Using Haskell to output a UTF-8-encoded ByteString

Question

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, although 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?

Answer 1

I investigated this a while ago, and found this survey of Haskell unicode support libraries. It looks like iconv may be what you want.

Answer 2

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

Answer 3

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

Answer 4

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"