gistfile1.txt

sexprParser :: Parser SExpr
sexprParser = choice [intParser, symParser, listParser]

symParser :: Parser SExpr
symParser = AtomSym <$> ident variable

variable :: TokenParsing m => IdentifierStyle m
variable = IdentifierStyle
  { _styleName = "identifier"
  , _styleStart = varInit
  , _styleLetter = varSubsequent
  , _styleReserved = HashSet.empty
  , _styleHighlight = Highlight.Identifier
  , _styleReservedHighlight = Highlight.ReservedConstructor
} where
  varInit = letter <|> oneOf "!$%&*/:<=>?~_^"
  varSubsequent = varInit <|> digit <|> oneOf ".+="

intParser :: Parser SExpr
intParser = AtomNum . fromInteger <$> integer

listParser :: Parser SExpr
listParser = List <$> (parens $ some sexprParser)

runParser :: Parser a -> String -> ParseResult a
runParser p s = case parseByteString p mempty (UTF8.fromString s) of
  Failure xs -> Left $ show xs
  Success a -> Right a