(defun square (i) (* i i))
(defun nl () (princ "\n"))

;; looping structures

(define counter 0)
(while (< counter 5)
  (print (list counter (square counter)))
  (setq counter (+ counter 1)))
(nl)

(do
 ((i 0 (+ i 1)))                        ; bindings: (var init step)
 ((= i 10))                             ; until
 (princ i))
(nl)

(let sum
  ((rest '(1 2 3 4 5)) (total 0))
  (if (null rest)
      total
    (sum (cdr rest) (+ total (car rest))))
  (princ total)
  (princ " "))
(nl)

(mapcar (lambda (x) (print (square x))) '(1 2 3 4 5))
(nl)

;; conditional structures

(if (= 3 (max 1 2 3))
    (princ "true-forms\n")
  (princ "false-forms\n"))

(when t
  (princ "true-forms\n"))

(unless nil
  (princ "false-forms\n"))

(cond
 ((< counter 5) (princ "counter < 5\n"))
 ((>= counter 5) (princ "counter >= 5\n"))
 (t (error "counter has gone wild")))

(case counter
      ((1 2 3 4 5) (princ "counter in 1..5\n"))
      ((6 7) (princ "counter in 6..7\n"))
      (t (princ "counter is something else\n")))

(princ (or nil 1 nil "or"))
(princ (and 1 2 nil "and"))
(princ (not t))
(princ (not nil))
(princ "\n")