function validateTokenid($sValue, \Formal\Form\Morphology $oMorpho, \Formal\Element $oElement)
{
if (!preg_match("/^[a-z0-9\\-_]+\$/", $sValue)) {
return "<strong>" . $oElement->option("label") . "</strong> is not valid. Allowed characters are digits, lowercase letters, the dash and underscore symbol.";
}
return true;
}