Data.PrimRef

Mutable references in monads which are instances of MonadPrim.

PrimRefs

data PrimRef m a

Mutable variable which full analog of IORef or STRef but could use either of the monads. Unfortunately there's no way to convert PrimRef to STRef or IORef.

newPrimRef :: PrimMonad m => a -> m (PrimRef m a)

Create new mutable variable with initial value a.

readPrimRef :: PrimMonad m => PrimRef m a -> m a

Read value of PrimRef.

writePrimRef :: PrimMonad m => PrimRef m a -> a -> m ()

Write value to PrimRef.

modifyPrimRef :: PrimMonad m => PrimRef m a -> (a -> a) -> m ()

Modify content of PrimRef using function.

modifyPrimRef' :: PrimMonad m => PrimRef m a -> (a -> a) -> m ()

Modify content of PrimRef using function and evaluate result of function application to WHNF before storing it in the variable.