22.2. The “Computation with a Hole”

To understand exactly what a continuation captures, it is useful to think of the shift block as a “hole” inside the reset block. When you invoke the continuation, you can pass a value into the hole, and the computation runs as if the shift had that value. Consider this artificial example:

var cont : (Int => Double) = null
reset {
  0.5 * shift { k : (Int => Double) => cont = k } + 1
}