How to use Function Literals with Receiver in Kotlin

Issue #139

From https://kotlinlang.org/docs/reference/lambdas.html

class HTML {
    fun body() { ... }
}

fun html(init: HTML.() -> Unit): HTML {
    val html = HTML()  // create the receiver object
    html.init()        // pass the receiver object to the lambda
    return html
}


html {       // lambda with receiver begins here
    body()   // calling a method on the receiver object
}

From https://github.com/JetBrains/kotlin/blob/master/libraries/stdlib/src/kotlin/util/Standard.kt

@kotlin.internal.InlineOnly
public inline fun <T> T.apply(block: T.() -> Unit): T {
    contract {
        callsInPlace(block, InvocationKind.EXACTLY_ONCE)
    }
    block()
    return this
}

val person = Person().apply {
  name = "Superman"
  age = 20
}

From https://academy.realm.io/posts/kau-jake-wharton-testing-robots/

fun payment(func: PaymentRobot.() -> Unit) = PaymentRobot().apply { func() }

class PaymentRobot {
	fun amount(amount: Long) {

	}

	fun recipient(recipient: String) {

	}

	infix fun send(func: ResultRobot.() -> Unit): ResultRobot {
	  // ...
	  return ResultRobot().apply { func() }
	}
}

class ResultRobot {
	func isSuccess() {

	}
}

payment {
	amount(4200)
	recipient(superman@google.com)
} send {
	isSuccess()
}