Crate hv_ecs 

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

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
for (id, (number, &flag)) in world.query_mut::<(&mut i32, &bool)>() {
  if flag { *number *= 2; }
}
// Random access is simple and safe
assert_eq!(*world.get::<i32>(a).unwrap(), 246);
assert_eq!(*world.get::<i32>(b).unwrap(), 42);

Structs

Archetype

A collection of entities having the same component types

ArchetypesGeneration

Determines freshness of information derived from World::archetypes

Batch

A sequence of entities yielded by BatchedIter

BatchIncomplete

Error indicating that a ColumnBatchBuilder was missing components

BatchWriter

Handle for appending components

BatchedIter

Batched version of QueryIter

BuiltEntity

The output of an EntityBuilder, suitable for passing to World::spawn or World::insert

Cloneable

Type parameter for EntityBuilders with cloneable components

ColumnBatch

A collection of component data for entities with the same component types

ColumnBatchBuilder

An incomplete collection of component data for entities with the same component types

ColumnBatchType

A collection of component types

DynamicComponent

A handle to a component of type T returned from a dynamic query, obtained by DynamicItem::take.

DynamicItem

A set of components returned from some dynamic query, which belong to some entity satisfying that query.

DynamicItemRef

Immutable borrow of a DynamicComponent.

DynamicItemRefMut

Mutable borrow of a DynamicComponent.

DynamicQuery

A dynamic query; the dynamic equivalent of the Query trait. Used with World::dynamic_query and World::dynamic_query_one.

DynamicQueryBorrow

A borrow of a World sufficient to execute some dynamic query.

DynamicQueryIter

Iterator over the set of entities which satisfy some DynamicQuery.

DynamicWith

A dynamic query transformer which requires that entities satisfying some dynamic query also have some component type, without needing to borrow it.

DynamicWithout

A dynamic query transformer which requires that entities satisfying the subquery also not contain some component type.

Entity

Lightweight unique ID, or handle, of an entity

EntityBuilder

Helper for incrementally constructing a bundle of components with dynamic component types

EntityRef

Handle to an entity with any component types

Iter

Iterator over all of a world’s entities

MissingComponent

Error indicating that an entity did not have a required component

NoSuchEntity

Error indicating that no entity with a particular ID exists

PreparedQuery

A prepared query can be stored independently of the World to amortize query set-up costs.

PreparedQueryBorrow

Combined borrow of a PreparedQuery and a World

PreparedQueryIter

Iterates over all entities matching a PreparedQuery

QueryBorrow

A borrow of a World sufficient to execute the query Q

QueryIter

Iterator over the set of entities with the components in Q

QueryMut

A query builder that’s convertible directly into an iterator

QueryOne

A borrow of a World sufficient to execute the query Q on a single entity

Ref

Shared borrow of an entity’s component

RefMut

Unique borrow of an entity’s component

ReusableBuiltEntity

A collection of components that implement Clone

Satisfies

A query that yields true iff an entity would satisfy the query Q

SpawnBatchIter

Entity IDs created by World::spawn_batch

SpawnColumnBatchIter

Iterator over Entitys spawned by World::spawn_column_batch()

With

Query transformer skipping entities that do not have a T component

Without

Query transformer skipping entities that have a T component

World

An unordered collection of entities, each having any number of distinctly typed components

Enums

Access

Type of access a Query may have to an Archetype

ComponentError

Errors that arise when accessing components

Or

Holds an L, or an R, or both

QueryOneError

Errors that arise when querying a single entity

Traits

Bundle

A statically typed collection of components

Component

Types that can be components, implemented automatically for all Send + Sync + 'static types

DynamicBundle

A dynamically typed collection of components

Query

A collection of component types to fetch from a World

Type Aliases

QueryItem

Type of values yielded by a query