Course of Raku / Addendum 🆕 / Types and text machines / Objects and classes / Exercises / Animals that speak

Solution: Animals that speak

Here is a possible solution to the task.

Code

class Animal {
    has $.name;
    method speak { '...' }
    method greet { "{$.name} says {self.speak}" }
}

class Dog is Animal { method speak { 'Woof' } }
class Cat is Animal { method speak { 'Meow' } }

for Dog.new(name => 'Rex'), Cat.new(name => 'Tom') -> $pet {
    say $pet.greet;
}

🦋 You can find the source code in the file animal-inheritance.raku.

Output

Rex says Woof
Tom says Meow

Comments

1. greet is defined once in the base class, but it calls self.speak. Because self is the actual object, the call reaches the subclass’s own speak.

2. This is polymorphism: the same greet produces Woof for a dog and Meow for a cat without any conditional code.

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