diff --git a/pj1-go/lexer.go b/pj1-go/lexer.go
index 1f5c38e..d81f74d 100644
--- a/pj1-go/lexer.go
+++ b/pj1-go/lexer.go
@@ -23,9 +23,10 @@ const (
 	MINUS
 	PLUS
 	SEMICOLON
-	STAR
 
 	// One or two character tokens.
+	STAR
+	STAR_STAR
 	BANG
 	BANG_EQUAL
 	EQUAL
@@ -156,6 +157,11 @@ func (l *Lexer) scanToken() {
 	case ';':
 		l.addSimpleToken(SEMICOLON)
 	case '*':
+		if l.match('*') {
+			l.addSimpleToken(STAR_STAR)
+		} else {
+			l.addSimpleToken(STAR)
+		}
 		l.addSimpleToken(STAR)
 	case '!':
 		if l.match('=') {