doc: minor changes

README.md

@@ -112,14 +112,10 @@ mind.
 
 ```cpp
 #include <entt/entt.hpp>
-#include <cstdint>
 
 struct position {
     float x;
     float y;
-    position(float x, float y)
-      : x(x), y(y)
-    {}
 };
 
 struct velocity {
@@ -128,47 +124,37 @@ struct velocity {
 };
 
 void update(entt::registry &registry) {
-    auto view = registry.view<position, velocity>();
+    auto view = registry.view<const position, velocity>();
 
-    for(auto entity: view) {
-        // gets only the components that are going to be used ...
+    // use a callback
+    view.each([](const auto &pos, auto &vel) { /* ... */ });
 
-        auto &vel = view.get<velocity>(entity);
-
-        vel.dx = 0.;
-        vel.dy = 0.;
+    // use an extended callback
+    view.each([](const auto entity, const auto &pos, auto &vel) { /* ... */ });
 
+    // use a range-for
+    for(auto [entity, pos, vel]: view.each()) {
         // ...
     }
-}
-
-void update(std::uint64_t dt, entt::registry &registry) {
-    registry.view<position, velocity>().each([dt](auto &pos, auto &vel) {
-        // gets all the components of the view at once ...
-
-        pos.x += vel.dx * dt;
-        pos.y += vel.dy * dt;
 
+    // use forward iterators and get only the components of interest
+    for(auto entity: view) {
+        auto &vel = view.get<velocity>(entity);
         // ...
-    });
+    }
 }
 
 int main() {
     entt::registry registry;
-    std::uint64_t dt = 16;
+    entt::entity entities[10u];
 
-    for(auto i = 0; i < 10; ++i) {
-        auto entity = registry.create();
-        // uses parameterized constructor ...
+    for(auto i = 0u; i < 10u; ++i) {
+        const auto entity = registry.create();
         registry.emplace<position>(entity, i * 1.f, i * 1.f);
-        // uses aggregate initialization ...
         if(i % 2 == 0) { registry.emplace<velocity>(entity, i * .1f, i * .1f); }
     }
 
-    update(dt, registry);
     update(registry);
-
-    // ...
 }
 ```
 

docs/md/entity.md

@@ -230,43 +230,12 @@ vel.dx = 0.;
 vel.dy = 0.;
 ```
 
-The `emplace` member function utilizes [std::forward](https://en.cppreference.com/w/cpp/utility/forward)
-to allow you to pass your component's parameterized constructor's arguments:
+The default storage _detects_ aggregate types internally and exploits aggregate
+initialization when possible.<br/>
+Therefore, it's not strictly necessary to define a constructor for each type, in
+accordance with the rules of the language.
 
-```cpp
-struct position {
-    float x;	    
-    float y;
-    position(float x, float y)
-      : x(x), y(y)
-    {}
-};
-
-
-// ...
-
-auto &vel = registry.emplace<position>(entity,  100.0f, 100.0f);
-```
-
-Using `emplace`, you can take advantage of [aggregate initialization](https://en.cppreference.com/w/cpp/language/aggregate_initialization). As long as your component structs adhere to 
-the rules of aggregate types, registry.emplace will utilize aggregate
-initializatiion which sets property values in the order in which they are 
-declared in the structure.
-
-```cpp
-struct velocity {
-    float dx;
-    float dy;
-}
-
-// ...
-
-auto &vel = registry.emplace<velocity>(entity,  0.0f, 0.0f);
-```
-
-
-Similarly, `insert` does it for multiple entities and accepts a range rather
-than a single entity in order to:
+On the other hand, `insert` works with _ranges_ and can be used to:
 
 * Assign the same component to all entities at once when a type is specified as
   a template parameter or an instance is passed as an argument:
@@ -279,7 +248,7 @@ than a single entity in order to:
   registry.insert(from, to, position{0., 0.});
   ```
 
-* Assign a range of components to the entities when a range is provided (the
+* Assign a set of components to the entities when a range is provided (the
   length of the range of components must be the same of that of entities):
 
   ```cpp