borrow 2.0.0

Zero-overhead, safe implementation of partial borrows. This crate allows you to borrow selected fields from a struct and split structs into non-overlapping sets of borrowed fields.
Documentation 
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#![allow(dead_code)]

use borrow::partial as p;
use borrow::traits::*;
use std::fmt::Debug;
use std::vec::Vec;

// ============
// === Data ===
// ============

#[derive(Debug, Default)]
pub struct Geometry {
    label: String,
}

#[derive(Debug, Default)]
pub struct Material {
    label: String,
}

#[derive(Debug, Default)]
pub struct Mesh {
    pub geometry: usize,
    pub material: usize,
}

#[derive(Debug, Default)]
pub struct Scene {
    pub meshes: Vec<usize>,
}

// ==================
// === Registries ===
// ==================

#[derive(Debug, Default)]
pub struct GeometryCtx {
    pub data: Vec<Geometry>,
}

#[derive(Debug, Default)]
pub struct MaterialCtx {
    pub data: Vec<Material>,
}

#[derive(Debug, Default)]
pub struct MeshCtx {
    pub data: Vec<Mesh>,
}

#[derive(Debug, Default)]
pub struct SceneCtx {
    pub data: Vec<Scene>,
}

// =====================
// === Root Registry ===
// =====================

#[derive(Debug, borrow::Partial)]
#[module(crate)]
pub struct Ctx<'v, V: Debug> {
    version: &'v V,
    pub geometry: GeometryCtx,
    pub material: MaterialCtx,
    pub mesh: MeshCtx,
    pub scene: SceneCtx,
}

fn render_pass1<'v, V: Debug>
(ctx: p!(&<mut *> Ctx<'v, V>)) {
    let (scene, mut ctx2) = ctx.borrow_scene();
    for scene in &scene.data {
        for mesh in &scene.meshes {
            render_scene(p!(&mut ctx2), *mesh)
        }
    }
}

fn render_scene<'v, V: Debug>
(_ctx: p!(&<mesh, mut geometry, mut material> Ctx<'v, V>), _mesh: usize) {
    // ...
}