showError :: LispError -> String
showError (ArityError exp var fnd) =
  "Expected " ++ show exp ++ (if var then "+" else "") ++ " args, found " ++ show (length fnd) ++ " args: " ++ "(" ++ unwordsCol fnd ++ ")"
showError :: LispError -> String
showError (ArityError exp var fnd) =
  "Expected " ++ show exp ++ (if var then "+" else "") ++ " args, found " ++ show (length fnd) ++ " args: " ++ "(" ++ unwordsCol fnd ++ ")"
showError (ArityError exp var fnd) =
  "Expected " ++ show exp ++ (if var then "+" else "") ++ " args, found " ++ show (length fnd) ++ " args: " ++ "(" ++ unwordsCol fnd ++ ")"