/*  Title:      Pure/Concurrent/volatile.scala

    Module:     PIDE

    Author:     Makarius

Volatile variables.

*/

package isabelle

object Volatile

{

  def apply[A](init: A): Volatile[A] = new Volatile(init)

}

class Volatile[A] private(init: A)

{

  @volatile private var state: A = init

  def apply(): A = state

  def >> (f: A => A) { state = f(state) }

  def >>>[B] (f: A => (B, A)): B =

  {

    val (result, new_state) = f(state)

    state = new_state

    result

  }

}