Mainly a proof of concept. There are better ways to do this, but it was a quick experiment to create something like Python’s slicing in Kotlin.

kotlin-python-slice.kt

import kotlin.math.min

object start {
    infix fun to(other: Int) = RangeTuple(0, other)
    infix fun to(other: end) = RangeTuple(0, Int.MAX_VALUE)
}

object end

infix fun Int.to(other: end) = RangeTuple(this, Int.MAX_VALUE)

class RangeTuple(val first: Int, val last: Int)

fun <T> effectiveIndex(index: Int, list: List<T>): Int {
    return min(list.size, if (index < 0) list.size + index else index)
}

operator fun <T> List<T>.get(range: RangeTuple): List<T> {
    return this.subList(effectiveIndex(range.first, this), effectiveIndex(range.last, this))
}

infix fun Int.to(other: Int): RangeTuple {
    return RangeTuple(this, other)
}

fun main() {
    val list = listOf(1, 2, 3, 4)
    println(list[1 to 3]) // [2, 3]
    println(list[0 to -1]) // [1, 2, 3]
    println(list[-2 to -1]) // [3]
    println(list[start to end]) // [1, 2, 3, 4]
    println(list[start to 3]) // [1, 2, 3]
    println(list[-2 to end]) // [3, 4]
}