Bas van Dijk <v.dijk....@gmail.com> wrote: > On 1 April 2011 21:59, Dmitry Olshansky <olshansk...@gmail.com> 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.
I don't think that's possible, because Iteratee is based on CPS. I think, so far nobody has come up with an instance definition for monad-peel or monad-control for CPS-based monads like ContT or Iteratee. However, it is easy to write an own handle enumerator, which uses monad-peel or monad-control exception handling to convert errors to iteratee exceptions. On the other hand, as has been noted, there is enumHandle, which does that by itself. Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/ _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe