Crate ruint_macro

The uint! macro for Uint and Bits literals

Within the uint! macro arguments, you can write Uint and Bits literals using the same syntax as Rust integer literals, but using a capital U or B suffix respectively. Note that there is ambiguity for hexadecimals with a B suffix, to lessen the impact an underscore is required in this case.

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 and Bits literals