8 files changed, 195 insertions, 143 deletions

diff --git a/engine-ecs/src/actions.rs b/engine-ecs/src/actions.rs
index 69605b3..cef51cc 100644
--- a/engine-ecs/src/actions.rs
+++ b/engine-ecs/src/actions.rs
@@ -1,12 +1,17 @@
 use std::borrow::Cow;
 
 use crate::bundle::Bundle;
-use crate::component::{Component, IntoParts, Parts as ComponentParts};
+use crate::component::{
+    Component,
+    IntoParts,
+    Parts as ComponentParts,
+    RemovableTuple as RemovableComponentTuple,
+};
 use crate::entity::Name as EntityName;
 use crate::event::component::Removed;
 use crate::pair::Pair;
 use crate::system::{Metadata as SystemMetadata, Param as SystemParam};
-use crate::uid::{Uid, WithUidTuple};
+use crate::uid::Uid;
 use crate::{ActionQueue, World};
 
 /// Used to to queue up actions for a [`World`] to perform.
@@ -174,9 +179,9 @@ impl Actions<'_>
     }
 
     /// Queues up removing component(s) from a entity at the end of the current tick.
-    pub fn remove_comps<Ids: WithUidTuple>(&mut self, entity_uid: Uid)
+    pub fn remove_comps<Components: RemovableComponentTuple>(&mut self, entity_uid: Uid)
     {
-        self.remove_components(entity_uid, Ids::uids());
+        self.remove_components(entity_uid, Components::ids());
     }
 
     /// Queues up setting the target of a entity's pair at the end of the current tick.
diff --git a/engine-ecs/src/component.rs b/engine-ecs/src/component.rs
index 400b12c..d424e16 100644
--- a/engine-ecs/src/component.rs
+++ b/engine-ecs/src/component.rs
@@ -3,6 +3,7 @@ use std::fmt::Debug;
 use std::ops::{Deref, DerefMut};
 
 use engine_ecs_macros::Component;
+use seq_macro::seq;
 
 use crate::event::component::Changed;
 use crate::event::Submitter as EventSubmitter;
@@ -23,13 +24,9 @@ pub mod local;
 
 pub(crate) mod storage;
 
-pub trait Component: SystemInput + Any + IntoParts
+/// A component that is not a pair and is not a sole.
+pub trait Component: WithAssociatedId + SystemInput + Any + IntoParts
 {
-    /// Returns the ID of this component.
-    fn id() -> Uid
-    where
-        Self: Sized;
-
     fn type_reflection() -> Option<&'static TypeReflection>
     where
         Self: Sized;
@@ -38,32 +35,50 @@ pub trait Component: SystemInput + Any + IntoParts
     fn name(&self) -> &'static str;
 }
 
-impl dyn Component
+pub trait WithAssociatedId
 {
-    pub fn downcast_mut<Real: 'static>(&mut self) -> Option<&mut Real>
-    {
-        (self as &mut dyn Any).downcast_mut()
-    }
+    /// Returns the ID of this component.
+    fn id() -> Uid;
+}
 
-    pub fn downcast_ref<Real: 'static>(&self) -> Option<&Real>
-    {
-        (self as &dyn Any).downcast_ref()
-    }
+/// A component that is removable from it's entity.
+///
+/// This trait is implemented for [`crate::pair::Pair`] so it does not have [`Component`]
+/// as supertrait.
+pub trait Removable: WithAssociatedId {}
 
-    pub fn is<Other: 'static>(&self) -> bool
-    {
-        (self as &dyn Any).is::<Other>()
-    }
-}
+impl<ComponentT: Component> Removable for ComponentT {}
 
-impl Debug for dyn Component
+/// Implemented by tuples of types implementing [`Removable`].
+///
+/// This trait is sealed so it cannot be implemented by types outside of this module.
+pub trait RemovableTuple: sealed::Sealed
 {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
-    {
-        formatter.debug_struct("Component").finish_non_exhaustive()
-    }
+    fn ids() -> impl IntoIterator<Item = Uid>;
+}
+
+macro_rules! gen_removable_tuple_impl {
+    ($c: tt) => {
+        seq!(I in 0..=$c {
+            impl<#(RemovableT~I: Removable,)*> RemovableTuple for (#(RemovableT~I,)*)
+            {
+                fn ids() -> impl IntoIterator<Item = Uid>
+                {
+                    [#(RemovableT~I::id(),)*]
+                }
+            }
+
+            impl<#(RemovableT~I: Removable,)*> sealed::Sealed for (#(RemovableT~I,)*)
+            {
+            }
+        });
+    };
 }
 
