[msgilligan]

> Thus Kotlin will always be a guest language

If you a writing libraries for the JVM, Java is preferred to Kotlin because it does not drag along a standard library dependency.

To be fair there is Kotlin Multiplatform where this is not the case. https://kotlinlang.org/docs/multiplatform.html

[pjmlp]

Yes, and it has the issue of having its own way of #ifdef, because not all platforms offer the same semantics.

It is no different than writing C code across UNIX, Windows, mainframe, microcomputers and embedded, consoles, and somehow work across all of them.