InheritanceCompositionExample_1D.swift

// A dog has bark + eat
class Dog {
  let dogBark = BarkingSkill()
  let dogEat = EatingSkill()
 
  public func bark() {
    dogBark.bark()
  }
  
  public func eat() {
    dogEat.eat()
  }
}

// A robot has clean
class Robot {
  let robotClean = CleaningSkill()
  
  public func clean() {
    robotClean.clean()
  }
}

// A robot dog has barker + cleaner
class RobotDog {
  let dogBark = BarkingSkill()
  let dogClean = CleaningSkill()
  
  public func bark() {
    dogBark.bark()
  }
  
  public func clean() {
    dogClean.clean()
  }
}

var Quinn = Dog()
Quinn.bark() // "woof!"
Quinn.eat()  // "nom nom nom"

var Alfred = Robot()
Alfred.clean() // "Cleaning! beep boop"

var Sparky = RobotDog()
Sparky.bark() // "woof!"
Sparky.clean() // "Cleaning! beep boop"