Hal\Resource::_addData PHP Method

    protected function _addData(SimpleXMLElement $xml, array $data, $keyOverride = null)
    {
        foreach ($data as $key => $value) {
            // alpha-numeric key => array value
            if (!is_numeric($key) && is_array($value)) {
                $c = $xml->addChild($key);
                $this->_addData($c, $value, $key);
            } elseif (!is_numeric($key) && !is_array($value)) {
                $xml->addChild($key, $value);
                // numeric key => array value
            } elseif (is_array($value)) {
                $this->_addData($xml, $value);
                // numeric key => non-array value
            } else {
                $xml->addChild($keyOverride, $value);
            }
        }
    }