# pin-project
[![crates-badge]][crates-url]
[![docs-badge]][docs-url]
[![license-badge]][license]
[![rustc-badge]][rustc-url]
[crates-badge]: https://img.shields.io/crates/v/pin-project.svg
[crates-url]: https://crates.io/crates/pin-project
[docs-badge]: https://docs.rs/pin-project/badge.svg
[docs-url]: https://docs.rs/pin-project
[license-badge]: https://img.shields.io/badge/license-Apache--2.0%20OR%20MIT-blue.svg
[license]: #license
[rustc-badge]: https://img.shields.io/badge/rustc-1.34+-lightgray.svg
[rustc-url]: https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html
A crate for safe and ergonomic [pin-projection].
## Usage
Add this to your `Cargo.toml`:
```toml
[dependencies]
pin-project = "1.0.0-alpha.1"
```
The current pin-project requires Rust 1.34 or later.
## Examples
[`#[pin_project]`][`pin_project`] attribute creates projection types
covering all the fields of struct or enum.
```rust
use pin_project::pin_project;
use std::pin::Pin;
#[pin_project]
struct Struct<T, U> {
#[pin]
pinned: T,
unpinned: U,
}
impl<T, U> Struct<T, U> {
fn method(self: Pin<&mut Self>) {
let this = self.project();
let _: Pin<&mut T> = this.pinned; // Pinned reference to the field
let _: &mut U = this.unpinned; // Normal reference to the field
}
}
```
[*code like this will be generated*][struct-default-expanded]
See [documentation][docs-url] for more details, and
see [examples] directory for more examples and generated code.
[`pin_project`]: https://docs.rs/pin-project/1.0.0-alpha.1/pin_project/attr.pin_project.html
[examples]: examples/README.md
[pin-projection]: https://doc.rust-lang.org/nightly/std/pin/index.html#projections-and-structural-pinning
[struct-default-expanded]: examples/struct-default-expanded.rs
## Related Projects
* [pin-project-lite]: A lightweight version of pin-project written with declarative macros.
[pin-project-lite]: https://github.com/taiki-e/pin-project-lite
## 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, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.