https://skydrive.live.com/?cid=f1b8ff18a2aec5c5&id=F1B8FF18A2AEC5C5!1158&authkey=!APo6bfP5sJ8EmH4

Expected.hpp

template <class T>
class Expected {
  union {
		T ham;
		std::exception_ptr spam;
	};
	bool gotHam;
	Expected() {} // used internally
public:
	Expected(const T& rhs) : ham(rhs), gotHam(true) {}
	Expected(T&& rhs)
		: ham(std::move(rhs))
		, gotHam(true) {}
	Expected(const Expected& rhs) : gotHam(rhs.gotHam) {
		if (gotHam) new(&ham) T(rhs.ham);
		else new(&spam) std::exception_ptr(rhs.spam);
	}
	Expected(Expected&& rhs) : gotHam(rhs.gotHam) {
		if (gotHam) new(&ham) T(std::move(rhs.ham));
		else new(&spam)
			std::exception_ptr(std::move(rhs.spam));
	}
	void swap(Expected& rhs) {
		if (gotHam) {
			if (rhs.gotHam) {
				using std::swap;
				swap(ham, rhs.ham);
			} else {
				auto t = std::move(rhs.spam);
				new(&rhs.ham) T(std::move(ham));
				new(&spam) std::exception_ptr(t);
				std::swap(gotHam, rhs.gotHam);
			}
		} else {
			if (rhs.gotHam) {
				rhs.swap(*this);
			} else {
				spam.swap(rhs.spam);
				std::swap(gotHam, rhs.gotHam);
			}
		}
	}
	template <class E>
	static Expected<T> fromException(const E& exception) {
		if (typeid(exception) != typeid(E)) {
			throw std::invalid_argument(
				"slicing detected");
		}
		return fromException(
			std::make_exception_ptr(exception));
	}
	static Expected<T> fromException(std::exception_ptr p) {
		Expected<T> result;
		result.gotHam = false;
		new(&result.spam) std::exception_ptr(std::move(p));
		return result;
	}
	static Expected<T> fromException() {
		return fromException(std::current_exception());
	}
	bool valid() const {
		return gotHam;
	}
	T& get() {
		if (!gotHam) std::rethrow_exception(spam);
		return ham;
	}
	const T& get() const {
		if (!gotHam) std::rethrow_exception(spam);
		return ham;
	}
	template <class E>
	bool hasException() const {
		try {
			if (!gotHam) std::rethrow_exception(spam);
		} catch (const E& object) {
			return true;
		} catch (...) {
		}
		return false;
	}
	template <class F>
	static Expected fromCode(F fun) {
		try {
			return Expected(fun());
		} catch (...) {
			return fromException();
		}
	}
};