如何在Ruby中实现私有内部类(How to implement private inner class in Ruby)

 来自Java，我想在Ruby中实现LinkedList。 我在Java中实现这种方法的常用方法是使用名为LinkedList的类和名为Node的私有内部类，并将LinkedList的每个对象都作为Node对象。 
 
class LinkedList
  private
  class Node
    attr_accessor :val, :next
  end
end
 
 我不想将Node类暴露给外部世界。 但是使用Ruby中的这个设置，我可以使用以下方法访问LinkedList类之外的私有Node类对象 - 
 
node = LinkedList::Node.new
 
 我知道，使用Ruby 1.9，我们可以使用private_constant方法将Node指定为私有常量。 但我想知道这是否是实现这一目标的正确方法？ 为什么我能够在LinkedList类之外创建Node对象，即使它被声明为私有？ 

Coming from Java, I am trying to implement LinkedList in Ruby. The usual way I would implement this in Java is have an class called LinkedList and private inner class called Node with each object of LinkedList as Node object.
 
class LinkedList
  private
  class Node
    attr_accessor :val, :next
  end
end
 
I do not want to expose the Node class to external world. However with this setup in Ruby, I can access the private Node class object outside the LinkedList class using this -
 
node = LinkedList::Node.new
 
I know, with Ruby 1.9, we can use private_constant method to designate Node as private constant. But I am wondering if this is the right way to accomplish this? Also why am I able to create Node objects outside the LinkedList class even though it is declared as private?

原文：https://stackoverflow.com/questions/39716799