+seq!(C in 0..=16 {
+    gen_removable_tuple_impl!(C);
+});
+
 #[derive(Debug)]
 pub struct Handle<'a, DataT: ?Sized + 'static>
 {
@@ -394,3 +409,8 @@ pub struct Info
     pub name: &'static str,
     pub is_sole: bool,
 }
+
+mod sealed
+{
+    pub trait Sealed {}
+}
diff --git a/engine-ecs/src/lib.rs b/engine-ecs/src/lib.rs
index a752f6a..6028cf7 100644
--- a/engine-ecs/src/lib.rs
+++ b/engine-ecs/src/lib.rs
@@ -22,6 +22,7 @@ use crate::component::{
     Info as ComponentInfo,
     IntoParts as IntoComponentParts,
     Parts as ComponentParts,
+    WithAssociatedId,
 };
 use crate::entity::{
     Declaration as EntityDeclaration,
diff --git a/engine-ecs/src/pair.rs b/engine-ecs/src/pair.rs
index 834077c..efeead9 100644
--- a/engine-ecs/src/pair.rs
+++ b/engine-ecs/src/pair.rs
@@ -8,6 +8,8 @@ use crate::component::{
     HandleMut as ComponentHandleMut,
     IntoParts as IntoComponentParts,
     Parts as ComponentParts,
+    Removable as RemovableComponent,
+    WithAssociatedId as ComponentWithAssociatedId,
 };
 use crate::entity::{
     Handle as EntityHandle,
@@ -21,7 +23,7 @@ use crate::query::{
     TermsBuilderInterface,
 };
 use crate::reflection::Type as TypeReflection;
-use crate::uid::{PairParams as UidPairParams, Uid, With as WithUid};
+use crate::uid::{PairParams as UidPairParams, Uid};
 use crate::util::impl_multiple;
 use crate::{Component, EntityComponentRef, World};
 
@@ -265,7 +267,7 @@ where
         _term_metadata: QueryTermMetadata,
     )
     {
-        terms_builder.present([Pair::<Relation, Target>::uid()]);
+        terms_builder.present([Pair::<Relation, Target>::id()]);
     }
 
     fn fields(
@@ -276,7 +278,7 @@ where
     {
         let target_component = search_result
             .entity_handle
-            .get_matching_components(Pair::<Relation, Target>::uid())
+            .get_matching_components(Pair::<Relation, Target>::id())
             .next()
             .expect("Not possible");
 
@@ -308,7 +310,7 @@ where
         _term_metadata: QueryTermMetadata,
     )
     {
-        terms_builder.present([Pair::<Relation, Target>::uid()]);
+        terms_builder.present([Pair::<Relation, Target>::id()]);
     }
 
     fn fields(
@@ -319,7 +321,7 @@ where
     {
         let target_component = search_result
             .entity_handle
-            .get_matching_components(Pair::<Relation, Target>::uid())
+            .get_matching_components(Pair::<Relation, Target>::id())
             .next()
             .expect("Not possible");
 
@@ -355,7 +357,7 @@ where
         _term_metadata: QueryTermMetadata,
     )
     {
-        terms_builder.present([Self::uid()]);
+        terms_builder.present([Self::id()]);
     }
 
     fn fields(
@@ -366,7 +368,7 @@ where
     {
         let first_matching_comp = search_result
             .entity_handle
-            .get_matching_components(Self::uid())
+            .get_matching_components(Self::id())
             .next()
             .expect("Not possible");
 
@@ -378,12 +380,12 @@ where
     }
 }
 
-impl<Relation, Target> WithUid for Pair<Relation, Target>
+impl<Relation, Target> ComponentWithAssociatedId for Pair<Relation, Target>
 where
     Relation: Component,
     Target: Component,
 {
-    fn uid() -> Uid
+    fn id() -> Uid
     {
         Uid::new_pair(&UidPairParams {
             relation: Relation::id(),
@@ -392,15 +394,28 @@ where
     }
 }
 
