regex/priorityQueue.go

@@ -15,8 +15,8 @@ const (
 
 func getPriority(state *nfaState) int {
 	if state.isKleene {
-		return kleene_priority
-	} else if state.isQuestion || state.isAlternation {
+		return zerostate_priority
+	} else if state.isAlternation {
 		return alternation_priority
 	} else {
 		if state.isEmpty {
@@ -33,6 +33,14 @@ type priorQueueItem struct {
 	index    int
 }
 
+func newPriorQueueItem(state *nfaState) *priorQueueItem {
+	return &priorQueueItem{
+		state:    state,
+		index:    -1,
+		priority: getPriority(state),
+	}
+}
+
 type priorityQueue []*priorQueueItem
 
 func (pq priorityQueue) Len() int {
@@ -41,7 +49,7 @@ func (pq priorityQueue) Len() int {
 
 func (pq priorityQueue) Less(i, j int) bool {
 	if pq[i].priority == pq[j].priority {
-		return pq[i].index > pq[j].index
+		return pq[i].index < pq[j].index
 	}
 	return pq[i].priority > pq[j].priority // We want max-heap, so we use greater-than
 }
@@ -68,6 +76,11 @@ func (pq *priorityQueue) Pop() any {
 	*pq = old[0 : n-1]
 	return item
 }
+func (pq *priorityQueue) peek() any {
+	queue := *pq
+	n := len(queue)
+	return queue[n-1]
+}
 
 func (pq *priorityQueue) update(item *priorQueueItem, value *nfaState, priority int) {
 	item.state = value