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 $class = shift; |
de3d4906 |
24 | strictures->import; |
c3736593 |
25 | if ($Role::Tiny::INFO{$target} and $Role::Tiny::INFO{$target}{is_role}) { |
1791ba32 |
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 | $maker_class->new; |
134 | } |
135 | } |
136 | |
a16d301e |
137 | sub _constructor_maker_for { |
8dee08c1 |
138 | my ($class, $target) = @_; |
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 | |
8dee08c1 |
145 | my $t_new = $target->can('new'); |
146 | if ($t_new) { |
147 | if ($t_new == Moo::Object->can('new')) { |
148 | $moo_constructor = 1; |
149 | } elsif (my $defer_target = (Sub::Defer::defer_info($t_new)||[])->[0]) { |
150 | my ($pkg) = ($defer_target =~ /^(.*)::[^:]+$/); |
151 | if ($MAKERS{$pkg}) { |
c4570291 |
152 | $moo_constructor = 1; |
8dee08c1 |
153 | $con = $MAKERS{$pkg}{constructor}; |
c4570291 |
154 | } |
c4570291 |
155 | } |
8dee08c1 |
156 | } else { |
157 | $moo_constructor = 1; # no other constructor, make a Moo one |
158 | } |
02e9ef74 |
159 | ($con ? ref($con) : 'Method::Generate::Constructor') |
a16d301e |
160 | ->new( |
161 | package => $target, |
02e9ef74 |
162 | accessor_generator => $class->_accessor_maker_for($target), |
53875e2c |
163 | construction_string => ( |
164 | $moo_constructor |
165 | ? ($con ? $con->construction_string : undef) |
e963cc96 |
166 | : ('$class->'.$target.'::SUPER::new($class->can(q[FOREIGNBUILDARGS]) ? $class->FOREIGNBUILDARGS(@_) : @_)') |
e0e12d16 |
167 | ), |
76ab3977 |
168 | subconstructor_handler => ( |
169 | ' if ($Moo::MAKERS{$class}) {'."\n" |
170 | .' '.$class.'->_constructor_maker_for($class,'.perlstring($target).');'."\n" |
171 | .' return $class->new(@_)'.";\n" |
346177ba |
172 | .' } elsif ($INC{"Moose.pm"} and my $meta = Class::MOP::get_metaclass_by_name($class)) {'."\n" |
eea41fb2 |
173 | .' return $meta->new_object($class->BUILDARGS(@_));'."\n" |
76ab3977 |
174 | .' }'."\n" |
e0e12d16 |
175 | ), |
a16d301e |
176 | ) |
177 | ->install_delayed |
de5c0e53 |
178 | ->register_attribute_specs(%{$con?$con->all_attribute_specs:{}}) |
a16d301e |
179 | } |
180 | } |
181 | |
6c74d087 |
182 | 1; |
a17be455 |
183 | =pod |
184 | |
185 | =encoding utf-8 |
8146585e |
186 | |
505f8b7a |
187 | =head1 NAME |
188 | |
c1c6bd6d |
189 | Moo - Minimalist Object Orientation (with Moose compatibility) |
505f8b7a |
190 | |
8146585e |
191 | =head1 SYNOPSIS |
192 | |
193 | package Cat::Food; |
194 | |
195 | use Moo; |
8146585e |
196 | |
197 | sub feed_lion { |
198 | my $self = shift; |
199 | my $amount = shift || 1; |
200 | |
201 | $self->pounds( $self->pounds - $amount ); |
202 | } |
203 | |
204 | has taste => ( |
205 | is => 'ro', |
206 | ); |
207 | |
208 | has brand => ( |
209 | is => 'ro', |
210 | isa => sub { |
211 | die "Only SWEET-TREATZ supported!" unless $_[0] eq 'SWEET-TREATZ' |
212 | }, |
16382e05 |
213 | ); |
8146585e |
214 | |
215 | has pounds => ( |
216 | is => 'rw', |
c9f73a63 |
217 | isa => sub { die "$_[0] is too much cat food!" unless $_[0] < 15 }, |
8146585e |
218 | ); |
219 | |
220 | 1; |
221 | |
52e8f144 |
222 | And elsewhere: |
8146585e |
223 | |
224 | my $full = Cat::Food->new( |
225 | taste => 'DELICIOUS.', |
226 | brand => 'SWEET-TREATZ', |
227 | pounds => 10, |
228 | ); |
229 | |
230 | $full->feed_lion; |
231 | |
232 | say $full->pounds; |
233 | |
234 | =head1 DESCRIPTION |
235 | |
71bd6a81 |
236 | This module is an extremely light-weight subset of L<Moose> optimised for |
52e8f144 |
237 | rapid startup and "pay only for what you use". |
71bd6a81 |
238 | |
8146585e |
239 | It also avoids depending on any XS modules to allow simple deployments. The |
52e8f144 |
240 | name C<Moo> is based on the idea that it provides almost -- but not quite -- two |
8146585e |
241 | thirds of L<Moose>. |
242 | |
52e8f144 |
243 | Unlike L<Mouse> this module does not aim at full compatibility with |
71bd6a81 |
