Access helper functions in a State monad

- set :: Monad m => T r a -> a -> StateT r m ()
- get :: Monad m => T r a -> StateT r m a
- modify :: Monad m => T r a -> (a -> a) -> StateT r m ()
- getAndModify :: Monad m => T r a -> (a -> a) -> StateT r m a
- modifyAndGet :: Monad m => T r a -> (a -> a) -> StateT r m a
- (%=) :: Monad m => T r a -> a -> StateT r m ()
- (%:) :: Monad m => T r a -> (a -> a) -> StateT r m ()
- lift :: Monad m => T r s -> State s a -> StateT r m a
- liftT :: Monad m => T r s -> StateT s m a -> StateT r m a

# accessors in the form of actions in the state monad

getAndModify :: Monad m => T r a -> (a -> a) -> StateT r m aSource

Modify a record element and return its old value.

modifyAndGet :: Monad m => T r a -> (a -> a) -> StateT r m aSource

Modify a record element and return its new value.