ruby-on-rails - 如何在 Ruby 中关联来自不同类的实例

Question

我希望能够初始化一个新的 Car 对象并在参数中将一个 Person 对象传递给它，这样它就可以保存在那个 Person 的 @cars 数组中。目前，我采用这种方法:

person = Person.new("Michael")
car = Car.new("Honda", "Accord")
person.add_car(car)
person.add_car(Car.new("Ford", "Taurus"))
person.add_car(Car.new("Toyota", "Prius"))
person.display

但是，我希望能够创建一个新的汽车实例并将它传递给我希望与之关联的 Person 对象。例如:

person = Person.new("Michael")
Car.new("Honda", "Accord", person)
Car.new("Toyota", "Camry", person)
Car.new("Chevy", "Tahoe", person)
person.display

这可能吗？

class Person

  attr_accessor :name

  def initialize(name)
    super
    @name = name
    @cars = []
  end

  def display
    puts "#{@name} has #{@cars.length} cars"
    puts "----------------------------"
    @cars.each do |car|
      puts "#{car.make} #{car.model}"
    end
  end

  def add_car(car)
    @cars.push(car)
  end

end 

class Car

  attr_accessor :make, :model

  def initialize(make, model)
    @model = model
    @make = make
  end

  def display
    puts "#{@make} #{@model}"
  end

end

Answer 1

是的，这是可能的，Car#initialize 可以在其参数上调用方法:

class Car
  def initialize(make, model, person = nil)
    @model = model
    @make  = make
    person.add_car(self) if(person)
  end
  #...
end