244 | L<Moose>'s surface syntax, preferring instead of provide full interoperability |
5f0ba39b |
245 | via the metaclass inflation capabilities described in L</MOO AND MOOSE>. |
71bd6a81 |
246 | |
247 | For a full list of the minor differences between L<Moose> and L<Moo>'s surface |
21717718 |
248 | syntax, see L</INCOMPATIBILITIES WITH MOOSE>. |
8146585e |
249 | |
5d5bb71d |
250 | =head1 WHY MOO EXISTS |
251 | |
252 | If you want a full object system with a rich Metaprotocol, L<Moose> is |
253 | already wonderful. |
254 | |
71bd6a81 |
255 | However, sometimes you're writing a command line script or a CGI script |
256 | where fast startup is essential, or code designed to be deployed as a single |
257 | file via L<App::FatPacker>, or you're writing a CPAN module and you want it |
258 | to be usable by people with those constraints. |
259 | |
5d5bb71d |
260 | I've tried several times to use L<Mouse> but it's 3x the size of Moo and |
261 | takes longer to load than most of my Moo based CGI scripts take to run. |
262 | |
263 | If you don't want L<Moose>, you don't want "less metaprotocol" like L<Mouse>, |
52e8f144 |
264 | you want "as little as possible" -- which means "no metaprotocol", which is |
5d5bb71d |
265 | what Moo provides. |
266 | |
71bd6a81 |
267 | Better still, if you install and load L<Moose>, we set up metaclasses for your |
268 | L<Moo> classes and L<Moo::Role> roles, so you can use them in L<Moose> code |
269 | without ever noticing that some of your codebase is using L<Moo>. |
5d5bb71d |
270 | |
52e8f144 |
271 | Hence, Moo exists as its name -- Minimal Object Orientation -- with a pledge |
5d5bb71d |
272 | to make it smooth to upgrade to L<Moose> when you need more than minimal |
273 | features. |
274 | |
71bd6a81 |
275 | =head1 MOO AND MOOSE |
1fce5bc9 |
276 | |
277 | If L<Moo> detects L<Moose> being loaded, it will automatically register |
278 | metaclasses for your L<Moo> and L<Moo::Role> packages, so you should be able |
a297a9ab |
279 | to use them in L<Moose> code without anybody ever noticing you aren't using |
1fce5bc9 |
280 | L<Moose> everywhere. |
281 | |
9a3fc505 |
282 | L<Moo> will also create L<Moose type constraints|Moose::Manual::Types> for |
283 | classes and roles, so that C<< isa => 'MyClass' >> and C<< isa => 'MyRole' >> |
284 | work the same as for L<Moose> classes and roles. |
285 | |
a297a9ab |
286 | Extending a L<Moose> class or consuming a L<Moose::Role> will also work. |
1fce5bc9 |
287 | |
a297a9ab |
288 | So will extending a L<Mouse> class or consuming a L<Mouse::Role> - but note |
289 | that we don't provide L<Mouse> metaclasses or metaroles so the other way |
290 | around doesn't work. This feature exists for L<Any::Moose> users porting to |
52e8f144 |
291 | L<Moo>; enabling L<Mouse> users to use L<Moo> classes is not a priority for us. |
c100c04c |
292 | |
660f3db2 |
293 | This means that there is no need for anything like L<Any::Moose> for Moo |
c100c04c |
294 | code - Moo and Moose code should simply interoperate without problem. To |
295 | handle L<Mouse> code, you'll likely need an empty Moo role or class consuming |
296 | or extending the L<Mouse> stuff since it doesn't register true L<Moose> |
71bd6a81 |
297 | metaclasses like L<Moo> does. |
298 | |
299 | If you want types to be upgraded to the L<Moose> types, use |
300 | L<MooX::Types::MooseLike> and install the L<MooseX::Types> library to |
301 | match the L<MooX::Types::MooseLike> library you're using - L<Moo> will |
302 | load the L<MooseX::Types> library and use that type for the newly created |
303 | metaclass. |
660f3db2 |
304 | |
1fce5bc9 |
305 | If you need to disable the metaclass creation, add: |
306 | |
307 | no Moo::sification; |
308 | |
309 | to your code before Moose is loaded, but bear in mind that this switch is |
a297a9ab |
310 | currently global and turns the mechanism off entirely so don't put this |
311 | in library code. |
1fce5bc9 |
312 | |
dcbfe1d9 |
313 | =head1 MOO AND CLASS::XSACCESSOR |
