public function rule_regex($a)
{
$opt = array();
$rule = $this->pullRule();
if ($rule[0] != '/') {
$rule = '/^' . $rule . '*$/';
}
$opt['regexp'] = $rule;
if (!filter_var($a, FILTER_VALIDATE_REGEXP, ['options' => $opt])) {
return $this->fail('does not match the pattern');
}
}