Is there any plan to add support for different con...

# multiplatform

[zalewski.se]

Is there any plan to add support for different constructor per platform with `expect`/`actual` mechanism? For example with Android and iOS, usually for Android there is a need to pass a context while for iOS there is no such thing. Currently I’m playing around with some setup() functions that initialize my object and I hide the real constructor from the client. This approach seems far from perfect though 🤔

[Giorgos Neokleous]

I think it makes more sense to use an interface with platform specific concrete implementations in this case. expect/actual make it easy to use the expected class in common which won't make it possible to use in common with platform specific dependencies in constructor

[mbonnin]

You can have non-expected platform-specific constructors and expected common constructors in the same class

[zalewski.se]

@mbonnin
Oh, how you do non-expected platform-specific constructors?

[mbonnin]

Nothing specific to do, write them as you would write a regular constructor

[mbonnin]

There's an exemple there: https://github.com/apollographql/apollo-android/blob/main/apollo-normalized-cache-sqlite/src/androidMain/kotlin/com/apollographql/apollo/cache/normalized/sql/SqlNormalizedCacheFactory.kt#L21

[mbonnin]

Although TBH I found that this creates some confusion for users. Maybe it's because it's still the early days of multiplatform but having the same class callable from common code and platform-specific code feels a bit weird

[zalewski.se]

I see, so it’s already inside of the actual class! It’s not really non-expected platform-specific. I think this is something worth to try! Well definitely there is some confusion in it. In my case, I just need to expose a platform specific constructor for a client and this approach along with interface might work quite well 💡 Thanks!

[Giorgos Neokleous]

TIL! Thanks @mbonnin

[rocketraman]

Here is an approach with MPP and Kodein DI -- the actual factory class either takes the context or not, and is instantiated via Kodein modules within iosMain and androidMain -- the factory is used in the common code module to bind the interface implementation: https://stackoverflow.com/questions/63020969/kotlin-mpp-expect-actual-with-different-signatures/64141659#64141659

[zalewski.se]

@rocketraman
I’m using Kodein DI too but it’s not helpful in context of exposing different constructor per platform to a client (i’m developing an sdk)

[rocketraman]

@zalewski.se Right, if you're developing an SDK, there isn't much you can do, nor probably should you. I think a good model to follow is SQLDelight. They simply expose platform-specific driver classes that implement an interface. No `expect`/`actual` at all.