314 | |
315 | If a new enough version of L<Class::XSAccessor> is available, it |
316 | will be used to generate simple accessors, readers, and writers for |
317 | a speed boost. Simple accessors are those without lazy defaults, |
318 | type checks/coercions, or triggers. Readers and writers generated |
319 | by L<Class::XSAccessor> will behave slightly differently: they will |
320 | reject attempts to call them with the incorrect number of parameters. |
321 | |
c687d016 |
322 | =head1 MOO VERSUS ANY::MOOSE |
323 | |
324 | L<Any::Moose> will load L<Mouse> normally, and L<Moose> in a program using |
325 | L<Moose> - which theoretically allows you to get the startup time of L<Mouse> |
326 | without disadvantaging L<Moose> users. |
327 | |
328 | Sadly, this doesn't entirely work, since the selection is load order dependent |
329 | - L<Moo>'s metaclass inflation system explained above in L</MOO AND MOOSE> is |
330 | significantly more reliable. |
331 | |
332 | So if you want to write a CPAN module that loads fast or has only pure perl |
333 | dependencies but is also fully usable by L<Moose> users, you should be using |
334 | L<Moo>. |
335 | |
336 | For a full explanation, see the article |
337 | L<http://shadow.cat/blog/matt-s-trout/moo-versus-any-moose> which explains |
338 | the differing strategies in more detail and provides a direct example of |
339 | where L<Moo> succeeds and L<Any::Moose> fails. |
340 | |
8146585e |
341 | =head1 IMPORTED METHODS |
342 | |
343 | =head2 new |
344 | |
345 | Foo::Bar->new( attr1 => 3 ); |
346 | |
347 | or |
348 | |
349 | Foo::Bar->new({ attr1 => 3 }); |
350 | |
2e575bcd |
351 | =head2 BUILDARGS |
352 | |
f2eac33e |
353 | sub BUILDARGS { |
a17be455 |
354 | my ( $class, @args ) = @_; |
355 | |
356 | unshift @args, "attr1" if @args % 2 == 1; |
357 | |
f2eac33e |
358 | return { @args }; |
a17be455 |
359 | }; |
360 | |
361 | Foo::Bar->new( 3 ); |
362 | |
363 | The default implementation of this method accepts a hash or hash reference of |
364 | named parameters. If it receives a single argument that isn't a hash reference |
365 | it throws an error. |
366 | |
367 | You can override this method in your class to handle other types of options |
368 | passed to the constructor. |
369 | |
370 | This method should always return a hash reference of named options. |
2e575bcd |
371 | |
76a0beff |
372 | =head2 FOREIGNBUILDARGS |
373 | |
374 | If you are inheriting from a non-Moo class, the arguments passed to the parent |
375 | class constructor can be manipulated by defining a C<FOREIGNBUILDARGS> method. |
416bcb6c |
376 | It will receive the same arguments as C<BUILDARGS>, and should return a list |
76a0beff |
377 | of arguments to pass to the parent class constructor. |
378 | |
2d00f3d6 |
379 | =head2 BUILD |
8146585e |
380 | |
2d00f3d6 |
381 | Define a C<BUILD> method on your class and the constructor will automatically |
382 | call the C<BUILD> method from parent down to child after the object has |
383 | been instantiated. Typically this is used for object validation or possibly |
384 | logging. |
8146585e |
385 | |
2d00f3d6 |
386 | =head2 DEMOLISH |
c2cc003f |
387 | |
debb3fcd |
388 | If you have a C<DEMOLISH> method anywhere in your inheritance hierarchy, |
389 | a C<DESTROY> method is created on first object construction which will call |
c2cc003f |
390 | C<< $instance->DEMOLISH($in_global_destruction) >> for each C<DEMOLISH> |
debb3fcd |
391 | method from child upwards to parents. |
392 | |
393 | Note that the C<DESTROY> method is created on first construction of an object |
394 | of your class in order to not add overhead to classes without C<DEMOLISH> |
395 | methods; this may prove slightly surprising if you try and define your own. |
c2cc003f |
396 | |
8146585e |
397 | =head2 does |
398 | |
399 | if ($foo->does('Some::Role1')) { |
400 | ... |
401 | } |
402 | |
403 | Returns true if the object composes in the passed role. |
