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role Metamodel::AttributeContainer
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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.

Methods

method add_attribute

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

method attributes($obj)

Returns a list of attributes. For most Raku types, these will be objects of type Attribute.

method set_rw

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=> 2);
$p.x = 42;

method rw

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.