Hands-On Design Patterns with Swift

Going further with decorator

As you may have noticed, most of the decorator interfaces are the same and can be abstracted as (Burger) -> Burger functions. All the constructors take Burger as the first parameter and return a new instance of their class, which is BurgerDecorator, which in turn is a Burger.

It is possible to add a method to the toppings enum so that it can decorate a Burger:

extension Topping {    func decorate(burger: Burger) -> WithTopping {        return WithTopping(burger: burger, topping: self)    }}// Topping.ketchup.decorate(burger: burger)

It would technically be possible to gather all the functions that decorate a burger, and finally apply them to a burger:

var decorators = [(Burger) -> Burger]decorators.append(Topping.ketchup.decorate) ...