Appendix: Unsetting Old Data

/**
 * Unsets data under the current element using the DataFields array.
 *
 * @param  string    $Elem  the current element name
 */
function unsetFields($Elem) {
    foreach ($this->DataFields[$this->ParentElements[0]][$Elem] AS $Field => $Type) {
        unset($this->Data[$Field]);
    }
}