root = group-toplevel

group-toplevel = group .within { "groups" => any }
group-nested = group .within { "title" => tstr, any => any }

group = {
    ? "title" => tstr,
    ? "help" => tstr,
    ? "features" => [ + feature ],
    ? "groups" => [ + group-nested ],
    }

feature = {
    "name" => tstr,
    ? "help" => tstr,
}