#lang racket (define (double f) (lambda (x) (f (f x)) );lambda );double (define ((double1 f) x) (f (f x)) ) (define (inc x) (+ x 1) );inc (((double (double double))inc )5) (((double1 (double1 double1)) inc) 0 )
最后的结果：21 16
原文：http://www.cnblogs.com/wizzhangquan/p/4392398.html