<@UE7URQL10> I would go to a terminal `IO&lt;Unit&...

# arrow

[raulraja]

@noiano I would go to a terminal IO<Unit> then at the very edge where you need to perform the action you can call unsafeRunAsync or any other variation of that method to run the program.
What attempt does is turn IO<A> into IO<Either<Throwable, A>> forcing the receiver of the last typed value to deal in composition with the fact that the operation may have failed with an exception which can be found in the Left

[noiano]

woud runAsync block the current thread? or will it run a separated thread therefore requiring me to do some sort of

waitForCompletion

kinda thing?

[noiano]

given the name I’d say the second

[simon.vergauwen]

You can either use unsafeRunSync() which blocks the callers thread or unsafeRunAsync { } which allows the run IO to fork execution

[simon.vergauwen]

You can also use unsafeRynAsyncCancellable { } which returns a typealias Disposable = () -> Unit which you can use to cancel the running IO.

[simon.vergauwen]

IO cancelation gets checked on flatMap boundaries.

[noiano]

Thank you so much... I need to block otherwise the program exits and with that the spark session is killed

[simon.vergauwen]

Any time 🙂 Awesome to see Arrow being used with Spark!

[simon.vergauwen]

Haven’t seen a lot of Spark in Kotlin yet

[noiano]

Yeah because it's not good since you have to use the spark Java API

[noiano]

But it's company mandated so I cannot switch to scala...at least I can ease the pain with kotlin

[simon.vergauwen]

Hopefully Arrow can fill some gaps as well 👍

[noiano]

Oh absolutely

[noiano]

It's a godsend