lam_ :: forall tf a. TF.Eval (tf String) a => a -> EADT (BASE tf) -> EADT (BASE tf)
lam_ t b = lam (TF.from t) b

a = lam_ (Tuple "x" TInt) (var "y") :: STLC
b = lam_ "y" (var "x") :: UTLC

class ShowLamAlg a where
  showLamAlg :: a -> String

instance sshowLamAlg :: ShowLamAlg String where
  showLamAlg s = s

instance ttshowLamAlg :: ShowLamAlg (Tuple String Type) where
  showLamAlg (Tuple v t) = "(" <> v <> ": " <> show t <> ")"

instance showAlgLam :: (Eval (tf String) a, ShowLamAlg a) => ShowAlg (LamF tf) where
  showAlg (LamF t b) = "\\" <> showLamAlg (TF.to t) <> "." <> b