Ruby Module.extend_object用法及代码示例

extend_object(obj) → obj

通过添加此模块的常量和方法(作为单例方法添加)扩展指定对象。这是 Object#extend 使用的回调方法。

module Picky
  def Picky.extend_object(o)
    if String === o
      puts "Can't add Picky to a String"
    else
      puts "Picky added to #{o.class}"
      super
    end
  end
end
(s = Array.new).extend Picky  # Call Object.extend
(s = "quick brown fox").extend Picky

产生：

Picky added to Array
Can't add Picky to a String