抽象层 abstraction layer

sicp-mit-4_yilu_beiyu的博客-CSDN博客

;;; data abstraction
;;; use                | +rat *rat -rat
;;; =========================================
;;; abstraction layer  | make-rat numer denom
;;; =========================================
;;; representation     | pairs


;;;中心思想为要建立层次化的系统
;;;建立抽象屏障将细节隔离在底层
;;;将细节与你所工作的高层环境隔离开
;;;the key idea is that you're going to build the system in layers
;;;and set up abstraction barries that isolate the details at the lower layers
;;;from the thing that's going on at the upper layers

use and representation