https://github.com/worldsender/type-equalities-rs

https://github.com/worldsender/type-equalities-rs

Last synced: 3 months ago
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• Host: GitHub
• URL: https://github.com/worldsender/type-equalities-rs
• Owner: WorldSEnder
• License: apache-2.0
• Created: 2021-05-06T03:08:38.000Z (over 3 years ago)
• Default Branch: master
• Last Pushed: 2022-01-04T17:15:36.000Z (about 3 years ago)
• Last Synced: 2024-10-07T08:08:32.765Z (4 months ago)
• Language: Rust
• Size: 29.3 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-APACHE

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README

        
# type-equalities

[![Documentation](https://docs.rs/type-equalities/badge.svg)](https://docs.rs/type-equalities/)

[![Further crate info](https://img.shields.io/crates/v/type-equalities.svg)](https://crates.io/crates/type-equalities)

The central type, `TypeEq<_, _>`, allows for zero-overhead, safe value coercions and is itself zero-sized.

Further, naming `TypeEq` is well-formed for any types, but an inhabitant is available only if the

equality holds. For trait-level type equality, `T: IsEqual` can be used.

The zero overhead claim can be seen in the provided benchmarks:

```rust

let eq = refl::().lift_through::>();

b.iter(|| [0; BENCH_LEN]);            // bench_no_coerce

b.iter(|| eq.coerce([0; BENCH_LEN])); // bench_coerce_array_refl

> running 2 tests

test benches::bench_no_coerce         ... bench:      10,570 ns/iter (+/- 569)

test benches::bench_coerce_array_refl ... bench:      10,557 ns/iter (+/- 605)

```

This crate is **no-std** and has a (default: enabled) feature for **alloc** features, i.e. coercing `Box`.

## License

Licensed under either of

 * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)

 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted

for inclusion in the work by you shall be dual licensed as above, without any

additional terms or conditions.