fix scanner

main.go

@@ -20,8 +20,7 @@ func main() {
 
 func repl() {
 	scanner := bufio.NewScanner(os.Stdin)
-	for scanner.Scan() {
-		fmt.Print("> ")
+	for fmt.Print("> "); scanner.Scan(); fmt.Print("> ") {
 		line := scanner.Text()
 		if len(line) == 0 {
 			return