小编Gra*_*oom的帖子

当我在本书提供的最终产品中遇到错误时,我正在阅读Practical Common Lisp一书中的第一个示例项目.

该项目是一个存储有关cds信息的基本数据库.它支持select和update语句以及where宏.

我已经使用clisp和sbcl编译器测试了代码,两者都发生了同样的错误.

这是代码:

(defvar *db*)

(defun make-cd (title artist rating ripped)
  (list :title title :artist artist :rating rating :ripped ripped))

(defun add-record (cd) (push cd *db*))

(defun dump-db ()
  (format t "~{~{~a:~10t~a~%~}~%~}" *db*))

(defun prompt-read (prompt)
  (format *query-io* "~a: " prompt)
  (force-output *query-io*)
  (read-line *query-io*))

(defun prompt-for-cd ()
  (make-cd
   (prompt-read "Title")
   (prompt-read "Artist")
   (or (parse-integer (prompt-read "Rating") :junk-allowed t) 0)
   (y-or-n-p "Ripped [y/n]: ")))

(defun add-cds ()
  (loop (add-record (prompt-for-cd))
    (if (not (y-or-n-p "Another? [y/n]: …