Macro u64 

macro_rules! u64 {
    ($($body:tt)*) => { ... };
}

A macro to construct 64-bit U64 unsigned integer from literals.

Examples:

use fastnum::{u64, U64};

const N: U64 = u64!(100);
let x = u64!(1);
assert!(u64!(0).is_zero());
println!("{x}");