aoc2024/day03/main.go

@@ -22,33 +22,66 @@ type result struct {
 func (r result) String() string { return fmt.Sprintf("%#v", r) }
 
 func run(read io.Reader) (*result, error) {
-
 	sum := 0
+	sum2 := 0
 
 	lexer := Lexer(read)
-	for typ, token := range lexer.Iter() {
+	active := true
 
-		if m := readMul(lexer); m != 0 {
-			fmt.Println(typ, string(token))
-			sum += m
+	for typ, _ := range lexer.Iter() {
+		// fmt.Println(typ, string(token))
+		switch {
+		case typ == "TokMUL":
+			if m := readMul(lexer); m != 0 {
+				sum += m
+				if active {
+					sum2 += m
+				}
+			}
+		case typ == "TokDONT":
+			if readDont(lexer) {
+				println("don't()", active)
+				active = false
+			}
+
+		case typ == "TokDO":
+			if readDo(lexer) {
+				println("do()", active)
+				active = true
+			}
 		}
 	}
 
-
-	return &result{sum, -1}, nil
+	return &result{sum, sum2}, nil
 }
 
 func Lexer(in io.Reader) *lexer {
 	seq := func(yield func(rune) bool) {
+		defer func() {
+			if err := recover(); err != nil {
+				fmt.Println("ERR", err)
+				return
+			}
+			fmt.Println("NO DEFER AND NO PANIC??")
+		}()
+
 		buf := make([]byte, 256)
 		s, _ := in.Read(buf)
 		buf = buf[:s]
 
 		for len(buf) > 0 {
-			for _, r := range string(buf) {
+			for i, r := range string(buf) {
+				println(i, r)
+				if i >= 72 {
+					fmt.Println("START")
+				}
 				if !yield(r) {
 					return
 				}
+				if i >= 72 {
+					fmt.Println("STOP")
+				}
+
 			}
 			s, _ := in.Read(buf)
 			buf = buf[:s]
@@ -71,8 +104,8 @@ type lexer struct {
 	iter func() (rune, bool)
 	stop func()
 
-	buf   []rune
-	token string
+	buf     []rune
+	token   string
 	literal []rune
 }
 
@@ -118,7 +151,24 @@ func (l *lexer) NextTok() bool {
 	case 'm':
 		l.loadString("mul")
 		l.token = "TokMUL"
+		if string(l.literal) != "mul" {
+			l.token = "TokILLEGAL"
+			return false
+		}
 		return true
+	case 'd':
+		l.loadString("don't")
+		switch string(l.literal) {
+		case "don't":
+			l.token = "TokDONT"
+		case "do":
+			l.token = "TokDO"
+		default:
+			l.token = "TokILLEGAL"
+			return false
+		}
+		return true
+
 	case '(':
 		l.loadRune("TokLPAREN")
 		return true
@@ -162,7 +212,7 @@ func readMul(lex *lexer) int {
 	if !lex.NextTok() || lex.token != "TokLPAREN" {
 		return 0
 	}
-	
+
 	if !lex.NextTok() || lex.token != "TokNUMBER" {
 		return 0
 	}
@@ -183,3 +233,29 @@ func readMul(lex *lexer) int {
 	fmt.Println(a, "*", b)
 	return a * b
 }
+
+func readDont(lex *lexer) bool {
+	if lex.token != "TokDONT" || string(lex.literal) != "don't" {
+		return false
+	}
+	if !lex.NextTok() || lex.token != "TokLPAREN" {
+		return false
+	}
+	if !lex.NextTok() || lex.token != "TokRPAREN" {
+		return false
+	}
+	return true
+}
+
+func readDo(lex *lexer) bool {
+	if lex.token != "TokDO" || string(lex.literal) != "do" {
+		return false
+	}
+	if !lex.NextTok() || lex.token != "TokLPAREN" {
+		return false
+	}
+	if !lex.NextTok() || lex.token != "TokRPAREN" {
+		return false
+	}
+	return true
+}