Add GFTag class and related tests

cpp/src/doc_classes/GFComponent.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="GFComponent" inherits="GFRegisterableEntity"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
+<class name="GFComponent" inherits="GFRegisterableEntity" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
 	<brief_description>
 		A reference to a Glecs component from a [GFWorld] that is attatached to an entity.
 	</brief_description>

cpp/src/doc_classes/GFComponentBuilder.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="GFComponentBuilder" inherits="RefCounted" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
+<class name="GFComponentBuilder" inherits="RefCounted"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
 	<brief_description>
 		Builder for a new component type.
 	</brief_description>

cpp/src/doc_classes/GFEntity.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<class name="GFEntity" inherits="RefCounted"
-	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
+<class name="GFEntity" inherits="RefCounted" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
 	<brief_description>
 		A reference to an entity from a [GFWorld].
 	</brief_description>
@@ -10,6 +9,20 @@
 		<link title="More on Flecs Entities">https://www.flecs.dev/flecs/md_docs_2EntitiesComponents.html</link>
 	</tutorials>
 	<methods>
+		<method name="add" qualifiers="const vararg">
+			<return type="GFEntity" />
+			<param index="0" name="component" type="Variant" />
+			<description>
+				Adds component data of type [param component] to this entity.
+				The component's type ID is coerced from a [Variant]. To learn more about [Variant] coercion see [method GFWorld.coerce_id].
+				[codeblock]
+				var entity:= GFEntity.new()
+				entity.add(GFPosition2D, Vector2(10, 10))
+				entity.get(GFPosition2D).get_vec() == Vector2(10, 10) # true
+				[/codeblock]
+				This method returns [code]self[/code] for chaining.
+			</description>
+		</method>
 		<method name="add_child">
 			<return type="GFEntity" />
 			<param index="0" name="entity" type="Variant" />
@@ -32,20 +45,6 @@
 				This codeblock returns [code]self[/code] for chaining.
 			</description>
 		</method>
-		<method name="add" qualifiers="const vararg">
-			<return type="GFEntity" />
-			<param index="0" name="component" type="Variant" />
-			<description>
-				Adds component data of type [param component] to this entity.
-				The component's type ID is coerced from a [Variant]. To learn more about [Variant] coercion see [method GFWorld.coerce_id].
-				[codeblock]
-				var entity:= GFEntity.new()
-				entity.add(GFPosition2D, Vector2(10, 10))
-				entity.get(GFPosition2D).get_vec() == Vector2(10, 10) # true
-				[/codeblock]
-				This method returns [code]self[/code] for chaining.
-			</description>
-		</method>
 		<method name="add_pair" qualifiers="const vararg">
 			<return type="GFEntity" />
 			<param index="0" name="first" type="Variant" />

cpp/src/doc_classes/GFTag.xml

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="GFTag" inherits="GFRegisterableEntity"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="https://raw.githubusercontent.com/godotengine/godot/master/doc/class.xsd">
+	<brief_description>
+		A reference to an entity with no data.
+	</brief_description>
+	<description>
+		Tags are a kind of entity that can be attached to other entities to mark them without adding data, unlike components which will add data when attatched.
+	</description>
+	<tutorials>
+		<link title="More on Flecs Tags">https://www.flecs.dev/flecs/md_docs_2Quickstart.html#tag</link>
+	</tutorials>
+	<methods>
+		<method name="from" qualifiers="static">
+			<return type="GFTag" />
+			<param index="0" name="tag" type="Variant" />
+			<param index="1" name="world" type="GFWorld" default="null" />
+			<description>
+				Returns an entity from an ID coerced from a [Variant].
+				If no world is specified, a default world is used.
+				To learn more about [Variant] coercion see [method GFWorld.coerce_id].
+				[codeblock]
+				var entity:= GFTag.from("flecs/core/Trait")
+				[/codeblock]
+			</description>
+		</method>
+		<method name="from_id" qualifiers="static">
+			<return type="GFTag" />
+			<param index="0" name="tag_id" type="int" />
+			<param index="1" name="world" type="GFWorld" default="null" />
+			<description>
+				Returns an tag from an ID.
+				If no world is specified, a default world is used.
+				[codeblock]
+				var entity:= GFEntity.from_id(255)
+				[/codeblock]
+			</description>
+		</method>
+		<method name="new_in_world" qualifiers="static">
+			<return type="GFTag" />
+			<param index="0" name="world" type="GFWorld" />
+			<description>
+				Returns a reference to a new entity created within [param world].
+				[codeblock]
+				var world:= GFWorld.new()
+				var entity:= GFEntity.new_in_world(world)
+				[/codeblock]
+			</description>
+		</method>
+	</methods>
+</class>

cpp/src/register_types.cpp

@@ -6,6 +6,7 @@
 #include "entity_builder.h"
 #include "gdextension_interface.h"
 #include "godot_cpp/classes/engine.hpp"
+#include "godot_cpp/core/memory.hpp"
 #include "module.h"
 #include "observer_builder.h"
 #include "pair.h"
@@ -16,6 +17,7 @@
 #include "register_types.h"
 #include "registerable_entity.h"
 #include "system_builder.h"
+#include "tag.h"
 #include "world.h"
 
 using namespace godot;
@@ -34,6 +36,7 @@ void initialize_module(ModuleInitializationLevel p_level) {
 			godot::ClassDB::register_class<GFRegisterableEntity>();
 			godot::ClassDB::register_class<GFComponent>();
 			godot::ClassDB::register_class<GFModule>();
+			godot::ClassDB::register_class<GFTag>();
 
