(defun extend-null (the-list)
  (cond
   ((equal (length the-list) 0) t)
   (t nil)))

(defun mapcar (function-name the-list)
  (if the-list
    (cons
      (funcall function-name (first the-list))
      (mapcar function-name (rest the-list)))))

(defun maplist (function-name the-list)
  (cond
   ((null the-list) nil)
   (t (cons (funcall function-name the-list)
       (maplist function-name (rest the-list))))))

(defun extend-apply (function-name param-list)
  (eval (cons function-name param-list)))

(defun append (listA listB)
  (cond
   ((null listA) listB)
   (t (cons (first listA) (append (rest listA) listB)))))

(defun nth (n listA)
  (cond
   ((equal 0 n) (first listA))
   (t (nth (- n 1) (rest listA)))))