Metaobject that can hold attributes
role Metamodel::AttributeContainer {}
Warning: this role is part of the Rakudo implementation, and is not a part of the language specification.
Classes, roles and grammars can have attributes. Storage and introspection of attributes is implemented by this role.
method add_attribute($obj, $attribute)
Adds an attribute. $attribute must be an object that supports the methods name, type and package, which are called without arguments. It can for example be of type Attribute.
method attributes($obj)
Returns a list of attributes. For most Raku types, these will be objects of type Attribute.
method set_rw($obj)
Marks a type whose attributes default to having a write accessor. For example in
class Point is rw {
has $.x;
has $.y;
}
The is rw trait on the class calls the set_rw method on the metaclass, making all the attributes implicitly writable, so that you can write;
my $p = Point.new(x => 1, y => 2);
$p.x = 42;
method rw($obj)
Returns a true value if method set_rw has been called on this object, that is, if new public attributes are writable by default.