Control.Effect.State.Internal

State effect

data State s m k

Constructors

Get (s -> m k)

Put s (m k)

Instances

Effect (State s)

Defined in Control.Effect.State.Internal

Methods

handle :: (Functor f, Monad m) => f () -> (forall x. f (m x) -> n (f x)) -> State s m a -> State s n (f a)

HFunctor (State s)

Defined in Control.Effect.State.Internal

Methods

fmap' :: Functor (State s f) => (a -> b) -> State s f a -> State s f b

hmap :: Functor m => (forall x. m x -> n x) -> State s m a -> State s n a

Generic1 (State s m :: Type -> Type)

Defined in Control.Effect.State.Internal

Associated Types

type Rep1 (State s m) :: k -> Type

Methods

from1 :: State s m a -> Rep1 (State s m) a

to1 :: Rep1 (State s m) a -> State s m a

Functor m => Functor (State s m)

Defined in Control.Effect.State.Internal

Methods

fmap :: (a -> b) -> State s m a -> State s m b

(<$) :: a -> State s m b -> State s m a

(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m)

Defined in Control.Effect.State.Strict

Methods

eff :: (State s :+: sig) (StateC s m) a -> StateC s m a

(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m)

Defined in Control.Effect.State.Lazy

Methods

eff :: (State s :+: sig) (StateC s m) a -> StateC s m a

type Rep1 (State s m :: Type -> Type)

Defined in Control.Effect.State.Internal

type Rep1 (State s m :: Type -> Type) = D1 (MetaData "State" "Control.Effect.State.Internal" "fused-effects-0.5.0.0-inplace" False) (C1 (MetaCons "Get" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (((->) s :: Type -> Type) :.: Rec1 m)) :+: C1 (MetaCons "Put" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 s) :*: S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec1 m)))

get :: (Member (State s) sig, Carrier sig m) => m s

Get the current state value.

snd (run (runState a get)) === a

gets :: (Member (State s) sig, Carrier sig m) => (s -> a) -> m a

Project a function out of the current state value.

snd (run (runState a (gets (applyFun f)))) === applyFun f a

put :: (Member (State s) sig, Carrier sig m) => s -> m ()

Replace the state value with a new value.

fst (run (runState a (put b))) === b

snd (run (runState a (get <* put b))) === a

snd (run (runState a (put b *> get))) === b

modify :: (Member (State s) sig, Carrier sig m) => (s -> s) -> m ()

Replace the state value with the result of applying a function to the current state value. This is strict in the new state.

fst (run (runState a (modify (+1)))) === (1 + a :: Integer)

modifyLazy :: (Member (State s) sig, Carrier sig m) => (s -> s) -> m ()

Replace the state value with the result of applying a function to the current state value. This is lazy in the new state; injudicious use of this function may lead to space leaks.

Re-exports

class Member (sub :: (* -> *) -> * -> *) sup

Minimal complete definition

inj, prj

Instances

Member sub sub

Defined in Control.Effect.Sum

Methods

inj :: sub m a -> sub m a

prj :: sub m a -> Maybe (sub m a)

Member sub sup => Member sub (sub' :+: sup)

Defined in Control.Effect.Sum

Methods

inj :: sub m a -> (sub' :+: sup) m a

prj :: (sub' :+: sup) m a -> Maybe (sub m a)

Member sub (sub :+: sup)

Defined in Control.Effect.Sum

Methods

inj :: sub m a -> (sub :+: sup) m a

prj :: (sub :+: sup) m a -> Maybe (sub m a)