We can view selectors as methods which themselves are not dynamically linked but still behave like polymorphic functions because they let dynamically linked functions do their real work 我們可以認(rèn)為選擇器是不動(dòng)態(tài)鏈接但仍然被認(rèn)為行為類(lèi)似多態(tài)函數(shù)的方法,這是因?yàn)樗麄兪窃谡嬲ぷ鞯臅r(shí)候才進(jìn)行動(dòng)態(tài)鏈接。