parseBinaryNumber :: Parser LispVal
parseBinaryNumber = parseRadixNumber "01" readBin
  where
    readBin = readInt 2 (`elem` "01") (read . return)
parseBinaryNumber :: Parser LispVal
parseBinaryNumber = parseRadixNumber "01" readBin
  where
    readBin = readInt 2 (`elem` "01") (read . return)
parseBinaryNumber = parseRadixNumber "01" readBin
  where
    readBin = readInt 2 (`elem` "01") (read . return)