SICP Ref 环境安装教程 Notes Chapter01 Applicative-order vs normal-order Normal Order and Applicative Order (define (try a b) (if (= a 0) 1 b)) (try 0 (/ 1 0))会报错,【mit-scheme默认是applicative-order,all arguments will be evaluated when procedure is applied】 如果是normal-order就不会报错,它会使用lazy evaluation,当参数需要的时候才会计算