- | Parse a single new line.
--
-- > \n|\r\n|\r|\f
--
nl :: Parser String
nl =   try (string "\r\n")
   <|> string "\n"
   <|> string "\r"
   <|> string "\f"
   <?> "new line"

nl :: Parser String
nl =   try (string "\r\n")
   <|> string "\n"
   <|> string "\r"
   <|> string "\f"
   <?> "new line"
nl =   try (string "\r\n")
   <|> string "\n"
   <|> string "\r"
   <|> string "\f"
   <?> "new line"