DiDom\Query::getSegments PHP Метод

    public static function getSegments($selector)
    {
        $selector = trim($selector);
        if ($selector === '') {
            throw new InvalidArgumentException('The selector must not be empty');
        }
        $tag = '(?P<tag>[\\*|\\w|\\-]+)?';
        $id = '(?:#(?P<id>[\\w|\\-]+))?';
        $classes = '(?P<classes>\\.[\\w|\\-|\\.]+)*';
        $attrs = '(?P<attrs>(?:\\[.+?\\])*)?';
        $name = '(?P<pseudo>[\\w\\-]+)';
        $expr = '(?:\\((?P<expr>[^\\)]+)\\))';
        $pseudo = '(?::' . $name . $expr . '?)?';
        $rel = '\\s*(?P<rel>>)?';
        $regexp = '/' . $tag . $id . $classes . $attrs . $pseudo . $rel . '/is';
        if (preg_match($regexp, $selector, $segments)) {
            if ($segments[0] === '') {
                throw new RuntimeException('Invalid selector');
            }
            $result['selector'] = $segments[0];
            if (isset($segments['tag']) and $segments['tag'] !== '') {
                $result['tag'] = $segments['tag'];
            }
            // if the id attribute specified
            if (isset($segments['id']) and $segments['id'] !== '') {
                $result['id'] = $segments['id'];
            }
            // if the attributes specified
            if (isset($segments['attrs'])) {
                $attributes = trim($segments['attrs'], '[]');
                $attributes = explode('][', $attributes);
                foreach ($attributes as $attribute) {
                    if ($attribute !== '') {
                        list($name, $value) = array_pad(explode('=', $attribute, 2), 2, null);
                        if ($name === '') {
                            throw new RuntimeException('Invalid selector: attribute name must not be empty');
                        }
                        // equal null if specified only the attribute name
                        $result['attributes'][$name] = is_string($value) ? trim($value, '\'"') : null;
                    }
                }
            }
            // if the class attribute specified
            if (isset($segments['classes'])) {
                $classes = trim($segments['classes'], '.');
                $classes = explode('.', $classes);
                foreach ($classes as $class) {
                    if ($class !== '') {
                        $result['classes'][] = $class;
                    }
                }
            }
            // if the pseudo class specified
            if (isset($segments['pseudo']) and $segments['pseudo'] !== '') {
                $result['pseudo'] = $segments['pseudo'];
                if (isset($segments['expr']) and $segments['expr'] !== '') {
                    $result['expr'] = $segments['expr'];
                }
            }
            // if it is a direct descendant
            if (isset($segments['rel'])) {
                $result['rel'] = $segments['rel'];
            }
            return $result;
        }
        throw new RuntimeException('Invalid selector');
    }

 /**
  * Create new element node by CSS selector.
  *
  * @param string $selector
  * @param string $value
  * @param array $attributes
  *
  * @return \DiDom\Element
  */
 public function createElementBySelector($selector, $value = null, $attributes = [])
 {
     $segments = Query::getSegments($selector);
     $name = array_key_exists('tag', $segments) ? $segments['tag'] : 'div';
     if (array_key_exists('attributes', $segments)) {
         $attributes = array_merge($attributes, $segments['attributes']);
     }
     if (array_key_exists('id', $segments)) {
         $attributes['id'] = $segments['id'];
     }
     if (array_key_exists('classes', $segments)) {
         $attributes['class'] = implode(' ', $segments['classes']);
     }
     return $this->createElement($name, $value, $attributes);
 }