Metaprogramming-impl.hpp

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#ifndef DART_COMMON_DETAIL_METAPROGRAMMING_HPP_
#define DART_COMMON_DETAIL_METAPROGRAMMING_HPP_
 
#include <type_traits>
 
#include "dart/common/Metaprogramming.hpp"
 
namespace dart::common::detail {
 
// Inspired by https://stackoverflow.com/a/6324863/3122234
 
// Variadic to force ambiguity of class members. C++11 and up.
template <typename... Args>
struct ambiguate : public Args...
{
};
 
// Non-variadic version of the line above.
// template <typename A, typename B> struct ambiguate : public A, public B {};
 
template <typename A, typename = void>
struct got_type : std::false_type
{
};
 
template <typename A>
struct got_type<A> : std::true_type
{
  using type = A;
};
 
template <typename T, T>
struct sig_check : std::true_type
{
};
 
template <typename Alias, typename AmbiguitySeed>
struct has_member
{
  template <typename C>
  static char (&f(decltype(&C::value)))[1];
 
  template <typename C>
  static char (&f(...))[2];
 
  // Make sure the member name is consistently spelled the same.
  static_assert(
      (sizeof(f<AmbiguitySeed>(0)) == 1),
      "Member name specified in AmbiguitySeed is different from member name "
      "specified in Alias, or wrong Alias/AmbiguitySeed has been specified.");
 
  static bool const value = sizeof(f<Alias>(0)) == 2;
};
 
} // namespace dart::common::detail
 
#endif // DART_COMMON_DETAIL_METAPROGRAMMING_HPP_