key-value 用hash; hash 作为公共接口是没有访问限制的。Reading = Struct.new(:data, :high, :low); Reading.new(Date.parse(..),..,..) Struct是属性列表；里面也可以定义方法； 将Struct返回值设置为常量，像类一样使用他。
>> Effective Ruby

Are you insisting he didn't? In the future we can parse any document into manageable phrases. You can sing them, swear them, rehearse them til you get the rhythm and flow; that, combined with your growing confidence... Bertie doesn't want to hear.
>> 国王的演讲 The King's Speech Movie Script