mandelbrot.fe

; printed output should be written to a .pgm file

(do
  (let width  500)
  (let height 300)
  (let maxiter 16)

  ; write header
  (print "P2")
  (print width height)
  (print maxiter)

  ; write pixels
  (let ypixel 0)
  (while (< ypixel height)
    (let y (- (/ ypixel (/ height 2)) 1))
    (let xpixel 0)
    (while (< xpixel width)
      (let x (- (/ xpixel (/ width 3)) 2))
      (let x0 x)
      (let y0 y)
      (let iter 0)
      (while (and (< iter maxiter) (<= (+ (* x0 x0) (* y0 y0)) 4))
        (let x1 (+ (- (* x0 x0) (* y0 y0)) x))
        (let y1 (+ (* 2 x0 y0) y))
        (= x0 x1)
        (= y0 y1)
        (= iter (+ iter 1))
      )
      (print iter)
      (= xpixel (+ xpixel 1))
    )
    (= ypixel (+ ypixel 1))
  )
)