src/Pure/General/uuid.scala

removed outcommented example which seems not to work as advertized

/*  Title:      Pure/General/uuid.scala
    Author:     Makarius

Universally unique identifiers.
*/

package isabelle


object UUID
{
  type T = java.util.UUID

  def random(): T = java.util.UUID.randomUUID()
  def random_string(): String = random().toString

  def unapply(s: String): Option[T] =
    try { Some(java.util.UUID.fromString(s)) }
    catch { case _: IllegalArgumentException => None }
}