ruby-on-rails – 覆盖has_many上的ActiveRecord <<运算符

>一个人has_many：目录,：通过=> ：位置.
>目录has_many：people,：through => ：位置.
>人员和目录has_many：职位.
>除了具有id,person_id和directory_id之外,Position模型还具有一个或多个附加字段(例如,标题).

我希望能够做的是每次我将一个人添加到Directory.people集合时,将数据添加到连接模型,例如标题字段.通常的<<运算符不会削减它. Id est：

directory = Directory.last     # Let's assume that retrieves a Directory object
person = Person.last           # Let's assume that retrieves a Person object
directory.people << person

这会将人员添加到Directory对象的people集合中,但不允许我有机会将数据分配给连接模型.因此,在对该网站进行了大量研究之后,我发现了另一种方法将Person添加到人员集合中,并将数据添加到链接Person和Directory的位置,id：

directory = Directory.last     # Let's assume that retrieves a Directory object
person = Person.last           # Let's assume that retrieves a Person object
position = person.positions.build(:directory_id => directory.id,:title => "Administrative Assistant") 
position.save

这很麻烦.同样繁琐的方式是：

directory = Directory.last     # Let's assume that retrieves a Directory object
person = Person.last           # Let's assume that retrieves a Person object
position = Position.new(directory_id: directory.id,person_id: person.id,title: "Administrative Assistant")

再次,似乎错了,因为我希望能够强调Person和Directory之间的关系,我相信这是使用has_many的原因：通过适当的.

我希望能够做的是使用<<运算符,只是传递附加数据,例如：

directory = Directory.last # Let's assume that retrieves a Directory object
person = Person.last # Let's assume that retrieves a Person object
directory.people << person,:position => {:title => "Administrative Assistant"}

我重载了<<我的has_many中的运算符：通过声明,如下：

has_many :people,:through => :positions do
  def << *args
    arg = args.first
    if arg.is_a?(Person)
      self.push([arg]) 
    elsif arg.is_a?(Hash)
      # Don't know what to do in here (see below)
    else
      raise "Invalid Value" # There's a better error to raise here,but good enough for now.
    end
  end
end

获得这个工作的好处是它在语法上很好地工作,并允许我简洁地将数据分配给连接对象(位置),同时将Person添加到Directory对象的people集合.

但是我无法使它工作,因为我需要能够访问<<<<<<<<<<<<<<< operator是一个属性,用于构建Position并将其保存到数据库中. 所以,我的问题是：
>有没有办法从对象的属性访问对象？
>在另一种选择中,是否有另一种方法来重载<<运算符,以便我可以轻松地将数据分配给连接模型,同时将一个对象添加到集合中？
非常感谢您的帮助和深思熟虑的回复.我一直在这里乱砍半天无济于事.

回答
感谢回答这个问题的PinnyM,我能够提出这个实现：

module AddToPeopleAndPositionExtension
  def << *args
    arg = args.first
      if arg.is_a?(Person)
        self.push([arg]) 
        return self
      elsif arg.is_a?(Hash)
        directory = proxy_association.owner
        person = arg[:person]
        position = person.positions.build(:directory_id => directory.id,:title => arg[:position][:title]) 
        position.save
      else
        raise "Invalid Value"
      end
  end
end

class Directory < ActiveRecord::Base  
  # Relationships
  has_many :positions
  has_many :people,:through => :positions,:extend => AddToPeopleAndPositionExtension
end

这让我可以调用<<如果我不关心连接模型上发生了什么,请以标准方式运算符,例如：

directory = Directory.last     # Let's assume that retrieves a Directory object
person = Person.last           # Let's assume that retrieves a Person object
directory.people << person

而且,我也可以通过指定连接模型的属性来调用它,如：

directory = Directory.last     # Let's assume that retrieves a Directory object
person = Person.last           # Let's assume that retrieves a Person object
directory.people << {:person => person,:position => {:title => "Administrative Assistant"}}