Adds paragraph about Edict 0.2

Author: zakarumych

content/news/037/index.md

@@ -185,6 +185,82 @@ users to define their own dynamic assets.
 [bevy_asset_loader]: https://github.com/NiklasEi/bevy_asset_loader/
 [Bevy]: https://bevyengine.org/
 
+### [Edict]
+
+[Edict] by [@zakarumych] is powerful Rust ECS crate
+that expands traditional ECS feature set.
+
+New version 0.2 is getting [ready for release].
+
+This ECS is based on archetypes (aka SOA storage) to allow fast cache-friendly
+iteration. And there are quite a few novel features:
+
+[Edict] allows users to express relations between entities using [`Relation`]
+trait. Conceptually they are components that gets attached to a pair of
+entities - origin and target. Relation is automatically removed when one of the entity
+is despawned. Additionally relation may be "owned", automatically triggering 
+despawn for "owned" entities when last owner is despawned. Relation may be 
+declared as "exclusive" so that it is replaces old relation on origin entity.
+Provided out of the box relation [`ChildOf`] is exactly this - "exclusive" and
+"owned" - and can be used to define entity hierarchies.
+
+User may define hooks for components and relations to trigger arbitrary actions
+when component is dropped or replaced, or if relation target is dropped.
+Hooks can be defined in [`Component`] trait implementation.
+Also [`WorldBuilder`] allows to dynamically override hooks for the component
+type.
+
+Unlike most ECS with [`Component`] trait [Edict] allows using component types
+that do not implement [`Component`]. Component inserting methods
+(spawn, insert etc) can be used only with components that implement
+[`Component`].
+Each such method has [`*_external`] counterpart that allows for [`!Component`]
+types but require explicit registration.
+
+Built-in change tracking with fast and flexible queries for modified components
+can be used to implement complex use cases. For example incremental saves can
+fetch all components modified since previous save. For netcode components
+modified since last ACK can be fetched as efficiently.
+
+Another novel feature is type-agnostic component borrowing.
+Component type may define list of types that can be borrowed from it. Important
+use case is borrowing [`dyn Traits`].
+Editor implementation may borrow some `dyn EditorComponent` and use it to show
+widget for recognized components. Borrowing can be used with runtime-known
+[`TypeId`] as well as without one.
+
+[Edict] supports parallel execution.
+There's [`System`] trait that works with built-in [`Scheduler`].
+Functions with certain argument types can be transformed into [`System`]s
+similarly to [`bevy_ecs`].
+The [`Scheduler`] is very easy to configure and use. Any conflicting pair of
+system define implicit dependency from system that was added earlier to a system
+that was added later. This way multi-threaded execution runs the same way as
+single-threaded would.
+[`Scheduler`] uses external executor using [`ScopedExecutor`] trait. Implemented
+for [`std::thread::Scope`] and [`rayon::Scope`] under "rayon" feature.
+[`Scheduler::run`] returns an iterator or [`ActionEncoder`]s that should be
+executed with mutable access to [`World`].
+
+[Edict]: https://github.com/zakarumych/edict
+[@zakarumych]: https://github.com/zakarumych
+[ready for release]: https://docs.rs/edict/0.2.0-rc.3/edict/
+[`Relation`]: https://docs.rs/edict/0.2.0-rc.3/edict/relation/trait.Relation.html
+[`ChildOf`]: https://docs.rs/edict/0.2.0-rc.3/edict/relation/struct.ChildOf.html
+[`Component`]: https://docs.rs/edict/0.2.0-rc.3/edict/component/trait.Component.html
+[`*_external`]: https://docs.rs/edict/0.2.0-rc.3/edict/world/struct.World.html#method.spawn_external
+[`dyn Traits`]: https://doc.rust-lang.org/book/ch17-02-trait-objects.html
+[`TypeId`]: https://doc.rust-lang.org/nightly/core/any/struct.TypeId.html
+[`System`]: https://docs.rs/edict/0.2.0-rc.3/edict/system/trait.System.html
+[`Scheduler`]: https://docs.rs/edict/0.2.0-rc.3/edict/scheduler/struct.Scheduler.html
+[`bevy_ecs`]: https://crates.io/crates/bevy_ecs
+[`ScopedExecutor`]: https://docs.rs/edict/0.2.0-rc.3/edict/executor/trait.ScopedExecutor.html
+[`std::thread::Scope`]: https://doc.rust-lang.org/stable/std/thread/struct.Scope.html
+[`rayon::Scope`]: https://docs.rs/rayon/1.5.3/rayon/struct.Scope.html
+[`Scheduler::run`]: https://docs.rs/edict/0.2.0-rc.3/edict/scheduler/struct.Scheduler.html#method.run
+[`ActionEncoder`]: https://docs.rs/edict/0.2.0-rc.3/edict/action/struct.ActionEncoder.html
+[`World`]: https://docs.rs/edict/0.2.0-rc.3/edict/world/struct.World.html
+
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