function unaccent_utf8($s) {
if(strpos($s = htmlentities($s, ENT_QUOTES, 'UTF-8'), '&') !== false)
$s = html_entity_decode(preg_replace('/&([a-z]{1,2})(?:acute|cedil|circ|grave|lig|orn|ring|slash|tilde|uml);/i', '$1', $s), ENT_QUOTES, 'UTF-8');
return $s;
}
$MarkupExpr['unaccent'] = 'unaccent_utf8($args[0])';