Manatee.Toolkit.General.State

Documentation

modifyM :: (Monad m, MonadTrans t, MonadState a (t m)) => (a -> m a) -> t m ()

Like modify, except use Monad wrap update function.

modifyM_ :: (Monad m, MonadTrans t, MonadState a1 (t m)) => (a1 -> m a) -> (a -> a1) -> (a -> a2) -> t m a2

Like modifyM, but add two functions filter new state and return value. This is handy when function return result including state. Example, state is (a,b), and function return (a,b,c), then you can write: result <- modifyM_ f fst snd.

modifyM' :: (Monad m, MonadTrans t, MonadState a1 (t m)) => (a1 -> m a) -> (a -> a1) -> t m ()

Like modifyM_, except don't return value.

modifyFst :: MonadState (t, t1) m => ((t, t1) -> t) -> m ()

Modify fst state of tuple.

modifySnd :: MonadState (t, t1) m => ((t, t1) -> t1) -> m ()

Modify snd state of tuple.

modifyFstM :: (Monad m, MonadTrans t1, MonadState (a, t) (t1 m)) => ((a, t) -> m a) -> t1 m ()

Like modifyFst, except use moand wrap function.

modifySndM :: (Monad m, MonadTrans t1, MonadState (t, a) (t1 m)) => ((t, a) -> m a) -> t1 m ()

Like modifySnd, except use moand wrap function.

getM :: (MonadState a (t m), MonadTrans t, Monad m) => (a -> m a1) -> t m a1

Like get, except use Monad wrap function.

runStateT_ :: b -> StateT b m a -> m (a, b)

Like runStateT, just reverse arguments order.

runStateT' :: Functor f => b -> StateT b f a -> f b

Like runStateT_, but just return last argument. It's useful that you just want use runStateT wrap *one* state.

runTVarStateT :: TVar a -> (a -> StateT a IO b) -> IO ()

Use runStateT' wrap TVar.

runTVarTupeStateT :: (TVar a, TVar b) -> (a -> b -> StateT (a, b) IO c) -> IO ()

Like runTVarStateT, but handle tuple TVar.