evalUArrayExpr (Sum (Vector x) (Vector y))  = Vector z where
  z = listArray (1,n) [(x ! i) + (y ! i) | i <- [1..n]] where
    n = snd $ bounds x
evalUArrayExpr (Sum (Vector x) (Vector y))  = Vector z where
  z = listArray (1,n) [(x ! i) + (y ! i) | i <- [1..n]] where
    n = snd $ bounds x
evalUArrayExpr (Sum (Vector x) (Vector y))  = Vector z where
  z = listArray (1,n) [(x ! i) + (y ! i) | i <- [1..n]] where
    n = snd $ bounds x