Data.Primitive.MutVar

Primitive boxed mutable variables

Documentation

data MutVar s a

A MutVar behaves like a single-element mutable array associated with a primitive state token.

Constructors

MutVar (MutVar# s a)

Instances

Eq (MutVar s a)

Methods

(==) :: MutVar s a -> MutVar s a -> Bool

(/=) :: MutVar s a -> MutVar s a -> Bool

PrimUnlifted (MutVar s a)

Methods

toArrayArray# :: MutVar s a -> ArrayArray#

fromArrayArray# :: ArrayArray# -> MutVar s a

newMutVar :: PrimMonad m => a -> m (MutVar (PrimState m) a)

Create a new MutVar with the specified initial value

readMutVar :: PrimMonad m => MutVar (PrimState m) a -> m a

Read the value of a MutVar

writeMutVar :: PrimMonad m => MutVar (PrimState m) a -> a -> m ()

Write a new value into a MutVar

atomicModifyMutVar :: PrimMonad m => MutVar (PrimState m) a -> (a -> (a, b)) -> m b

Atomically mutate the contents of a MutVar

atomicModifyMutVar' :: PrimMonad m => MutVar (PrimState m) a -> (a -> (a, b)) -> m b

Strict version of atomicModifyMutVar. This forces both the value stored in the MutVar as well as the value returned.

modifyMutVar :: PrimMonad m => MutVar (PrimState m) a -> (a -> a) -> m ()

Mutate the contents of a MutVar

modifyMutVar' :: PrimMonad m => MutVar (PrimState m) a -> (a -> a) -> m ()

Strict version of modifyMutVar