-impl<Relation> WithUid for Pair<Relation, Wildcard>
+impl<Relation, Target> RemovableComponent for Pair<Relation, Target>
 where
     Relation: Component,
+    Target: Component,
 {
-    fn uid() -> Uid
+}
+
+// TODO: Implement RemovableComponent for Pair<Relation, Wildcard>
+// and Pair<Wildcard, Target>.
+//
+// This should only be done after removal of wildcard pairs is added in lib.rs
+
+impl<Relation> Pair<Relation, Wildcard>
+where
+    Relation: Component,
+{
+    #[must_use]
+    pub fn id() -> Uid
     {
         Uid::new_pair(&UidPairParams {
             relation: Relation::id(),
-            target: Wildcard::uid(),
+            target: Wildcard::id(),
         })
     }
 }
@@ -464,19 +479,17 @@ impl<'query, Relation, Target> WithWildcard<'query, Relation, Target>
         assert!(component_id.is_pair());
 
         assert!(
-            Relation::uid() == Wildcard::uid()
+            Relation::uid() == Wildcard::id()
                 || component_id.relation() == Relation::uid()
         );
 
         assert!(
-            Target::uid() == Wildcard::uid() || component_id.target() == Target::uid()
+            Target::uid() == Wildcard::id() || component_id.target() == Target::uid()
         );
 
-        assert!(Relation::uid() == Wildcard::uid() || Target::uid() == Wildcard::uid());
+        assert!(Relation::uid() == Wildcard::id() || Target::uid() == Wildcard::id());
 
-        assert!(
-            !(Relation::uid() == Wildcard::uid() && Target::uid() == Wildcard::uid())
-        );
+        assert!(!(Relation::uid() == Wildcard::id() && Target::uid() == Wildcard::id()));
 
         WithWildcard {
             world,
@@ -641,11 +654,9 @@ impl<'query, Relation, Target> MultipleWithWildcard<'query, Relation, Target>
         Relation: ComponentOrWildcard,
         Target: ComponentOrWildcard,
     {
-        assert!(Relation::uid() == Wildcard::uid() || Target::uid() == Wildcard::uid());
+        assert!(Relation::uid() == Wildcard::id() || Target::uid() == Wildcard::id());
 
-        assert!(
-            !(Relation::uid() == Wildcard::uid() && Target::uid() == Wildcard::uid())
-        );
+        assert!(!(Relation::uid() == Wildcard::id() && Target::uid() == Wildcard::id()));
 
         MultipleWithWildcard {
             entity_handle,
@@ -691,7 +702,7 @@ impl<'a, Relation: Component> IntoIterator
         WithWildcardIter {
             inner: self
                 .entity_handle
-                .get_matching_components(Pair::<Relation, Wildcard>::uid()),
+                .get_matching_components(Pair::<Relation, Wildcard>::id()),
             world: self.world,
             _pd: PhantomData,
         }
@@ -736,7 +747,7 @@ pub struct Wildcard(Infallible);
 impl Wildcard
 {
     #[must_use]
-    pub fn uid() -> Uid
+    pub fn id() -> Uid
     {
         Uid::wildcard()
     }
@@ -761,7 +772,7 @@ impl ComponentOrWildcard for Wildcard
 {
     fn uid() -> Uid
     {
-        Wildcard::uid()
+        Wildcard::id()
     }
 }
 
diff --git a/engine-ecs/src/phase.rs b/engine-ecs/src/phase.rs
index 64c1593..e5008ad 100644
--- a/engine-ecs/src/phase.rs
+++ b/engine-ecs/src/phase.rs
@@ -1,3 +1,4 @@
+use crate::component::WithAssociatedId as _;
 use crate::{declare_entity, Component, World};
 #[cfg(debug_assertions)]
 use crate::{
diff --git a/engine-ecs/src/query/term.rs b/engine-ecs/src/query/term.rs
index 980ee87..f5fd531 100644
--- a/engine-ecs/src/query/term.rs
+++ b/engine-ecs/src/query/term.rs
@@ -5,7 +5,9 @@ use crate::component::{
     Component,
     Handle as ComponentHandle,
     HandleMut as ComponentHandleMut,
+    WithAssociatedId as _,
 };
+use crate::pair::{Pair, Wildcard};
 use crate::query::{
     FoundByTraversal,
     SearchResult,
@@ -17,19 +19,61 @@ use crate::query::{
     Traversal,
     TraversalKind,
 };
-use crate::uid::With as WithUid;
 use crate::World;
 
