Warning: this role is part of the Rakudo implementation, and is not a part of the language specification.
Classes, roles and grammars can have parent classes, that is, classes to which method lookups fall back to, and to whose type the child class conforms to.
This role implements the capability of having zero, one or more parent (or super) classes.
In addition, it supports the notion of hidden classes, whose methods are excluded from the normal dispatching chain, so that for example
nextsame ignores it.
This can come in two flavors: methods from a class marked as
is hidden are generally excluded from dispatching chains, and
class A hides B adds
B as a parent class to
A, but hides it from the method resolution order, so that mro_unhidden skips it.
method add_parent(, , :)
$parent as a parent type. If
$hides is set to a true value, the parent type is added as a hidden parent.
$parent must be a fully composed typed. Otherwise an exception of type X::Inheritance::NotComposed is thrown.
method parents(, :, :)
Returns the list of parent classes. By default it stops at Cool, Any or Mu, which you can suppress by supplying the
:all adverb. With
:tree, a nested list is returned.
;is D ;is D ;is C1 is C2 ;is B ;say A.^parents(:all).raku;# OUTPUT: «(B, C1, C2, D, Any, Mu)␤»say A.^parents(:all, :tree).raku;# OUTPUT: «[B, ([C1, [D, [Any, [Mu]]]], [C2, [D, [Any, [Mu]]]])]␤»
Returns a list of all hidden parent classes.
Returns a true value if (and only if) the class is marked with the trait
Marks the type as hidden.