Prod.Background

Documentation

data BackgroundVal a

A value that is coupled to an async in charge of updating the value.

Instances

Functor BackgroundVal

Defined in Prod.Background

Methods

fmap :: (a -> b) -> BackgroundVal a -> BackgroundVal b

(<$) :: a -> BackgroundVal b -> BackgroundVal a

type MicroSeconds n = n

Fantom type for annotating Int.

background

Arguments

:: Tracer IO (Track a)

-> b

initial state

-> a

initial value

-> (b -> IO (a, b))

state-influenced task

-> IO (BackgroundVal a)

Starts a background task continuously updating a value.

backgroundLoop

Arguments

:: Tracer IO (Track a)

-> a

initial value

-> IO a

periodic task

-> MicroSeconds Int

wait period between two executions

-> IO (BackgroundVal a)

Starts a background task continuously updating a value at a periodic interval. This is implemented by interspersing a threadDelay before the task and calling background and hiding the 'state-passing' arguments.

kill :: (HasCallStack, MonadIO m) => BackgroundVal a -> m ()

Kills the watchdog by killing the underlying async.

link :: BackgroundVal a -> BackgroundVal b -> IO ()

readBackgroundVal :: MonadIO m => BackgroundVal a -> m a

Kills the watchdog by killing the underlying async.

data Track r

Constructors

Init r

RunStart

RunDone r r

Kill CallStack

Instances

Functor Track

Defined in Prod.Background

Methods

fmap :: (a -> b) -> Track a -> Track b

(<$) :: a -> Track b -> Track a

Show r => Show (Track r)

Defined in Prod.Background

Methods

showsPrec :: Int -> Track r -> ShowS

show :: Track r -> String

showList :: [Track r] -> ShowS