A lightweight version of pin-project written with declarative macros.
Add this to your Cargo.toml:
[dependencies] pin-project-lite = "0.1"
The current pin-project-lite requires Rust 1.37 or later.
use pin_project_lite::pin_project; use std::pin::Pin; pin_project! { struct Struct<T, U> { #[pin] pinned: T, unpinned: U, } } impl<T, U> Struct<T, U> { fn foo(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 } }
Here are some similarities and differences compared to pin-project.
pin-project-lite guarantees safety in much the same way as pin-project. Both are completely safe unless you write other unsafe code.
This library does not tackle as expansive of a range of use cases as pin-project does. If your use case is not already covered, please use pin-project.
This is the only reason to use this crate. However, if you already have proc-macro related dependencies in your crate's dependency graph, there is no benefit from using this crate. (Note: There is almost no difference in the amount of code generated between pin-project and pin-project-lite.)
This macro does not handle any invalid input. So error messages are not to be useful in most cases. If you do need useful error messages, then upon error you can pass the same input to pin-project to receive a helpful description of the compile error.
pin-project-lite will refuse anything other than a braced struct with named fields. Enums and tuple structs are not supported.
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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.