#constants #macro #proc-macro #rust

macro const-random-macro

Provides the procedural macro used by const-random

16 releases

0.1.16 Oct 23, 2023
0.1.15 Oct 25, 2022
0.1.13 Dec 5, 2020
0.1.12 Nov 21, 2020
0.1.3 Mar 3, 2019

#1771 in Procedural macros

Download history 598111/week @ 2024-11-15 506035/week @ 2024-11-22 493186/week @ 2024-11-29 637004/week @ 2024-12-06 657615/week @ 2024-12-13 305755/week @ 2024-12-20 326182/week @ 2024-12-27 640221/week @ 2025-01-03 761062/week @ 2025-01-10 661300/week @ 2025-01-17 729638/week @ 2025-01-24 763956/week @ 2025-01-31 865854/week @ 2025-02-07 800421/week @ 2025-02-14 930242/week @ 2025-02-21 926156/week @ 2025-02-28

3,667,476 downloads per month
Used in 2,229 crates (via const-random)

MIT/Apache

7KB
138 lines

Random constants

This crate provides compile time random number generation. This allows you to insert random constants into your code that will be auto-generated at compile time.

A new value will be generated every time the file is rebuilt. This obviously makes the resulting binary or lib non-deterministic. (See below)

Example

use const_random::const_random  ;
const MY_RANDOM_NUMBER: u32 = const_random!(u32);

This works exactly as through you have called: OsRng.gen::<u32>() at compile time. So for details of the random number generation, see the rand crates documentation.

The following types are supported: u8, i8, u16, i16, u32, i32, u64, i64, u128, i128, usize, isize and [u8; N].

Deterministic builds

Sometimes it is an advantage for build systems to be deterministic. To support this const-random reads the environmental variable CONST_RANDOM_SEED. If this variable is set, it will be used as the seed for the random number generation. Setting the same seed on a build of the same code should result in identical output.

Dependencies

~145–335KB