NAME

       Mouse::Meta::Attribute - The Mouse attribute metaclass

VERSION

       This document describes Mouse version 2.1.0

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