1Object::Pad::MOP::ClassU(s3e)r Contributed Perl DocumentaOtbijoenct::Pad::MOP::Class(3)
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NAME

6       "Object::Pad::MOP::Class" - meta-object representation of a
7       "Object::Pad" class
8

DESCRIPTION

10       Instances of this class represent a class or role implemented by
11       Object::Pad. Accessors provide information about the class or role, and
12       methods that can alter the class, typically by adding new elements to
13       it, allow a program to extend existing classes.
14
15       Where possible, this API is designed to be compatible with MOP::Class.
16
17       This API should be considered experimental, and will emit warnings to
18       that effect. They can be silenced with
19
20          use Object::Pad qw( :experimental(mop) );
21
22       or
23
24          use Object::Pad::MOP::Class qw( :experimental(mop) );
25

CONSTRUCTOR

27   for_class
28          $metaclass = Object::Pad::MOP::Class->for_class( $class )
29
30       Since version 0.38.
31
32       Returns the metaclass instance associated with the given class name.
33
34   for_caller
35          $metaclass = Object::Pad::MOP::Class->for_caller;
36
37       Since version 0.38.
38
39       A convenient shortcut for obtaining the metaclass instance of the
40       calling package scope. Often handy during "BEGIN" blocks of the class
41       itself to perform adjustments or additions.
42
43          class Some::Class::Here 1.234 {
44             BEGIN {
45                my $meta = Object::Pad::MOP::Class->for_caller;
46                ...
47             }
48          }
49
50   create_class
51          my $metaclass = Object::Pad::MOP::Class->create_class( $name, %args )
52
53       Since version 0.61.
54
55       Creates a new class of the given name and yields the metaclass for it.
56
57       Takes the following additional named arguments:
58
59       extends => STRING
60       isa => STRING
61           An optional name of a superclass that this class will extend. These
62           options are synonyms; new code should use "isa", as "extends" will
63           eventually be removed.
64
65       Once created, this metaclass must be sealed using the "seal" method
66       before it can be used to actually construct object instances.
67
68   create_role
69          my $metaclass = Object::Pad::MOP::Class->create_role( $name, %args )
70
71       Since version 0.61.
72
73       As "create_class" but creates a role instead of a class.
74
75   begin_class
76          BEGIN {
77             my $metaclass = Object::Pad::MOP::Class->begin_class( $name, %args )
78             ...
79          }
80
81       Since version 0.46.
82
83       A variant of "create_class" which sets the newly-created class as the
84       current complication scope of the surrounding code, allowing it to
85       accept "Object::Pad" syntax forms such as "has" and "method".
86
87       This must be done during "BEGIN" time because of this compiletime
88       effect.  It additionally creates a deferred code block at "UNITCHECK"
89       time of its surrounding scope, which is used to finalise the
90       constructed class. In this case you do not need to remember to call
91       "seal" on it; this happens automatically.
92
93   begin_role
94       Since version 0.46.
95
96       As "begin_class" but creates a role instead of a class.
97

