#ifndef LIBSRK31CXX_UTIL_HPP_
#define LIBSRK31CXX_UTIL_HPP_

/* This is a hack. "using" is a better C++11 feature to use, but g++ doesn't support it yet.  */
#define forward_constructors(base_typename, this_typename) \
template <typename... Args>  \
this_typename(Args&&... args) \
: base_typename(std::forward<Args>(args)...) {}

/* This is something that really should be in C++1x.
 * Thanks to T.C.: 
 * https://stackoverflow.com/questions/27879815/c11-get-type-of-first-second-etc-argument-similar-to-result-of#27885283 */
// primary template.
template<class T>
struct function_traits : function_traits<decltype(&T::operator())> {
};

// partial specialization for function type
template<class R, class... Args>
struct function_traits<R(Args...)> {
	using result_type = R;
	using argument_types = std::tuple<Args...>;
};

// partial specialization for function pointer
template<class R, class... Args>
struct function_traits<R (*)(Args...)> {
	using result_type = R;
	using argument_types = std::tuple<Args...>;
};

// partial specialization for std::function
template<class R, class... Args>
struct function_traits<std::function<R(Args...)>> {
	using result_type = R;
	using argument_types = std::tuple<Args...>;
};

// partial specialization for pointer-to-member-function (i.e., operator()'s)
template<class T, class R, class... Args>
struct function_traits<R (T::*)(Args...)> {
	using result_type = R;
	using argument_types = std::tuple<Args...>;
};

template<class T, class R, class... Args>
struct function_traits<R (T::*)(Args...) const> {
	using result_type = R;
	using argument_types = std::tuple<Args...>;
};

template<class T>
using first_argument_type = typename std::tuple_element<0, typename function_traits<T>::argument_types>::type;

#endif