Object::Pad::MOP::ClasUsermContributed Perl DocumeObject::Pad::MOP::Class(3pm)
NAME
"Object::Pad::MOP::Class" - meta-object representation of a
"Object::Pad" class
DESCRIPTION
Instances of this class represent a class or role implemented by
Object::Pad. Accessors provide information about the class or role, and
methods that can alter the class, typically by adding new elements to
it, allow a program to extend existing classes.
Where possible, this API is designed to be compatible with MOP::Class.
This API should be considered experimental, and will emit warnings to
that effect. They can be silenced with
use Object::Pad qw( :experimental(mop) );
or
use Object::Pad::MOP::Class qw( :experimental(mop) );
CONSTRUCTOR
for_class
$metaclass = Object::Pad::MOP::Class->for_class( $class )
Since version 0.38.
Returns the metaclass instance associated with the given class name.
for_caller
$metaclass = Object::Pad::MOP::Class->for_caller;
Since version 0.38.
A convenient shortcut for obtaining the metaclass instance of the
calling package scope. Often handy during "BEGIN" blocks of the class
itself to perform adjustments or additions.
class Some::Class::Here 1.234 {
BEGIN {
my $meta = Object::Pad::MOP::Class->for_caller;
...
}
}
create_class
my $metaclass = Object::Pad::MOP::Class->create_class( $name, %args )
Since version 0.61.
Creates a new class of the given name and yields the metaclass for it.
Takes the following additional named arguments:
extends => STRING
isa => STRING
An optional name of a superclass that this class will extend. These
options are synonyms; new code should use "isa", as "extends" will
eventually be removed.
Once created, this metaclass must be sealed using the "seal" method
before it can be used to actually construct object instances.
create_role
my $metaclass = Object::Pad::MOP::Class->create_role( $name, %args )
Since version 0.61.
As "create_class" but creates a role instead of a class.
begin_class
BEGIN {
my $metaclass = Object::Pad::MOP::Class->begin_class( $name, %args )
...
}
Since version 0.46.
A variant of "create_class" which sets the newly-created class as the
current complication scope of the surrounding code, allowing it to
accept "Object::Pad" syntax forms such as "has" and "method".
This must be done during "BEGIN" time because of this compiletime
effect. It additionally creates a deferred code block at "UNITCHECK"
time of its surrounding scope, which is used to finalise the
constructed class. In this case you do not need to remember to call
"seal" on it; this happens automatically.
begin_role
Since version 0.46.
As "begin_class" but creates a role instead of a class.
METHODS
is_class
is_role
$bool = $metaclass->is_class
$bool = $metaclass->is_role
Exactly one of these methods will return true, depending on whether
this metaclass instance represents a true "class", or a "role".
name
$name = $metaclass->name
Returns the name of the class, as a plain string.
superclasses
@classes = $metaclass->superclasses
Returns a list of superclasses, as Object::Pad::MOP::Class instances.
Because "Object::Pad" does not support multiple superclasses, this list
will contain at most one item.
direct_roles
@roles = $metaclass->direct_roles
Returns a list of the roles introduced by this class (i.e. added by
`does` declarations but not inherited from the superclass), as
Object::Pad::MOP::Class instances.
This method is also aliased as "roles".
all_roles
@roles = $metaclass->all_roles
Since version 0.56.
Returns a list of all the roles implemented by this class (i.e.
including those inherited from the superclass), as
Object::Pad::MOP::Class instances.
add_role
$metaclass->add_role( $rolename )
$metaclass->add_role( $rolemeta )
Since version 0.56.
Adds a new role to the list of those implemented by the class.
The new role can be specified either as a plain string giving its name,
or as an "Object::Pad::MOP::Class" meta instance directly.
Before version 0.56 this was called "compose_role".
add_BUILD
$metaclass->add_BUILD( $code )
Adds a new "BUILD" block to the class, as a CODE reference.
add_method
$metamethod = $metaclass->add_method( $name, %args, $code )
Adds a new named method to the class under the given name, as CODE
reference.
Returns an instance of Object::Pad::MOP::Method to represent it.
