Asg5LispRun.txt

;;;  #1 removeNILTop
(defun removeNILTop (lst)
  (remove-if #'null lst))

(removeNILTop '(NIL X NIL NIL Y  NIL Z))
(removeNILTop '(X NIL Y NIL Z NIL))
(removeNILTop '(NIL (X NIL Y) (NIL NIL)))

;;; #2 removeNILMost
(defun removeNILMost (lst)
  (if (atom lst)
      lst
      (if (and (null (car lst)) (null (cdr lst)))
          nil
          (cons (removeNILMost (car lst))
                (removeNILMost (cdr lst))))))

(removeNILMost '(NIL X NIL NIL Y  NIL Z))
(removeNILMost '(X NIL (Y NIL Z) NIL))
(removeNILMost '(NIL (NIL) (X NIL Y) (NIL NIL) Z))
(removeNILMost '(NIL ( (((((NIL) NIL)))))))

;;; #3 reverseTop
(defun reverseTop (lst)
  (if (atom lst)
      lst
      (let ((result nil))
        (dolist (item lst)
          (setq result (cons item result)))
        result)))

(reverseTop '(X Y Z))
(reverseTop '(X (Y Z (A)) (W)))

;;; #4 reverseALL
(defun reverseAll (lst)
  (if (atom lst)
      lst
      (reverse (mapcar #'reverseAll lst))))

(reverseAll '(X Y Z))
(reverseAll '(X (Y Z (A)) (W)))

;;; #5 palindrome
(defun palindrome (lst)
  (equal lst (reverseTop lst)))

(palindrome '(R A C E C A R))
(palindrome '(W A S I T A C A R O R A C A T I S A W))
(palindrome '(N I X O N))