Data.Accessor.Monad.MTL.State

Access helper functions in the State monad class

accessors in the form of actions in the state monad

set :: MonadState r m => T r a -> a -> m ()

get :: MonadState r m => T r a -> m a

modify :: MonadState r m => T r a -> (a -> a) -> m ()

getAndModify :: MonadState r m => T r a -> (a -> a) -> m a

Modify a record element and return its old value.

modifyAndGet :: MonadState r m => T r a -> (a -> a) -> m a

Modify a record element and return its new value.

(%=) :: MonadState r m => T r a -> a -> m () infix 1

Infix variant of set.

(%:) :: MonadState r m => T r a -> (a -> a) -> m () infix 1

Infix variant of modify.

lift a state monadic accessor to an accessor of a parent record

lift :: MonadState r mr => T r s -> State s a -> mr a

liftT :: (Monad m, MonadTrans t, MonadState r (t m)) => T r s -> StateT s m a -> t m a