Metamodel::MROBasedMethodDispatch Reference

Metaobject that supports resolving inherited methods

What it is #

Position in the hierarchy #

Routines #

Signatures are reproduced from the documentation, including their declared return types. A routine listed here is part of the type's published interface; whether Raku++ implements it is a separate question, answered by the examples below.

method find_method #

method find_method($obj, $name, :$no_fallback, *%adverbs)

Given a method name, it returns the method object of that name which is closest in the method resolution order (MRO). If no method can be found, it returns a VM-specific sentinel value (typically a low-level NULL value) that can be tested for with a test for definedness: If :no_fallback is supplied, fallback methods are not considered.

method find_method_qualified #

method find_method_qualified($obj, $type, $name)

Given a method name and a type, returns the method from that type. This is used in calls like

method can #

method can($obj, $name)

Returns the list of methods of that name the object can do.

method publish_method_cache #

method publish_method_cache($obj)

Walk MRO and add methods to cache, unless another method lower in the class hierarchy "shadowed" it.

Examples, run three ways #

Every example below comes from the official documentation, together with the output that documentation asserts. Each was then executed by Rakudo and by Raku++ when this page was built. Where the three agree, one result is shown; where they do not, all three are — because which of them is wrong is exactly the information worth having.

3 no-output

role Metamodel::MROBasedMethodDispatch { }

for <uppercase  uc> {
Str.^find_method: $^meth andthen .("foo").say
    orelse "method `$meth` not found".say
}
# OUTPUT:
# method `uppercase` not found
# FOO

self.SomeParentClass::the_method();