virtual a {
    option "aaa aa cc";
    param { # comment 1
            a b;
            c d;
            x y z; # comment 2
    }
    param e f g h; # comment 3
    param e f g hlskdjflskdfjsd #comment 4
        flksdjf sldkfjsldkfjsdlf lsdkfjsldkfjlsdkjflskdjflsdkjfl lkjsdlfjsdlfkjsdlfj;
}