Kotlin functions inside a const - kotlin

Question

I am learning kotlin, and want to know how to add functions to a const,
here the JS example...
function suma (a, b){
return a + b
}
console.log("sua suma::", suma(2,3))
function multiplica (a, b){
return a * b
}
console.log("sua multiplik::", multiplica(2,3))
const operations = {
suma,
multiplica
}
console.log ("sum of first class::", operations.suma(2,3))
console.log ("mult of first class::", operations.multiplica(2,3))
so how do I achieve the same on Kotlin?
Here what I have tried:
fun suma(a: Int, b: Int): Int{
return a + b
}
fun multiplica (a: Int, b: Int): Int{
return a * b
}
const operations = {
suma(),
multiplica()
}
fun main() {
println("sua suma:: ${suma(2, 3)}")
println("sua multiplica:: ${multiplica(2, 3)}")
println("sua multiplica:: ${operations.multiplica(2,3)}")
}

Answer 1

It can be done using object keyword, like following:
fun suma(a: Int, b: Int): Int {
return a + b
}
fun multiplica(a: Int, b: Int): Int {
return a * b
}
fun main() {
val operations = object {
val _suma = ::suma
val _multiplica = ::multiplica
}
println("sua suma:: ${operations._suma(2, 3)}")
println("sua multiplica:: ${operations._multiplica(2, 3)}")
}
The only disadvantage is that you have to choose a name for operations.XXXXX that is different from the name of referenced function: note var _suma vs fun suma. Otherwise the compiler will consider it recursive problem

Answer 2

"Only Primitives and String are allowed" for const
The operator you're looking for is :: (Double colon)
An enum example of this is
enum class Operations(function: KFunction<Int>) {
Suma(function = ::suma),
Multiplica(function = ::multiplica)
}

Answer 3

The main issues here are that Kotlin is a statically typed language, and doesn't have the same idea of Objects that can contain arbitrary attributes, like Javascript does.
I'm kinda new to Kotlin, so there may be a better way to do this, but what I'd do is define a Map to do the same sort of thing:
fun suma(a: Int, b: Int): Int{
return a + b
}
fun multiplica (a: Int, b: Int): Int{
return a * b
}
val operations: Map<String, (a: Int, b:Int) -> Int> = hashMapOf(
"suma" to ::suma,
"multiplica" to ::multiplica)
fun main() {
println("sua suma:: " + operations.get("suma")?.invoke(2, 3))
println("sua multiplica:: " + operations.get("multiplica")?.invoke(2, 3))
}
Result:
sua suma:: 5
sua multiplica:: 6
Note that operations is an immutable Map ('const' kinda) in that its contents can't be changed once it's defined.
The access and having to use invoke seems kinda messy. This seems to be due to the fact that a Map can only contain nullable types. That's the main reason I think there's probably a better way to do this.