public function option_ext($k, $v) { $bool = self::boolval($v); if ($bool === false) { // `--ext=false` means no extension will be used $v = ""; Config::setExt($v); } elseif ($bool === null) { // `--ext=true` means use the default extension, // `--ext=".foo"` means use ".foo" as the extension Config::setExt($v); } }