Macro date_greg 

macro_rules! date_greg {
    ($year:literal - $month:literal - $day:literal) => { ... };
}

Creates a Gregorian Calendar date with a statically known and compile time checked value.

Example

use sac13::prelude::*;

let date = date_greg!(2020 - 04 - 17);
let date = date_greg!(2020 - 02 - 29);  // leap year

// the following line would not compile (because 2021 wasn't a leap year)
// let date = date_greg!(2021 - 02 - 29);