Mario.hs

import Prelude hiding (Either(..))
import FRP.Helm

data Direction = Left | Right

data Mario =
  Mario { mX :: Double, mY :: Double,
          vX :: Double, vY :: Double,
          dir :: Direction }

jump :: (Int, Int) -> Mario -> Mario
jump (_, y) m@(Mario mX1 mY1 vX1 vY1 dir1)
  | y > 0 && mY1 == 0 = Mario { mX = mX1, mY = mY1, vX = vX1, vY = 5, dir = dir1 }
  | otherwise = m 

gravity :: Time -> Mario -> Mario
gravity t m@(Mario mX1 mY1 vX1 vY1 dir1)
  | mY1 > 0 = Mario { mX = mX1, mY = mY1, vX = vX1, vY = vY1 - (t/4), dir = dir1 }
  | otherwise = m 

physics :: Time -> Mario -> Mario
physics t (Mario mX1 mY1 vX1 vY1 dir1)
  = Mario { mX = mX1 + (t*vX1), mY = max 0 (mY1 + (t*vY1)), vX = vX1, vY = vY1, dir = dir1 }

walk :: (Int, Int) -> Mario -> Mario
walk (x, _) (Mario mX1 mY1 vX1 vY1 dir1) =
  Mario { mX = mX1, mY = mY1, vX = x, vY = vY1, dir = whatDir x } 
  where
    whatDir x
      | x < 0 = Left
      | x > 0 = Right
      | otherwise = dir1

step :: (Time, (Int, Int)) -> Mario -> Mario
step (t, arrows) = physics t . walk arrows . gravity t . jump arrows