Macro i128 

macro_rules! i128 {
    ($($body:tt)*) => { ... };
}

A macro to construct 128-bit I128 signed integer from literals.

Examples:

use fastnum::{i128, I128};

const N: I128 = i128!(100);
let x = i128!(1);
assert!(i128!(0).is_zero());
println!("{x}");