So maybe this is asked here already but we have an...

# multiplatform

[Juhani Lehtimäki]

So maybe this is asked here already but we have an issue. All functions in our shared code marked as

suspend

do not show up in the compiled iOS code and cannot be called. Do we have to remove coroutine support from our shared code or is there some trick to make it work?

[kpgalligan]

iOS has no concept of suspend. You need to pass a callback

[Juhani Lehtimäki]

This confuses me a bit as there is a KMP library for coroutines and no compilation errors. The functions just are missing

[Juhani Lehtimäki]

ktor also uses coroutines to make calls.

[Juhani Lehtimäki]

is there a nice pattern to implement a multi-platform API that calls backend with ktor

[Juhani Lehtimäki]

but doesn’t use suspend in the interface

[kpgalligan]

You can’t expose suspend methods to the iOS header. We just have the external method take a lambda and have Swift pass that in.

[Juhani Lehtimäki]

ok

[Juhani Lehtimäki]

but you can’t use launch{} in KMP either, as far as I figured out, or?

[kpgalligan]

On phone right now, but can dig up a sample in a bit

[Juhani Lehtimäki]

so how can I call Ktor.

[Juhani Lehtimäki]

cool, thanks 🙂

[kpgalligan]

Why can't you use launch?

[Juhani Lehtimäki]

does not compile 😕

[Juhani Lehtimäki]

sigh. Maybe somethign is missing

[Larten]

You can use launch and works

[Juhani Lehtimäki]

okay, must be gradle messed up then, thanks. I’ll dig into it

[Olenyov Kirill]

Also there are solutions to generate callbacks:
https://github.com/andrewemery/recast
https://github.com/feilfeilundfeil/kotlin-native-suspend-function-callback

[Juhani Lehtimäki]

oh, that’s cool. Thanks!

[kpgalligan]

Interesting. Never heard of these

[Juhani Lehtimäki]

These both look a bit old. Are they still active?

[kpgalligan]

They’re def old. Digging a bit

[Juhani Lehtimäki]

We had an issue with older libraries that they don’t compile anymore as they were compiled by older Kotlin verison

[Juhani Lehtimäki]

as an idea, these look amazing

[Juhani Lehtimäki]

especially

@Recast

[kpgalligan]

Native libraries need to be updated. There look like compiler plugins, although that seems like a strange/risky place to be just now

[kpgalligan]

Got it. For “recast”, you need to use kapt to make source for iOS

[kpgalligan]

[Juhani Lehtimäki]

do you feel it’s a worth a try at this stage?

[kpgalligan]

The other one uses https://github.com/Foso/MpApt, which I’ve avoided, but see how it goes

[kpgalligan]

Not even close

[kpgalligan]

But that’s me

[Juhani Lehtimäki]

I’m a complete n00b stumblin in dark trying to get our lib working so I happily take in your input

[kpgalligan]

I don’t find the callback scheme to be that difficult to implement, and I’d expect to spend more time on sorting out config

[Juhani Lehtimäki]

I’ll just write a wrapper into the repository that calls the suspend ones and responds in callbacks

[kpgalligan]

Yeah, it’s extra “code” but not that hard to do

[Juhani Lehtimäki]

yeah, exactly. And if something breaks at least I know I did it 😄

[kpgalligan]

I was going to send a sample, but then updated intellij, then got distracted…

[Juhani Lehtimäki]

Thanks. Much appreciate the expertise 🙂

[kpgalligan]

What’s your github? I’ll add you to our new sample app.

[Juhani Lehtimäki]

JuhaniLehtimaeki

[Juhani Lehtimäki]

thanks 🙂

[ribesg]

My solution is to not write any Swift code 😛

[kpgalligan]

Added, but forgot we’re using Flow, not passing in callbacks to methods.

[kpgalligan]

Droidcon app has more examples, although we’re super overdue for an update: https://github.com/touchlab/DroidconKotlin/blob/kpg/mt_coroutines/sessionize/lib/src/commonMain/kotlin/co/touchlab/sessionize/AboutModel.kt#L14