iracket中有第一个和休息功能吗？

Question

我刚刚设置了iracket.但有些功能似乎不起作用.

(define (f z) (first (rest z)))
(f '(1 2 3))
first: undefined;
 cannot reference an identifier before its definition
  in module: top-level
  internal name: first
  context...:

我想知道iracket中有第一个和休息功能吗？

Answer 1

IRacket从racket/base模块的绑定开始,不包括first和rest.运行(require racket/list)或(require racket)在函数定义之前.