METHODS

99   is_class
100   is_role
101          $bool = $metaclass->is_class
102          $bool = $metaclass->is_role
103
104       Exactly one of these methods will return true, depending on whether
105       this metaclass instance represents a true "class", or a "role".
106
107   name
108          $name = $metaclass->name
109
110       Returns the name of the class, as a plain string.
111
112   superclasses
113          @classes = $metaclass->superclasses
114
115       Returns a list of superclasses, as Object::Pad::MOP::Class instances.
116
117       Because "Object::Pad" does not support multiple superclasses, this list
118       will contain at most one item.
119
120   direct_roles
121          @roles = $metaclass->direct_roles
122
123       Returns a list of the roles introduced by this class (i.e. added by
124       `does` declarations but not inherited from the superclass), as
125       Object::Pad::MOP::Class instances.
126
127       This method is also aliased as "roles".
128
129   all_roles
130          @roles = $metaclass->all_roles
131
132       Since version 0.56.
133
134       Returns a list of all the roles implemented by this class (i.e.
135       including those inherited from the superclass), as
136       Object::Pad::MOP::Class instances.
137
138   add_role
139          $metaclass->add_role( $rolename )
140          $metaclass->add_role( $rolemeta )
141
142       Since version 0.56.
143
144       Adds a new role to the list of those implemented by the class.
145
146       The new role can be specified either as a plain string giving its name,
147       or as an "Object::Pad::MOP::Class" meta instance directly.
148
149       Before version 0.56 this was called "compose_role".
150
151   add_BUILD
152          $metaclass->add_BUILD( $code )
153
154       Adds a new "BUILD" block to the class, as a CODE reference.
155
156   add_method
157          $metamethod = $metaclass->add_method( $name, %args, $code )
158
159       Adds a new named method to the class under the given name, as CODE
160       reference.
161
162       Returns an instance of Object::Pad::MOP::Method to represent it.
163
164       Recognises the following additional named arguments:
165
166       common => BOOL
167           Since version 0.62.
168
169           If true, the method is a class-common method.
170
171   get_direct_method
172          $metamethod = $metaclass->get_direct_method( $name )
173
174       Returns an instance of Object::Pad::MOP::Method to represent the method
175       of the given name, if one exists. If not an exception is thrown.
176
177       This can only see directly-applied methods; that is, methods created by
178       the "method" keyword on the class itself, or added via "add_method".
179       This will not see other names in the package stash, even if they
180       contain a "CODE" slot, nor will it see methods inherited from a
181       superclass.
182
183       This is also aliased as "get_own_method" for compatibility with the
184       MOP::Class interface.
185
186   get_method
187          $metamethod = $metaclass->get_method( $name )
188
189       Since version 0.57.
190
191       Returns an instance of Object::Pad::MOP::Method to represent the method
192       of the given name, if one exists. If not an exception is thrown.
193
194       This will additionally search superclasses, and may return a method
195       belonging to a parent class.
196
197   direct_methods
198          @metamethods = $metaclass->direct_methods
199
200       Since version 0.57.
201
202       Returns a list of Object::Pad::MOP::Method instances to represent all
203       the direct methods of the class. This list may be empty.
204
205   all_methods
206          @metamethods = $metaclass->all_methods
207
208       Since version 0.57.
209
210       Returns a list of Object::Pad::MOP::Method instances to represent all
211       the methods of the class, including those inherited from superclasses.
212       This list may be empty.
213
214   add_field
215          $metafield = $metaclass->add_field( $name, %args )
216
217       since version 0.60.
218
219       Adds a new field to the class, using the given name (which must begin
220       with the sigil character "$", "@" or "%").
221
222       Recognises the following additional named arguments:
223
224       default => SCALAR
225           Since version 0.43.
226
227           Provides a default value for the field; similar to using the syntax
228
229              has $field = SCALAR;
230
231           This value may be "undef", to set the value as being optional if it
232           additionally has a parameter name.
233
234       param => STRING
235           Since version 0.43.
236
237           Provides a parameter name for the field; similar to setting it
238           using the ":param" attribute. This parameter will be required
239           unless a default value is set (such value may still be "undef").
240
241       reader => STRING
242       writer => STRING
243       mutator => STRING
244           Since version 0.46.
245
246       accessor => STRING
247           Since version 0.56.
248
249           Provides method names for generated reader, writer, lvalue-mutator
250           or reader+writer accessor methods, similar to setting them via the
251           ":reader", ":writer", ":mutator" or ":accessor" attributes.
252
253       weak => BOOL
254           Since version 0.46.
255
256           If true, reference values assigned into the field by the
257           constructor or accessor methods will be weakened, similar to
258           setting the ":weak" attribute.
259
260       Returns an instance of Object::Pad::MOP::Field to represent it.
261
262   add_slot
263          $metafield = $metaclass->add_slot( $name, %args )
264
265       Now deprecated.
266
267       Back-compatibility alias for "add_field".
268
269   get_field
270          $metafield = $metaclass->get_field( $name )
271
272       Since version 0.60.
273
274       Returns an instance of Object::Pad::MOP::Field to represent the field
275       of the given name, if one exists. If not an exception is thrown.
276
277   get_slot
278          $metafield = $metaclass->get_slot( $name )
279
280       Now deprecated.
281
282       Back-compatibility alias for "get_field".
283
284   fields
285          @metafields = $metaclass->fields
286
287       Since version 0.60.
288
289       Returns a list of Object::Pad::MOP::Field instances to represent all
290       the fields of the class. This list may be empty.
291
292   slots
293          @metafields = $metaclass->slots
294
295       Since version 0.42; now deprecated.
296
297       Back-compatibility alias for "fields".
298
299   add_required_method
300          $metaclass->add_required_method( $name )
301
302       Since version 0.61.
303
304       Adds a new required method to the role, whose name is given as a plain
305       string.
306
307       Currently returns nothing. This should be considered temporary, as
308       eventually a metatype for required methods will be added, at which
309       point this method can return instances of it. It may also take
310       additional parameters to define the required method with. Currently
311       extra parameters are not permitted.
312
313   required_method_names
314          @names = $metaclass->required_method_names
315
316       Since version 0.61.
317
318       Returns a list names of required methods for the role, as plain
319       strings.
320
321       This should be considered a temporary method. Currently there is no
322       metatype for required methods, so they are represented as plain
323       strings. Eventually a type may be defined and a "required_methods"
324       method will be added.
325
326   seal
327          $metaclass->seal
328
329       Since version 0.61.
330
331       If the metaclass was created by "create_class" or "create_role", this
332       method must be called once everything has been added into it, as the
333       class will not yet be ready to construct actual object instances before
334       this is done.
335

AUTHOR

337       Paul Evans <leonerd@leonerd.org.uk>
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341perl v5.36.1                      2023-05-15        Object::Pad::MOP::Class(3)