takes a method name which will be called to create the attribute - functions |
590 | exactly like default except that instead of calling |
591 | |
592 | $default->($self); |
593 | |
594 | Moo will call |
595 | |
596 | $self->$builder; |
8146585e |
597 | |
4752c97b |
598 | The following features come from L<MooseX::AttributeShortcuts>: |
599 | |
ba19b6a9 |
600 | If you set this to just C<1>, the builder is automatically named |
4752c97b |
601 | C<_build_${attr_name}>. |
602 | |
603 | If you set this to a coderef or code-convertible object, that variable will be |
604 | installed under C<$class::_build_${attr_name}> and the builder set to the same |
605 | name. |
71db76ce |
606 | |
52e8f144 |
607 | =item * C<clearer> |
8146585e |
608 | |
609 | Takes a method name which will clear the attribute. |
610 | |
71db76ce |
611 | If you set this to just C<1>, the clearer is automatically named |
612 | C<clear_${attr_name}> if your attribute's name does not start with an |
613 | underscore, or <_clear_${attr_name_without_the_underscore}> if it does. |
614 | This feature comes from L<MooseX::AttributeShortcuts>. |
615 | |
52e8f144 |
616 | =item * C<lazy> |
8146585e |
617 | |
618 | B<Boolean>. Set this if you want values for the attribute to be grabbed |
619 | lazily. This is usually a good idea if you have a L</builder> which requires |
620 | another attribute to be set. |
621 | |
52e8f144 |
622 | =item * C<required> |
8146585e |
623 | |
624 | B<Boolean>. Set this if the attribute must be passed on instantiation. |
625 | |
52e8f144 |
626 | =item * C<reader> |
1eba910c |
627 | |
628 | The value of this attribute will be the name of the method to get the value of |
629 | the attribute. If you like Java style methods, you might set this to |
630 | C<get_foo> |
631 | |
52e8f144 |
632 | =item * C<writer> |
1eba910c |
633 | |
634 | The value of this attribute will be the name of the method to set the value of |
635 | the attribute. If you like Java style methods, you might set this to |
52e8f144 |
636 | C<set_foo>. |
1eba910c |
637 | |
52e8f144 |
638 | =item * C<weak_ref> |
8146585e |
639 | |
640 | B<Boolean>. Set this if you want the reference that the attribute contains to |
641 | be weakened; use this when circular references are possible, which will cause |
642 | leaks. |
643 | |
52e8f144 |
644 | =item * C<init_arg> |
8146585e |
645 | |
646 | Takes the name of the key to look for at instantiation time of the object. A |
647 | common use of this is to make an underscored attribute have a non-underscored |
648 | initialization name. C<undef> means that passing the value in on instantiation |
71db76ce |
649 | is ignored. |
8146585e |
650 | |
7887ffd0 |
651 | =item * C<moosify> |
652 | |
653 | Takes either a coderef or array of coderefs which is meant to transform the |
654 | given attributes specifications if necessary when upgrading to a Moose role or |
655 | class. You shouldn't need this by default, but is provided as a means of |
656 | possible extensibility. |
657 | |
8146585e |
658 | =back |
659 | |
660 | =head2 before |
661 | |
662 | before foo => sub { ... }; |
663 | |
664 | See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full |
665 | documentation. |
666 | |
667 | =head2 around |
668 | |
669 | around foo => sub { ... }; |
670 | |
671 | See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full |
672 | documentation. |
673 | |
674 | =head2 after |
675 | |
676 | after foo => sub { ... }; |
677 | |
678 | See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full |
679 | documentation. |
680 | |
8146585e |
681 | =head1 SUB QUOTE AWARE |
682 | |
683 | L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable," |
684 | giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote> |
685 | aware can take advantage of this. |
686 | |
c9f73a63 |
687 | To do this, you can write |
688 | |
689 | use Moo; |
690 | use Sub::Quote; |
691 | |
692 | has foo => ( |
3b4a915a |
693 | is => 'ro', |
