5 files changed, 64 insertions, 11 deletions
diff --git a/yage/entity/README.md b/yage/entity/README.md
index 6a7704c6..18ac16cf 100644
--- a/yage/entity/README.md
+++ b/yage/entity/README.md
@@ -1,9 +1,10 @@
 # Entity Component System (ECS)
 
-This ECS is heavily inspired from the [Entityx component system](__fix
-link__). It is a much simpler and less efficient implementation, as it does not
-support dedicated pools for the different components, and only stores them on
-the heap and are directed to by pointers.
+This ECS is heavily inspired from the [Entityx component
+system](https://github.com/alecthomas/entityx). It is a much simpler and less
+efficient implementation, as it does not support dedicated pools for the
+different components, and only stores them on the heap and are directed to by
+pointers.
 
 A future improvement would be to store the components in a contiguous area in
 memory, so that the iteration through them can be more efficient.
diff --git a/yage/entity/component.cpp b/yage/entity/component.cpp
index eba2ad0a..4c0eae82 100644
--- a/yage/entity/component.cpp
+++ b/yage/entity/component.cpp
@@ -1,8 +1,24 @@
 #include "component.h"
 
+#include <memory>
+
 namespace yage
 {
 
 GroupId BaseComponent::group_id_counter_ = 0;
 
+ComponentGroup &ComponentGroup::add(std::unique_ptr<BaseComponent> &&component)
+{
+    components_.push_back(std::move(component));
+    return *this;
+}
+
+ComponentGroup::Container::iterator ComponentGroup::begin() {
+    return components_.begin();
+}
+
+ComponentGroup::Container::iterator ComponentGroup::end() {
+    return components_.end();
+}
+
 } // namespace yage
diff --git a/yage/entity/component.h b/yage/entity/component.h
index a21409ff..3f2b3a81 100644
--- a/yage/entity/component.h
+++ b/yage/entity/component.h
@@ -28,13 +28,21 @@ private:
 template <typename T>
 class Component : public BaseComponent
 {
+private:
     GroupId getGroup() override;
 };
 
 class ComponentGroup
 {
 public:
-    std::vector<std::unique_ptr<BaseComponent>> components_;
+    typedef std::vector<std::unique_ptr<BaseComponent>> Container;
+
+    ComponentGroup &add(std::unique_ptr<BaseComponent> &&component);
+    Container::iterator begin();
+    Container::iterator end();
+
+private:
+    Container components_;
 };
 
 template <typename T>
diff --git a/yage/entity/entity.cpp b/yage/entity/entity.cpp
index 25e8e2d0..c20d15d6 100644
--- a/yage/entity/entity.cpp
+++ b/yage/entity/entity.cpp
@@ -3,6 +3,8 @@
 #include "component.h"
 
 #include <algorithm>
+#include <iostream>
+#include <memory>
 
 namespace yage
 {
@@ -29,12 +31,17 @@ bool EntityManager::is_valid(Entity entity) const
     return false;
 }
 
-EntityManager &EntityManager::add_component(Entity entity,
-                                            BaseComponent *component)
+EntityManager &
+EntityManager::add_component(Entity entity,
+                             std::unique_ptr<BaseComponent> &&component)
 {
     auto id = component->getGroup();
     component_masks_[entity] =
         component_masks_[entity] | ComponentMask(1 << id);
+    if (id+1 > component_group_.size()) {
+        component_group_.resize(id+1);
+    }
+    component_group_[id].add(std::move(component));
     return *this;
 }
 
diff --git a/yage/entity/entity.h b/yage/entity/entity.h
index 2aa31a66..93bea8fb 100644
--- a/yage/entity/entity.h
+++ b/yage/entity/entity.h
@@ -1,9 +1,12 @@
 #pragma once
 
-#include <vector>
-
 #include "component.h"
 
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <vector>
+
 namespace yage
 {
 
@@ -24,17 +27,35 @@ public:
     Entity create_entity();
     EntityManager &delete_entity(Entity entity);
     bool is_valid(Entity entity) const;
-    EntityManager &add_component(Entity entity, BaseComponent *component);
+    EntityManager &add_component(Entity entity,
+                                 std::unique_ptr<BaseComponent> &&component);
+    template <typename T>
+    EntityManager &each(std::function<void(T &)> update);
 
 private:
     Entity update_next_entity();
 
     Entity next_entity_ = 0;
 
-public:
     std::vector<ComponentGroup> component_group_;
     std::vector<ComponentMask> component_masks_;
     std::vector<Entity> deleted_;
 };
 
+template <typename T>
+EntityManager &EntityManager::each(std::function<void(T &)> update)
+{
+    T c;
+    auto id = static_cast<BaseComponent *>(&c)->getGroup();
+    for (auto it = component_group_[id].begin();
+         it != component_group_[id].end(); ++it) {
+        auto iteration = it - component_group_[id].begin();
+        if (is_valid(iteration) && component_masks_[iteration][id]) {
+            update(*static_cast<T *>((*it).get()));
+        }
+    }
+
+    return *this;
+}
+
 } // namespace yage