#include <boost/di.hpp>
namespace di = boost::di;

class ctor {
public:
  explicit ctor(int i) : i(i) {}
  int i;
};

struct aggregate {
  double d;
};

class example {
 public:
  example(aggregate a, const ctor& c) {
    assert(87.0 == a.d);
    assert(42 == c.i);
  };
};

int main() {
  const auto injector = di::make_injector(
    di::bind<int>.to(42),
    di::bind<double>.to(87.0)
  );

  injector.create<example>();
}

struct interface {
  virtual ~interface() noexcept = default;
  virtual int get() const = 0;
};

class implementation : public interface {
public:
  int get() const override { return 42; }
};

struct example {
  example(std::shared_ptr<interface> i) {
    assert(42 == i->get());
  }
};

int main() {
  const auto injector = di::make_injector(
    di::bind<interface>.to<implementation>()
  );

  injector.create<std::unique_ptr<example>>();
}

template<class ErrorPolicy = class TErrorPolicy>
class simple_updater {
public:
  void update() const {
    ErrorPolicy::on("update");
  }
};

template<class Updater = class TUpdater>
class example {
public:
  explicit example(const Updater& updater)
    : updater(updater)
  { }

  void update() {
    updater.update();
  }

private:
  const Updater& updater;
};

int main() {
  struct throw_policy {
    static void on(const std::string& str) {
      throw std::runtime_error(str);
    }
  };

  const auto injector = di::make_injector(
    di::bind<class TErrorPolicy>.to<throw_policy>(),
    di::bind<class TUpdater>.to<simple_updater>()
  );

  injector.create<example>().update();
  // Terminates with an uncaught exception because of our bound error policy
}

struct Streamable {
 template<class T>
 auto requires(T&& t) -> decltype(
   int( t.read() ),
   t.write(int)
 );
};

template<class Exchange = Streamable(class ExchangeStream)
         class Engine   = Streamable(class EngineStream)>
class example {
public:
  example(Exchange exchange, Engine engine)
    : exchange(std::move(exchange)), engine(std::move(engine))
  { }
  
private:
  Exchange exchange;
  Engine engine;
};

int main() {
  const auto injector = di::make_injector(
    di::bind<Streamable(class ExchangeStream)>.to<exchange>(),
    di::bind<Streamable(class EngineStream)>.to<engine>()
  );

  injector.create<example>();
}