694 | isa => quote_sub(q{ die "Not <3" unless $_[0] < 3 }) |
c9f73a63 |
695 | ); |
696 | |
697 | which will be inlined as |
698 | |
699 | do { |
700 | local @_ = ($_[0]->{foo}); |
701 | die "Not <3" unless $_[0] < 3; |
702 | } |
703 | |
704 | or to avoid localizing @_, |
705 | |
706 | has foo => ( |
3b4a915a |
707 | is => 'ro', |
708 | isa => quote_sub(q{ my ($val) = @_; die "Not <3" unless $val < 3 }) |
c9f73a63 |
709 | ); |
710 | |
711 | which will be inlined as |
712 | |
713 | do { |
714 | my ($val) = ($_[0]->{foo}); |
715 | die "Not <3" unless $val < 3; |
716 | } |
717 | |
718 | See L<Sub::Quote> for more information, including how to pass lexical |
52e8f144 |
719 | captures that will also be compiled into the subroutine. |
c9f73a63 |
720 | |
2e575bcd |
721 | =head1 INCOMPATIBILITIES WITH MOOSE |
8146585e |
722 | |
52e8f144 |
723 | There is no built-in type system. C<isa> is verified with a coderef; if you |
8146585e |
724 | need complex types, just make a library of coderefs, or better yet, functions |
5902c1fc |
725 | that return quoted subs. L<MooX::Types::MooseLike> provides a similar API |
726 | to L<MooseX::Types::Moose> so that you can write |
727 | |
728 | has days_to_live => (is => 'ro', isa => Int); |
729 | |
730 | and have it work with both; it is hoped that providing only subrefs as an |
731 | API will encourage the use of other type systems as well, since it's |
732 | probably the weakest part of Moose design-wise. |
8146585e |
733 | |
2e575bcd |
734 | C<initializer> is not supported in core since the author considers it to be a |
0e43f98f |
735 | bad idea and Moose best practices recommend avoiding it. Meanwhile C<trigger> or |
f88623a1 |
736 | C<coerce> are more likely to be able to fulfill your needs. |
8146585e |
737 | |
738 | There is no meta object. If you need this level of complexity you wanted |
2e575bcd |
739 | L<Moose> - Moo succeeds at being small because it explicitly does not |
f9755246 |
740 | provide a metaprotocol. However, if you load L<Moose>, then |
741 | |
742 | Class::MOP::class_of($moo_class_or_role) |
743 | |
744 | will return an appropriate metaclass pre-populated by L<Moo>. |
8146585e |
745 | |
13e41b70 |
746 | No support for C<super>, C<override>, C<inner>, or C<augment> - the author |
747 | considers augment to be a bad idea, and override can be translated: |
748 | |
749 | override foo => sub { |
750 | ... |
751 | super(); |
752 | ... |
753 | }; |
754 | |
755 | around foo => sub { |
756 | my ($orig, $self) = (shift, shift); |
757 | ... |
758 | $self->$orig(@_); |
759 | ... |
760 | }; |
8146585e |
761 | |
f2eac33e |
762 | The C<dump> method is not provided by default. The author suggests loading |
c96a6326 |
763 | L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and |
764 | using C<$obj-E<gt>$::Dwarn()> instead. |
765 | |
0e43f98f |
766 | L</default> only supports coderefs and plain scalars, because passing a hash |
767 | or array reference as a default is almost always incorrect since the value is |
768 | then shared between all objects using that default. |
8146585e |
769 | |
f9755246 |
770 | C<lazy_build> is not supported; you are instead encouraged to use the |
52e8f144 |
771 | C<< is => 'lazy' >> option supported by L<Moo> and L<MooseX::AttributeShortcuts>. |
8146585e |
772 | |
0e43f98f |
773 | C<auto_deref> is not supported since the author considers it a bad idea and |
774 | it has been considered best practice to avoid it for some time. |
8146585e |
775 | |
f9755246 |
776 | C<documentation> will show up in a L<Moose> metaclass created from your class |
c4074652 |
777 | but is otherwise ignored. Then again, L<Moose> ignores it as well, so this |
f9755246 |
778 | is arguably not an incompatibility. |
40f3e3aa |
779 | |
c4074652 |
780 | Since C<coerce> does not require C<isa> to be defined but L<Moose> does |
52e8f144 |
781 | require it, the metaclass inflation for coerce alone is a trifle insane |
c4074652 |