404 | |
405 | =head1 IMPORTED SUBROUTINES |
406 | |
407 | =head2 extends |
408 | |
409 | extends 'Parent::Class'; |
410 | |
2e575bcd |
411 | Declares base class. Multiple superclasses can be passed for multiple |
412 | inheritance (but please use roles instead). |
413 | |
414 | Calling extends more than once will REPLACE your superclasses, not add to |
415 | them like 'use base' would. |
8146585e |
416 | |
417 | =head2 with |
418 | |
419 | with 'Some::Role1'; |
8146585e |
420 | |
f9755246 |
421 | or |
422 | |
423 | with 'Some::Role1', 'Some::Role2'; |
424 | |
425 | Composes one or more L<Moo::Role> (or L<Role::Tiny>) roles into the current |
426 | class. An error will be raised if these roles have conflicting methods. |
8146585e |
427 | |
428 | =head2 has |
429 | |
430 | has attr => ( |
431 | is => 'ro', |
432 | ); |
433 | |
434 | Declares an attribute for the class. |
435 | |
1c9916fa |
436 | package Foo; |
437 | use Moo; |
438 | has 'attr' => ( |
439 | is => 'ro' |
440 | ); |
d56136b9 |
441 | |
1c9916fa |
442 | package Bar; |
443 | use Moo; |
444 | extends 'Foo'; |
d56136b9 |
445 | has '+attr' => ( |
446 | default => sub { "blah" }, |
447 | ); |
448 | |
449 | Using the C<+> notation, it's possible to override an attribute. |
450 | |
8146585e |
451 | The options for C<has> are as follows: |
452 | |
453 | =over 2 |
454 | |
455 | =item * is |
456 | |
6577509a |
457 | B<required>, may be C<ro>, C<lazy>, C<rwp> or C<rw>. |
71db76ce |
458 | |
459 | C<ro> generates an accessor that dies if you attempt to write to it - i.e. |
460 | a getter only - by defaulting C<reader> to the name of the attribute. |
461 | |
71db76ce |
462 | C<lazy> generates a reader like C<ro>, but also sets C<lazy> to 1 and |
463 | C<builder> to C<_build_${attribute_name}> to allow on-demand generated |
464 | attributes. This feature was my attempt to fix my incompetence when |
465 | originally designing C<lazy_build>, and is also implemented by |
876b1e94 |
466 | L<MooseX::AttributeShortcuts>. There is, however, nothing to stop you |
467 | using C<lazy> and C<builder> yourself with C<rwp> or C<rw> - it's just that |
468 | this isn't generally a good idea so we don't provide a shortcut for it. |
71db76ce |
469 | |
470 | C<rwp> generates a reader like C<ro>, but also sets C<writer> to |
471 | C<_set_${attribute_name}> for attributes that are designed to be written |
472 | from inside of the class, but read-only from outside. |
473 | This feature comes from L<MooseX::AttributeShortcuts>. |
8146585e |
474 | |
6577509a |
475 | C<rw> generates a normal getter/setter by defaulting C<accessor> to the |
476 | name of the attribute. |
477 | |
8146585e |
478 | =item * isa |
479 | |
52e8f144 |
480 | Takes a coderef which is meant to validate the attribute. Unlike L<Moose>, Moo |
8146585e |
481 | does not include a basic type system, so instead of doing C<< isa => 'Num' >>, |
482 | one should do |
483 | |
c9f73a63 |
484 | isa => sub { |
8146585e |
485 | die "$_[0] is not a number!" unless looks_like_number $_[0] |
486 | }, |
487 | |
9a3fc505 |
488 | Note that the return value is ignored, only whether the sub lives or |
489 | dies matters. |
490 | |
8146585e |
491 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
492 | |
c4074652 |
493 | Since L<Moo> does B<not> run the C<isa> check before C<coerce> if a coercion |
494 | subroutine has been supplied, C<isa> checks are not structural to your code |
495 | and can, if desired, be omitted on non-debug builds (although if this results |
496 | in an uncaught bug causing your program to break, the L<Moo> authors guarantee |
497 | nothing except that you get to keep both halves). |
498 | |
71db76ce |
499 | If you want L<MooseX::Types> style named types, look at |
500 | L<MooX::Types::MooseLike>. |
501 | |
502 | To cause your C<isa> entries to be automatically mapped to named |
503 | L<Moose::Meta::TypeConstraint> objects (rather than the default behaviour |
