From 5feeaf154a8b729873c729b4488f28536cf4ae24 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Sat, 21 Dec 2024 14:43:53 +0100
Subject: feat(ecs): add support for entities without components

---
 ecs/src/component.rs | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

(limited to 'ecs/src/component.rs')

diff --git a/ecs/src/component.rs b/ecs/src/component.rs
index 85c556f..1fde5b4 100644
--- a/ecs/src/component.rs
+++ b/ecs/src/component.rs
@@ -351,3 +351,51 @@ macro_rules! inner {
 seq!(C in 0..=64 {
     inner!(C);
 });
+
+impl Sequence for ()
+{
+    type MutRefs<'component> = ();
+    type Refs<'component> = ();
+
+    fn into_vec(self) -> Vec<Box<dyn Component>>
+    {
+        Vec::new()
+    }
+
+    fn metadata() -> Vec<Metadata>
+    {
+        Vec::new()
+    }
+
+    fn added_event_ids() -> Vec<Uid>
+    {
+        Vec::new()
+    }
+
+    fn removed_event_ids() -> Vec<Uid>
+    {
+        Vec::new()
+    }
+
+    #[inline]
+    fn from_components_mut<'component>(
+        _components: &'component [EntityComponent],
+        _component_index_lookup: impl Fn(Uid) -> Option<usize>,
+        _world: &'component World,
+        _lock_component: fn(&EntityComponent) -> WriteGuard<'_, Box<dyn Component>>,
+    ) -> Self::MutRefs<'component>
+    {
+        ()
+    }
+
+    #[inline]
+    fn from_components<'component>(
+        _components: &'component [EntityComponent],
+        _component_index_lookup: impl Fn(Uid) -> Option<usize>,
+        _world: &'component World,
+        _lock_component: fn(&EntityComponent) -> ReadGuard<'_, Box<dyn Component>>,
+    ) -> Self::Refs<'component>
+    {
+        ()
+    }
+}
-- 
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