Question: Suppose I have this: ```open class MyFla...

# getting-started

[Kelvin Chung]

Question: Suppose I have this:

open class MyFlagDelegate(property: KProperty0<Int>) : ReadOnlyProperty<Any?, Boolean>
class MyMutableFlagDelegate(property: KMutableProperty0<Int>) : MyFlagDelegate(property), ReadWriteProperty<Any?, Boolean>

Is it possible to create an extension function on Int that returns one of these two delegates, and properly supplying the property argument? ie.

var myInt: Int
var myFlag: Boolean by MyMutableFlagDelegate(::myInt)
var myFlagAgain: Boolean by myInt.doSomething() // <-- something like this

[Nicolai C.]

Well, in this case myInt is still just of type Int, so what you can do is create a doSomething extension function on Int that returns a ReadWriteProperty instance like the following:

fun Int.doSomething() = object : ReadWriteProperty<Any?, Boolean> {
    override fun getValue(thisRef: Any?, property: KProperty<*>): Boolean = TODO()
    override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) = TODO()
}

[Nicolai C.]

Alternatively you could also add an operator provideDelegate extension function directly on Int that returns a property delegate, so you do not need to call a special extension function on Int .

https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.properties/-property-delegate-provider/provide-delegate.html

Example:

operator fun Int.provideDelegate(thisRef: Any?, property: KProperty<*>) =
    object : ReadWriteProperty<Any?, Boolean> {
        override fun getValue(thisRef: Any?, property: KProperty<*>): Boolean = TODO()
        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) = TODO()
    }