Re: [Haskell-cafe] using IO monad in Iteratee

Very interesting, thanks. I didn't feel your classes yet... Do you think that provide these instances for Iteratee is possible? 2011/4/2 Bas van Dijk

On 1 April 2011 21:59, Dmitry Olshansky wrote:

...

Is it possible to change enumFile to using MonadIO class?

No because it uses the control operation Control.Exception.finally :: IO a -> IO b -> IO a internally. You can't lift control operations with liftIO :: MonadIO m => IO a -> m a.

However if you are able to define a MonadTransControl and MonadControlIO instance (from the monad-control package[1]) for Iteratee and use Control.Exception.Control.finally instead of the regular finally, you can use your MyMonad with the modified enumFile.

Good luck,

Bas

[1] http://hackage.haskell.org/package/monad-control