Course of Raku / Objects, I/O, and exceptions / Classes and objects / Introspecting objects

The inheritance chain

When one class inherits from another, you can ask for the whole chain of types it is built on. The .^mro meta-method returns this chain — the name stands for method resolution order, the order in which Raku looks for a method.

class Animal {
}

class Dog is Animal {
}

say Dog.^mro; # ((Dog) (Animal) (Any) (Mu))

Reading from the left: a Dog is first itself, then an Animal (its parent), then Any and Mu — the two types that every Raku object inherits from at the very top. When you call a method on a Dog, Raku searches this list from left to right and uses the first matching method it finds. That is exactly why a child’s method overrides the parent’s: the child appears earlier in the chain.

For a class with no explicit parent, the chain is shorter — just the class itself, followed by Any and Mu.

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