782 | and if you attempt to subtype the result will almost certainly break. |
783 | |
69673ca7 |
784 | Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest |
785 | similar invocation for L<Moose> would be: |
786 | |
787 | use Moose; |
788 | use warnings FATAL => "all"; |
789 | |
790 | Additionally, L<Moo> supports a set of attribute option shortcuts intended to |
791 | reduce common boilerplate. The set of shortcuts is the same as in the L<Moose> |
239d4711 |
792 | module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you: |
69673ca7 |
793 | |
794 | package MyClass; |
795 | use Moo; |
796 | |
797 | The nearest L<Moose> invocation would be: |
798 | |
799 | package MyClass; |
800 | |
801 | use Moose; |
802 | use warnings FATAL => "all"; |
803 | use MooseX::AttributeShortcuts; |
804 | |
5902c1fc |
805 | or, if you're inheriting from a non-Moose class, |
806 | |
807 | package MyClass; |
808 | |
809 | use Moose; |
810 | use MooseX::NonMoose; |
811 | use warnings FATAL => "all"; |
812 | use MooseX::AttributeShortcuts; |
813 | |
814 | Finally, Moose requires you to call |
815 | |
816 | __PACKAGE__->meta->make_immutable; |
817 | |
818 | at the end of your class to get an inlined (i.e. not horribly slow) |
819 | constructor. Moo does it automatically the first time ->new is called |
917f27ca |
820 | on your class. (C<make_immutable> is a no-op in Moo to ease migration.) |
5902c1fc |
821 | |
6ad9aeab |
822 | An extension L<MooX::late> exists to ease translating Moose packages |
823 | to Moo by providing a more Moose-like interface. |
824 | |
660f3db2 |
825 | =head1 SUPPORT |
826 | |
cb21f16e |
827 | Users' IRC: #moose on irc.perl.org |
9836a6ee |
828 | |
cb21f16e |
829 | =for html <a href="http://chat.mibbit.com/#moose@irc.perl.org">(click for instant chatroom login)</a> |
830 | |
831 | Development and contribution IRC: #web-simple on irc.perl.org |
832 | |
833 | =for html <a href="http://chat.mibbit.com/#web-simple@irc.perl.org">(click for instant chatroom login)</a> |
072d158f |
834 | |
835 | Bugtracker: L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Moo> |
836 | |
837 | Git repository: L<git://git.shadowcat.co.uk/gitmo/Moo.git> |
838 | |
839 | Git web access: L<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo/Moo.git> |
660f3db2 |
840 | |
40f3e3aa |
841 | =head1 AUTHOR |
842 | |
843 | mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk> |
844 | |
845 | =head1 CONTRIBUTORS |
846 | |
5da684a2 |
847 | dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx> |
848 | |
849 | frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com> |
850 | |
851 | hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org> |
852 | |
853 | jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com> |
854 | |
855 | ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org> |
40f3e3aa |
856 | |
11f7a042 |
857 | chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com> |
858 | |
a17be455 |
859 | ajgb - Alex J. G. Burzyński (cpan:AJGB) <ajgb@cpan.org> |
860 | |
7b8177f8 |
861 | doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net> |
862 | |
1fb2de92 |
863 | perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org> |
864 | |
3202e039 |
865 | Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com> |
866 | |
e355471c |
867 | ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org> |
868 | |
1d17c7c1 |
869 | tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org> |
870 | |
d092b5ff |
871 | haarg - Graham Knop (cpan:HAARG) <haarg@cpan.org> |
872 | |
80fd66d7 |
873 | mattp - Matt Phillips (cpan:MATTP) <mattp@cpan.org> |
874 | |
40f3e3aa |
875 | =head1 COPYRIGHT |
876 | |
a958e36d |
877 | Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS> |
40f3e3aa |
878 | as listed above. |
879 | |
880 | =head1 LICENSE |
881 | |
882 | This library is free software and may be distributed under the same terms |
072d158f |
883 | as perl itself. See L<http://dev.perl.org/licenses/>. |
40f3e3aa |
884 | |
885 | =cut |