Reader nested with IO and other [somemonad]T's

nested-reader.hs

import Control.Monad.Trans.Reader
import Control.Monad.Trans.Maybe

import Control.Monad.IO.Class
import Control.Monad.Trans
--import Control.Monad.State

m :: IO ()
m = do
  runReaderT r2 5
  putStrLn "done"
  
r2 :: ReaderT Int IO ()
r2 = do
  res <- runMaybeT $ do
    r <- respond2
    b <- respond3
    return (r ++ b)
  list <- respond4
  lift $ putStrLn $ show list
  lift $ putStrLn $ (show $ res) ++ " in r2"

  
respond2 :: MaybeT (ReaderT Int IO) String
respond2 = do
  e <- lift $ (ask :: (ReaderT Int IO) Int)
  liftIO $ putStrLn "in respond2"
  bar <- MaybeT $ return $ Just ("foo" ++ (show e))
  return bar

respond3 :: MaybeT (ReaderT Int IO) String
respond3 = do
  e <- lift $ (ask :: (ReaderT Int IO) Int)
  liftIO $ putStrLn "in respond3"
  bar <- MaybeT $ return $ Just ("foo" ++ (show e))
  return bar

-- how to do with other than transformers?
respond4 :: (ReaderT Int IO) [String]
respond4 = do
  e <- (ask :: (ReaderT Int IO) Int)
  return $ ["foo", "bar", show e]