P18 - Extract a slice from a list.

> slice(3, 7, "abcdefghijk".toList())
[d, e, f, g]

kotlin

package org.kotlin99.lists

import com.natpryce.hamkrest.assertion.assertThat
import com.natpryce.hamkrest.equalTo
import org.junit.Test
import org.kotlin99.common.tail

fun <T> slice(from: Int, to: Int, list: List<T>): List<T> =
    when {
        from > 0 -> slice(from - 1, to - 1, list.tail())
        to > 0   -> listOf(list.first()) + slice(from, to - 1, list.tail())
        else     -> emptyList()
    }

@Suppress("unused")
fun <T> slice_(from: Int, to: Int, list: List<T>) = list.subList(from, to)

class P18Test {
    @Test fun `extract a slice from a list`() {
        assertThat(slice(3, 7, "abcdefghijk".toList()), equalTo("defg".toList()))
    }
}