Class Visitor

examples/event_handling/EventHandling.cpp:49–116

    // Make sure all defined operator()s return the same type.
    // The operator()s can also have void return type if there is nothing to return.
    struct Visitor
    {
        explicit Visitor(Application& app) : application(app)
        {
        }

        std::optional<std::string> operator()(const sf::Event::Closed&)
        {
            application.m_window.close();
            return std::nullopt;
        }

        std::optional<std::string> operator()(const sf::Event::KeyPressed& keyPress)
        {
            // When the enter key is pressed, switch to the next handler type
            if (keyPress.code == sf::Keyboard::Key::Enter)
            {
                application.m_handlerType = HandlerType::Overload;
                application.m_handlerText.setString("Current Handler: Overload");
            }

            return "Key Pressed: " + sf::Keyboard::getDescription(keyPress.scancode).toAnsiString();
        }

        std::optional<std::string> operator()(const sf::Event::KeyReleased& keyRelease)
        {
            return "Key Released: " + sf::Keyboard::getDescription(keyRelease.scancode).toAnsiString();
        }

        std::optional<std::string> operator()(const sf::Event::MouseMoved& mouseMoved)
        {
            return "Mouse Moved: " + vec2ToString(mouseMoved.position);
        }

        std::optional<std::string> operator()(const sf::Event::MouseButtonPressed&)
        {
            return "Mouse Pressed";
        }

        std::optional<std::string> operator()(const sf::Event::TouchBegan& touchBegan)
        {
            return "Touch Began: " + vec2ToString(touchBegan.position);
        }

        std::optional<std::string> operator()(const sf::Event::TouchEnded& touchEnded)
        {
            return "Touch Ended: " + vec2ToString(touchEnded.position);
        }

        std::optional<std::string> operator()(const sf::Event::TouchMoved& touchMoved)
        {
            return "Touch Moved: " + vec2ToString(touchMoved.position);
        }

        // When defining a visitor, make sure all event types can be handled by it.
        // If you don't intend on exhaustively specifying an operator() for each
        // event type, you can provide a templated operator() that will be selected
        // by overload resolution when no other event type matches.