pin-project

![crates-badge] ![docs-badge] ![license-badge] ![rustc-badge]

A crate for safe and ergonomic [pin-projection].

Usage

Add this to your Cargo.toml:

toml [dependencies] pin-project = "1"

The current pin-project requires Rust 1.37 or later.

Examples

[#[pin_project]][pin_project] attribute creates projection types covering all the fields of struct or enum.

```rust use pinproject::pinproject; use std::pin::Pin;

[pin_project]

struct Struct { #[pin] pinned: T, unpinned: U, }

impl Struct { 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

To use #[pin_project] on enums, you need to name the projection type returned from the method.

```rust use pinproject::pinproject; use std::pin::Pin;

[pin_project(project = EnumProj)]

enum Enum { Pinned(#[pin] T), Unpinned(U), }

impl Enum { fn method(self: Pin<&mut Self>) { match self.project() { EnumProj::Pinned(x) => { let _: Pin<&mut T> = x; } EnumProj::Unpinned(y) => { let _: &mut U = y; } } } } ```

code like this will be generated

See documentation for more details, and see [examples] directory for more examples and generated code.

Related Projects

• [pin-project-lite]: A lightweight version of pin-project written with declarative macros.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (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.