Text.Megaparsec.String

Make Strings an instance of Stream with Char token type.

Documentation

type Parser = Parsec String

Different modules corresponding to various types of streams (String, Text, ByteString) define it differently, so user can use “abstract” Parser type and easily change it by importing different “type modules”. This one is for strings.

parseFromFile :: Parser a -> String -> IO (Either ParseError a)

parseFromFile p filePath runs a string parser p on the input read from filePath using readFile. Returns either a ParseError (Left) or a value of type a (Right).

main = do
  result <- parseFromFile numbers "digits.txt"
  case result of
    Left err -> print err
    Right xs -> print (sum xs)