; quicksort
(defun quick-sort (l)
    (if (<= (len l) 1)
        l
        (do
            (define pivot (first l))
            (+
                (quick-sort (filter (lambda (n) (> pivot n)) l))
                (list pivot)
                (quick-sort (tail (filter (lambda (n) (<= pivot n)) l)))
            ))
    ))

; decrement a number
(defun dec (n) (- n 1))

; increment a number
(defun inc (n) (+ n 1))

; not a bool
(defun not (x) (if x 0 1))

; negate a number
(defun neg (n) (- 0 n))

; is a number positive?
(defun is-pos? (n) (> n 0))

; is a number negative?
(defun is-neg? (n) (< n 0))