prettyPrint()

list.joinToString(",\n  ", "[\n  ", "\n]")

fun <T> List<T>.toPrettyString() = joinToString(",\n  ", "[\n  ", "\n]")

Nothing

TODO()

open class AbstractStupidClass : StupidInterface{
  override fun annoyingMethodOne(p1: Type1, p2: Type2): Type3 = TODO(); //please note, this is not shorthand, this is compliable kotlin code
  override fun annoyingMethodTwo(p1: Type1) : Type 4 = TODO();
  //...
  override fun usefulMethod(interesting: InterestingType1): SomeType = TODO();
}

class MyUsefulType : AbstractStupidClass {
  overridefun usefulMethod(interesting: InterestingType1): SomeType{
    val x = doThings()//...
  }
}

StupidInterface

val aStupidInstance = NullInstance() as AStupidInterface;
val usefulInstance = object: AStupidInterface by aStupidInstance {
  override fun usefulMethod(intersting: Interesting): AnotherInteresting {
    //...
  }
}

dynamic

val Any.log : Logger get() = Logger.getLogger(this.javaclass.canonicalName)
operator fun Logger.get(level: Level) = //... would have to return some intermediate type 'LeveledLogger'
operator fun LeveledLogger.plusAssign(entryContent: () -> Pair<String, Exception>) = //...

fun someMethod(){
  try {
    somethingComplicated();
  }
  catch(ex: ItWentBadException){
    log[WARNING] += { "Its gonna blow!" to ex }
  }
}