70 lines
2.4 KiB
Rust
70 lines
2.4 KiB
Rust
//! Illustrates how to make a single system from multiple functions running in sequence,
|
|
//! passing the output of the first into the input of the next.
|
|
|
|
use bevy::prelude::*;
|
|
use std::num::ParseIntError;
|
|
|
|
use bevy::log::LogPlugin;
|
|
use bevy::utils::tracing::Level;
|
|
|
|
fn main() {
|
|
App::new()
|
|
.insert_resource(Message("42".to_string()))
|
|
.insert_resource(OptionalWarning(Err("Got to rusty?".to_string())))
|
|
.add_plugin(LogPlugin {
|
|
level: Level::TRACE,
|
|
filter: "".to_string(),
|
|
})
|
|
.add_systems(
|
|
Update,
|
|
(
|
|
parse_message_system.pipe(handler_system),
|
|
data_pipe_system.pipe(info),
|
|
parse_message_system.pipe(dbg),
|
|
warning_pipe_system.pipe(warn),
|
|
parse_error_message_system.pipe(error),
|
|
parse_message_system.pipe(ignore),
|
|
),
|
|
)
|
|
.run();
|
|
}
|
|
|
|
#[derive(Resource, Deref)]
|
|
struct Message(String);
|
|
|
|
#[derive(Resource, Deref)]
|
|
struct OptionalWarning(Result<(), String>);
|
|
|
|
// This system produces a Result<usize> output by trying to parse the Message resource.
|
|
fn parse_message_system(message: Res<Message>) -> Result<usize, ParseIntError> {
|
|
message.parse::<usize>()
|
|
}
|
|
|
|
// This system produces a Result<()> output by trying to parse the Message resource.
|
|
fn parse_error_message_system(message: Res<Message>) -> Result<(), ParseIntError> {
|
|
message.parse::<usize>()?;
|
|
Ok(())
|
|
}
|
|
|
|
// This system takes a Result<usize> input and either prints the parsed value or the error message
|
|
// Try changing the Message resource to something that isn't an integer. You should see the error
|
|
// message printed.
|
|
fn handler_system(In(result): In<Result<usize, ParseIntError>>) {
|
|
match result {
|
|
Ok(value) => println!("parsed message: {value}"),
|
|
Err(err) => println!("encountered an error: {err:?}"),
|
|
}
|
|
}
|
|
|
|
// This system produces a String output by trying to clone the String from the Message resource.
|
|
fn data_pipe_system(message: Res<Message>) -> String {
|
|
message.0.clone()
|
|
}
|
|
|
|
// This system produces an Result<String> output by trying to extract a String from the
|
|
// OptionalWarning resource. Try changing the OptionalWarning resource to None. You should
|
|
// not see the warning message printed.
|
|
fn warning_pipe_system(message: Res<OptionalWarning>) -> Result<(), String> {
|
|
message.0.clone()
|
|
}
|