> class StreamMonad m where
> fetchLine = m
> sendLine = String -> m ()
>
> instance StreamMonad IO where
> fetchLine = getLine
> sendLine = putLine
>
> fetchLineFromStream = lift fetchLine
> sendLineToStream = lift . sendLine
This approach makes more sense to me. The
> Instead of specifying the monad implementation, specify the interface.
> That is, you are using state operations (from MonadState) and IO
> operations (from MonadIO). Try removing all the type signatures that
> mention PDState and see what you get.
>
> E.g., loop :: (MonadState PD m, MonadIO m) =
The code below is a little interactive program that uses some state.
It uses StateT with IO to keep state. My question is: what is the
best way to generalize this program to work with any IO-like
monad/medium? For example, I would like the program to function as it
does now using stdin but I woul
