1 stable release
1.0.0 | Apr 24, 2024 |
---|
#351 in Configuration
105 downloads per month
Used in spawn64
17KB
101 lines
const_array_init
Rust crate
Macros used to initialize an array in const context using closure
syntax or const fn
.
All macros in this crate implemented using macro_rules!
which is very IDE-friendly way.
Examples
Using const_arr!
macro:
use const_array_init::const_arr;
const ARR1: [i32; 5] = const_arr!([i32; 5], |i| i as i32 + 1);
assert_eq!(ARR1, [1, 2, 3, 4, 5]);
const fn to_i32_plus_one(n: usize) -> i32 {
n as i32 + 1
}
const ARR2: [i32; 5] = const_arr!([i32; 5], to_i32_plus_one);
assert_eq!(ARR2, [1, 2, 3, 4, 5]);
Using make_const_arr!
macro:
use const_array_init::make_const_arr;
make_const_arr!(ARR1, [i32; 5], |i| i as i32 + 1);
assert_eq!(ARR1, [1, 2, 3, 4, 5]);
const fn to_i32_plus_one(n: usize) -> i32 {
n as i32 + 1
}
make_const_arr!(ARR2, [i32; 5], to_i32_plus_one);
assert_eq!(ARR2, [1, 2, 3, 4, 5]);
Advanced usage:
- Note that
User
isn'tCopy
, yet still you can use it inconst
context with this macro.
use const_array_init::const_arr;
#[derive(Debug, PartialEq, Eq)]
struct User { id: u32 }
const fn create_user_from_i(i: usize) -> User {
User { id: i as u32 }
}
const USERS: [User; 1024] = const_arr!([User; 1024], create_user_from_i);
const USERS2: [User; 1024] = const_arr!([User; 1024], |i| User { id: i as u32 });