Question

我正在尝试在Lisp中编写一个数字猜谜游戏作为一个耗时的项目。但是，当我尝试使用SBCL加载程序时，我收到以下错误：

debugger invoked on a SB-C::INPUT-ERROR-IN-COMPILE-FILE in thread #<THREAD
                                                                    "initial thread" RUNNING
                                                                    {AA14959}>:
  READ failure in COMPILE-FILE at character 477:
    end of file on #<SB-SYS:FD-STREAM
                     for "file /home/andy/Dropbox/Programming/Common Lisp/number-game.lisp"
                     {B4F45F9}>

Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [CONTINUE] Ignore runtime option --load "number-game.lisp".
  1: [ABORT   ] Skip rest of --eval and --load options.
  2:            Skip to toplevel READ/EVAL/PRINT loop.
  3: [QUIT    ] Quit SBCL (calling #'QUIT, killing the process).

(SB-C::READ-FOR-COMPILE-FILE
 #<SB-SYS:FD-STREAM
   for "file /home/andy/Dropbox/Programming/Common Lisp/number-game.lisp"
   {B4F45F9}>
 477)

这个错误是什么意思？代码如下，加载文件并从REPL调用(play)时出现错误：

;;;; number-game.lisp
;;;;
;;;; Andrew Levenson
;;;; 10/25/2010
;;;;
;;;; Simple number guessing game. User has
;;;; five guesses to determine a number between
;;;; one and one hundred, inclusive (1-100).

;;; Set global variable for the target number:
(defparameter *target* nil) 

;;; Set the iterator so we may check the number of guesses
(defparameter *number-of-guesses* 0)

;;; Welcome the user
(defun welcome-user ()
    (format t "Welcome to the number guessing game!~%"))

;;; Prompt for a guess
(defun prompt-for-guess ()
    (format t "Please enter your guess (1-100): ")
    (finish-output nil) ; nil directs finish-output to standard IO
    (check-guess((read-guess)))

;;; Read in a guess
(defun read-guess ()
    (let ((guess (read)))
        (if (numberp guess) ; If true, return guess. Else, call prompt-for-guess
            (progn
                (setq *number-of-guesses* (+ *number-of-guesses* 1))
                guess)
            (prompt-for-guess))))

;;; Check if the guess is higher than, lower than, or equal to, the target
(defun check-guess (guess)
    (if (equal guess *target*)
        (equal-to)
        (if (> guess *target*)
            (greater-than (guess))
            (if (< guess *target*)
                (less-than (guess))))))

;;; If the guess is equal to the target, the game is over
(defun equal-to ()
    (format t "Congratulations! You have guessed the target number, ~a!~%" *target*)
    (y-or-n-p "Play again? [y/n] "))

;;; If the guess is greater than the target, inform the player.
(defun greater-than (guess)
    (format t "Sorry, ~a is greater than the target.~%" guess)
    (if (< *number-of-guesses* 6)
        (prompt-for-guess)
        (game-over)))

;;; If the guess is less than the target, inform the player.
(defun less-than (guess)
    (format t "Sorry, ~a is less than the target.~%" guess)
    (if (< *number-of-guesses* 6)
        (prompt-for-guess)
        (game-over)))

;;; If the player has run out of guesses, give them the option
;;; of playing the game again.
(defun game-over ()
    (y-or-n-p "You have run out of guesses. Play again? [y/n] "))


;;; Play the game
(defun play ()
    ;; If it's their first time playing this session,
    ;; make sure to greet the user.
    (unless (> *number-of-guesses* 0)
        (welcome-user))
    ;; Reset their remaining guesses
    (setq *number-of-guesses* 0)
    ;; Set the target value
    (setq *target*
        ;; Random can return float values,
        ;; so we must round the result to get
        ;; an integer value.
        (round
            ;; Add one to the result, because
            ;; (random 100) yields a number between
            ;; 0 and 99, whereas we want a number
            ;; from 1 to 100 inclusive.
            (+ (random 100) 1)))
    (if (equal (prompt-for-guess) "y")
        (play)
        (quit)))

（我相当确定程序不起作用减去那个错误，我还是一个完全新手的Lisp。这只是我遇到的第一个我无法想象的错误独自一人。）

哦，这个问题很可能与prompt-for-guess，read-guess和check-guess函数有关，因为当出现此错误时，我正在弄乱这些函数。< / p>

Answer 1

看起来你的prompt-for-guess defun上没有足够的parens。

读者已经到了文件的末尾，注意到它的表单仍然打开，无法弄清楚它的来源。

我用来查找这样的错误的一种简单方法是让我的文本编辑器缩进该区域，并确保所有内容都按照我认为的方式排列。

Answer 2

Emacs中的命令是M-x check-parens（它会检查需要平衡的所有内容，如引号）。如果一切平衡，可能会有点神秘，因为在这种情况下它什么都不做。

签括号命令：检查当前缓冲区中的不平衡括号。更准确地说，检查缓冲区的狭窄部分是否不平衡表达式（“sexps”）一般。这是根据当前语法表并将找到不平衡的括号或引号适当。（请参阅信息节点`（emacs）括号'。）如果不平衡发现，发出错误信号，并在第一个不平衡点处留下点字符。

Answer 3

在读取期间

文件结尾，缺少一个右括号（或类似的）。字符477.将文本中的光标移动到477并检查它是哪个表达式。

检查IDE以获取查找不平衡表达式的命令。

在LispWorks中，这将是 M-x Find Unbalanced Parentheses 。

SLIME也应该有一些命令。

Common Lisp错误未被理解

3 个答案: