src/Pure/General/uuid.scala

clarified signature;

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

  def unapply(body: XML.Body): Option[T] = unapply(XML.content(body))
}