/*
 *  call-seq:
 *     pq.top -> elem
 *  
 *  Returns the top element in the queue but does not remove it from the
 *  queue.
 */
static VALUE
frt_pq_top(VALUE self)
{
    PriQ *pq;
    GET_PQ(pq, self);
    return (pq->size > 0) ? pq->heap[1] : Qnil;
}