504 | of creating an anonymous type), set: |
505 | |
506 | $Moo::HandleMoose::TYPE_MAP{$isa_coderef} = sub { |
507 | require MooseX::Types::Something; |
508 | return MooseX::Types::Something::TypeName(); |
509 | }; |
510 | |
511 | Note that this example is purely illustrative; anything that returns a |
512 | L<Moose::Meta::TypeConstraint> object or something similar enough to it to |
513 | make L<Moose> happy is fine. |
514 | |
8146585e |
515 | =item * coerce |
516 | |
517 | Takes a coderef which is meant to coerce the attribute. The basic idea is to |
518 | do something like the following: |
519 | |
c9f73a63 |
520 | coerce => sub { |
8146585e |
521 | $_[0] + 1 unless $_[0] % 2 |
522 | }, |
523 | |
52e8f144 |
524 | Note that L<Moo> will always fire your coercion: this is to permit |
525 | C<isa> entries to be used purely for bug trapping, whereas coercions are |
c4074652 |
526 | always structural to your code. We do, however, apply any supplied C<isa> |
527 | check after the coercion has run to ensure that it returned a valid value. |
8146585e |
528 | |
23a3e34e |
529 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
2e575bcd |
530 | |
e1efec09 |
531 | =item * handles |
532 | |
533 | Takes a string |
534 | |
69673ca7 |
535 | handles => 'RobotRole' |
536 | |
537 | Where C<RobotRole> is a role (L<Moo::Role>) that defines an interface which |
538 | becomes the list of methods to handle. |
e1efec09 |
539 | |
540 | Takes a list of methods |
541 | |
542 | handles => [ qw( one two ) ] |
543 | |
544 | Takes a hashref |
545 | |
546 | handles => { |
547 | un => 'one', |
548 | } |
549 | |
cc7ad717 |
550 | =item * C<trigger> |
8146585e |
551 | |
6fe5100d |
552 | Takes a coderef which will get called any time the attribute is set. This |
cc7ad717 |
553 | includes the constructor, but not default or built values. Coderef will be |
554 | invoked against the object with the new value as an argument. |
8146585e |
555 | |
71db76ce |
556 | If you set this to just C<1>, it generates a trigger which calls the |
557 | C<_trigger_${attr_name}> method on C<$self>. This feature comes from |
558 | L<MooseX::AttributeShortcuts>. |
559 | |
2e575bcd |
560 | Note that Moose also passes the old value, if any; this feature is not yet |
561 | supported. |
562 | |
8146585e |
563 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
564 | |
52e8f144 |
565 | =item * C<default> |
8146585e |
566 | |
2e575bcd |
567 | Takes a coderef which will get called with $self as its only argument |
568 | to populate an attribute if no value is supplied to the constructor - or |
569 | if the attribute is lazy, when the attribute is first retrieved if no |
570 | value has yet been provided. |
571 | |
0e43f98f |
572 | If a simple scalar is provided, it will be inlined as a string. Any non-code |
573 | reference (hash, array) will result in an error - for that case instead use |
574 | a code reference that returns the desired value. |
575 | |
2e575bcd |
576 | Note that if your default is fired during new() there is no guarantee that |
577 | other attributes have been populated yet so you should not rely on their |
578 | existence. |
8146585e |
579 | |
580 | L<Sub::Quote aware|/SUB QUOTE AWARE> |
581 | |
52e8f144 |
582 | =item * C<predicate> |
8146585e |
583 | |
2e575bcd |
584 | Takes a method name which will return true if an attribute has a value. |
8146585e |
585 | |
71db76ce |
586 | If you set this to just C<1>, the predicate is automatically named |
587 | C<has_${attr_name}> if your attribute's name does not start with an |
157aa466 |
588 | underscore, or C<_has_${attr_name_without_the_underscore}> if it does. |
71db76ce |
589 | This feature comes from L<MooseX::AttributeShortcuts>. |
8146585e |
590 | |
52e8f144 |
591 | =item * C<builder> |
8146585e |
592 | |
2e575bcd |
593 | Takes a method name which will be called to create the attribute - functions |
594 | exactly like default except that instead of calling |
