Crate bevy_discovery 

Bevy Discovery

This crate adds #[derive(DiscoveryPlugin)] which will scan the project files for functions annotated with #[system] and register them automagically. Example:

use bevy::prelude::*;
 
#[macro_use]
extern crate bevy_discovery;

fn main() {
    App::build()
        .add_plugin(DiscoveryPlugin)
        .run();
}

#[system]
fn discovered_system() {
    println!("Woo, discovered system!");
}

#[system(stage::POST_UPDATE)]
fn post_update_system() {
    println!("Hey, post update system!");
}
#[derive(DiscoveryPlugin)]
struct DiscoveryPlugin;

Compile time performance

	Full rebuild	Incremental
Normal	198.982 ± 1.167 s	25.944 ± 1.486 s
Discovered	207.636 ± 3.785 s	26.546 ± 1.782 s

These are the compile times for my fork of bevy-robbo, averaged over five runs with a discarded warmup round each using hyperfine.

Attribute Macros

system

Use this macro to annotate systems that need to be registered. Optionally, you can pass a value that evaluates to &str to register the macro in a specific stage.

Derive Macros

DiscoveryPlugin

Annotating a struct with this will implement Plugin for it, registering all functions with the #[system] attribute accessible from the root file. By default, the root file is src/main.rs, but this can be overriden using #[root(path/to/root.rs)]