Crate hecs

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();
let a = world.spawn((123, true, "abc"));
let b = world.spawn((42, false));
for (id, (number, &flag)) in world.query::<(&mut i32, &bool)>() {
  if flag { *number *= 2; }
}
assert_eq!(*world.get::<i32>(a).unwrap(), 246);
assert_eq!(*world.get::<i32>(b).unwrap(), 42);

Structs

BuiltEntity	The output of an EntityBuilder, suitable for passing to World::spawn or World::insert
Entity	Lightweight unique ID 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
QueryIter	Iterator over the set of entities with the components in Q
Ref	Shared borrow of an entity's component
RefMut	Unique borrow of an entity's component
World	An unordered collection of entities, each having any number of distinctly typed components

Enums

ComponentError

Errors that arise when accessing components

Traits

Bundle	A statically typed collection of components
Component	Types that can be components (implemented automatically)
DynamicBundle	A dynamically typed collection of components
Query	A collection of component types to fetch from a World

Derive Macros

Bundle	Implement Bundle for a monomorphic struct
Query	Implement Query for a struct whose fields are queries