Problem Statement

Several programming languages offer syntax shortcuts to deal with the notion of "current" or "topic" variable. A topic variable is a special variable with a very short name which can also often be omitted. Demonstrate the utilization and behaviour of the topic variable within the language and explain or demonstrate how the topic variable behaves under different levels of nesting or scope, if this applies, within the language. For instance you can (but you don't have to) show how the topic variable can be used by assigning the number

3

{\displaystyle 3}

to it and then computing its square and square root.

Let's start with the solution:

object TopicVar extends App {
  class SuperString(val org: String){
    def it(): Unit = println(org)
  }

  new SuperString("FvdB"){it()}
  new SuperString("FvdB"){println(org)}

  Seq(1).foreach {println}
  Seq(2).foreach {println(_)}
  Seq(4).foreach { it => println(it)}
  Seq(8).foreach { it => println(it + it)}
}