595 | |
596 | $default->($self); |
597 | |
598 | Moo will call |
599 | |
600 | $self->$builder; |
8146585e |
601 | |
4752c97b |
602 | The following features come from L<MooseX::AttributeShortcuts>: |
603 | |
ba19b6a9 |
604 | If you set this to just C<1>, the builder is automatically named |
4752c97b |
605 | C<_build_${attr_name}>. |
606 | |
607 | If you set this to a coderef or code-convertible object, that variable will be |
608 | installed under C<$class::_build_${attr_name}> and the builder set to the same |
609 | name. |
71db76ce |
610 | |
52e8f144 |
611 | =item * C<clearer> |
8146585e |
612 | |
613 | Takes a method name which will clear the attribute. |
614 | |
71db76ce |
615 | If you set this to just C<1>, the clearer is automatically named |
616 | C<clear_${attr_name}> if your attribute's name does not start with an |
617 | underscore, or <_clear_${attr_name_without_the_underscore}> if it does. |
618 | This feature comes from L<MooseX::AttributeShortcuts>. |
619 | |
52e8f144 |
620 | =item * C<lazy> |
8146585e |
621 | |
622 | B<Boolean>. Set this if you want values for the attribute to be grabbed |
623 | lazily. This is usually a good idea if you have a L</builder> which requires |
624 | another attribute to be set. |
625 | |
52e8f144 |
626 | =item * C<required> |
8146585e |
627 | |
628 | B<Boolean>. Set this if the attribute must be passed on instantiation. |
629 | |
52e8f144 |
630 | =item * C<reader> |
1eba910c |
631 | |
632 | The value of this attribute will be the name of the method to get the value of |
633 | the attribute. If you like Java style methods, you might set this to |
634 | C<get_foo> |
635 | |
52e8f144 |
636 | =item * C<writer> |
1eba910c |
637 | |
638 | The value of this attribute will be the name of the method to set the value of |
639 | the attribute. If you like Java style methods, you might set this to |
52e8f144 |
640 | C<set_foo>. |
1eba910c |
641 | |
52e8f144 |
642 | =item * C<weak_ref> |
8146585e |
643 | |
644 | B<Boolean>. Set this if you want the reference that the attribute contains to |
645 | be weakened; use this when circular references are possible, which will cause |
646 | leaks. |
647 | |
52e8f144 |
648 | =item * C<init_arg> |
8146585e |
649 | |
650 | Takes the name of the key to look for at instantiation time of the object. A |
651 | common use of this is to make an underscored attribute have a non-underscored |
652 | initialization name. C<undef> means that passing the value in on instantiation |
71db76ce |
653 | is ignored. |
8146585e |
654 | |
7887ffd0 |
655 | =item * C<moosify> |
656 | |
657 | Takes either a coderef or array of coderefs which is meant to transform the |
658 | given attributes specifications if necessary when upgrading to a Moose role or |
659 | class. You shouldn't need this by default, but is provided as a means of |
660 | possible extensibility. |
661 | |
8146585e |
662 | =back |
663 | |
664 | =head2 before |
665 | |
666 | before foo => sub { ... }; |
667 | |
668 | See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full |
669 | documentation. |
670 | |
671 | =head2 around |
672 | |
673 | around foo => sub { ... }; |
674 | |
675 | See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full |
676 | documentation. |
677 | |
678 | =head2 after |
679 | |
680 | after foo => sub { ... }; |
681 | |
682 | See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full |
683 | documentation. |
684 | |
8146585e |
685 | =head1 SUB QUOTE AWARE |
686 | |
687 | L<Sub::Quote/quote_sub> allows us to create coderefs that are "inlineable," |
688 | giving us a handy, XS-free speed boost. Any option that is L<Sub::Quote> |
689 | aware can take advantage of this. |
690 | |
c9f73a63 |
691 | To do this, you can write |
692 | |
693 | use Moo; |
694 | use Sub::Quote; |
695 | |
696 | has foo => ( |
3b4a915a |
697 | is => 'ro', |
698 | isa => quote_sub(q{ die "Not <3" unless $_[0] < 3 }) |
c9f73a63 |
699 | ); |
700 | |
