Destructuring Declarations in Kotlin - kotlin

Question

I want to return multiple values from a function. As suggested by another SO answer, I used Destructuring with public class, but the problem is I can't assign the returned destructured result to already existing variables.
data class Result(val res1 :Int, val res2: Int)
class test{
fun retresult():Result{
return Result(2,2)
}
}
fun main(args: Array<String>) {
var var1:Int = 0
var var2:Int = 0
var des = test()
//(var1, var2) = des.retresult() this doesn't work
var1 = des.retresult().res1
var2 = des.retresult().res2 // **works but calls function twice**
}
I don't want to initialize local vals at return point like
val (var1, var2) = des.retresult()

Answer 1

You can assign these two variables without calling the function twice, using with:
fun main(args: Array<String>) {
var var1:Int = 0
var var2:Int = 0
var des = test()
with (des.retresult()) {
var1 = res1
var2 = res2
}
}
Alternatively, your function could take function arguments for setting the results, and then you can pass the setters for these properties. This wouldn't work for local variables, only member properties. If you use C, this is kind of like passing a pointer to a function so it can directly modify a variable rather than returning something.
class Test (var one: Int, var two: Int)
fun doSomething(result1: (Int) -> Unit, result2: (Int) -> Unit) {
result1(2)
result2(2)
}
fun main() {
val test = Test(1, 1)
doSomething(test::one::set, test::two::set)
}
There's an open (and mostly forgotten, it seems) feature request for what you suggested, destructuring assignment to existing variables.