human.swift

human.swift

class Human {
  // The eat function returns an indicator,
  // whether or not the food has been eaten.
  // Our human has free choice.
  func eat(_ food: Food) -> Bool {
    // But they're a simple person,
    // that eats everything that's edible.
    return food.isEdible
  }
}

// Now we want to define a sub-class of Human
// to give our objects a more detailed definition.
class Vegan: Human {
  // We're overriding eat to change the output.
  override func eat(_ food: Food) -> Bool {
    // Our Vegan only eats edible food that's vegan.
    return food.isEdible && food.isVegan
  }
}