Add EntityRef.CreateOrNull

src/gaemstone/ECS/EntityRef.cs

@@ -14,7 +14,6 @@ public unsafe sealed class EntityRef
 	public Entity Entity { get; }
 	public uint ID => Entity.ID;
 
-	public bool IsValid => ecs_is_valid(Universe, this);
 	public bool IsAlive => ecs_is_alive(Universe, this);
 	public EntityType Type => new(Universe, ecs_get_type(Universe, this));
 
@@ -29,18 +28,22 @@ public unsafe sealed class EntityRef
 		      ecs_set_symbol(Universe, this, alloc.AllocateCString(value)); }
 	}
 
-	// public IEnumerable<Entity> Children { get {
-	//
-	// } }
 
-	public EntityRef(Universe universe, Entity entity, bool throwOnInvalid = true)
+	private EntityRef(Universe universe, Entity entity, bool throwOnInvalid)
 	{
+		if (throwOnInvalid && !ecs_is_valid(universe, entity))
+			throw new InvalidOperationException($"The entity {entity} is not valid");
 		Universe = universe;
 		Entity   = entity;
-		if (throwOnInvalid && !IsValid) throw new InvalidOperationException(
-			$"The entity {entity} is not valid");
 	}
 
+	public EntityRef(Universe universe, Entity entity)
+		: this(universe, entity, true) {  }
+
+	public static EntityRef? CreateOrNull(Universe universe, Entity entity)
+		=> ecs_is_valid(universe, entity) ? new(universe, entity) : null;
+
+
 	public void Delete()
 		=> ecs_delete(Universe, this);
 

src/gaemstone/ECS/Universe+Lookup.cs

@@ -9,15 +9,15 @@ public unsafe partial class Universe
 {
 	private readonly Dictionary<Type, Entity> _lookupByType = new();
 
-
 	public void AddLookupByType(Type type, Entity entity)
 		=> _lookupByType.Add(type, entity);
 	public void RemoveLookupByType(Type type)
 		{ if (!_lookupByType.Remove(type)) throw new InvalidOperationException(
 			$"Lookup for {type} does not exist"); }
 
-	private EntityRef? GetOrNull(Entity entity)
-		{ var e = new EntityRef(this, entity, false); return e.IsValid ? e : null; }
+
+	private EntityRef? CreateOrNull(Entity entity)
+		=> EntityRef.CreateOrNull(this, entity);
 
 	public EntityRef? Lookup<T>()
 		=> Lookup(typeof(T));
@@ -25,16 +25,16 @@ public unsafe partial class Universe
 		=> Lookup(_lookupByType.GetValueOrDefault(type));
 
 	public EntityRef? Lookup(Entity value)
-		=> GetOrNull(new(ecs_get_alive(this, value)));
+		=> CreateOrNull(new(ecs_get_alive(this, value)));
 
 	public EntityRef? Lookup(EntityPath path)
 		=> Lookup(default, path);
 	public EntityRef? Lookup(Entity parent, EntityPath path)
-		=> GetOrNull(EntityPath.Lookup(this, parent, path));
+		=> CreateOrNull(EntityPath.Lookup(this, parent, path));
 	public EntityRef? LookupSymbol(string symbol)
 	{
 		using var alloc = TempAllocator.Use();
-		return GetOrNull(new(ecs_lookup_symbol(this, alloc.AllocateCString(symbol), false)));
+		return CreateOrNull(new(ecs_lookup_symbol(this, alloc.AllocateCString(symbol), false)));
 	}
 
 	public EntityRef LookupOrThrow<T>() => LookupOrThrow(typeof(T));