{-# LANGUAGE ExistentialQuantification #-}

module Debris ( Debris(..)
              , SomeDebris(..)
              ) where

import Tank

class Show a => Debris a where
    collideTank :: a -> Tank -> Tank


data SomeDebris = forall a. Debris a => SomeDebris a

instance Show SomeDebris
    where
      show (SomeDebris a) = show a

instance Debris SomeDebris
    where
      collideTank (SomeDebris a) = collideTank a