partial_ref - Type checked partial references.

crates.io docs.rs

This crate provides type checked partial references for rust. Type checked partial references are one solution to solve interprocedural borrowing conflicts.

Soundness Issues

Since I initially wrote this library, Rust's unsafe code guarantees and requirements have been mode more clear. I now believe that the current approach used to implement this library is technically undefined behavior, although the same technique is also used in other crates and so far does not cause issues in practice. Right now there is no suitable alternative to implement this in stable Rust, but when raw_const and raw_mut land I plan to update this library, solving this issue.

Deprecation

I wrote this library for its use in [Varisat]. After making extensive use of this, I am not convinced that overall this is a good approach to solve interprocedural borrowing conflict issues. In particular I think the implementation is way too complex for the functionality it provides. I plan to eventually remove the use of this library from Varisat and will only maintain this library up to that point. Thus I do not recommend anyone building upon this.

Example

```rust use partial_ref::*;

part!(pub Neighbors: Vec>); part!(pub Colors: Vec); part!(pub Weights: Vec);

[derive(PartialRefTarget, Default)]

pub struct Graph { #[part(Neighbors)] pub neighbors: Vec>, #[part(Colors)] pub colors: Vec, #[part(Weights)] pub weights: Vec, }

let mut g = Graph::default(); let mut gref = g.intopartialrefmut();

gref.partmut(Colors).extend(&[0, 1, 0]); gref.partmut(Weights).extend(&[0.25, 0.5, 0.75]);

gref.partmut(Neighbors).push(vec![1, 2]); gref.partmut(Neighbors).push(vec![0, 2]); gref.partmut(Neighbors).push(vec![0, 1]);

pub fn addcolortoweight( mut g: partial!(Graph, mut Weights, Colors), index: usize, ) { g.partmut(Weights)[index] += g.part(Colors)[index] as f32; }

let (neighbors, mut gref) = gref.splitpartmut(Neighbors); let (colors, mut gref) = gref.split_part(Colors);

for (edges, &color) in neighbors.iter_mut().zip(colors.iter()) { edges.retain(|&neighbor| colors[neighbor] != color);

for &neighbor in edges.iter() {
    add_color_to_weight(g_ref.borrow(), neighbor);
}

} ```

Documentation

License

The partial_ref source code is licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in partial_ref by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.