@yoavst Is it not?

If you want to leave it localised you can do this too:

interface MyInterface {
    object Prop {
        operator fun getValue(thisRef: Any, property: KProperty<*>): Int = 123
    }
}

val MyInterface.prop: Int by MyInterface.Prop

Also worth to say that it’s a global. If you want to do it for each subclass it’s a bit more complicated (especially if you want a

var

instead of a

val

) You may have to start using a companion cache and such, potentially giving you leaks (unless you use WeakReferences)

without knowing the problem is hard to give a good answer but the closest I see to get what you want is this:

interface MyInterface { var _prop: Int? var prop: Int get() = if (_prop!=null) _prop!! else 1 set(value) { _prop = value } }