Kotlin call function only if all arguments are not null

Question

Is there a way in kotlin to prevent function call if all (or some) arguments are null? For example Having function:

fun test(a: Int, b: Int) { /* function bo         


        

Answer 1

Let for Tuples (Pair & Triple)

I think the spirit of the OP was syntax, so my answer focuses on providing "let" for tuple types:

Example use:

fun main() {
    val p1: Int? = 10 // or null
    val p2: Int? = 20 // or null
    val p3: Int? = 30 // or null

    val example1 = (p1 to p2).let(::testDouble)
    val example2 = (p1 to p2).let { a, b -> a * b }

    val example3 = (p1 to p2 to p3).let(::testTriple)
    val example4 = (p1 to p2 to p3).let { a, b, c -> a * b * c }
}

fun testDouble(a: Int, b: Int): Int {
    return a + b
}

fun testTriple(a: Int, b: Int, c: Int): Int {
    return a + b + c
}

Extension Funs:

// Define let for Pair & Triple
fun  Pair.let(f: (P1, P2) -> R): R? {
    return f(first ?: return null, second ?: return null)
}

fun  Triple.let(f: (P1, P2, P3) -> R): R? {
    return f(first ?: return null, second ?: return null, third ?: return null)
}

// Cute "to" syntax for Triple
infix fun  Pair.to(third: P3?): Triple {
    return Triple(first, second, third)
}

You can replace "to" with another word (see Triple extension as a guide), and you could extend to larger tuples (but Kotlin only provides 2 out-of-the-box & sadly I don't think it can be generic).