"Dynamic" dispatch...

Event.cpp

#include <unordered_map>
#include <functional>
#include <typeindex>
#include <typeinfo>
#include <memory>

class Event {
 public:
  virtual ~Event(){};
};

template <class EventT>
class EventHandler : std::function<void(Event*)> {
 public:
  EventHandler(std::function<void(EventT*)> handler) : m_handler(handler){};

  void operator()(Event* event) { m_handler(static_cast<EventT*>(event)); };

  ~EventHandler() = default;

 protected:
  std::function<void(EventT*)> m_handler;
};

class HandlerMap {
 public:
  void handle(Event* event) {
    auto iter = handlers.find(std::type_index(typeid(*event)));
    if (iter != handlers.end()) {
      iter->second(event);
    }
  };

  template <class EventT>
  void registerHandler(std::function<void(EventT*)> handler) {
    handlers[std::type_index(typeid(EventT))] = EventHandler(handler);
  }

  template <class EventT>
  void registerHandler(EventHandler<EventT> handler) {
    handlers[std::type_index(typeid(EventT))] = handler;
  }
  ~HandlerMap() = default;

 protected:
  typedef std::unordered_map<std::type_index, std::function<void(Event*)>>
      Handlers;
  Handlers handlers;
};

int main() {
  HandlerMap map;

  map.registerHandler(EventHandler<IntEvent>(foo));
  map.registerHandler(EventHandler<FloatEvent>(bar));
  map.handle(new IntEvent(5));
  map.handle(new FloatEvent(20));

  std::cout << "Press any key to quit..." << std::endl;
  (void)getchar();

  return 0;
}