macro_rules! update {
        (&$data:ident, $( $key:ident = $x:expr ),*) => (
            {
                fn clone<T>(data: &T) -> T
                    where T: Clone {
                        data.clone()
                    }
                let cp =  clone(&$data);
                update!(cp,  $( $key = $x ),*)
            }
        );
        ($data:ident, $( $key:ident = $x:expr ),*) => (
            {
                let mut data_m =  $data;
                $(
                    data_m.$key=$x;
                )*
                data_m
            }
        );
        ($data_e:expr, $( $key:ident = $x:expr ),*) => (
            {
                let data = $data_e;
                update!(data, $( $key = $x ),*)
            }
        );
}


#[derive(Debug, Clone, Default)]
struct Point {
    x: i64,
    y: i64,
    s: String,
}

fn main() {
    let u = update!(Point::default(), x = 10);
    println!("{:?}", u);
}