state package:rio

state :: MonadState s m => (s -> (a, s)) -> m a
rio RIO.State
Embed a simple state action into the monad.
module RIO.State
rio
Provides reexports of MonadState and related helpers.
type State s = StateT s Identity
rio RIO.State
A state monad parameterized by the type s of the state to carry. The return function leaves the state unchanged, while >>= uses the final state of the first computation as the initial state of the second.
stateRefL :: HasStateRef s env => Lens' env (SomeRef s)
rio RIO
newtype StateT s (m :: Type -> Type) a
rio RIO.State
A state transformer monad parameterized by:
  • s - The state.
  • m - The inner monad.
The return function leaves the state unchanged, while >>= uses the final state of the first computation as the initial state of the second.
StateT :: (s -> m (a, s)) -> StateT s (m :: Type -> Type) a
rio RIO.State
class HasStateRef s env | env -> s
rio RIO
Environment values with stateful capabilities to SomeRef
type family PrimState (m :: Type -> Type)
rio RIO.Prelude.Types
class Monad m => MonadState s (m :: Type -> Type) | m -> s
rio RIO.State
Minimal definition is either both of get and put or just state
evalState :: State s a -> s -> a
rio RIO.State
Evaluate a state computation with the given initial state and return the final value, discarding the final state.
evalStateT :: Monad m => StateT s m a -> s -> m a
rio RIO.State
Evaluate a state computation with the given initial state and return the final value, discarding the final state.
execState :: State s a -> s -> s
rio RIO.State
Evaluate a state computation with the given initial state and return the final state, discarding the final value.
execStateT :: Monad m => StateT s m a -> s -> m s
rio RIO.State
Evaluate a state computation with the given initial state and return the final state, discarding the final value.
mapState :: ((a, s) -> (b, s)) -> State s a -> State s b
rio RIO.State
Map both the return value and final state of a computation using the given function.
mapStateT :: (m (a, s) -> n (b, s)) -> StateT s m a -> StateT s n b
rio RIO.State
Map both the return value and final state of a computation using the given function.
runState :: State s a -> s -> (a, s)
rio RIO.State
Unwrap a state monad computation as a function. (The inverse of state.)
runStateT :: StateT s (m :: Type -> Type) a -> s -> m (a, s)
rio RIO.State
withState :: (s -> s) -> State s a -> State s a
rio RIO.State
withState f m executes action m on a state modified by applying f.
withStateT :: forall s (m :: Type -> Type) a . (s -> s) -> StateT s m a -> StateT s m a
rio RIO.State
withStateT f m executes action m on a state modified by applying f.