Demostrates Power of Kotlin's multi-declarations

multi-declarations-with-regex.kt

import java.util.*
import java.util.regex.Pattern


fun main(args: Array<String>) {
    x("http://localhost:9090")
    x("http://localhost")
    x("http://localhost/path/to/it")
    x("http://localhost:9091/path/to/it")
    x("http://localhost:9091/?p=1")
}

fun x(url: String) {
    val (proto, host, port, path, query) = 
        "^([a-z]+)://([^:/]+)(?::([0-9]+))?(?:(/[^?]*)(\\?.*)?)?$"
            .toRegex()
            .match(url)
            ?.groups
            ?.map { it?.value }
            ?.drop(1) ?: Collections.nCopies(5, null)

    println(url)
    println("proto = ${proto}")
    println("host = ${host}")
    println("port = ${port}")
    println("path = ${path}")
    println("query = ${query}")
    println()
}