t.rs

use std::fmt::Display;
use std::fmt::Formatter;

struct A(u64);

impl Display for A {
    fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
        write!(fmt, "{}", self.0)
    }
}
impl PartialEq for A {
    fn eq(&self, x: &Self) -> bool {
        self.0 == x.0
    }
}
impl Eq for A {}
impl PartialOrd for A {
    fn partial_cmp(&self, x: &Self) -> Option<std::cmp::Ordering> {
        self.0.partial_cmp(&x.0)
    }
}
impl Ord for A {
    fn cmp(&self, x: &Self) -> std::cmp::Ordering {
        self.0.cmp(&x.0)
    }
}

fn main() {
    let a = A(1);

    match a {
        A(0) => {
            println!("0");
        }
        A(1) => {
            println!("1");
        }
        x @ _ => {
            println!("{}", x);
        }
    }
}