Design Pattern: Decorator and Waffle

waffle_decorator.rb

class WaffleDecorator
  attr_reader   :waffle
  
  def initialize(waffle)
    @waffle = waffle
  end
  
  def serve
    waffle.serve
    puts "  topped with #{topping}"
  end
  
  def eat
    waffle.eat
    puts "  and then eat some #{topping}"
  end
  
  def topping
    raise NotImplementedError
  end
end