Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Carrier.State.Church

Contents

State carrier
State effect

Description

A church-encoded carrier for the State effect.

Note that the parameter order in runState, evalState, and execState is reversed compared the equivalent functions provided by transformers. This is an intentional decision made to enable the composition of effect handlers with . without invoking flip.

Since: 1.1.0.0

Synopsis

runState :: forall s m a b. (s -> a -> m b) -> s -> StateC s m a -> m b
evalState :: forall s m a. Applicative m => s -> StateC s m a -> m a
execState :: forall s m a. Applicative m => s -> StateC s m a -> m s
newtype StateC s m a = StateC (forall r. (s -> a -> m r) -> s -> m r)
module Control.Effect.State

State carrier

runState :: forall s m a b. (s -> a -> m b) -> s -> StateC s m a -> m b Source #

Run a State effect starting from the passed value, applying a continuation to the final state and result.

runState k s (pure a) = k s a

runState k s get = k s s

runState k s (put t) = k t ()

Since: 1.1.0.0

evalState :: forall s m a. Applicative m => s -> StateC s m a -> m a Source #

Run a State effect, yielding the result value and discarding the final state.

evalState = runState (const pure)

Since: 1.1.0.0

execState :: forall s m a. Applicative m => s -> StateC s m a -> m s Source #

Run a State effect, yielding the final state and discarding the return value.

execState = runState (const . pure)

Since: 1.1.0.0

newtype StateC s m a Source #

Since: 1.1.0.0

Constructors

StateC (forall r. (s -> a -> m r) -> s -> m r)

Instances

Instances details

MonadTrans (StateC s) Source #
Instance details Defined in Control.Carrier.State.Church Methods lift :: Monad m => m a -> StateC s m a #
MonadFail m => MonadFail (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods fail :: String -> StateC s m a #
MonadFix m => MonadFix (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods mfix :: (a -> StateC s m a) -> StateC s m a #
MonadIO m => MonadIO (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods liftIO :: IO a -> StateC s m a #
Alternative m => Alternative (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods empty :: StateC s m a # (<\|>) :: StateC s m a -> StateC s m a -> StateC s m a # some :: StateC s m a -> StateC s m [a] # many :: StateC s m a -> StateC s m [a] #
Applicative (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods pure :: a -> StateC s m a # (<>) :: StateC s m (a -> b) -> StateC s m a -> StateC s m b # liftA2 :: (a -> b -> c) -> StateC s m a -> StateC s m b -> StateC s m c # (>) :: StateC s m a -> StateC s m b -> StateC s m b # (<*) :: StateC s m a -> StateC s m b -> StateC s m a #
Functor (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods fmap :: (a -> b) -> StateC s m a -> StateC s m b # (<$) :: a -> StateC s m b -> StateC s m a #
Monad (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods (>>=) :: StateC s m a -> (a -> StateC s m b) -> StateC s m b # (>>) :: StateC s m a -> StateC s m b -> StateC s m b # return :: a -> StateC s m a #
(Alternative m, Monad m) => MonadPlus (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods mzero :: StateC s m a # mplus :: StateC s m a -> StateC s m a -> StateC s m a #
Algebra sig m => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Church Methods alg :: forall ctx (n :: Type -> Type) a. Functor ctx => Handler ctx n (StateC s m) -> (State s :+: sig) n a -> ctx () -> StateC s m (ctx a) Source #

State effect

module Control.Effect.State