checked_expr!() { /* proc-macro */ }Expand description
Procedural macro to convert normal integer operations into overflow-checked operations.
The expression will evaluate to Some(result) if all operations succed or to None if any of
the operations fails.
This Macro supports checked functions for these operators:
- (neg),+ (add), - (sub), * (mul), / (div), % (rem), << (shl), >> (shr)
And it also substitutes these methods with their checked variants:
abs, pow
ยงExamples
use checked_expr::checked_expr;
assert_eq!(checked_expr!(254_u8 + 1), Some(255));
assert_eq!(checked_expr!(255_u8 + 1), None);
assert_eq!(checked_expr!(-(-127_i8)), Some(127));
assert_eq!(checked_expr!(-(-128_i8)), None);
// also works with `pow` and `abs`
assert_eq!(checked_expr!((-128_i8).abs()), None);
assert_eq!(checked_expr!(10_u16.pow(100)), None);
// you can also arbitrarily nest expressions although you sometimes need to be very
// explicit with the types on literals on the left hand side of operations
assert_eq!(checked_expr!((10_i32 - 8) * (3_i32 + 6) % 8), Some(2));