var ResultTrait={
    Ok:func(val) {
        me.ok=val;
        me.flag=0;
        return me;
    },
    Err:func(info) {
        me.err=info;
        me.flag=1;
        return me;
    },
    unwrap:func() {
        if (me.flag)
            die(me.err);
        return me.ok;
    }
};

var Result = func() {
    return{
        ok:nil,
        err:"",
        flag:1,
        parents:[ResultTrait]
    };
};

var a = func() {
    return Result().Ok("hello world");
}

var b = func() {
    return Result().Err("exception test");
}

println(a().unwrap());
b().unwrap();