pin-project

An attribute that would create a projection struct covering all the fields.

Documentation

Usage

Add this to your Cargo.toml:

toml [dependencies] pin-project = "0.2.0"

Now, you can use pin-project:

rust use pin_project::unsafe_project;

The current version of pin-project requires Rust 1.33 or later.

Examples

Structs and enums are supported.

Structs

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

[unsafe_project(Unpin)]

struct Foo { #[pin] future: T, field: U, }

impl Foo { fn baz(mut self: Pin<&mut Self>) { let this = self.project(); let _: Pin<&mut T> = this.future; // Pinned reference to the field let _: &mut U = this.field; // Normal reference to the field } }

// Automatically create the appropriate conditional Unpin implementation. // impl Unpin for Foo where T: Unpin {} // Conditional Unpin impl ```

Code like this will be generated

Enums

```rust use pinproject::{project, unsafeproject}; use std::pin::Pin;

[unsafe_project(Unpin)]

enum Foo { Future(#[pin] T), Done(U), }

impl Foo { #[project] // Nightly does not need a dummy attribute to the function. fn baz(mut self: Pin<&mut Self>) { #[project] match self.project() { Foo::Future(future) => { let _: Pin<&mut T> = future; } Foo::Done(value) => { let _: &mut U = value; } } } }

// Automatically create the appropriate conditional Unpin implementation. // impl Unpin for Foo where T: Unpin {} // Conditional Unpin impl ```

Code like this will be generated

See the documentation for more details.

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.