1 stable release
Uses old Rust 2015
1.0.0 | Jun 30, 2022 |
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#1818 in Procedural macros
7KB
89 lines
wrapping_macros
A macro for scoped wrapping arithmetic.
Any code within a wrapping! { .. }
block will be transformed as follows:
a + b
becomesa.wrapping_add(b)
. Similarly for-
,*
,/
,%
,<<
,>>
.a += b
becomesa = a.wrapping_add(b)
. Similarly for-=
,*=
,/=
,%=
,<<=
,>>=
.-a
becomesa.wrapping_neg()
.
Cargo
Add this to your Cargo.toml
:
wrapping_macros = "*"
Examples
let a = 128u8;
let b = wrapping! { a * 2 };
assert_eq!(b, 0);
let mut a = 250u8;
let mut b = 4u8;
let mut c = 100u8;
wrapping! {
a += 10;
b -= 10;
c *= 10;
}
assert_eq!(a, 4);
assert_eq!(b, 250);
assert_eq!(c, 232);
use wrapping_macros::wrapping;
fn main() {
let mut sum = 0u8;
wrapping! {
for x in 0u8..50 {
sum += x;
}
}
}
assert_eq!(sum, 201);
Caveat
You cannot nest another macro invocation within a wrapping!
block. For example, this will not work:
let x = 128u8;
wrapping! {
println!("The answer is {}", x + 128) // Error
}
Instead, move the macro call out of the wrapping!
block:
let x = 128u8;
println!("The answer is {}", wrapping! { x + 128 })
Inspired by wrapping_macros
crate by lfairy
Dependencies
~1.5MB
~34K SLoC