https://github.com/usagi/arithmetic-sign
Arithmetic `Sign`(≈+1|-1) to/from arithmetic types such as `f64`, `i32` utility.
https://github.com/usagi/arithmetic-sign
arithmetic math negative positive rust sign
Last synced: about 2 months ago
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Arithmetic `Sign`(≈+1|-1) to/from arithmetic types such as `f64`, `i32` utility.
- Host: GitHub
- URL: https://github.com/usagi/arithmetic-sign
- Owner: usagi
- License: mit
- Created: 2020-09-14T13:37:57.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2020-09-14T13:38:26.000Z (over 4 years ago)
- Last Synced: 2025-03-23T21:11:24.434Z (2 months ago)
- Topics: arithmetic, math, negative, positive, rust, sign
- Language: Rust
- Homepage:
- Size: 4.88 KB
- Stars: 2
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Arithmetic-sign
Arithmetic `Sign`(≈+1|-1) to/from arithmetic types such as `f64`, `i32` utility.
## Feature
- [x] `From` and `TryFrom`: An arithmetic type such as `f64`, `i32` =(`from`/`try_from`)> `Sign`
- [x] `From`: For an integral such as `i32`.; It has no infinite pattern.
- [x] `TryFrom`: For an float such as `f64`.; It has +inf, -inf and NaN infinite patterns.
- [x] A finite, +inf, -inf are valid => `Ok`, nan is invalid => `Err`.
- [x] `as_T`: `Sign` =(`as_T`)> an arithmetic type such as `f64`, `i32`
- [x] `as_uT`: Safety unsigned casting. eg. pos => Ok, neg => Err
- [x] `Display`: `Sign` =(`to_string`)> `"-"` or `"+"`
- [x] `Sign` =(`to_string_specified("S", "N")`)> `"S"` or `"N"`
- [x] `Mul` and `Div`: `Sign * Sign` or `Sign / Sign` -> `Sign`; eg. neg * neg => pos, pos / neg => neg
- [x] `Neg` and `Not`: `-Sign` or `!Sign` -> `Sign`; eg. -neg => pos, !pos => neg
- [x] `Eq`: `Sign` `==`|`!=` `Sign`; eg. neg == neg => true, pos != neg => true
- [x] `Ord`: `Sign` `<`|`<=`|`>=`|`>` `Sign`; eg. neg < pos => true, pos >= pos => true, neg > pos => false
## Usage
- See also: [tests/test.rs](tests/test.rs).
```rust
use arithmetic_sign::*;
```
```rust
let _sign = Sign::from( 123 ); // -> Sign::Positive
let _sign = Sign::from( 0 ); // -> Sign::Positive
let _sign = Sign::from( -0 ); // -> Sign::Positive
let _sign = Sign::from( -123 ); // -> Sign::Negative
let _sign_maybe = Sign::try_from( 1.23 ); // -> Ok( Sign::Positive )
let _sign_maybe = Sign::try_from( 0.0 ); // -> Ok( Sign::Positive )
let _sign_maybe = Sign::try_from( -0.0 ); // -> Ok( Sign::Positive )
let _sign_maybe = Sign::try_from( 1.23 ); // -> Ok( Sign::Negative )
let _sign_maybe = Sign::try_from( std::f64::inf() ); // -> Ok( Sign::Positive )
let _sign = Sign::from( -123 ) * Sign::from( 123 ); // -> Sign::Negative
let _sign = !Sign::from( -123 ); // -> Sign::Positive
let _f64 = Sign::Positive.as_f64(); // 1f64
let _i32 = Sign::Negative.as_i32(); // -1i32
let _u8 = Sign::Positive.as_u8().unwrap(); // 1u8
let _u8 = Sign::Negative.as_u8().is_err(); // true
```
## Motivation
- The std sign features such as `std::{f32|f64}::copysign` or `std::*::signum`s are regard to negative from `-0.0`.
- But, I author wanted to regard to "not a negative" as "positive" from `0.0` and `-0.0`.
- And, I author wanted to boolean-like type such as "positive" and "negative" that has only 2-variant.
- And, Infinity is a valid signed value, NaN is not a valid value.
## License
- [MIT](LICENSE.md)
## Author
- [USAGI.NETWORK / Usagi Ito](https://github.com/usagi)