bevy/crates/bevy_state/src/lib.rs
MichiRecRoom 447108b2a4
Downgrade clippy::allow_attributes and clippy::allow_attributes_without_reason to warn (#17320)
# Objective
I realized that setting these to `deny` may have been a little
aggressive - especially since we upgrade warnings to denies in CI.

## Solution
Downgrades these lints to `warn`, so that compiles can work locally. CI
will still treat these as denies.
2025-01-12 05:28:26 +00:00

97 lines
4.9 KiB
Rust

#![no_std]
//! In Bevy, states are app-wide interdependent, finite state machines that are generally used to model the large scale structure of your program: whether a game is paused, if the player is in combat, if assets are loaded and so on.
//!
//! This module provides 3 distinct types of state, all of which implement the [`States`](state::States) trait:
//!
//! - Standard [`States`](state::States) can only be changed by manually setting the [`NextState<S>`](state::NextState) resource.
//! These states are the baseline on which the other state types are built, and can be used on
//! their own for many simple patterns. See the [state example](https://github.com/bevyengine/bevy/blob/latest/examples/state/state.rs)
//! for a simple use case.
//! - [`SubStates`](state::SubStates) are children of other states - they can be changed manually using [`NextState<S>`](state::NextState),
//! but are removed from the [`World`](bevy_ecs::prelude::World) if the source states aren't in the right state. See the [sub_states example](https://github.com/bevyengine/bevy/blob/latest/examples/state/sub_states.rs)
//! for a simple use case based on the derive macro, or read the trait docs for more complex scenarios.
//! - [`ComputedStates`](state::ComputedStates) are fully derived from other states - they provide a [`compute`](state::ComputedStates::compute) method
//! that takes in the source states and returns their derived value. They are particularly useful for situations
//! where a simplified view of the source states is necessary - such as having an `InAMenu` computed state, derived
//! from a source state that defines multiple distinct menus. See the [computed state example](https://github.com/bevyengine/bevy/blob/latest/examples/state/computed_states.rs)
//! to see usage samples for these states.
//!
//! Most of the utilities around state involve running systems during transitions between states, or
//! determining whether to run certain systems, though they can be used more directly as well. This
//! makes it easier to transition between menus, add loading screens, pause games, and more.
//!
//! Specifically, Bevy provides the following utilities:
//!
//! - 3 Transition Schedules - [`OnEnter<S>`](crate::state::OnEnter), [`OnExit<S>`](crate::state::OnExit) and [`OnTransition<S>`](crate::state::OnTransition) - which are used
//! to trigger systems specifically during matching transitions.
//! - A [`StateTransitionEvent<S>`](crate::state::StateTransitionEvent) that gets fired when a given state changes.
//! - The [`in_state<S>`](crate::condition::in_state) and [`state_changed<S>`](crate::condition::state_changed) run conditions - which are used
//! to determine whether a system should run based on the current state.
#![cfg_attr(
any(docsrs, docsrs_dep),
expect(
internal_features,
reason = "rustdoc_internals is needed for fake_variadic"
)
)]
#![cfg_attr(any(docsrs, docsrs_dep), feature(rustdoc_internals))]
#![warn(
clippy::allow_attributes,
clippy::allow_attributes_without_reason,
reason = "See #17111; To be removed once all crates are in-line with these attributes"
)]
#[cfg(feature = "std")]
extern crate std;
extern crate alloc;
#[cfg(feature = "bevy_app")]
/// Provides [`App`](bevy_app::App) and [`SubApp`](bevy_app::SubApp) with state installation methods
pub mod app;
/// Provides extension methods for [`Commands`](bevy_ecs::prelude::Commands).
pub mod commands;
/// Provides definitions for the runtime conditions that interact with the state system
pub mod condition;
/// Provides definitions for the basic traits required by the state system
pub mod state;
/// Provides [`StateScoped`](crate::state_scoped::StateScoped) and
/// [`clear_state_scoped_entities`](crate::state_scoped::clear_state_scoped_entities) for managing lifetime of entities.
pub mod state_scoped;
#[cfg(feature = "bevy_app")]
/// Provides [`App`](bevy_app::App) and [`SubApp`](bevy_app::SubApp) with methods for registering
/// state-scoped events.
pub mod state_scoped_events;
#[cfg(feature = "bevy_reflect")]
/// Provides definitions for the basic traits required by the state system
pub mod reflect;
/// The state prelude.
///
/// This includes the most common types in this crate, re-exported for your convenience.
pub mod prelude {
#[cfg(feature = "bevy_app")]
#[doc(hidden)]
pub use crate::{app::AppExtStates, state_scoped_events::StateScopedEventsAppExt};
#[cfg(feature = "bevy_reflect")]
#[doc(hidden)]
pub use crate::reflect::{ReflectFreelyMutableState, ReflectState};
#[doc(hidden)]
pub use crate::{
commands::CommandsStatesExt,
condition::*,
state::{
last_transition, ComputedStates, EnterSchedules, ExitSchedules, NextState, OnEnter,
OnExit, OnTransition, State, StateSet, StateTransition, StateTransitionEvent, States,
SubStates, TransitionSchedules,
},
state_scoped::StateScoped,
};
}