I would really appreciate it if someone could review my LISP code. I was attempting to write a quicksort implementation. Additionally, I generated my list dynamically and wrote a couple of tests. Of course, I realize that the tests are not complete, but I decided to stop where I was and see if I could get some feedback. Thanks in advance for any help you can offer!
(defun categorize_list(pivot thelist less more)
(let ((comparee (car thelist)) (therest (cdr thelist)))
(if (null thelist)
(list less more)
(if (< comparee pivot)
(categorize_list pivot therest (append less (list comparee)) more)
(categorize_list pivot therest less (append more (list comparee)))
)
)
)
)
(defun quicksort(thelist)
(if (null thelist)
()
(let (
(pivot (car thelist))
(therest (cdr thelist))
)
(let ((categorized_list (categorize_list pivot therest () ())))
(append (quicksort (nth 0 categorized_list)) (list pivot) (quicksort (nth 1 categorized_list)))
)
)
)
)
(defun make_list(thelist remaininglength)
(if (eq remaininglength 0)
thelist
(make_list (append (list (random 25)) thelist) (- remaininglength 1))
)
)
(defun should_be_least_to_greatest(thelist)
(if (< (length thelist) 2)
nil
(if (<= (nth 0 thelist) (nth 1 thelist))
(should_be_least_to_greatest (cdr thelist))
(error "Out of order: ~d !< ~d ~%" (nth 0 thelist) (nth 1 thelist))
)
)
)
(defun test_should_become_in_order(thelist)
(let ((sortedList (quicksort thelist)))
(format t "IN: ~a ~% SD: ~a ~% Testing sort.~%" thelist sortedList)
(should_be_least_to_greatest sortedList)
)
)
(defun test_should_maintain_length(thelist)
(if (not (eql (length thelist) (length (quicksort thelist))))
(error "The sorted list is a different length than the original list! ~%")
)
)
(let ((thelist (make_list () 10)))
(test_should_become_in_order thelist)
(test_should_maintain_length thelist)
)
