bevy/examples/ecs/system_closure.rs
Mark Schmale 1ba7429371 Doc/module style doc blocks for examples (#4438)
# Objective

Provide a starting point for #3951, or a partial solution. 
Providing a few comment blocks to discuss, and hopefully find better one in the process. 

## Solution

Since I am pretty new to pretty much anything in this context, I figured I'd just start with a draft for some file level doc blocks. For some of them I found more relevant details (or at least things I considered interessting), for some others there is less. 

## Changelog

- Moved some existing comments from main() functions in the 2d examples to the file header level
- Wrote some more comment blocks for most other 2d examples

TODO: 
- [x] 2d/sprite_sheet, wasnt able to come up with something good yet 
- [x] all other example groups...


Also: Please let me know if the commit style is okay, or to verbose. I could certainly squash these things, or add more details if needed. 
I also hope its okay to raise this PR this early, with just a few files changed. Took me long enough and I dont wanted to let it go to waste because I lost motivation to do the whole thing. Additionally I am somewhat uncertain over the style and contents of the commets. So let me know what you thing please.
2022-05-16 13:53:20 +00:00

47 lines
1.6 KiB
Rust

//! Shows how anonymous functions / closures can be used as systems.
use bevy::{log::LogPlugin, prelude::*};
fn main() {
// create a simple closure.
let simple_closure = || {
// this is a closure that does nothing.
info!("Hello from a simple closure!");
};
// create a closure, with an 'input' value.
let complex_closure = |mut value: String| {
move || {
info!("Hello from a complex closure! {:?}", value);
// we can modify the value inside the closure. this will be saved between calls.
value = format!("{} - updated", value);
// you could also use an outside variable like presented in the inlined closures
// info!("outside_variable! {:?}", outside_variable);
}
};
let outside_variable = "bar".to_string();
App::new()
.add_plugin(LogPlugin)
// we can use a closure as a system
.add_system(simple_closure)
// or we can use a more complex closure, and pass an argument to initialize a Local variable.
.add_system(complex_closure("foo".into()))
// we can also inline a closure
.add_system(|| {
info!("Hello from an inlined closure!");
})
// or use variables outside a closure
.add_system(move || {
info!(
"Hello from an inlined closure that captured the 'outside_variable'! {:?}",
outside_variable
);
// you can use outside_variable, or any other variables inside this closure.
// their states will be saved.
})
.run();
}