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 would also like it to function over IRC using the Net monad from http://haskell.org/haskellwiki/Roll_your_own_IRC_bot. Thanks for any suggestions. -- begin code -- import Control.Monad import Control.Monad.State import Data.List data PD = PD { pdCount :: Int , pdList :: [String] } deriving (Show) type PDState = StateT PD IO main = runStateT loop (PD { pdCount = 0, pdList = [] }) loop :: PDState a loop = forever $ do cmd <- liftIO getLine runCmd cmd runCmd :: String -> PDState () runCmd "Inc" = increment runCmd "PrintCount" = liftIO . print =<< getCount runCmd "PrintList" = liftIO . print =<< getList runCmd str | "Add " `isPrefixOf` str = addToList $ drop 4 str runCmd _ = return () getCount :: PDState Int getCount = pdCount `liftM` get getList :: PDState [String] getList = pdList `liftM` get increment :: PDState () increment = modify $ \st -> st { pdCount = pdCount st + 1 } addToList :: String -> PDState () addToList str = modify $ \st -> st { pdList = pdList st ++ [str]} -- end code --