From 139c88dd58d44372bc6977c16c0699bfbc3660a4 Mon Sep 17 00:00:00 2001
From: Aadhavan Srinivasan <aadhavan@twomorecents.org>
Date: Thu, 24 Oct 2024 14:39:28 -0400
Subject: [PATCH] Started working on '+' operator

---
 main.go     | 6 ++++--
 matching.go | 7 +++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/main.go b/main.go
index 968dbee..3d765a8 100644
--- a/main.go
+++ b/main.go
@@ -11,7 +11,7 @@ import (
 const CONCAT rune = '~'
 
 func isOperator(c rune) bool {
-	if c == '*' || c == '|' || c == CONCAT {
+	if c == '+' || c == '*' || c == '|' || c == CONCAT {
 		return true
 	}
 	return false
@@ -19,7 +19,7 @@ func isOperator(c rune) bool {
 
 /* priority returns the priority of the given operator */
 func priority(op rune) int {
-	precedence := []rune{'|', CONCAT, '*'}
+	precedence := []rune{'|', CONCAT, '+', '*'}
 	return slices.Index(precedence, op)
 }
 
@@ -138,6 +138,8 @@ func thompson(re string) *State {
 			}
 			stateToAdd.transitions[s1.content] = append(stateToAdd.transitions[s1.content], s1)
 			nfa = append(nfa, stateToAdd)
+		case '+':
+
 		case '|':
 			s1 := pop(&nfa)
 			s2 := pop(&nfa)
diff --git a/matching.go b/matching.go
index 6904cf5..07a7eff 100644
--- a/matching.go
+++ b/matching.go
@@ -40,15 +40,16 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
 	currentStates := make([]*State, 0)
 	tempStates := make([]*State, 0) // Used to store states that should be used in next loop iteration
 	i := 0                          // Index in string
+	startingFrom := i               // Store starting index
 	// Increment until we hit a character matching the start state (assuming not 0-state)
 	if start.isEmpty == false {
 		for i < len(str) && int(str[i]) != start.content {
 			i++
 		}
 		startIdx = i
+		startingFrom = 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
 	}
-	startingFrom := i
 	currentStates = append(currentStates, start)
 
 	// Main loop
@@ -57,6 +58,7 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
 
 		zeroStates := make([]*State, 0)
 		// Keep taking zero-states, until there are no more left to take
+		// Objective: If any of our current states have transitions to 0-states, replace them with the 0-state. Do this until there are no more transitions to 0-states
 		zeroStates, isZero := takeZeroState(currentStates)
 		tempStates = append(tempStates, zeroStates...)
 		for isZero == true {
@@ -105,7 +107,8 @@ func findAllMatchesHelper(start *State, str string, indices []matchIndex, offset
 	tempStates = nil
 
 	for _, state := range currentStates {
-		if state.isLast {
+		// Only add the match if we the start index is in bounds
+		if state.isLast && startIdx+offset < len(str)+offset {
 			endIdx = i
 			indices = append(indices, matchIndex{startIdx + offset, endIdx + offset})
 		}