static function get_exsetIds() { if (EIConfig::$exsetIds == null) { EIConfig::load_examplesXML(); $ids = EIConfig::$examplesXML->xpath("/examples/exset/@id"); $exsetIds = array(); $i = 0; foreach ($ids as $id) { $exsetIds[$i] = (string) $id; $i++; } EIConfig::$exsetIds = $exsetIds; } return EIConfig::$exsetIds; }