Lisp 关联列表

Question

(defun next ()
  (defparameter *sentences*
    '(
      (1 . "Test 1")
      (2 . "Test 2")))

  (let (sentence '(assoc 2 *sentences*)) ;This quote is needed, another program evaluates this.
    (format t "*sentences*:~%~a~%sentence: ~a~%" *sentences* sentence)))

它给出了输出“*句子*:((1 . 测试 1) (2 . 测试 2))句子:无。

为什么它不给出 (2 . Test 2) 作为“句子”的值？

提前致谢。

编辑:添加括号。原程序有匹配的括号。

Answer 1

您的 let 表单中缺少括号:

(defun next ()
  (defparameter *sentences*
    '(
      (1 . "Test 1")
      (2 . "Test 2")))
  (let ((sentence (assoc 2 *sentences*))) ;no quote, just parentheses ;-)
    (format t "*sentences*:~%~a~%sentence: ~a~%" *sentences* sentence)))