Ruby：在包含時間存儲值

Question

在Ruby類中，我想在包含給定模塊時存儲變量的值。下面是一個人爲的例子：

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 

我這個嘗試任何方式（attr_accessor，set_constant，等），但最終的結果總是相同的。所有的類都有最後設定的值。

我該如何解決這個問題？

Answer 1

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