Now calling this DinkyECS and will use it in the game to move the enemies and such.

dinkyecs.hpp

@@ -0,0 +1,92 @@
+#pragma once
+
+#include <functional>
+#include <typeindex>
+#include <typeinfo>
+#include <unordered_map>
+#include <any>
+
+namespace DinkyECS {
+
+  typedef unsigned long Entity;
+
+  typedef std::unordered_map<Entity, std::any> EntityMap;
+
+  struct World {
+    unsigned long entity_count = 0;
+    std::unordered_map<std::type_index, EntityMap> $components;
+    std::unordered_map<std::type_index, std::any> $facts;
+
+    Entity entity() {
+      return ++entity_count;
+    }
+
+    template <typename Comp>
+      EntityMap& entity_map_for() {
+        return $components[std::type_index(typeid(Comp))];
+      }
+
+    template <typename Comp>
+      void set(Comp val) {
+        $facts[std::type_index(typeid(Comp))] = val;
+      }
+
+    template <typename Comp>
+      Comp &get() {
+        // use .at to get std::out_of_range if fact not set
+        std::any &res = $facts.at(std::type_index(typeid(Comp)));
+        return std::any_cast<Comp&>(res);
+      }
+
+    template <typename Comp>
+      void assign(Entity ent, Comp val) {
+        EntityMap &map = entity_map_for<Comp>();
+        map[ent] = val;
+      }
+
+    template <typename Comp>
+      Comp &component(Entity ent) {
+        EntityMap &map = entity_map_for<Comp>();
+        // use .at for bounds checking
+        std::any &res = map.at(ent);
+        return std::any_cast<Comp&>(res);
+      }
+
+    template<typename Comp>
+      void system(std::function<void(const Entity&, Comp&)> cb) {
+        EntityMap &map = entity_map_for<Comp>();
+        for(auto& [entity, any_comp] : map) {
+          Comp &res = std::any_cast<Comp&>(any_comp);
+          cb(entity, res);
+        }
+      }
+
+    template<typename Comp>
+      void remove(Entity ent) {
+        EntityMap &map = entity_map_for<Comp>();
+        map.erase(ent);
+      }
+
+    template<typename CompA, typename CompB>
+      void system(std::function<void(const Entity&, CompA&, CompB&)> cb) {
+        EntityMap &map_a = entity_map_for<CompA>();
+        EntityMap &map_b = entity_map_for<CompB>();
+
+        for(auto& [entity, any_a] : map_a) {
+          if(map_b.contains(entity)) {
+            CompA &res_a = std::any_cast<CompA&>(any_a);
+            CompB &res_b = component<CompB>(entity);
+            cb(entity, res_a, res_b);
+          }
+        }
+      }
+
+    template<typename CompA, typename CompB>
+      std::function<void()> runner(std::function<void(const Entity&, CompA&, CompB&)> cb) {
+        return [&]{
+          system<CompA, CompB>(cb);
+        };
+      }
+  };
+
+}

scratchpad/myecstest.cpp

@@ -1,92 +1,10 @@
+#include "dinkyecs.hpp"
+
 #include <iostream>
-#include <functional>
-#include <typeindex>
-#include <typeinfo>
-#include <unordered_map>
 #include <fmt/core.h>
-#include <any>
 
 using namespace fmt;
-typedef unsigned long Entity;
-
-typedef std::unordered_map<Entity, std::any> EntityMap;
-
-struct World {
-  unsigned long entity_count = 0;
-  std::unordered_map<std::type_index, EntityMap> $components;
-  std::unordered_map<std::type_index, std::any> $facts;
-
-  Entity entity() {
-    return ++entity_count;
-  }
-
-  template <typename Comp>
-  EntityMap& entity_map_for() {
-    return $components[std::type_index(typeid(Comp))];
-  }
-
-  template <typename Comp>
-  void set(Comp val) {
-    $facts[std::type_index(typeid(Comp))] = val;
-  }
-
-  template <typename Comp>
-  Comp &get() {
-    // use .at to get std::out_of_range if fact not set
-    std::any &res = $facts.at(std::type_index(typeid(Comp)));
-    return std::any_cast<Comp&>(res);
-  }
-
-  template <typename Comp>
-  void assign(Entity ent, Comp val) {
-    EntityMap &map = entity_map_for<Comp>();
-    map[ent] = val;
-  }
-
-  template <typename Comp>
-  Comp &component(Entity ent) {
-    EntityMap &map = entity_map_for<Comp>();
-    // use .at for bounds checking
-    std::any &res = map.at(ent);
-    return std::any_cast<Comp&>(res);
-  }
-
-  template<typename Comp>
-  void system(std::function<void(const Entity&, Comp&)> cb) {
-    EntityMap &map = entity_map_for<Comp>();
-    for(auto& [entity, any_comp] : map) {
-      Comp &res = std::any_cast<Comp&>(any_comp);
-      cb(entity, res);
-    }
-  }
-
-  template<typename Comp>
-  void remove(Entity ent) {
-    EntityMap &map = entity_map_for<Comp>();
-    map.erase(ent);
-  }
-
-  template<typename CompA, typename CompB>
-  void system(std::function<void(const Entity&, CompA&, CompB&)> cb) {
-    EntityMap &map_a = entity_map_for<CompA>();
-    EntityMap &map_b = entity_map_for<CompB>();
-
-    for(auto& [entity, any_a] : map_a) {
-      if(map_b.contains(entity)) {
-        CompA &res_a = std::any_cast<CompA&>(any_a);
-        CompB &res_b = component<CompB>(entity);
-        cb(entity, res_a, res_b);
-      }
-    }
-  }
-
-  template<typename CompA, typename CompB>
-  std::function<void()> runner(std::function<void(const Entity&, CompA&, CompB&)> cb) {
-    return [&]{
-      system<CompA, CompB>(cb);
-    };
-  }
-};
+using DinkyECS::Entity, DinkyECS::World;
 
 struct Position {
   double x, y;