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3 months ago
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What is nutype?
Nutype is a proc macro that adds sanitization_ and validation to newtypes, ensuring values always pass checks.
Changes in v0.6.2
- [FEATURE] Introduce derive_unsafe(..) attribute to derive any arbitrary trait (requires derive_unsafe feature to be enabled).
- [FIX] Updated the Rust edition: 2021 → 2024.
- [FIX] Improved error messages for len_char_max and len_char_min validators. They are now clearer and easier to understand.
derive_unsafe
You can now use the new derive_unsafe(..) attribute to derive arbitrary traits, including third-party ones, which are not known to nutype.
Unlike derive(..), this mechanism bypasses nutype’s internal safety checks, meaning it's possible to violate validation rules at runtime if you're deriving a trait that has methods that instantiate or mutate a value.
It requires derive_unsafe feature flag to be enabled.
Example (do not copy blindly):
use derive_more::{Deref, DerefMut};
use nutype::nutype;
#[nutype(
derive(Debug, AsRef),
derive_unsafe(Deref, DerefMut),
validate(greater_or_equal = 0.0, less_or_equal = 2.0)
)]
struct LlmTemperature(f64);
fn main() {
let mut temperature = LlmTemperature::try_new(1.5).unwrap();
// This is not what nutype is designed for!
*temperature = 2.5;
// OH no, we've just violated the validation rule!
assert_eq!(temperature.as_ref(), &2.5);
}
The takeaway: derive_unsafe gives you raw power—but you’re on your own to ensure your type’s invariants aren't broken.
On that note, have a nice day!.
