"coordinate" iteration, e.g

(0 to 0)..(1 to 1)

iterates through

0 to 0, 0 to 1, 1 to 0, 1 to 1

. Might be a stretch, but I think it's intuitive.

operator fun Pair<Int, Int>.rangeTo(that: Pair<Int, Int>) = object : Iterable<Pair<Int, Int>> {
    override fun iterator() = object : Iterator<Pair<Int, Int>> {
        var i = this@rangeTo.first
        var j = this@rangeTo.second
        
        val m = that.first - i
        val n = that.second - j

        override fun hasNext() = i <= m && j <= n

        override fun next(): Pair<Int, Int> {
            val res = i to j
            
            if (j == n) {
                j = 0
                i++
            } else {
                j++
            }
            
            return res
        }
    }
}

could also be expanded to higher dimensions with

List<Int>.rangeTo(other: List<Int>)

,

IntArray

, etc

If anything, this should be a separate type, and I dont think it deserves a place in the stdlib atm. At least it may be difficult to collect all use cases under the same name if so.

Yeah, it's more appropriate for a

Vector

type, which Kotlin does not have

Kotlin has

data class

which partially covers the use case of

Vector

I'd be happier with a general Cartesian product instead of only for ranges

yeah, but i do think that the rangeTo operator is a great operator for cartesian product. If they add cartesian product, anyone can create the operator function that calls it should they choose to

operator fun <T> Iterable<T>.rangeTo(other: Iterable<T>) = this cart other

I don't really get what you're saying.

Hes saying he doesn't mind your idea because he can declare his own operator delegating it

Huh so he wants

..

to represent cartesian product? Isn't that something different from the code sample, where

..

is a kind of specific range-cartesian on pairs?

ah, yeah