Safe Haskell	Safe-Inferred
Language	Haskell2010

Effectful.Prim.IORef

Contents

Effect
- Handlers
IORef

Description

Lifted Data.IORef.

Note: it requires Prim because MutVar from the primitive library is a generalization of IORef.

Since: 2.4.0.0

Synopsis

data Prim (a :: Type -> Type) b
runPrim :: forall (es :: [Effect]) a. (HasCallStack, IOE :> es) => Eff (Prim ': es) a -> Eff es a
data IORef a
newIORef :: Prim :> es => a -> Eff es (IORef a)
readIORef :: Prim :> es => IORef a -> Eff es a
writeIORef :: Prim :> es => IORef a -> a -> Eff es ()
modifyIORef :: Prim :> es => IORef a -> (a -> a) -> Eff es ()
modifyIORef' :: Prim :> es => IORef a -> (a -> a) -> Eff es ()
atomicModifyIORef :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b
atomicModifyIORef' :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b
atomicWriteIORef :: Prim :> es => IORef a -> a -> Eff es ()
mkWeakIORef :: (HasCallStack, Prim :> es) => IORef a -> Eff es () -> Eff es (Weak (IORef a))

Effect

data Prim (a :: Type -> Type) b #

Provide the ability to perform primitive state-transformer actions.

Instances

Instances details

type DispatchOf Prim
Instance details Defined in Effectful.Internal.Monad type DispatchOf Prim = 'Static 'WithSideEffects
data StaticRep Prim
Instance details Defined in Effectful.Internal.Monad data StaticRep Prim = Prim

Handlers

runPrim :: forall (es :: [Effect]) a. (HasCallStack, IOE :> es) => Eff (Prim ': es) a -> Eff es a #

Run an Eff computation with primitive state-transformer actions.

IORef

data IORef a #

A mutable variable in the IO monad.

>>> import Data.IORef
>>> r <- newIORef 0
>>> readIORef r
0
>>> writeIORef r 1
>>> readIORef r
1
>>> atomicWriteIORef r 2
>>> readIORef r
2
>>> modifyIORef' r (+ 1)
>>> readIORef r
3
>>> atomicModifyIORef' r (\a -> (a + 1, ()))
>>> readIORef r
4

Instances

Instances details

NFData1 IORef	Since: deepseq-1.4.3.0
Instance details Defined in Control.DeepSeq Methods liftRnf :: (a -> ()) -> IORef a -> () #
NFData (IORef a)	NOTE: Only strict in the reference and not the referenced value. Since: deepseq-1.4.2.0
Instance details Defined in Control.DeepSeq Methods rnf :: IORef a -> () #
Eq (IORef a)	Pointer equality. Since: base-4.0.0.0
Instance details Defined in GHC.IORef Methods (==) :: IORef a -> IORef a -> Bool # (/=) :: IORef a -> IORef a -> Bool #

newIORef :: Prim :> es => a -> Eff es (IORef a) Source #

Lifted newIORef.

readIORef :: Prim :> es => IORef a -> Eff es a Source #

Lifted readIORef.

writeIORef :: Prim :> es => IORef a -> a -> Eff es () Source #

Lifted writeIORef.

modifyIORef :: Prim :> es => IORef a -> (a -> a) -> Eff es () Source #

Lifted modifyIORef.

modifyIORef' :: Prim :> es => IORef a -> (a -> a) -> Eff es () Source #

Lifted modifyIORef'.

atomicModifyIORef :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b Source #

Lifted atomicModifyIORef.

atomicModifyIORef' :: Prim :> es => IORef a -> (a -> (a, b)) -> Eff es b Source #

Lifted atomicModifyIORef'.

atomicWriteIORef :: Prim :> es => IORef a -> a -> Eff es () Source #

Lifted atomicWriteIORef'.

mkWeakIORef :: (HasCallStack, Prim :> es) => IORef a -> Eff es () -> Eff es (Weak (IORef a)) Source #

Lifted mkWeakIORef.

Note: the finalizer will run a cloned environment, so any changes it makes to thread local data will not be visible outside of it.