Stateful loop with different types of breaks

Question

I am trying to convert the following stateful imperative code into Haskell.

while (true) {
  while (get()) {
    if (put1()) {
      failImmediately();
    }
  }
  if (put2()) {
    succeedImmediately();
  }
}

Both the put1 and put2 read a state of the system and modify it. get can for simplicity just read the state. failImmediately should break out of the endless-loop and present one type of result, succeedImmediately should also break out but present a different result.

What I tried to use was State Env Result where Env represented the state of environment and Result was something like Either Failure Success for some custom Failure and Success.

I struggle with the requirement that the whole resulting expression should collapse into the Failure/Success once one of them is produced (breaking the loop) and otherwise keep going.

One idea I had was use Either Exit () where data Exit = Success | Failure and use StateT somehow to behave upon Left of the Either as if Either was the monad being chained, i.e. ignoring any subsequent actions.

I would really appreciate any inspiration or sample of haskell code that would achieve the same behaviour as the snippet above.

Edit: refined version moved to a separate question "Stateful computation with different types of short-circuit (Maybe, Either)".

Answer 1

Using the kit from @chi's answer, just highlighting that you don't need the full power of ContT, the direct-short-circuiting semantics of EitherT is enough:

import Control.Monad.Trans.Either

data Result a = Failure | Success a

foo :: EitherT (Result Int) IO Int
foo = forever $ do
    whileM get $ do
        whenM put1 $ do
            left Failure
    whenM put2 $ do
        left $ Success 42

run :: (Monad m) => EitherT (Result a) m a -> m (Maybe a)
run act = do
    res <- runEitherT act
    return $ case res of
        Left Failure -> Nothing
        Left (Success x) -> Just x
        Right x -> Just x

-- whenM / whileM and get/put1/put2 as per @chi's answeer