Recognises the following additional named arguments:
common => BOOL
Since version 0.62.
If true, the method is a class-common method.
get_direct_method
$metamethod = $metaclass->get_direct_method( $name )
Returns an instance of Object::Pad::MOP::Method to represent the method
of the given name, if one exists. If not an exception is thrown.
This can only see directly-applied methods; that is, methods created by
the "method" keyword on the class itself, or added via "add_method".
This will not see other names in the package stash, even if they
contain a "CODE" slot, nor will it see methods inherited from a
superclass.
This is also aliased as "get_own_method" for compatibility with the
MOP::Class interface.
get_method
$metamethod = $metaclass->get_method( $name )
Since version 0.57.
Returns an instance of Object::Pad::MOP::Method to represent the method
of the given name, if one exists. If not an exception is thrown.
This will additionally search superclasses, and may return a method
belonging to a parent class.
direct_methods
@metamethods = $metaclass->direct_methods
Since version 0.57.
Returns a list of Object::Pad::MOP::Method instances to represent all
the direct methods of the class. This list may be empty.
all_methods
@metamethods = $metaclass->all_methods
Since version 0.57.
Returns a list of Object::Pad::MOP::Method instances to represent all
the methods of the class, including those inherited from superclasses.
This list may be empty.
add_field
$metafield = $metaclass->add_field( $name, %args )
since version 0.60.
Adds a new field to the class, using the given name (which must begin
with the sigil character "$", "@" or "%").
Recognises the following additional named arguments:
default => SCALAR
Since version 0.43.
Provides a default value for the field; similar to using the syntax
has $field = SCALAR;
This value may be "undef", to set the value as being optional if it
additionally has a parameter name.
param => STRING
Since version 0.43.
Provides a parameter name for the field; similar to setting it
using the ":param" attribute. This parameter will be required
unless a default value is set (such value may still be "undef").
reader => STRING
writer => STRING
mutator => STRING
Since version 0.46.
accessor => STRING
Since version 0.56.
Provides method names for generated reader, writer, lvalue-mutator
or reader+writer accessor methods, similar to setting them via the
":reader", ":writer", ":mutator" or ":accessor" attributes.
weak => BOOL
Since version 0.46.
If true, reference values assigned into the field by the
constructor or accessor methods will be weakened, similar to
setting the ":weak" attribute.
Returns an instance of Object::Pad::MOP::Field to represent it.
add_slot
$metafield = $metaclass->add_slot( $name, %args )
Now deprecated.
Back-compatibility alias for "add_field".
get_field
$metafield = $metaclass->get_field( $name )
Since version 0.60.
Returns an instance of Object::Pad::MOP::Field to represent the field
of the given name, if one exists. If not an exception is thrown.
get_slot
$metafield = $metaclass->get_slot( $name )
Now deprecated.
Back-compatibility alias for "get_field".
fields
@metafields = $metaclass->fields
Since version 0.60.
Returns a list of Object::Pad::MOP::Field instances to represent all
the fields of the class. This list may be empty.
slots
@metafields = $metaclass->slots
Since version 0.42; now deprecated.
Back-compatibility alias for "fields".
add_required_method
$metaclass->add_required_method( $name )
Since version 0.61.
Adds a new required method to the role, whose name is given as a plain
string.
Currently returns nothing. This should be considered temporary, as
eventually a metatype for required methods will be added, at which
point this method can return instances of it. It may also take
additional parameters to define the required method with. Currently
extra parameters are not permitted.
required_method_names
@names = $metaclass->required_method_names
Since version 0.61.
Returns a list names of required methods for the role, as plain
strings.
This should be considered a temporary method. Currently there is no
metatype for required methods, so they are represented as plain
strings. Eventually a type may be defined and a "required_methods"
method will be added.
seal
$metaclass->seal
Since version 0.61.
If the metaclass was created by "create_class" or "create_role", this
method must be called once everything has been added into it, as the
class will not yet be ready to construct actual object instances before
this is done.
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.36.0 2023-01-13 Object::Pad::MOP::Class(3pm)
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