Merge f912866fcb into 65a27a798a

jecs.d.ts

@@ -7,10 +7,14 @@ export type Entity<TData = unknown> = number & {
 	readonly __type_TData: TData;
 };
 
+type TagDiscriminator = {
+	readonly __nominal_Tag: unique symbol;
+};
+
 /**
  * An entity with no associated data when used as a component
  */
-export type Tag = Entity<undefined>;
+export type Tag = Entity<TagDiscriminator>;
 
 /**
  * A pair of entities:
@@ -26,12 +30,12 @@ export type Pair<P = unknown, O = unknown> = number & {
  * An `Id` can be either a single Entity or a Pair of Entities.
  * By providing `TData`, you can specifically require an Id that yields that type.
  */
-export type Id<TData = unknown> = Entity<TData> | Pair<TData, unknown> | Pair<undefined, TData>;
+export type Id<TData = unknown> = Entity<TData> | Pair<TData, unknown> | Pair<TagDiscriminator, TData>;
 
 export type InferComponent<E> = E extends Entity<infer D>
 	? D
 	: E extends Pair<infer P, infer O>
-	? P extends undefined
+	? P extends TagDiscriminator
 		? O
 		: P
 	: never;
@@ -119,7 +123,7 @@ export class World {
 	 * @returns An entity (Tag) with no data.
 	 */
 	entity(): Tag;
-	entity<T extends Entity>(id: T): InferComponent<T> extends undefined ? Tag : T;
+	entity<T extends Entity>(id: T): T;
 
 	/**
 	 * Creates a new entity in the first 256 IDs, typically used for static
@@ -148,7 +152,7 @@ export class World {
 	 * @param entity The target entity.
 	 * @param component The component (or tag) to add.
 	 */
-	add<C>(entity: Entity, component: undefined extends InferComponent<C> ? C : Id<undefined>): void;
+	add<C>(entity: Entity, component: TagDiscriminator extends InferComponent<C> ? C : Id<TagDiscriminator>): void;
 
 	/**
 	 * Installs a hook on the given component.

jecs.luau

@@ -126,6 +126,8 @@ type world = {
 
 	max_component_id: number,
 	max_archetype_id: number,
+    start_component_id: number,
+    start_tag_id: number,
 
 	observable: Map<i53, Map<i53, { Observer }>>,
 
@@ -163,6 +165,8 @@ export type World = {
 
 	max_component_id: number,
 	max_archetype_id: number,
+    start_component_id: number,
+    start_tag_id: number,
 
 	observable: Map<Id, Map<Id, { Observer }>>,
 
@@ -760,6 +764,12 @@ local function ECS_ID_IS_WILDCARD(e: i53): boolean
 	return first == EcsWildcard or second == EcsWildcard
 end
 
+local function get_max_ids_difference(world: World): (number, number)
+    local diff_components = world.start_component_id - ecs_max_component_id
+    local diff_tags = world.start_tag_id - ecs_max_tag_id
+    return diff_components, diff_tags
+end
+
 local function id_record_get(world: World, id: Entity): ComponentRecord?
 	local component_index = world.component_index
 	local idr: ComponentRecord = component_index[id]
@@ -2264,6 +2274,9 @@ local function world_new()
 		max_archetype_id = 0,
 		max_component_id = ecs_max_component_id,
         
+        start_component_id = ecs_max_component_id,
+        start_tag_id = ecs_max_tag_id,
+
 		observable = observable,
 		signals = signals,
 	} :: world
@@ -3366,6 +3379,7 @@ return {
 	pair_first = ecs_pair_first :: <P, O>(world: World, pair: Pair<P, O>) -> Id<P>,
 	pair_second = ecs_pair_second :: <P, O>(world: World, pair: Pair<P, O>) -> Id<O>,
 	entity_index_get_alive = entity_index_get_alive,
+    get_max_ids_difference = get_max_ids_difference,
 
 	archetype_append_to_records = archetype_append_to_records,
 	id_record_ensure = id_record_ensure :: (World, Id) -> ComponentRecord,