Streamly.Internal.Data.Fold.Async

Trimming

takeInterval :: MonadAsync m => Double -> Fold m a b -> Fold m a b

takeInterval n fold uses fold to fold the input items arriving within a window of first n seconds.

>>> input = Stream.delay 0.1 $ Stream.fromList [1..]
>>> Stream.fold (Fold.takeInterval 1.0 Fold.toList) input
[1,2,3,4,5,6,7,8,9,10,11]

Stops when fold stops or when the timeout occurs. Note that the fold needs an input after the timeout to stop. For example, if no input is pushed to the fold until one hour after the timeout had occurred, then the fold will be done only after consuming that input.

Pre-release

Splitting

intervalsOf :: MonadAsync m => Double -> Fold m a b -> Fold m b c -> Fold m a c

Group the input stream into windows of n second each using the first fold and then fold the resulting groups using the second fold.

>>> intervals = Fold.intervalsOf 0.5 Fold.toList Fold.toList
>>> Stream.fold intervals $ Stream.delay 0.2 $ Stream.fromList [1..10]
[[1,2,3,4],[5,6,7],[8,9,10]]

intervalsOf n split = many (takeInterval n split)

Pre-release