Hi <@UE3D4UE15>, I saw in the channel history that...

# arrow

[Rafal Piotrowski]

Hi @Bob Glamm, I saw in the channel history that you were working with ktor and you were trying to use IO as a ktor handler (which is suspended function). Have you managed to do that using Arrow 0.9.0 or you had to use snapshot version (0.10.0-SNAPSHOT)?

[Bob Glamm]

0.10.0-SNAPSHOT

[Bob Glamm]

Let me put up a gist of that on GitHub

[Bob Glamm]

Actually, check that, it works with 0.9.0

[Bob Glamm]

https://gist.github.com/glammr1/79e0fe62da5e5b7ccfe332c27b4b6ba6

[Bob Glamm]

Bear in mind that it's really rough and fixed to IO

[Rafal Piotrowski]

Thanks! use of suspendCoroutine is a clue here, I'm checking is it possible to make this more abstract with Async typeclass still I cannot figure out is it possible or not

[Bob Glamm]

I am pretty sure it is possible to bound it to Async. One nice signature is suspend MonadThrowSyntax<F>.(args) -> Kind<F, result> which enables fx syntax within the adapted method block

[Bob Glamm]

Are you tied to 0.9.0 or can you migrate to 0.10.0-SNAPSHOT?

[Rafal Piotrowski]

well, it's internal project, but some people will use, so I have some doubts should I switch to snapshot 😄

[Rafal Piotrowski]

I can at least experiment and see what will hapend 😉

[Bob Glamm]

IIRC the .suspended() boilerplate is built into 0.10.0-SNAPSHOT, so it would make it a little simpler. Let me see if I can make it polymorphic on Async<F>

[Bob Glamm]

Updated with parts of it polymorphic on Async<F>

[Bob Glamm]

I think the routing {} block needs to be adapted to IO/F, though

[Bob Glamm]

hmm, PipelineContext and Async<F>.later() might be promising

[Bob Glamm]

This works as a starting point but is wrong:

get("quux") {
                IO.async().effect(this.coroutineContext) {
                    call.respondText("QUUXER", ContentType.Text.Html)
                }.fix().suspended()
            }

[Bob Glamm]

I think the general structure we would want to expose is suspend (PipelineContext<Unit, ApplicationCall>) -> Kind<F, A>.. I think

[Bob Glamm]

The trick is that every call to ApplicationCall is a side-effect

[Bob Glamm]

The following is closer, I think:

fun <F, TSubject: Any, TContext: Any> bridgeFactory(
        AF: Async<F>,
        PC: PipelineContext<TSubject, TContext>
): PipelineAsyncBridge<F, TSubject, TContext> =
        object: PipelineAsyncBridge<F, TSubject, TContext>, Async<F> by AF, PipelineContext<TSubject, TContext> by PC {}

then in `routing`:

get("q2") { bridgeFactory(IO.async(), this).run {
                effect(this.coroutineContext) {
                    call.respondText("Q2", ContentType.Text.Html)
                }.fix().suspended()
            }}