 			godot::ClassDB::register_class<GFEntityBuilder>();
 			godot::ClassDB::register_class<GFComponentBuilder>();
@@ -44,6 +47,12 @@ void initialize_module(ModuleInitializationLevel p_level) {
 			godot::ClassDB::register_class<GFObserverBuilder>();
 			godot::ClassDB::register_class<GFQueryBuilder>();
 			godot::ClassDB::register_class<GFSystemBuilder>();
+
+			if (Engine::get_singleton()->has_singleton(GFWorld::SINGLETON_NAME)) {
+				Object* world = Engine::get_singleton()->get_singleton(GFWorld::SINGLETON_NAME);
+				Engine::get_singleton()->unregister_singleton(GFWorld::SINGLETON_NAME);
+				memdelete(world);
+			}
      	   	Engine::get_singleton()->register_singleton(GFWorld::SINGLETON_NAME, memnew(GFWorld));
 			break;
         case MODULE_INITIALIZATION_LEVEL_EDITOR:

cpp/src/tag.cpp

@@ -0,0 +1,46 @@
+
+#include "tag.h"
+#include "utils.h"
+#include <stdint.h>
+#include <flecs.h>
+#include "godot_cpp/classes/wrapped.hpp"
+#include "godot_cpp/variant/array.hpp"
+#include "world.h"
+#include <godot_cpp/core/class_db.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+
+using namespace godot;
+
+GFTag::~GFTag() {
+}
+
+Ref<GFTag> GFTag::new_in_world(GFWorld* world) {
+	return memnew(GFTag(world));
+}
+
+Ref<GFTag> GFTag::from(Variant tag, GFWorld* world) {
+	ecs_entity_t tag_id = world->coerce_id(tag);
+	return from_id(tag_id, world);
+}
+
+Ref<GFTag> GFTag::from_id(ecs_entity_t tag_id, GFWorld* world_) {
+	GFWorld* world = GFWorld::world_or_singleton(world_);
+	Ref<GFTag> ett = memnew(GFTag(
+		tag_id,
+		world
+	));
+	if (!ett->is_alive()) {
+		ERR(nullptr,
+			"Could not instantiate tag from ID\n",
+			"World/ID is not valid/alive"
+		);
+	}
+	return ett;
+}
+
+
+void GFTag::_bind_methods() {
+	godot::ClassDB::bind_static_method(get_class_static(), D_METHOD("new_in_world", "world"), &GFTag::new_in_world);
+	godot::ClassDB::bind_static_method(get_class_static(), D_METHOD("from", "tag", "world"), &GFTag::from, nullptr);
+	godot::ClassDB::bind_static_method(get_class_static(), D_METHOD("from_id", "tag_id", "world"), &GFTag::from_id, nullptr);
+}

cpp/src/tag.h

@@ -0,0 +1,63 @@
+
+#ifndef GF_TAG_H
+#define GF_TAG_H
+
+#include "registerable_entity.h"
+#include "world.h"
+
+#include <flecs.h>
+#include <godot_cpp/classes/ref_counted.hpp>
+#include <godot_cpp/variant/string.hpp>
+
+namespace godot {
+
+	class GFTag : public GFRegisterableEntity {
+		GDCLASS(GFTag, GFRegisterableEntity)
+
+	public:
+		/// Create a new named module
+		GFTag(GFWorld* world):
+			GFRegisterableEntity(
+				ecs_new(
+					world->raw()
+				),
+				world
+			)
+		{}
+		/// Create from existing ID
+		GFTag(ecs_entity_t id, GFWorld* world):
+			GFRegisterableEntity(
+				id,
+				world
+			)
+		{}
+		GFTag():
+			GFRegisterableEntity(GFWorld::singleton())
+		{}
+
+		~GFTag();
+
+		// --------------------------------------
+		// --- Exposed
+		// --------------------------------------
+
+		static Ref<GFTag> new_in_world(GFWorld* world);
+		static Ref<GFTag> new_named_in_world(String name, GFWorld*);
+		static Ref<GFTag> from(Variant module, GFWorld*);
+		static Ref<GFTag> from_id(ecs_entity_t, GFWorld*);
+
+		// --------------------------------------
+		// --- Unexposed
+		// --------------------------------------
+
+	protected:
+		static void _bind_methods();
+
+
+	private:
+
+	};
+
+}
+
+#endif

unittests/test_entities.gd

@@ -3,10 +3,10 @@ extends GutTest
 
 var world:GFWorld = null
 
-func before_all():
+func before_each():
 	world = GFWorld.new()
 
-func after_all():
+func after_each():
 	world.free()
 
 #region Tests

unittests/test_tags.gd

@@ -0,0 +1,29 @@
+
+extends GutTest
+
+var world:GFWorld = null
+
+func before_each():
+	world = GFWorld.new()
+
+func after_each():
+	world.free()
+
+#region Tests
+
+func _test_tag_creation():
+	var enemy:= GFTag.new_in_world(world)
+	var robot:=GFEntity.new_in_world(world) \
+		.add(enemy)
+
+	assert_true(robot.has_entity(enemy), "Expected `robot` to have the `enemy` tag")
+
+#endregion
+
+#region Classes
+
+class Eats extends GFTag: pass
+
+class Grass extends GFTag: pass
+
+#endregion