Visitor pattern with match/case

carvisit.py

# Compare https://en.wikipedia.org/wiki/Visitor_pattern#Python_example

from dataclasses import dataclass

class CarElement:
    def visit(self, func):
        func(self)

class Body(CarElement):
    pass

class Engine(CarElement):
    pass

@dataclass
class Wheel(CarElement):
    name: str

class Car(CarElement):
    def __init__(self):
        self.elements = [
            Wheel("front left"), Wheel("front right"),
            Wheel("back left"), Wheel("back right"),
            Body(), Engine()
        ]
    def visit(self, func):
        for element in self.elements:
            element.visit(func)
        func(self)

def do_car_element(elem):
    match elem:
        case Body():
            print("Moving my body.")
        case Car():
            print("Starting my car.")
        case Wheel(name):
            print(f"Kicking my {name} wheel.")
        case Engine():
            print("Starting my engine.")

def print_car_element(elem):
    match elem:
        case Body():
            print("Visiting body.")
        case Car():
            print("Visiting car.")
        case Wheel(name):
            print(f"Visiting {name} wheel.")
        case Engine():
            print("Visiting engine.")

car = Car()
car.visit(print_car_element)
car.visit(do_car_element)