Crate ruint_macro

The uint! macro for Uint literals

The above can also be written using the uint! macro. Within the macro arguments, you can write Uint literals using the same syntax as Rust integer literals, but using a capital U in the suffix instead of lowercase.

To use it simply import it in scope:

use ruint::uint;

Now constants can be created in decimal, hex, binary and even octal:

let avogadro = uint!(602_214_076_000_000_000_000_000_U256);
let cow_key = uint!(0xee79b5f6e221356af78cf4c36f4f7885a11b67dfcc81c34d80249947330c0f82_U256);
let bender = uint!(0b1010011010_U10);

The uint! macro recurses through the parse tree, so the above can equivalently be written

uint!{
let avogadro = 602_214_076_000_000_000_000_000_U256;
let cow_key = 0xee79b5f6e221356af78cf4c36f4f7885a11b67dfcc81c34d80249947330c0f82_U256;
let bender = 0b1010011010_U10;
}

This latter form is particularly useful for lookup tables:

const PRIMES: [Uint<128, 2>; 3] = uint!([
    170141183460469231731687303715884105757_U128,
    170141183460469231731687303715884105773_U128,
    170141183460469231731687303715884105793_U128,
]);

The macro will throw a compile time error if you try to create a constant that does not fit the type:

let sparta = 300_U8;

error: Value too large for Uint<8>: 300
 --> src/example.rs:1:14
  |
1 | let sparta = 300_U8;
  |              ^^^^^^

References

• Rust integer literals syntax.

Macros

uint

The uint! macro for Uint literals