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module T17810a where
import Control.Monad
import Control.Monad.IO.Class
import Control.Monad.Except
import Control.Monad.Trans
class Monad m => ReadTCState m where
locallyTCState :: m ()
liftReduce :: m ()
instance ReadTCState m => ReadTCState (ExceptT err m) where
locallyTCState = undefined
liftReduce = lift liftReduce
instance MonadIO m => ReadTCState (TCMT m) where
locallyTCState = (undefined <$> liftReduce) <* TCM (\_ -> return ())
liftReduce = undefined
newtype TCMT m a = TCM { unTCM :: () -> m a }
instance MonadIO m => Functor (TCMT m) where
fmap f (TCM m) = TCM $ \r -> liftM f (m r )
instance MonadIO m => Applicative (TCMT m) where
pure x = TCM (\_ -> return x)
(<*>) (TCM mf) (TCM m) = TCM $ \r -> ap (mf r) (m r)
instance MonadIO m => Monad (TCMT m) where
(>>=) (TCM m) k = TCM $ \r -> m r >>= \x -> unTCM (k x) r
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