If we get used to the OOP, we know that it often mentioned the concept about "Reusable", actually that bring different layers of meanings about software design, one could be, if it's reusable, then we will be able to use it in new software with
按照一定规则使用匹配模式在目标空间进行搜索,然后执行相应操作: 运行时系统将kvc的运行机制解释为模式匹配,将值的兼容性问题解释为装包解包问题 一.模式匹配 The default implementation of the NSKeyValueCoding protocol provided by NSObject maps key-based accessor calls to an object’s underlying properties using a clearly defined