701 | which will be inlined as |
702 | |
703 | do { |
704 | local @_ = ($_[0]->{foo}); |
705 | die "Not <3" unless $_[0] < 3; |
706 | } |
707 | |
708 | or to avoid localizing @_, |
709 | |
710 | has foo => ( |
3b4a915a |
711 | is => 'ro', |
712 | isa => quote_sub(q{ my ($val) = @_; die "Not <3" unless $val < 3 }) |
c9f73a63 |
713 | ); |
714 | |
715 | which will be inlined as |
716 | |
717 | do { |
718 | my ($val) = ($_[0]->{foo}); |
719 | die "Not <3" unless $val < 3; |
720 | } |
721 | |
722 | See L<Sub::Quote> for more information, including how to pass lexical |
52e8f144 |
723 | captures that will also be compiled into the subroutine. |
c9f73a63 |
724 | |
2e575bcd |
725 | =head1 INCOMPATIBILITIES WITH MOOSE |
8146585e |
726 | |
52e8f144 |
727 | There is no built-in type system. C<isa> is verified with a coderef; if you |
8146585e |
728 | need complex types, just make a library of coderefs, or better yet, functions |
5902c1fc |
729 | that return quoted subs. L<MooX::Types::MooseLike> provides a similar API |
730 | to L<MooseX::Types::Moose> so that you can write |
731 | |
732 | has days_to_live => (is => 'ro', isa => Int); |
733 | |
734 | and have it work with both; it is hoped that providing only subrefs as an |
735 | API will encourage the use of other type systems as well, since it's |
736 | probably the weakest part of Moose design-wise. |
8146585e |
737 | |
2e575bcd |
738 | C<initializer> is not supported in core since the author considers it to be a |
0e43f98f |
739 | bad idea and Moose best practices recommend avoiding it. Meanwhile C<trigger> or |
f88623a1 |
740 | C<coerce> are more likely to be able to fulfill your needs. |
8146585e |
741 | |
742 | There is no meta object. If you need this level of complexity you wanted |
2e575bcd |
743 | L<Moose> - Moo succeeds at being small because it explicitly does not |
f9755246 |
744 | provide a metaprotocol. However, if you load L<Moose>, then |
745 | |
746 | Class::MOP::class_of($moo_class_or_role) |
747 | |
748 | will return an appropriate metaclass pre-populated by L<Moo>. |
8146585e |
749 | |
13e41b70 |
750 | No support for C<super>, C<override>, C<inner>, or C<augment> - the author |
751 | considers augment to be a bad idea, and override can be translated: |
752 | |
753 | override foo => sub { |
754 | ... |
755 | super(); |
756 | ... |
757 | }; |
758 | |
759 | around foo => sub { |
760 | my ($orig, $self) = (shift, shift); |
761 | ... |
762 | $self->$orig(@_); |
763 | ... |
764 | }; |
8146585e |
765 | |
f2eac33e |
766 | The C<dump> method is not provided by default. The author suggests loading |
c96a6326 |
767 | L<Devel::Dwarn> into C<main::> (via C<perl -MDevel::Dwarn ...> for example) and |
768 | using C<$obj-E<gt>$::Dwarn()> instead. |
769 | |
0e43f98f |
770 | L</default> only supports coderefs and plain scalars, because passing a hash |
771 | or array reference as a default is almost always incorrect since the value is |
772 | then shared between all objects using that default. |
8146585e |
773 | |
f9755246 |
774 | C<lazy_build> is not supported; you are instead encouraged to use the |
52e8f144 |
775 | C<< is => 'lazy' >> option supported by L<Moo> and L<MooseX::AttributeShortcuts>. |
8146585e |
776 | |
0e43f98f |
777 | C<auto_deref> is not supported since the author considers it a bad idea and |
778 | it has been considered best practice to avoid it for some time. |
8146585e |
779 | |
f9755246 |
780 | C<documentation> will show up in a L<Moose> metaclass created from your class |
c4074652 |
781 | but is otherwise ignored. Then again, L<Moose> ignores it as well, so this |
f9755246 |
782 | is arguably not an incompatibility. |
40f3e3aa |
783 | |
c4074652 |
784 | Since C<coerce> does not require C<isa> to be defined but L<Moose> does |
52e8f144 |
785 | require it, the metaclass inflation for coerce alone is a trifle insane |
c4074652 |
786 | and if you attempt to subtype the result will almost certainly break. |
