Use new API for findAllMatches

nfa.go

@@ -122,13 +122,21 @@ func (s State) checkAssertion(str []rune, idx int) bool {
 		// 		2. Run it on a subset of the test string, that ends after the current index in the string
 		// 		3. Based on the kind of lookaround (and the indices we get), determine what action to take.
 		startState := s.lookaroundNFA
-		var strToMatch []rune
+		var runesToMatch []rune
+		var strToMatch string
 		if s.assert == PLA || s.assert == NLA {
-			strToMatch = str[idx:]
+			runesToMatch = str[idx:]
 		} else {
-			strToMatch = str[:idx]
+			runesToMatch = str[:idx]
 		}
-		matchIndices := findAllMatches(startState, strToMatch, startState.lookaroundNumCaptureGroups)
+
+		if len(runesToMatch) == 0 {
+			strToMatch = ""
+		} else {
+			strToMatch = string(runesToMatch)
+		}
+
+		matchIndices := findAllMatches(Reg{startState, startState.lookaroundNumCaptureGroups}, strToMatch)
 
 		numMatchesFound := 0
 		for _, matchIdx := range matchIndices {