Prelude> import Control.Monad.Cont

Prelude Control.Monad.Cont> :t Cont

<interactive>:1:1:

    Not in scope: data constructor `Cont'

    Perhaps you meant `ContT' (imported from Control.Monad.Cont)

Prelude Control.Monad.Cont> :t runCont

runCont :: Cont r a -> (a -> r) -> r

Prelude Control.Monad.Cont> :t ContT

ContT :: ((a -> m r) -> m r) -> ContT r m a

Prelude Control.Monad.Cont>