fix(aoc2024): clean up day 3

aoc2024/day03/main.go

@@ -25,7 +25,9 @@ func run(read io.Reader) (*result, error) {
 	sum := 0
 	sum2 := 0
 
-	lexer := Lexer(read)
+	lexer, stop := Lexer(read)
+	defer stop()
+
 	active := true
 
 	for lexer.NextTok() {
@@ -52,7 +54,7 @@ func run(read io.Reader) (*result, error) {
 	return &result{sum, sum2}, nil
 }
 
-func Lexer(in io.Reader) *lexer {
+func Lexer(in io.Reader) (*lexer, func()) {
 	seq := func(yield func(rune) bool) {
 		buf := make([]byte, 256)
 		s, _ := in.Read(buf)
@@ -72,10 +74,10 @@ func Lexer(in io.Reader) *lexer {
 		}
 	}
 	next, stop := iter.Pull(seq)
-	lex := lexer{iter: next, stop: stop}
+	lex := lexer{iter: next}
 	lex.readRune()
 	lex.readRune()
-	return &lex
+	return &lex, stop
 }
 
 type lexer struct {
@@ -83,15 +85,12 @@ type lexer struct {
 	next rune
 
 	iter func() (rune, bool)
-	stop func()
 
 	buf     []rune
 	token   string
 	literal []rune
 }
 
-func (l *lexer) Stop() { l.stop() }
-
 func (l *lexer) readRune() {
 	if l.rune == -1 {
 		return
@@ -172,16 +171,6 @@ func (l *lexer) NextTok() bool {
 	return true
 }
 
-func (l *lexer) Iter() iter.Seq2[string, string] {
-	return func(yield func(string, string) bool) {
-		for l.NextTok() {
-			if !yield(l.token, string(l.literal)) {
-				return
-			}
-		}
-	}
-}
-
 func readMul(lex *lexer) int {
 	if lex.token != "TokMUL" || string(lex.literal) != "mul" {
 		return 0