simple_html_dom_node::parse_selector PHP Method

    protected function parse_selector($selector_string)
    {
        global $debugObject;
        if (is_object($debugObject)) {
            $debugObject->debugLogEntry(1);
        }
        // pattern of CSS selectors, modified from mootools
        // Paperg: Add the colon to the attrbute, so that it properly finds <tag attr:ibute="something" > like google does.
        // Note: if you try to look at this attribute, yo MUST use getAttribute since $dom->x:y will fail the php syntax check.
        // Notice the \[ starting the attbute?  and the @? following?  This implies that an attribute can begin with an @ sign that is not captured.
        // This implies that an html attribute specifier may start with an @ sign that is NOT captured by the expression.
        // farther study is required to determine of this should be documented or removed.
        //        $pattern = "/([\w-:\*]*)(?:\#([\w-]+)|\.([\w-]+))?(?:\[@?(!?[\w-]+)(?:([!*^$]?=)[\"']?(.*?)[\"']?)?\])?([\/, ]+)/is";
        $pattern = "/([\\w-:\\*]*)(?:\\#([\\w-]+)|\\.([\\w-]+))?(?:\\[@?(!?[\\w-:]+)(?:([!*^\$]?=)[\"']?(.*?)[\"']?)?\\])?([\\/, ]+)/is";
        preg_match_all($pattern, trim($selector_string) . ' ', $matches, PREG_SET_ORDER);
        if (is_object($debugObject)) {
            $debugObject->debugLog(2, "Matches Array: ", $matches);
        }
        $selectors = array();
        $result = array();
        //print_r($matches);
        foreach ($matches as $m) {
            $m[0] = trim($m[0]);
            if ($m[0] === '' || $m[0] === '/' || $m[0] === '//') {
                continue;
            }
            // for browser generated xpath
            if ($m[1] === 'tbody') {
                continue;
            }
            list($tag, $key, $val, $exp, $no_key) = array($m[1], null, null, '=', false);
            if (!empty($m[2])) {
                $key = 'id';
                $val = $m[2];
            }
            if (!empty($m[3])) {
                $key = 'class';
                $val = $m[3];
            }
            if (!empty($m[4])) {
                $key = $m[4];
            }
            if (!empty($m[5])) {
                $exp = $m[5];
            }
            if (!empty($m[6])) {
                $val = $m[6];
            }
            // convert to lowercase
            if ($this->dom->lowercase) {
                $tag = strtolower($tag);
                $key = strtolower($key);
            }
            //elements that do NOT have the specified attribute
            if (isset($key[0]) && $key[0] === '!') {
                $key = substr($key, 1);
                $no_key = true;
            }
            $result[] = array($tag, $key, $val, $exp, $no_key);
            if (trim($m[7]) === ',') {
                $selectors[] = $result;
                $result = array();
            }
        }
        if (count($result) > 0) {
            $selectors[] = $result;
        }
        return $selectors;
    }