showTerm (Structure s ts) = s ++ "(" ++ (intercalate ", " . map showTerm $ ts) ++ ")"
showTerm (Structure s ts) = s ++ "(" ++ (intercalate ", " . map showTerm $ ts) ++ ")"
showTerm (Structure s ts) = s ++ "(" ++ (intercalate ", " . map showTerm $ ts) ++ ")"