PHP Quickbase do_query

/* API_DoQuery: http://www.quickbase.com/api-guide/index.html#do_query.html */
    public function do_query($queries = 0, $qid = 0, $qname = 0, $clist = 0, $slist = 0, $fmt = 'structured', $options = "")
    {
        if ($this->xml) {
            //A query in queries has the following items in this order:
            //field id, evaluator, criteria, and/or
            //The first element will not have an and/or
            $xml_packet = '<qdbapi>';
            $pos        = 0;
            if ($queries) {
                $xml_packet .= '<query>';
                foreach ($queries as $query) {
                    $criteria = "";
                    if (isset($query['cx'])) {
                        $xml_packet .= $query['cx']; //append any parentheses and boolean connectors
                    } else {
                        if ($pos > 0) {
                            if(isset($query['ao'])) {
                                $criteria .= $query['ao'];
                            }
                        }
                        $criteria .= "{'" . $query['fid'] . "'." . $query['ev'] . ".'" . $query['cri'] . "'}";
                        $xml_packet .= $criteria;
                    }
                    $pos++;
                }
                $xml_packet .= '</query>';
            } else if ($qid) {
                $xml_packet .= '<qid>' . $qid . '</qid>';
            } else if ($qname) {
                $xml_packet .= '<qname>' . $qname . '</qname>';
            } else {
                return false;
            }
            $xml_packet .= '<fmt>' . $fmt . '</fmt>';
            if ($clist) {
                $xml_packet .= '<clist>' . $clist . '</clist>';
            }

            if ($slist) {
                $xml_packet .= '<slist>' . $slist . '</slist>';
                $xml_packet .= '<options>' . $options . '</options>';
            }
            if ($this->app_token) {
                $xml_packet .= '<apptoken>' . $this->app_token . '</apptoken>';
            }

            $xml_packet .= '<ticket>' . $this->ticket . '</ticket></qdbapi>';
            $response = $this->transmit($xml_packet, 'API_DoQuery');
        } else {
            // If not an xml packet
            $url_string = $this->qb_ssl . $this->db_id . "?act=API_DoQuery&ticket=" . $this->ticket . "&fmt=" . $fmt;
            $pos        = 0;
            if ($queries) {
                $url_string .= "&query=";
                foreach ($queries as $query) {
                    $criteria = "";
                    if ($pos > 0) {
                        $criteria .= $query['ao'];
                    }
                    $criteria .= "{'" . $query['fid'] . "'." . $query['ev'] . ".'" . $query['cri'] . "'}";
                    $url_string .= $criteria;
                    $pos++;
                }
            } else if ($qid) {
                $url_string .= "&qid=" . $qid;
            } else if ($qname) {
                $url_string .= "&qname=" . $qname;
            } else {
                return false;
            }
            if ($clist) {
                $url_string .= "&clist=" . $clist;
            }

            if ($slist) {
                $url_string .= "&slist=" . $slist;
            }

            if ($options) {
                $url_string .= "&options=" . $options;
            }

            $response = $this->transmit($url_string);
        }
        if ($response) {
            return $response;
        }
        return false;
    }