bevy/crates/bevy_ecs/hecs/src/lib.rs

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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
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// modified by Bevy contributors
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//! A handy ECS
//!
//! hecs provides a high-performance, minimalist entity-component-system (ECS) world. It is a
//! library, not a framework. In place of an explicit "System" abstraction, a `World`'s entities are
//! easily queried from regular code. Organize your application however you like!
//!
//! In order of importance, hecs pursues:
//! - fast traversals
//! - a simple interface
//! - a small dependency closure
//! - exclusion of externally-implementable functionality
//!
//! ```
//! # use hecs::*;
//! let mut world = World::new();
//! // Nearly any type can be used as a component with zero boilerplate
//! let a = world.spawn((123, true, "abc"));
//! let b = world.spawn((42, false));
//! // Systems can be simple for loops
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//! for (id, mut number, &flag) in &mut world.query::<(Entity, &mut i32, &bool)>() {
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//! if flag { *number *= 2; }
//! }
//! assert_eq!(*world.get::<i32>(a).unwrap(), 246);
//! assert_eq!(*world.get::<i32>(b).unwrap(), 42);
//! ```
#![warn(missing_docs)]
#![no_std]
#[cfg(feature = "std")]
extern crate std;
extern crate alloc;
/// Imagine macro parameters, but more like those Russian dolls.
///
/// Calls m!(A, B, C), m!(A, B), m!(B), and m!() for i.e. (m, A, B, C)
/// where m is any macro, for any number of parameters.
#[macro_export]
macro_rules! smaller_tuples_too {
($m: ident, $ty: ident) => {
$m!{$ty}
$m!{}
};
($m: ident, $ty: ident, $($tt: ident),*) => {
$m!{$ty, $($tt),*}
smaller_tuples_too!{$m, $($tt),*}
};
}
mod archetype;
mod borrow;
mod bundle;
mod entities;
mod entity_builder;
mod query;
mod query_one;
#[cfg(feature = "serde")]
mod serde;
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mod world;
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pub use archetype::Archetype;
pub use borrow::{EntityRef, Ref, RefMut};
pub use bundle::{Bundle, DynamicBundle, MissingComponent};
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pub use entities::{Entity, Location, NoSuchEntity};
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pub use entity_builder::{BuiltEntity, EntityBuilder};
pub use query::{
Access, Added, BatchedIter, Changed, Mut, Mutated, Query, QueryBorrow, QueryIter, With, Without,
};
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pub use query_one::QueryOne;
pub use world::{ArchetypesGeneration, Component, ComponentError, Iter, SpawnBatchIter, World};
// Unstable implementation details needed by the macros
#[doc(hidden)]
pub use archetype::TypeInfo;
#[cfg(feature = "macros")]
#[doc(hidden)]
pub use lazy_static;
#[doc(hidden)]
pub use query::Fetch;
#[cfg(feature = "macros")]
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pub use hecs_macros::Bundle;