Use std::invocable<T&...>

tests/zecsy.cpp

@@ -1,5 +1,4 @@
 #include <catch2/catch_test_macros.hpp>
-#include <string>
 #define CATCH_CONFIG_MAIN
 #include <catch2/catch_all.hpp>
 
@@ -74,9 +73,9 @@ TEST_CASE("Attach a simple component to an entity and verify it is correctly "
     REQUIRE(w.has<ChoosenOne>(e2));
 }
 
-struct Name
+struct Comp
 {
-    std::string value;
+    int v = 0;
 };
 
 TEST_CASE("Retrieve a component from an entity and verify its data matches "
@@ -85,13 +84,13 @@ TEST_CASE("Retrieve a component from an entity and verify its data matches "
     world w;
 
     auto e = w.make_entity();
-    w.set(e, Name{"zecsy!"});
+    w.set(e, Comp());
 
-    REQUIRE(w.get<Name>(e).value == "zecsy!");
+    REQUIRE(w.get<Comp>(e).v == 0);
 
-    w.get<Name>(e).value = "super-zecsy!";
+    w.get<Comp>(e).v = 77;
 
-    REQUIRE(w.get<Name>(e).value == "super-zecsy!");
+    REQUIRE(w.get<Comp>(e).v == 77);
 }
 
 TEST_CASE(
@@ -161,15 +160,15 @@ TEST_CASE("Attach multiple components to an entity and verify all are "
     world w;
 
     auto e = w.make_entity();
-    w.set(e, ChoosenOne{}, Name{"zecsy"});
+    w.set(e, ChoosenOne{}, Comp{});
 
-    REQUIRE(w.has<ChoosenOne, Name>(e));
+    REQUIRE(w.has<ChoosenOne, Comp>(e));
 
-    w.remove<ChoosenOne, Name>(e);
+    w.remove<ChoosenOne, Comp>(e);
 
-    REQUIRE_FALSE(w.has<ChoosenOne, Name>(e));
+    REQUIRE_FALSE(w.has<ChoosenOne, Comp>(e));
     REQUIRE_FALSE(w.has<ChoosenOne>(e));
-    REQUIRE_FALSE(w.has<Name>(e));
+    REQUIRE_FALSE(w.has<Comp>(e));
 }
 
 TEST_CASE("Create a simple system that processes entities with a specific "

zecsy.hpp

@@ -1,11 +1,13 @@
 #pragma once
 #include <algorithm>
+#include <concepts>
 #include <cstdint>
 #include <cstdlib>
 #include <format>
 #include <functional>
 #include <set>
 #include <stdexcept>
+#include <type_traits>
 #include <unordered_map>
 #include <vector>
 
@@ -13,6 +15,23 @@ namespace zecsy
 {
     using entity_id = uint64_t;
 
+    /*
+     * Actually, not a pure POD. Gotta figure out a better name
+     */
+    template<typename... T>
+    concept Component = []
+    {
+        static_assert((std::is_default_constructible_v<T> && ...),
+                      "Should have a default constructor");
+        static_assert((std::is_trivially_copyable_v<T> && ...),
+                      "Should be trivially copyable");
+        static_assert((std::is_trivially_destructible_v<T> && ...),
+                      "Should be trivially destructible");
+        static_assert((std::is_standard_layout_v<T> && ...),
+                      "Should have standard layout");
+        return true;
+    }();
+
     /*
      * Using std::set for entities_set to maintain sorted order, which can
      * improve cache locality during queries and iterations.
@@ -22,32 +41,32 @@ namespace zecsy
     class component_storage final
     {
     public:
-        template<typename T>
+        template<Component T>
         bool has(entity_id e) const;
 
-        template<typename First, typename Second, typename... Rest>
+        template<Component First, Component Second, Component... Rest>
         bool has(entity_id e) const;
 
-        template<typename T>
+        template<Component T>
         T& get(entity_id e);
 
-        template<typename T>
+        template<Component T>
         void set(entity_id e);
 
-        template<typename T>
+        template<Component T>
         void set(entity_id e, const T& comp);
 
-        template<typename First, typename Second, typename... Rest>
+        template<Component First, Component Second, Component... Rest>
         void set(entity_id e);
 
-        template<typename First, typename Second, typename... Rest>
+        template<Component First, Component Second, Component... Rest>
         void set(entity_id e, const First& comp0, const Second& comp1,
                  const Rest&... rest_comps);
 
