I’m having a hard time with `companion` and `object` usage inside my Swift code. Let say we have thi...

# multiplatform

[Sebastien Leclerc Lavallee]

I’m having a hard time with companion and object usage inside my Swift code. Let say we have this Kotlin code:

class SomeClass {
    companion object {
        fun someIntFunction(): Int {
            return 1
        }
    }
}

fun SomeClass.someBoolFunction(): Boolean {
    return false
}

fun SomeClass.Companion.toSomeString(): String {
    return "to Some String"
}

object SomeOtherStatic {
    fun stringStuff(): String {
        return "String Stuff"
    }
}

And with that Swift code:

let some = SomeClass()
let someBool = some.someBoolFunction()
let someInt = SomeClass.Companion.someIntFunction()
let someString = SomeClass.Companion.toSomeString()

let otherString = SomeOtherStatic.stringStuff()

I get errors from inside Xcode: Instance member 'someIntFunction' cannot be used on type 'SomeClass.Companion'; did you mean to use a value of this type instead? I have this error for someIntFunction , toSomeString and stringStuff . The compile thinks they are instance functions 🤔
Is there something I am doing wrong?

Thanks!

[Casey Brooks]

Yes, companion and object singletons must be accessed through a factory method when called in Swift https://kotlinlang.org/docs/reference/native/objc_interop.html#kotlin-singletons

[Sebastien Leclerc Lavallee]

As far as I know, those aren’t singleton members. Maybe I’m wrong. And I don’t see any singleton property in my Swift code. And the mapping table has different for ``companion` member` and Singleton

[basher]

try SomeClass.Companion().toSomeString

[Sebastien Leclerc Lavallee]

Yep! That seems to work. Strange I have to instanciate my companion each time. 🤷‍♂️
Thanks!

[saket]

You’ll always get the same instance of the companion

[Sebastien Leclerc Lavallee]

Thanks! Makes sense 🙂