----------------------------------------------------------------------------- -- | -- Module : Text.Parsec.ByteString.Lazy -- Copyright : (c) Paolo Martini 2007 -- License : BSD-style (see the LICENSE file) -- -- Maintainer : derek.a.elkins@gmail.com -- Stability : provisional -- Portability : portable -- -- Make lazy ByteStrings an instance of 'Stream' with 'Char' token type. -- ----------------------------------------------------------------------------- {-# LANGUAGE FlexibleInstances #-} {-# OPTIONS_GHC -fno-warn-orphans #-} module Text.Parsec.ByteString.Lazy ( Parser, GenParser, parseFromFile ) where import Text.Parsec.Error import Text.Parsec.Prim import qualified Data.ByteString.Lazy.Char8 as C instance (Monad m) => Stream C.ByteString m Char where uncons = return . C.uncons type Parser = Parsec C.ByteString () type GenParser t st = Parsec C.ByteString st -- | @parseFromFile p filePath@ runs a lazy bytestring parser @p@ on the -- input read from @filePath@ using 'ByteString.Lazy.Char8.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) -- > } parseFromFile :: Parser a -> String -> IO (Either ParseError a) parseFromFile p fname = do input <- C.readFile fname return (runP p () fname input)