diff --git a/main.go b/main.go
index 51cdd66..782ed02 100644
--- a/main.go
+++ b/main.go
@@ -6,29 +6,13 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"slices"
 
 	"github.com/fatih/color"
 )
 
-const CONCAT rune = '~'
-
 var notDotChars []rune
 var caseInsensitiveFlag *bool // Whether we are running in case-insensitive mode
 
-func isOperator(c rune) bool {
-	if c == '+' || c == '?' || c == '*' || c == '|' || c == CONCAT {
-		return true
-	}
-	return false
-}
-
-/* priority returns the priority of the given operator */
-func priority(op rune) int {
-	precedence := []rune{'|', CONCAT, '+', '*', '?'}
-	return slices.Index(precedence, op)
-}
-
 func main() {
 	invertFlag := flag.Bool("v", false, "Invert match.")
 	// This flag has two 'modes':
@@ -83,7 +67,6 @@ func main() {
 	var re string
 	re = flag.Args()[0]
 	var test_str string
-	var test_runes []rune // Rune-slice representation of test_str
 	var err error
 	var linesRead bool // Whether or not we have read the lines in the file
 	lineNum := 0       // Current line number
@@ -91,8 +74,11 @@ func main() {
 	reader := bufio.NewReader(os.Stdin)
 	out := bufio.NewWriter(os.Stdout)
 
-	re_postfix := shuntingYard(re)
-	startState, numGroups := thompson(re_postfix)
+	regComp, err := Compile(re)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
 	for true {
 		if linesRead {
 			break
@@ -129,15 +115,14 @@ func main() {
 				panic(err)
 			}
 		}
-		test_runes = []rune(test_str)
 		matchIndices := make([]Match, 0)
 		if matchNumFlagEnabled {
-			tmp, err := findNthMatch(startState, test_runes, numGroups, *matchNum)
+			tmp, err := findNthMatch(regComp, test_str, *matchNum)
 			if err == nil {
 				matchIndices = append(matchIndices, tmp)
 			}
 		} else {
-			matchIndices = findAllMatches(startState, test_runes, numGroups)
+			matchIndices = findAllMatches(regComp, test_str)
 		}
 
 		if *printMatchesFlag {
@@ -172,7 +157,7 @@ func main() {
 			// Find all numbers from 0 to len(test_str) that are NOT in oldIndices.
 			// These are the values we want to print, now that we have inverted the match.
 			// Re-initialize indicesToPrint and add all of these values to it.
-			indicesToPrint.add(setDifference(genRange(0, len(test_runes)), oldIndices)...)
+			indicesToPrint.add(setDifference(genRange(0, len(test_str)), oldIndices)...)
 
 		}
 		// If lineFlag is enabled, we should only print something if:
@@ -193,7 +178,7 @@ func main() {
 		//			the corresponding end index.
 		// 		3. If not, just print the character.
 		if substituteFlagEnabled {
-			for i := range test_runes {
+			for i := range test_str {
 				inMatchIndex := false
 				for _, m := range matchIndices {
 					if i == m[0].startIdx {
@@ -204,11 +189,11 @@ func main() {
 					}
 				}
 				if !inMatchIndex {
-					fmt.Fprintf(out, "%c", test_runes[i])
+					fmt.Fprintf(out, "%c", test_str[i])
 				}
 			}
 		} else {
-			for i, c := range test_runes {
+			for i, c := range test_str {
 				if indicesToPrint.contains(i) {
 					color.New(color.FgRed).Fprintf(out, "%c", c)
 					// Newline after every match - only if -o is enabled and -v is disabled.