Question

我正在尝试创建一个可以在LISP中解决Mastermind游戏的玩家。我尝试在辅助函数中使用以下嵌套循环

(defparameter *counter* 0) 

;analyze the score to determine whether points need to be added to counter
(defun analyze (last-response)
  (if (> (first last-response) 0)
      (setf *counter* (+ (first last-response) *counter*))))

;helper function for finding correct color
(defun guessColor (length colors last-response)
    (loop while (< *counter* 4) do
       (loop for i from 1 to length
          collect (first colors)
          (setf colors (rest colors)))
    (analyze (last-reponse))))

;baseline Holyguacamole player will guess all colors before trying all combinations of correct color 
(defun HolyGuacamole (board colors SCSA last-response)
  (declare (ignore SCSA))
  ;(print last-response)
  (guessColor board colors last-response)
  (print *counter*)
    ;(sortColor)
)

当全局变量*counter*小于4时，应该运行while循环。内部循环应该根据所需的挂钩长度（可变长度）猜测颜色。我一直在遇到编译错误

在宏扩展期间（LOOP WHILE（＆lt; COUNTER 4）...）。使用;
BREAK-ON-SIGNALS 拦截。

我不熟悉LISP所以我不确定错误代码是什么意思以及如何解决它。我觉得我用正确的括号正确地嵌套它，但我真的不确定它有什么问题。

Link到Mastermind环境。

Answer 1

原则上没有障碍将循环嵌套在另一个循环中。但是，正如@jkiiski指出的那样，COLLECT或COLLECTING子句只能采用一个表达式。

例如，以下程序

(defun nested-loop ()
  (loop for i from 1 to 10 doing
        (loop for j from 1 to 10 collecting
              (print "some string")
              (print (list 'nested-loop i j)))))

(nested-loop)

在CLISP下产生语法错误。

*** - LOOP: illegal syntax near (PRINT (LIST 'NESTED-LOOP I J)) in
       (LOOP FOR J FROM 1 TO 10 COLLECTING (PRINT "some string")
        (PRINT (LIST 'NESTED-LOOP I J)))

使用do或doing子句可以正常工作，将collecting子句与progn子句关联的多个表达式分组为(defun nested-loop () (loop for i from 1 to 10 doing (loop for j from 1 to 10 collecting (progn (print "some string") (print (list 'nested-loop i j)))))) (nested-loop)。

min_score

常见LISP中的嵌套循环

1 个答案: