What we missed

var stringRepresentation: String
    get() = this.toString()
    set(value) {
        setDataFromString(value) // parses the string and assigns values to other properties
    }

when (x) {
    is Foo -> ...
    is Bar -> ...
    else   -> ...
}

fun transform(color: String): Int {
    return when (color) {
        "Red" -> 0
        "Green" -> 1
        "Blue" -> 2
        else -> throw IllegalArgumentException("Invalid color param value")
    }
}

for (i in 1..100) { ... }  // closed range: includes 100
for (i in 1 until 100) { ... } // half-open range: does not include 100
for (x in 2..10 step 2) { ... }
for (x in 10 downTo 1) { ... }
if (x in 1..10) { ... }

val p: String by lazy {
    // compute the string
}

println(map["key"])
map["key"] = value

println(list[0])
list[0] = value

val result = try {
        count()
    } catch (e: ArithmeticException) {
        throw IllegalStateException(e)
    }

class Box<T>(t: T) {
    var value = t
}

val box: Box<Int> = Box<Int>(1)

interface Base {
    fun printMessage()
    fun printMessageLine()
}

class BaseImpl(val x: Int) : Base {
    override fun printMessage() { print(x) }
    override fun printMessageLine() { println(x) }
}

class Derived(b: Base) : Base by b {
    override fun printMessage() { print("abc") }
}

data class Point(val x: Int, val y: Int)

operator fun Point.unaryMinus() = Point(-x, -y)

val point = Point(10, 20)

fun main() {
   println(-point)  // prints "Point(x=-10, y=-20)"
}

fun result() =
    html {
        head {
            title {+"XML encoding with Kotlin"}
        }
        body {
            h1 {+"XML encoding with Kotlin"}
            p  {+"this format can be used as an alternative markup to XML"}

            // an element with attributes and text content
            a(href = "https://kotlinlang.org") {+"Kotlin"}

            // mixed content
            p {
                +"This is some"
                b {+"mixed"}
                +"text. For more see the"
                a(href = "https://kotlinlang.org") {+"Kotlin"}
                +"project"
            }
            p {+"some text"}

            // content generated by
            p {
                for (arg in args)
                    +arg
            }
        }
    }

// how it works        
fun html(init: HTML.() -> Unit): HTML {
    val html = HTML()
    html.init()
    return html
}