ruby - 从复杂的方法链中获取父实例化对象？

Question

原谅人为的例子，如果我有......

class Condiment
  def ketchup(quantity)
    puts "adding #{quantity} of ketchup!"
  end
end

class OverpricedStadiumSnack
  def add
    Condiment.new
  end
end

hotdog = OverpricedStadiumSnack.new

...调用时是否可以从内部访问hotdog实例化对象？Condiment#ketchuphotdog.add.ketchup('tons!')

---

到目前为止，我发现的唯一解决方案是hotdog显式传递，如下所示：

class Condiment
  def ketchup(quantity, snack)
    puts "adding #{quantity} of ketchup to your #{snack.type}!"
  end
end

class OverpricedStadiumSnack
  attr_accessor :type

  def add
    Condiment.new
  end
end

hotdog = OverpricedStadiumSnack.new
hotdog.type = 'hotdog'

# call with
hotdog.add.ketchup('tons!', hotdog)

...但我希望能够在不hotdog明确传递的情况下做到这一点。

Answer 1

或许：

class Condiment
  def initialize(snack)
    @snack = snack
  end

  def ketchup(quantity)
    puts "adding #{quantity} of ketchup! to your #{@snack.type}"
  end
end

class OverpricedStadiumSnack
  attr_accessor :type

  def add
    Condiment.new(self)
  end
end

hotdog = OverpricedStadiumSnack.new
hotdog.type = 'hotdog'
hotdog.add.ketchup(1)