protected static function convertVarPath($arg, $regexp = '/^%s|,%s/')
{
$pattern = '\\s*(\\${0,2}' . static::VARNAME . ')((\\.' . static::VARNAME . ')*)';
return preg_replace_callback(str_replace('%s', $pattern, $regexp), array(get_class(), 'convertVarPathCallback'), $arg);
}