Mouse::Meta::Attribute - The Mouse attribute metaclass
This document describes Mouse version v2.5.10
This is a meta object protocol for Mouse attributes, which is a subset of Moose::Meta::Attribute.
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',
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 confesses.
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.
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.
To install Mouse, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell
For more information on module installation, please visit the detailed CPAN module installation guide.