zcat with iterIO

myZcat.hs

module Main
    where

import Control.Monad.IO.Class (MonadIO)
import Data.ByteString.Lazy (ByteString)
import Data.IterIO
import Data.IterIO.Zlib (inumGunzip)
import System.Environment
import System.IO

printUsage :: IO ()
printUsage = putStrLn "Usage: myZcat FILENAME"

main :: IO ()
main = do fs <- getArgs
          case fs of
            [] -> processInum $ enumHandle' stdin
            _ | ("--help" `elem` fs) || ("-h" `elem` fs) -> printUsage
              | otherwise -> processInum $ (foldr1 cat [enumFile' f | f <- fs])

-- TODO: read up on what that (IterR ByteString m ()) thingy does.
processInum :: MonadIO m => Onum ByteString m (IterR ByteString m ()) -> m ()
processInum i = i |. (inumRepeat inumGunzip) |$ stdoutI