regex/nfa.go

@@ -47,7 +47,6 @@ type nfaState struct {
 	// The following properties depend on the current match - I should think about resetting them for every match.
 	zeroMatchFound bool    // Whether or not the state has been used for a zero-length match - only relevant for zero states
 	threadGroups   []Group // Assuming that a state is part of a 'thread' in the matching process, this array stores the indices of capturing groups in the current thread. As matches are found for this state, its groups will be copied over.
-	threadSP       int     // The string pointer of the thread - where it is in the input string
 }
 
 // Clones the NFA starting from the given state.
@@ -123,7 +122,6 @@ func resetThreadsHelper(state *nfaState, visitedMap map[*nfaState]bool) {
 	}
 	// Assuming it hasn't been visited
 	state.threadGroups = nil
-	state.threadSP = 0
 	visitedMap[state] = true
 	if state.isAlternation {
 		resetThreadsHelper(state.next, visitedMap)
@@ -408,3 +406,32 @@ func zeroLengthMatchState() nfaState {
 	start.assert = alwaysTrueAssert
 	return start
 }
+
+func (s nfaState) equals(other nfaState) bool {
+	return slices.Equal(s.content, other.content) &&
+		s.isEmpty == other.isEmpty &&
+		s.isLast == other.isLast &&
+		slices.Equal(s.output, other.output) &&
+		s.next == other.next &&
+		s.isKleene == other.isKleene &&
+		s.isQuestion == other.isQuestion &&
+		s.isAlternation == other.isAlternation &&
+		s.splitState == other.splitState &&
+		s.assert == other.assert &&
+		s.allChars == other.allChars &&
+		slices.Equal(s.except, other.except) &&
+		s.lookaroundNFA == other.lookaroundNFA &&
+		s.groupBegin == other.groupBegin &&
+		s.groupEnd == other.groupEnd &&
+		s.groupNum == other.groupNum &&
+		slices.Equal(s.threadGroups, other.threadGroups)
+}
+
+func stateExists(list []nfaState, s nfaState) bool {
+	for i := range list {
+		if list[i].equals(s) {
+			return true
+		}
+	}
+	return false
+}