-pub struct With<WithUidT>
+pub struct With<T>
+{
+    _pd: PhantomData<T>,
+}
+
+impl<'query, ComponentT: Component> Term<'query> for With<ComponentT>
+{
+    type Fields = ();
+
+    fn apply_to_terms_builder<const MAX_TERM_CNT: usize>(
+        terms_builder: &mut TermsBuilder<MAX_TERM_CNT>,
+        _term_metadata: TermMetadata,
+    )
+    {
+        terms_builder.present([ComponentT::id()]);
+    }
+
+    fn fields(
+        _world: &'query World,
+        _search_result: &SearchResult<'query, '_>,
+        _term_metadata: TermMetadata,
+    ) -> Self::Fields
+    {
+    }
+}
+
+impl<'query, Relation, Target> Term<'query> for With<Pair<Relation, Target>>
 where
-    WithUidT: WithUid,
+    Relation: Component,
+    Target: Component,
 {
-    _pd: PhantomData<WithUidT>,
+    type Fields = ();
+
+    fn apply_to_terms_builder<const MAX_TERM_CNT: usize>(
+        terms_builder: &mut TermsBuilder<MAX_TERM_CNT>,
+        _term_metadata: TermMetadata,
+    )
+    {
+        terms_builder.present([Pair::<Relation, Target>::id()]);
+    }
+
+    fn fields(
+        _world: &'query World,
+        _search_result: &SearchResult<'query, '_>,
+        _term_metadata: TermMetadata,
+    ) -> Self::Fields
+    {
+    }
 }
 
-impl<'query, WithUidT> Term<'query> for With<WithUidT>
+impl<'query, Relation> Term<'query> for With<Pair<Relation, Wildcard>>
 where
-    WithUidT: WithUid,
+    Relation: Component,
 {
     type Fields = ();
 
@@ -38,7 +82,7 @@ where
         _term_metadata: TermMetadata,
     )
     {
-        terms_builder.present([WithUidT::uid()]);
+        terms_builder.present([Pair::<Relation, Wildcard>::id()]);
     }
 
     fn fields(
@@ -50,16 +94,59 @@ where
     }
 }
 
-pub struct Without<WithUidT>
+pub struct Without<T>
+{
+    _pd: PhantomData<T>,
+}
+
+impl<'query, ComponentT: Component> Term<'query> for Without<ComponentT>
+{
+    type Fields = ();
+
+    fn apply_to_terms_builder<const MAX_TERM_CNT: usize>(
+        terms_builder: &mut TermsBuilder<MAX_TERM_CNT>,
+        _term_metadata: TermMetadata,
+    )
+    {
+        terms_builder.absent([ComponentT::id()]);
+    }
+
+    fn fields(
+        _world: &'query World,
+        _search_result: &SearchResult<'query, '_>,
+        _term_metadata: TermMetadata,
+    ) -> Self::Fields
+    {
+    }
+}
+
+impl<'query, Relation, Target> Term<'query> for Without<Pair<Relation, Target>>
 where
-    WithUidT: WithUid,
+    Relation: Component,
+    Target: Component,
 {
-    _pd: PhantomData<WithUidT>,
+    type Fields = ();
+
+    fn apply_to_terms_builder<const MAX_TERM_CNT: usize>(
+        terms_builder: &mut TermsBuilder<MAX_TERM_CNT>,
+        _term_metadata: TermMetadata,
+    )
+    {
+        terms_builder.absent([Pair::<Relation, Target>::id()]);
+    }
+
+    fn fields(
+        _world: &'query World,
+        _search_result: &SearchResult<'query, '_>,
+        _term_metadata: TermMetadata,
+    ) -> Self::Fields
+    {
+    }
 }
 
