fos.elm

import Color (..)
import Graphics.Collage (..)
import Graphics.Element (..)
import Time (fps, fpsWhen)
import Keyboard (isDown)
import Char (toCode)
import Signal (foldp,map2, (<~))
import Text(asText)
import List (map, (::))

(<--) = (<~)
infixr 4 <--

notes = [ (0.0,1.0),(20.0,30.0),(40.0,60.0),(87.0,160.0) ]

f = foldp (+) 0 <| fps 30

aDown = isDown <| toCode 'a'
aFps = fpsWhen 30 aDown
size = foldp (\x a -> if x == 0 then 0 else a + x) 0 aFps
size_reset = map2 (\x d -> if not d then 0 else x) size aDown

render_rect y (y1,y2) = filled black <| polygon [ (0.0,(y1-y)/10),(10.0,(y1-y)/10),(10.0,(y2-y)/10),(0.0,(y2-y)/10)]

render : Float -> List ( Float, Float ) -> Element
render f lf = collage 500 500 <| map (render_rect f) lf

fx (d1, f) (d2, a) =
  if d1 && (not d2)
  then (d1, (f, f)::a)
  else if d1 && d2 then case a of
    ((a1,a2)::ass) -> (d1, (a1, f)::ass)
    _ -> (d1, a)
  else (d1, a)


main = map2 render f (snd <-- foldp fx (False, []) (map2 (,) aDown (foldp (+) 0 <| fps 30)))