module Control.Monad.Class.MonadSay where import Control.Monad.State import qualified Data.ByteString.Char8 as BSC class Monad m => MonadSay m where say :: String -> m () instance MonadSay IO where say :: String -> IO () say = ByteString -> IO () BSC.putStrLn (ByteString -> IO ()) -> (String -> ByteString) -> String -> IO () forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> ByteString BSC.pack instance MonadSay m => MonadSay (StateT s m) where say :: String -> StateT s m () say = m () -> StateT s m () forall (t :: (* -> *) -> * -> *) (m :: * -> *) a. (MonadTrans t, Monad m) => m a -> t m a lift (m () -> StateT s m ()) -> (String -> m ()) -> String -> StateT s m () forall b c a. (b -> c) -> (a -> b) -> a -> c . String -> m () forall (m :: * -> *). MonadSay m => String -> m () say