protected function writeConstantElements($constants, $format = '%s %s\l', $indent = -1)
    {
        $constantString = '';

        foreach ($constants as $name => $value) {
            $line = sprintf($format, '+', $name);
            if ($indent >= 0) {
                $constantString .= $this->formatLine($line, $indent);
            } else {
                $constantString .= $line;
            }
        }
        return $constantString;
    }