Mouse::Meta::AttributeUser)Contributed Perl DocumenMouse::Meta::Attribute(3pm)
NAME
Mouse::Meta::Attribute - The Mouse attribute metaclass
VERSION
This document describes Mouse version v2.5.10
DESCRIPTION
This is a meta object protocol for Mouse attributes, which is a subset
of Moose::Meta::Attribute.
METHODS
"new(%options) -> Mouse::Meta::Attribute"
Instantiates a new Mouse::Meta::Attribute. Does nothing else.
It adds the following options to the constructor:
"is => 'ro', 'rw', 'bare'"
This provides a shorthand for specifying the "reader", "writer", or
"accessor" names. If the attribute is read-only ('ro') then it will
have a "reader" method with the same attribute as the name.
If it is read-write ('rw') then it will have an "accessor" method
with the same name. If you provide an explicit "writer" for a read-
write attribute, then you will have a "reader" with the same name
as the attribute, and a "writer" with the name you provided.
Use 'bare' when you are deliberately not installing any methods
(accessor, reader, etc.) associated with this attribute; otherwise,
Moose will issue a deprecation warning when this attribute is added
to a metaclass.
"isa => Type"
This option accepts a type. The type can be a string, which should
be a type name. If the type name is unknown, it is assumed to be a
class name.
This option can also accept a Moose::Meta::TypeConstraint object.
If you also provide a "does" option, then your "isa" option must be
a class name, and that class must do the role specified with
"does".
"does => Role"
This is short-hand for saying that the attribute's type must be an
object which does the named role.
This option is not yet supported.
"coerce => Bool"
This option is only valid for objects with a type constraint
("isa"). If this is true, then coercions will be applied whenever
this attribute is set.
You can make both this and the "weak_ref" option true.
"trigger => CodeRef"
This option accepts a subroutine reference, which will be called
after the attribute is set.
"required => Bool"
An attribute which is required must be provided to the constructor.
An attribute which is required can also have a "default" or
"builder", which will satisfy its required-ness.
A required attribute must have a "default", "builder" or a
non-"undef" "init_arg"
"lazy => Bool"
A lazy attribute must have a "default" or "builder". When an
attribute is lazy, the default value will not be calculated until
the attribute is read.
"weak_ref => Bool"
If this is true, the attribute's value will be stored as a weak
reference.
"auto_deref => Bool"
If this is true, then the reader will dereference the value when it
is called. The attribute must have a type constraint which defines
the attribute as an array or hash reference.
"lazy_build => Bool"
Setting this to true makes the attribute lazy and provides a number
of default methods.
has 'size' => (
is => 'ro',
lazy_build => 1,
);
is equivalent to this:
has 'size' => (
is => 'ro',
lazy => 1,
builder => '_build_size',
clearer => 'clear_size',
predicate => 'has_size',
);
"associate_method(MethodName)"
Associates a method with the attribute. Typically, this is called
internally when an attribute generates its accessors.
Currently the argument MethodName is ignored in Mouse.
"verify_against_type_constraint(Item) -> TRUE | ERROR"
Checks that the given value passes this attribute's type constraint.
Returns "true" on success, otherwise "confess"es.
"clone_and_inherit_options(options) -> Mouse::Meta::Attribute"
Creates a new attribute in the owner class, inheriting options from
parent classes. Accessors and helper methods are installed. Some error
checking is done.
"get_read_method_ref"
"get_write_method_ref"
Returns the subroutine reference of a method suitable for reading or
writing the attribute's value in the associated class. These methods
always return a subroutine reference, regardless of whether or not the
attribute is read- or write-only.
SEE ALSO
Moose::Meta::Attribute
Class::MOP::Attribute
perl v5.36.0 2022-10-20 Mouse::Meta::Attribute(3pm)
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