Guarantee that function arg gets called?

1

Can I tell the compiler that the function argument f is always called, in order to fix the error about the uninitialized variable x?

fun buildStuff(f: () -> Unit) {
    ...  f() ...
}

var x: Foo
buildStuff {
    x = ...
}
return x // ← error: Variable 'x' must be initialized
2

Yes and no. It is possible, but it is still an experimental feature.

That said, the functionality of contracts is stable. It’s already used in the standard library and I think the kotlin team guarantees that compiled code with contracts will not break in the future.
Only the syntax to create contracts might change in the future.

1 Like
3

Thanks, that’s a pleasant surprise. I didn’t know about contracts.

Kotlin is a great language.