foo.idr

data Identity a = MkId a

(>>=) : Identity a -> (a -> Identity b) -> Identity b
(>>=) (MkId x) f = f x

pure : a -> Identity a
pure = MkId

foo : Int -> Identity Balance
foo i = do
    False <- pure (i > 1)
      | True => pure RightHeavy
    False <- pure (i == 1)
      | True => pure RightLean
    False <- pure (i == -1)
      | True => pure LeftLean
    False <- pure (i < -1)
      | True => pure LeftHeavy
    pure Neutral