Quick question: For now, `fun suspendFlowFunction(...

# swift-export

[Guilherme Delgado]

Quick question: For now, fun suspendFlowFunction(): Flow<String> will create a public static func suspendFlowFunction() -> any ExportedKotlinPackages.kotlinx.coroutines.flow.Flow which loses its type (all generics are being transform into (*any* KotlinRuntimeSupport._KotlinBridgeable)?). So, if I need to type check, either I force cast in Swift or I’ll have to create a fun suspendFlowFunction(callback: (String) -> Unit) so that swiftExport translates to public static func suspendFlowFunction(callback: @escaping (Swift.String) -> Swift.Void) , but then it will make me collect the values inside Kotlin instead of Swift, am I correct? I know this is still in developing 😊 , just to check.

[Artem Olkov]

: Flow<String>

Interop with Flow is not designed and should be considered supported 🙂 If it works somehow on your side it's a coincidence, and it will be heavily reworked in the future.

But yeah, if you want to write a "collect" method wrapper(so that you get some type-safety) - you should call the original collect inside that wrapper.

[Guilherme Delgado]

I'm testing some scenarios and a simple data class I can force cast, but a List fails. Thanks for the info 😉

[Artem Olkov]

but a List fails

Yes, Lists(collections in general) are a special, same way as Strings, Closures and Primitives. We are currently focusing on coroutines support in general, so I don't have a timeline for you, when this quirk of the type system will be fixed(or if it's even fixable) 🙂

[Guilherme Delgado]

Hello again 🙂

suspend fun observeListOfMyClass(callback: (List<MyClass>) -> Unit) {...}

public func observeListOfMyClass(
    callback: @escaping (Swift.Array<Swift.Never>) -> Swift.Void
) async -> Swift.Void {
    fatalError()
}

I guess even with callbacks, List<T> is out of the question for now 😅 , am I correct?

[Guilherme Delgado]

humm…. strange, I can make it work in other situation:

public static func suspendFlowFunctionSpawn2(
    callback: @escaping (Swift.Array<ExportedKotlinPackages.com.playground.DataClass>) -> Swift.Void
) -> Swift.Void {
    return com_playground_suspendFlowFunctionSpawn2__TypesOfArguments__U28Swift_Array_ExportedKotlinPackages_com_playground_DataClass_U29202D_U20Swift_Void__({
        let originalBlock = callback
        return { arg0 in return originalBlock(arg0 as! Swift.Array<ExportedKotlinPackages.com.playground.DataClass>) }
    }())
}

[Guilherme Delgado]

ok found out my problem, ignore it 😅