showTerm (ListTerm ts) =
  "[" ++ intercalate ", " (map showTerm ts) ++ "]"
showTerm (ListTerm ts) =
  "[" ++ intercalate ", " (map showTerm ts) ++ "]"
showTerm (ListTerm ts) =
  "[" ++ intercalate ", " (map showTerm ts) ++ "]"