WithIndent.kt

package net.russianword.android

/**
 * Created by igushs on 4/25/16.
 */

class Translator {
    private var indentLevel = 0

    private fun writeLn(s: String) {
        println(" ".repeat(4 * indentLevel) + s)
    }

    private fun withIndent(action: () -> Unit) {
        ++indentLevel
        action()
        --indentLevel
    }

    fun f() {
        writeLn("123")
        withIndent {
            writeLn("abc")
            writeLn("def")
            withIndent {
                writeLn("xyz")
                writeLn("123")
            }
            writeLn("456")
        }
        writeLn("789")
    }
}

fun main(args: Array<String>) {
    Translator().f()
}