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