557ab9897a
# Objective - In the large majority of cases, users were calling `.unwrap()` immediately after `.get_resource`. - Attempting to add more helpful error messages here resulted in endless manual boilerplate (see #3899 and the linked PRs). ## Solution - Add an infallible variant named `.resource` and so on. - Use these infallible variants over `.get_resource().unwrap()` across the code base. ## Notes I did not provide equivalent methods on `WorldCell`, in favor of removing it entirely in #3939. ## Migration Guide Infallible variants of `.get_resource` have been added that implicitly panic, rather than needing to be unwrapped. Replace `world.get_resource::<Foo>().unwrap()` with `world.resource::<Foo>()`. ## Impact - `.unwrap` search results before: 1084 - `.unwrap` search results after: 942 - internal `unwrap_or_else` calls added: 4 - trivial unwrap calls removed from tests and code: 146 - uses of the new `try_get_resource` API: 11 - percentage of the time the unwrapping API was used internally: 93%
30 lines
738 B
Rust
30 lines
738 B
Rust
use bevy::prelude::*;
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use std::{io, io::BufRead};
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struct Input(String);
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/// This example demonstrates you can create a custom runner (to update an app manually). It reads
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/// lines from stdin and prints them from within the ecs.
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fn my_runner(mut app: App) {
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println!("Type stuff into the console");
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for line in io::stdin().lock().lines() {
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{
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let mut input = app.world.resource_mut::<Input>();
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input.0 = line.unwrap();
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}
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app.update();
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}
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}
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fn print_system(input: Res<Input>) {
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println!("You typed: {}", input.0);
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}
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fn main() {
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App::new()
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.insert_resource(Input(String::new()))
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.set_runner(my_runner)
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.add_system(print_system)
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.run();
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}
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