Introduction to Delimited Continuations/Using shift and reset

Let's rewrite run using Scala's delimited continuations primitives, shift and reset.

def run() = reset {
  println("What is your name?")
  val name = shift { k: (String => Unit) => 
    val name = readln()
    k(name)
  }
  println("Hello, " + name + "!")
}

The flow of the program has not changed. Printing the second message to the screen becomes a continuation of type String => Unit, which is passed into the shift block as the function k, to be invoked with the user's input.

Next Lesson Course Home Page