0.3

Bevy version

• Bump to bevy 0.11

New in 0.3

This is decently sized release with quite a few new things.

• New ControlFlow variant: Probe.
• ZSTs for relations are now enforced at compile time.

  ---- src/lib.rs - (line 20) stdout ----
  error[E0080]: evaluation of `<Likes as aery::relation::ZstOrPanic>::ZST_OR_PANIC` failed
     --> /home/yogii/Repos/aery/src/relation.rs:142:13
      |
  142 |             panic!("Not a ZST")
      |             ^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'Not a ZST', /home/yogii/Repos/aery/src/relation.rs:142:13
      |
      = note: this error originates in the macro `$crate::panic::panic_2021` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
  
  note: erroneous constant used
    --> src/lib.rs:47:10
     |
  29 | #[derive(Relation)]
     |          ^^^^^^^^
     |

• New Scope API to spawn and manipulate hierarchies.

  wrld.spawn(A)
      .scope::<R>(|_, mut ent| {
          ent.insert(B);
          ent.scope::<R>(|_, mut ent| {
              ent.insert(C);
          });
      });

• Symmetric Relations.

  #[derive(Relation)]
  #[symmetric]
  struct R;

• Relation events for target changes and entity cleanup.

  fn sys(mut events: EventReader<TargetEvent>) {
      for e in events.iter() {
          // Did some entity set an `R` to some other entity?
          if e.matches(Wc, TargetOp::Set, R, Wc) {
              // ..
          }
      }
  }

• Hierarchy ascent is now supported along side the existing descent.

  fn sys(query: Query<(A, Relations<R>)>, roots: Query<Entity, Root<R>>) {
      query.ops().traverse_targets::<R>().for_each(|a, a_ancestor| {
          // ..
      })
  }

Breaking

• Module restructures if you're not using prelude.
• .breadth_first::<R>(roots) -> .traverse::<R>(roots)
• Recursive cleanup no longer triggers when unsetting. This never made sense.
• RelationCommands reworked and no longer implemented for Commands and World. New implementation is for EntityMut<'_> with a new API.

Misc

• Many doc improvements & with illustrations in documentation with aquamarine.