Method enqueue

gecode/kernel/core.hpp:4069–4076

* Space * */

   *
   */
  forceinline void
  Space::enqueue(Propagator* p) {
    ActorLink::cast(p)->unlink();
    ActorLink* c = &pc.p.queue[p->cost(*this,p->u.med).ac];
    c->tail(ActorLink::cast(p));
    if (c > pc.p.active)
      pc.p.active = c;
  }

  forceinline void
  Space::fail(void) {