(defun factorial (n)
  (if (< n 1) (return 1))
  (define res n)
  (set! n (- n 1))
  (while (>= n 1)
    (set! res (* res n))
    (set! n (- n 1)))
  res)

(writeln (factorial 4))

(defun ramanujan ()
  (define total 0)
  (define k 0)
  (define factor (/ (* (sqrt 2) 2) 9801))
  (while true
    (define num (* (factorial (* 4 k)) (+ 1103 (* 26390 k))))
    (define den (* (pow (factorial k) 4) (pow 396 (* 4 k))))
    (define term (/ (* factor num) den))
    (set! total (+ total term))
    (if (< (abs term) 0.000001) (break))
    (set! k (+ k 1)))
  (/ 1 total))


(writeln (ramanujan))

(writeln "PI=" PI)
(writeln "sin(pi/4)=" (sin (/ PI 4)))

(defun test (n)
  (defun plus2n () (+ n 2))
  (plus2n)
)

(test 40)

(let ((a 40) (b 2))
  (writeln (+ a b)))

(defun mk-plusn (n)
  (defun res (x) (+ x n))
  (define ret res)
  (set! n (+ n 1))
  (writeln "n+1=" n)
  ret)

(define plus-two (mk-plusn 2))
(writeln "42=" (plus-two 40))