-        template<typename T>
+        template<Component T>
         void remove(entity_id e);
 
-        template<typename First, typename Second, typename... Rest>
+        template<Component First, Component Second, Component... Rest>
         void remove(entity_id e);
 
     private:
@@ -75,7 +94,7 @@ namespace zecsy
 
     inline component_storage::comp_id component_storage::next_component_id = 0;
 
-    template<typename T>
+    template<Component T>
     inline bool component_storage::has(entity_id e) const
     {
         auto id = get_component_id<T>();
@@ -86,7 +105,7 @@ namespace zecsy
         return false;
     }
 
-    template<typename T>
+    template<Component T>
     inline T& component_storage::get(entity_id e)
     {
         auto id = get_component_id<T>();
@@ -101,7 +120,7 @@ namespace zecsy
         return *reinterpret_cast<T*>(&pool.data[index * sizeof(T)]);
     }
 
-    template<typename T>
+    template<Component T>
     inline void component_storage::set(entity_id e, const T& comp)
     {
         auto id = get_component_id<T>();
@@ -124,13 +143,13 @@ namespace zecsy
         pool.index_to_entity[index] = e;
     }
 
-    template<typename T>
+    template<Component T>
     inline void component_storage::set(entity_id e)
     {
         set(e, T{});
     }
 
-    template<typename T>
+    template<Component T>
     inline void component_storage::remove(entity_id e)
     {
         auto id = get_component_id<T>();
@@ -153,13 +172,13 @@ namespace zecsy
         pool.index_to_entity.erase(index);
     }
 
-    template<typename First, typename Second, typename... Rest>
+    template<Component First, Component Second, Component... Rest>
     inline bool component_storage::has(entity_id e) const
     {
         return has<First>(e) && has<Second>(e) && (has<Rest>(e) && ...);
     }
 
-    template<typename First, typename Second, typename... Rest>
+    template<Component First, Component Second, Component... Rest>
     inline void component_storage::set(entity_id e)
     {
         set(e, First{});
@@ -167,7 +186,7 @@ namespace zecsy
         (set(e, Rest{}), ...);
     }
 
-    template<typename First, typename Second, typename... Rest>
+    template<Component First, Component Second, Component... Rest>
     inline void component_storage::set(entity_id e, const First& comp0,
                                        const Second& comp1,
                                        const Rest&... rest_comps)
@@ -177,7 +196,7 @@ namespace zecsy
         (set(e, rest_comps), ...);
     }
 
-    template<typename First, typename Second, typename... Rest>
+    template<Component First, Component Second, Component... Rest>
     inline void component_storage::remove(entity_id e)
     {
         remove<First>(e);
@@ -238,23 +257,23 @@ namespace zecsy
         void destroy_entity(entity_id e);
         bool is_alive(entity_id e) const;
 
-        template<typename... T>
+        template<Component... T>
         bool has(entity_id e) const;
 
-        template<typename T>
+        template<Component T>
         T& get(entity_id e);
 
-        template<typename... T>
+        template<Component... T>
         void set(entity_id e);
 
-        template<typename... T>
+        template<Component... T>
         void set(entity_id e, const T&... comps);
 
-        template<typename... T>
+        template<Component... T>
         void remove(entity_id e);
 
-        template<typename... T>
-        void query(auto&& system);
+        template<Component... T>
+        void query(std::invocable<T&...> auto&& system);
 
     private:
         entities_set alive_entities;
@@ -279,38 +298,38 @@ namespace zecsy
         return alive_entities.contains(e);
     }
 
-    template<typename... T>
+    template<Component... T>
     inline bool world::has(entity_id e) const
     {
         return storage.has<T...>(e);
     }
 
-    template<typename T>
+    template<Component T>
     inline T& world::get(entity_id e)
     {
         return storage.get<T>(e);
     }
 
-    template<typename... T>
+    template<Component... T>
     inline void world::set(entity_id e)
     {
         storage.set<T...>(e);
     }
 
-    template<typename... T>
+    template<Component... T>
     inline void world::set(entity_id e, const T&... comps)
     {
         storage.set(e, comps...);
     }
 
-    template<typename... T>
+    template<Component... T>
     inline void world::remove(entity_id e)
     {
         storage.remove<T...>(e);
     }
 
-    template<typename... T>
-    inline void world::query(auto&& system)
+    template<Component... T>
+    inline void world::query(std::invocable<T&...> auto&& system)
     {
         for(auto e: alive_entities)
         {