C++17 std::optional will not support optional references. Remove the …

…use of optional references in the ECS as a result.

examples/ex10/main.cpp

@@ -62,10 +62,10 @@ int left_x, right_x, top_y, bottom_y;
 
 struct actor_moved_message : base_message_t {
 	actor_moved_message() {}
-	actor_moved_message(boost::optional<entity_t &> ACTOR, const int fx, const int fy, const int dx, const int dy) :
+	actor_moved_message(entity_t * ACTOR, const int fx, const int fy, const int dx, const int dy) :
 		mover(ACTOR), from_x(fx), from_y(fy), destination_x(dx), destination_y(dy) {}
 
-	boost::optional<entity_t &> mover;
+	entity_t * mover;
 	int from_x, from_y, destination_x, destination_y;
 };
 

rltk/ecs.cpp

@@ -19,28 +19,28 @@ void unset_component_mask(const std::size_t id, const std::size_t family_id, boo
 	}
 }
 
-boost::optional<entity_t&> entity(const std::size_t id) noexcept {
-	boost::optional<entity_t&> result;
+entity_t * entity(const std::size_t id) noexcept {
+	entity_t * result = nullptr;
 	auto finder = entity_store.find(id);
 	if (finder == entity_store.end()) return result;
 	if (finder->second.deleted) return result;
-	result = finder->second;
+	result = &finder->second;
 	return result;
 }
 
-boost::optional<entity_t&> create_entity() {
-	entity_t new_entity;
+entity_t * create_entity() {
+    entity_t new_entity;
     while (entity_store.find(new_entity.id) != entity_store.end()) {
         ++entity_t::entity_counter;
         new_entity.id = entity_t::entity_counter;
     }
     //std::cout << "New Entity ID#: " << new_entity.id << "\n";
 
     entity_store.emplace(new_entity.id, new_entity);
-	return entity(new_entity.id);
+    return entity(new_entity.id);
 }
 
-boost::optional<entity_t&> create_entity(const std::size_t new_id) {
+entity_t * create_entity(const std::size_t new_id) {
 	entity_t new_entity(new_id);
     if (entity_store.find(new_entity.id) != entity_store.end()) {
         throw std::runtime_error("WARNING: Duplicate entity ID. Odd things will happen\n");
@@ -200,4 +200,4 @@ std::string ecs_profile_dump() {
 	return ss.str();
 }
 
-}
+}

rltk/ecs.hpp

@@ -15,7 +15,6 @@
 #include <queue>
 #include <future>
 #include <mutex>
-#include <boost/optional.hpp>
 #include <typeinfo>
 #include <atomic>
 #include "serialization_utils.hpp"
@@ -259,16 +258,16 @@ struct entity_t {
 	 * Find a component of the specified type that belongs to the entity.
 	 */
 	template <class C>
-	inline boost::optional<C&> component() noexcept {
-		boost::optional<C&> result;
+	inline C * component() noexcept {
+		C * result = nullptr;
 		if (deleted) return result;
 
 		C empty_component;
 		component_t<C> temp(empty_component);
 		if (!component_mask.test(temp.family_id)) return result;
 		for (component_t<C> &component : static_cast<component_store_t<component_t<C>> *>(component_store[temp.family_id].get())->components) {
 			if (component.entity_id == id) {
-				result = component.data;
+				result = &component.data;
 				return result;
 			}
 		}
@@ -290,18 +289,18 @@ void unset_component_mask(const std::size_t id, const std::size_t family_id, boo
  * entity(ID) is used to reference an entity. So you can, for example, do:
  * entity(12)->component<position_component>()->x = 3;
  */
-boost::optional<entity_t&> entity(const std::size_t id) noexcept;
+entity_t * entity(const std::size_t id) noexcept;
 
 /*
  * Creates an entity with a new ID #. Returns a pointer to the entity, to enable
  * call chaining. For example create_entity()->assign(foo)->assign(bar)
  */
-boost::optional<entity_t&> create_entity();
+entity_t * create_entity();
 
 /*
  * Creates an entity with a specified ID #. You generally only do this during loading.
  */
-boost::optional<entity_t&> create_entity(const std::size_t new_id);
+entity_t * create_entity(const std::size_t new_id);
 
 /*
  * Finds all entities that have a component of the type specified, and returns a