Using Haskell to output a UTF-8-encoded ByteString

I'm going out of my mind trying to simply output UTF-8-encoded data to the console.

I've managed to accomplish this using String, but now I'd like to do the same with ByteString. Is there a nice and fast way to do this?

This is what I've got so far, and it's not working:

import Prelude hiding (putStr)
import Data.ByteString.Char8 (putStr, pack)

main :: IO ()
main = putStr $ pack "čušpajž日本語"

It prints out uapaj~�,�, ugh.

I'd like an answer for the newest GHC 6.12.1 best, alth开发者_如何学运维ough I'd like to hear answers for previous versions as well.

Thanks!

Update: Simply reading and outputting the same UTF-8-encoded line of text seems to work correctly. (Using Data.ByteString.Char8, I just do a putStr =<< getLine.) But packed values from inside the .hs file, as in the above example, refuse to output properly... I must be doing something wrong?

utf8-string supports bytestrings.

import Prelude hiding (putStr)
import Data.ByteString.Char8 (putStr)
import Data.ByteString.UTF8 (fromString)

main :: IO ()
main = putStr $ fromString "čušpajž日本語"

bytestrings are strings of bytes. When they're output, they will be truncated to 8 bits, as it describes in the documentation for Data.ByteString.Char8. You'll need to explicitly convert them to utf8 - via the utf8-string package on Hackage, which contains support for bytestrings.

However, as of 2011, you should use the text package, for fast, packed unicode output. GHC truncating Unicode character output

Your example becomes a lot simpler:

{-# LANGUAGE OverloadedStrings #-}

import qualified Data.Text    as T
import qualified Data.Text.IO as T

main = T.putStrLn "čušpajž日本語"

Like so:

$ runhaskell A.hs
čušpajž日本語

This is a known ghc bug, marked "wontfix".