private function getStyleStack($string)
    {
        if (preg_match_all(static::REGEX_FORMAT, $string, $matches)) {
            foreach ($matches[1] as $grouping) {
                if (preg_match_all(static::REGEX_STYLE_ITEM, $grouping, $styles)) {
                    foreach ($styles[0] as $style) {
                        yield $style;
                    }
                } else {
                    yield static::STYLE_RESET;
                }
            }
        }
        return;
    }