vararg.h

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#pragma once

#include <type_traits>
#include <vector>

namespace tc {
namespace {

template <typename T>
void inplaceVectorFromArgs(std::vector<T>&) {
  // recursion stopper
}

template <typename T, typename Arg, typename... Args>
void inplaceVectorFromArgs(std::vector<T>& v, Arg arg, Args... args) {
  static_assert(
      std::is_same<T, typename std::remove_reference<Arg>::type>::value,
      "expected identical types");
  v.push_back(std::forward<Arg>(arg));
  inplaceVectorFromArgs(v, std::forward<Args>(args)...);
}
} // namespace

template <typename Arg>
std::vector<Arg> vectorFromArgs() {
  std::vector<Arg> v;
  return v;
}

template <typename Arg, typename... Args>
std::vector<typename std::remove_reference<Arg>::type> vectorFromArgs(
    Arg arg,
    Args... args) {
  std::vector<typename std::remove_reference<Arg>::type> v;
  inplaceVectorFromArgs(v, std::forward<Arg>(arg), std::forward<Args>(args)...);
  return v;
}

template <typename Arg, typename... Args>
std::vector<typename std::remove_reference<Arg>::type> vectorFromCastedArgs(
    Args... args) {
  std::vector<typename std::remove_reference<Arg>::type> v;
  inplaceVectorFromArgs(v, static_cast<Arg>(args)...);
  return v;
}

template <template <class> class ConditionType, typename T, typename... Args>
struct TemplArgsAll {
  const static bool value =
      ConditionType<T>::value && TemplArgsAll<ConditionType, Args...>::value;
};

template <template <class> class ConditionType, typename T>
struct TemplArgsAll<ConditionType, T> {
  const static bool value = ConditionType<T>::value;
};

template <template <class> class ConditionType>
struct TemplArgsAll<ConditionType, void> {
  const static bool value = true;
};

} // namespace tc