padded-number - For numbers containing significant leading zeros

Used when "0" and "00" should be considered as distinct values. Encapsulated in a PaddedNumber type with, length bounds, ordering, arithmetic, and const context features included.

use padded_number::padded_number;

// macros creates a valid `PaddedNumber` at compile time
assert_eq!(padded_number!("001"), padded_number!("001"));
assert_ne!(padded_number!("0"), padded_number!("00"));

Length bounds

use std::str::FromStr;
use padded_number::{PaddedNumber, bound_padded_number};

let from_macro = bound_padded_number!(2, 3, "123");
let from_str = PaddedNumber::<2, 3>::from_str("123").unwrap();
assert_eq!(from_macro, from_str);

// try_new is const fn compared to `FromStr`
assert!(PaddedNumber::<2, 3>::try_new("0").is_err());
assert!(PaddedNumber::<2, 3>::try_new("0000").is_err());

Ordering

use padded_number::padded_number;

let a = padded_number!("0");
let b = padded_number!("00");
assert!(a < b);

let u = padded_number!("10");
let v = padded_number!("001");
assert!(u < v);

Addition and subtraction with u64 as right-hand-side

Zeros being their own step is required to make padded number arithmetic consistent.

use padded_number::padded_number;

assert_eq!(
  padded_number!("9") + 1,
  padded_number!("00")
);

assert_eq!(
  padded_number!("000") - 1,
  padded_number!("99")
);

Feature flags

All are disabled by default.

• macros - Enables the padded_number! and bound_padded_number! macros.
• serde - Enabled serde support for PaddedNumber. Serialization is done to and from a plain string.