(defmacro $=
  "Formula macro translates from infix to prefix


   Examples:

    (use 'incanter.core)
    ($= 7 + 8)
    ($= [1 2 3] + [4 5 6])
    ($= [1 2 3] + (sin [4 5 6]))
    ($= [1 2 3] <*> (trans [1 2 3]))
    ($= [1 2 3] * [1 2 3])
    ($= [1 2 3]  [1 2 3])
    ($= 9 * 8 ** 3)
    ($= (sin Math/PI) * 10)

    ($= 10 + 20 * (4 - 5) / 6)

    ($= 20 * (4 - 5) / 6)

    (let [x 10
          y -5]
      ($= x + y / -10))

    ($= 3 ** 3)

    ($= [1 2 3] * [1 2 3])
    ($= [1 2 3] / (sq [1 2 3]) + [5 6 7])

    ($= (sqrt 5 * 5 + 3 * 3))
    ($= (sq [1 2 3] + [1 2 3]))
    ($= ((5 + 4) * 5))
    ($= ((5 + 4 * (3 - 4)) / (5 + 8) * 6))
    ($= [1 2 3] + 5)
    ($= (matrix [[1 2] [4 5]]) + 6)
    ($= (trans [[1 2] [4 5]]) + 6)

    ($= (trans [[1 2] [4 5]]) <*> (matrix [[1 2] [4 5]]))
    

    (use '(incanter core charts))
    (defn f [x] ($= x ** 2 + 3 * x + 5))
    (f 5)
    (view (function-plot f -10 10))
    (view (function-plot #($= % ** 2 + 3 * % + 5) -10 10))
    (view (function-plot (fn [x] ($= x ** 2 + 3 * x + 5)) -10 10))
    (let [x (range -10 10 0.1)] 
      (view (xy-plot x ($= x ** 3 - 5 * x ** 2 + 3 * x + 5))))

    ($= (5 + 7))
    ($= (trans [1 2 3 4]) <*> [1 2 3 4])
    ($= [1 2 3 4] <*> (trans [1 2 3 4]))

    ($= [1 2 3 4] <*> (trans [1 2 3 4]))
    ($= [1 2 3 4]  (trans [1 2 3 4]))


    ;; kronecker product example
    ($= (matrix [[1 2] [3 4] [5 6]])  4)
    ($= (matrix [[1 2] [3 4] [5 6]])  (matrix [[1 2] [3 4]]))
    ($= [1 2 3 4]  4)

    ($= 3 > (5 * 2/7))

    (use '(incanter core datasets charts))
    (with-data (get-dataset :cars)
      (doto (scatter-plot :speed :dist :data ($where ($fn [speed dist] ($= dist / speed < 2))))
        (add-points :speed :dist :data ($where ($fn [speed dist] ($= dist / speed >= 2))))
        (add-lines ($ :speed) ($= 2 * ($ :speed)))
        view))

   

"
  ([& equation]
     (infix-to-prefix equation)))