Fixed kleene star behavior, which used to behave like a '+'

matching.go

@@ -8,13 +8,14 @@ func match(start *State, str string) (startIdx int, endIdx int, matched bool) {
 	i := 0                          // Index in string
 	// Increment until we hit a character matching the start state
 	if start.isEmpty == false {
-		for int(str[i]) != start.content {
+		for i < len(str) && int(str[i]) != start.content {
 			i++
 		}
+		i++ // Advance to next character (if we aren't at a 0-state, which doesn't match anything), so that we can check for transitions. If we advance at a 0-state, we will never get a chance to match the first character
 	}
 	currentStates = append(currentStates, start)
 	startIdx = i
-	i++ // Advance to next character so that we can check for transitions
+
 	// Main loop
 	for i < len(str) {
 		// If there are any 0-transitions, take those
@@ -45,7 +46,15 @@ func match(start *State, str string) (startIdx int, endIdx int, matched bool) {
 		i++
 	}
 
-	// End-of-string reached. Check if any of our states is in the end position.
+	// End-of-string reached. Go to any 0-states. Then check if any of our states are in the end position.
+	for _, state := range currentStates {
+		if len(state.transitions[EPSILON]) > 0 {
+			tempStates = append(tempStates, state.transitions[EPSILON]...)
+		}
+	}
+	copy(currentStates, tempStates)
+	tempStates = nil
+
 	for _, state := range currentStates {
 		if state.isLast {
 			endIdx = i