From <#C0922A726|general> chanel How about somthi...

# language-proposals

[snrostov]

From #general chanel

How about somthing like type tokens for reifed type parameters?

Use case: serializetion

val list: List<String> = listOf("hello", "world")
val out = MyDataOutput(...)
out.write(list)

where out.write is something like this:

inline fun <reified T: Any> DataOutput.write(obj: T) {
    val type: KType = T::type
    // do something useful with KType and it's type arguments...
}

The only possible way I can see to do it for now:

abstract class TypeToken<T> {}

fun <T: Any> DataOutput.write(obj: T, typeToken: TypeToken) {
    val type = typeToken::class.supertypes[0].arguments[0].type
}

usage:

out.write(list, object: TypeToken<List<String>>(){})

For example, gson library use similar aproach