https://github.com/lu-zero/cow_struct

Derive per-field Cow Structures
https://github.com/lu-zero/cow_struct

Last synced: 3 months ago
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Derive per-field Cow Structures

• Host: GitHub
• URL: https://github.com/lu-zero/cow_struct
• Owner: lu-zero
• License: mit
• Created: 2021-01-25T17:37:58.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2021-01-25T20:21:10.000Z (over 4 years ago)
• Last Synced: 2025-01-17T13:17:04.915Z (5 months ago)
• Language: Rust
• Size: 2.93 KB
• Stars: 2
• Watchers: 3
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# derive CowStruct

This crate consists in a procedural macro derive that provides a struct that is Cow and the impl to create one from the target struct.

## Usage

``` rust

    use cow_struct::CowStruct;

    #[derive(Debug, Default, CowStruct)]

    struct A {

        a: LargeStruct,

        b: OtherLargeStruct,

        c: AnotherOne,

        ...

        z: YetAnother,

    }

    fn evaluation(cfg: &Config, state: &mut CowA) -> usize { ... }

    fn foo() {

        // original struct

        let a = A::new();

        let mut val = 0;

        // similar struct, with all the fields set as Cow::Borrowed from a;

        let mut cow = a.to_cow();

        let mut cow_out = cow.to_cow();

        let mut v_max = usize::min();

        for cfg in inputs() {

            // it is going to change cow, a remains untouched

            let val = evaluation(cfg, &mut cow);

            // let's pick the best candidate

            for candidate in candidates_b(val) {

                let mut cow2 = cow.to_cow();

                let v = evaluation_b(candidate, &mut cow2);

                if v > v_max {

                    v_max = v;

                    cow_out = cow2;

                }

            }

        }

    }

```