787 | |
69673ca7 |
788 | Handling of warnings: when you C<use Moo> we enable FATAL warnings. The nearest |
789 | similar invocation for L<Moose> would be: |
790 | |
791 | use Moose; |
792 | use warnings FATAL => "all"; |
793 | |
794 | Additionally, L<Moo> supports a set of attribute option shortcuts intended to |
795 | reduce common boilerplate. The set of shortcuts is the same as in the L<Moose> |
239d4711 |
796 | module L<MooseX::AttributeShortcuts> as of its version 0.009+. So if you: |
69673ca7 |
797 | |
798 | package MyClass; |
799 | use Moo; |
800 | |
801 | The nearest L<Moose> invocation would be: |
802 | |
803 | package MyClass; |
804 | |
805 | use Moose; |
806 | use warnings FATAL => "all"; |
807 | use MooseX::AttributeShortcuts; |
808 | |
5902c1fc |
809 | or, if you're inheriting from a non-Moose class, |
810 | |
811 | package MyClass; |
812 | |
813 | use Moose; |
814 | use MooseX::NonMoose; |
815 | use warnings FATAL => "all"; |
816 | use MooseX::AttributeShortcuts; |
817 | |
818 | Finally, Moose requires you to call |
819 | |
820 | __PACKAGE__->meta->make_immutable; |
821 | |
822 | at the end of your class to get an inlined (i.e. not horribly slow) |
823 | constructor. Moo does it automatically the first time ->new is called |
917f27ca |
824 | on your class. (C<make_immutable> is a no-op in Moo to ease migration.) |
5902c1fc |
825 | |
6ad9aeab |
826 | An extension L<MooX::late> exists to ease translating Moose packages |
827 | to Moo by providing a more Moose-like interface. |
828 | |
660f3db2 |
829 | =head1 SUPPORT |
830 | |
cb21f16e |
831 | Users' IRC: #moose on irc.perl.org |
9836a6ee |
832 | |
cb21f16e |
833 | =for html <a href="http://chat.mibbit.com/#moose@irc.perl.org">(click for instant chatroom login)</a> |
834 | |
835 | Development and contribution IRC: #web-simple on irc.perl.org |
836 | |
837 | =for html <a href="http://chat.mibbit.com/#web-simple@irc.perl.org">(click for instant chatroom login)</a> |
072d158f |
838 | |
839 | Bugtracker: L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Moo> |
840 | |
841 | Git repository: L<git://git.shadowcat.co.uk/gitmo/Moo.git> |
842 | |
843 | Git web access: L<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo/Moo.git> |
660f3db2 |
844 | |
40f3e3aa |
845 | =head1 AUTHOR |
846 | |
847 | mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk> |
848 | |
849 | =head1 CONTRIBUTORS |
850 | |
5da684a2 |
851 | dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx> |
852 | |
853 | frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com> |
854 | |
855 | hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org> |
856 | |
857 | jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com> |
858 | |
859 | ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org> |
40f3e3aa |
860 | |
11f7a042 |
861 | chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com> |
862 | |
a17be455 |
863 | ajgb - Alex J. G. Burzyński (cpan:AJGB) <ajgb@cpan.org> |
864 | |
7b8177f8 |
865 | doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net> |
866 | |
1fb2de92 |
867 | perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org> |
868 | |
3202e039 |
869 | Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com> |
870 | |
e355471c |
871 | ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org> |
872 | |
1d17c7c1 |
873 | tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org> |
874 | |
d092b5ff |
875 | haarg - Graham Knop (cpan:HAARG) <haarg@cpan.org> |
876 | |
80fd66d7 |
877 | mattp - Matt Phillips (cpan:MATTP) <mattp@cpan.org> |
878 | |
40f3e3aa |
879 | =head1 COPYRIGHT |
880 | |
a958e36d |
881 | Copyright (c) 2010-2011 the Moo L</AUTHOR> and L</CONTRIBUTORS> |
40f3e3aa |
882 | as listed above. |
883 | |
884 | =head1 LICENSE |
885 | |
886 | This library is free software and may be distributed under the same terms |
072d158f |
887 | as perl itself. See L<http://dev.perl.org/licenses/>. |
40f3e3aa |
888 | |
889 | =cut |