-impl<'query, WithUidT> Term<'query> for Without<WithUidT>
+impl<'query, Relation> Term<'query> for Without<Pair<Relation, Wildcard>>
 where
-    WithUidT: WithUid,
+    Relation: Component,
 {
     type Fields = ();
 
@@ -68,7 +155,7 @@ where
         _term_metadata: TermMetadata,
     )
     {
-        terms_builder.absent([WithUidT::uid()]);
+        terms_builder.absent([Pair::<Relation, Wildcard>::id()]);
     }
 
     fn fields(
diff --git a/engine-ecs/src/sole.rs b/engine-ecs/src/sole.rs
index 4047b48..9168414 100644
--- a/engine-ecs/src/sole.rs
+++ b/engine-ecs/src/sole.rs
@@ -4,18 +4,14 @@ use std::fmt::Debug;
 use crate::component::{
     HandleMut as ComponentHandleMut,
     IntoParts as IntoComponentParts,
+    WithAssociatedId as ComponentWithAssociatedId,
 };
 use crate::system::{Metadata as SystemMetadata, Param as SystemParam};
-use crate::uid::Uid;
 use crate::World;
 
 /// A component which has a single instance in the [`World`].
-pub trait Sole: Any + IntoComponentParts
+pub trait Sole: Any + IntoComponentParts + ComponentWithAssociatedId
 {
-    fn id() -> Uid
-    where
-        Self: Sized;
-
     fn type_reflection() -> Option<&'static crate::reflection::Type>
     where
         Self: Sized;
@@ -24,32 +20,6 @@ pub trait Sole: Any + IntoComponentParts
     fn name(&self) -> &'static str;
 }
 
-impl dyn Sole
-{
-    pub fn downcast_mut<Real: 'static>(&mut self) -> Option<&mut Real>
-    {
-        (self as &mut dyn Any).downcast_mut()
-    }
-
-    pub fn downcast_ref<Real: 'static>(&self) -> Option<&Real>
-    {
-        (self as &dyn Any).downcast_ref()
-    }
-
-    pub fn is<Other: 'static>(&self) -> bool
-    {
-        (self as &dyn Any).is::<Other>()
-    }
-}
-
-impl Debug for dyn Sole
-{
-    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
-    {
-        formatter.debug_struct("Sole").finish_non_exhaustive()
-    }
-}
-
 /// Holds a reference to a singleton component.
 #[derive(Debug)]
 pub struct Single<'world, SoleT: Sole>
diff --git a/engine-ecs/src/uid.rs b/engine-ecs/src/uid.rs
index 78ca2ad..6b1a4b5 100644
--- a/engine-ecs/src/uid.rs
+++ b/engine-ecs/src/uid.rs
@@ -1,10 +1,7 @@
 use std::fmt::{Debug, Display, Formatter};
 use std::sync::atomic::{AtomicU32, Ordering};
 
-use seq_macro::seq;
-
-use crate::component::Component;
-use crate::util::{gen_mask_64, Array, BitMask, NumberExt};
+use crate::util::{gen_mask_64, BitMask, NumberExt};
 
 static NEXT: AtomicU32 = AtomicU32::new(Uid::FIRST_UNIQUE_ID);
 
@@ -165,43 +162,3 @@ pub struct PairParams
     pub relation: Uid,
     pub target: Uid,
 }
-
-pub trait With: 'static
-{
-    fn uid() -> Uid;
-}
-
-impl<ComponentT: Component> With for ComponentT
-{
-    fn uid() -> Uid
-    {
-        Self::id()
-    }
-}
-
-pub trait WithUidTuple
-{
-    type UidsArray: Array<Uid>;
-
-    fn uids() -> Self::UidsArray;
-}
-
-macro_rules! impl_with_uid_tuple {
-    ($c: tt) => {
-        seq!(I in 0..=$c {
-            impl<#(WithUid~I: With,)*> WithUidTuple for (#(WithUid~I,)*)
-            {
-                type UidsArray = [Uid; $c + 1];
-
-                fn uids() -> Self::UidsArray
-                {
-                    [#(WithUid~I::uid(),)*]
-                }
-            }
-        });
-    };
-}
-
-seq!(C in 0..=16 {
-    impl_with_uid_tuple!(C);
-});