private function ignoreObjectBlock(Lexer $lexer) : int
    {
        do {
            $code = $lexer->lex();

            // recursively ignore nested objects
            if (self::JSON_OBJECT_START === $code) {
                $this->ignoreObjectBlock($lexer);
            }
        } while (self::JSON_OBJECT_END !== $code);

        return $lexer->lex();
    }