Ruby：在包含时存储值

在Ruby类中，我希望在包含给定模块时存储变量的值。下面是一个人为的例子：

module M
  def self.included(base)
    base.class_eval do
      @@inclusion_time = Time.now

      def included_at
        @@inclusion_time
      end
    end
  end
end

class A
  include M
end

sleep 3

class B
  include M
end

sleep 3

class C
  include M
end

a = A.new
b = B.new
c = C.new

puts a.included_at
puts b.included_at
puts c.included_at

我尝试过很多方法（attr\u访问器、set\u常量等），但最终结果总是一样的。所有类都具有上次设置的值

---

如何解决这个问题？

当我将SO的模块M替换为您的模块M时，

A.new.included\u at

返回nil（当然，B和C相同），而

def self.included（klass）klass.instance\u variable\u set（：@include\u time，time.now）end

给出了所需的结果。请注意，在包含的self.included中，self等于M。

module M
  def self.included _
    @inclusion_time = Time.now
  end
  def included_at
    self.class.instance_eval{@inclusion_time}
  end
end