typeChecks.hpp

#pragma once
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnonnull"
 
#include <type_traits>
 
namespace z {
namespace core {
namespace types {
class no {
    bool b[2];
};
template <typename T, typename Arg>
no operator==(const T &, const Arg &);
template <typename T, typename Arg>
no operator<(const T &, const Arg &);
template <typename T, typename Arg>
no operator>(const T &, const Arg &);
 
bool check(...);
no &check(const no &);
 
template <typename T, typename Arg = T>
struct equalExists {
    enum { value = (sizeof(check(*(T *)(0) == *(Arg *)(0))) != sizeof(no)) };
};
 
template <typename T, typename Arg = T>
struct lesserExists {
    enum { value = (sizeof(check(*(T *)(0) < *(Arg *)(0))) != sizeof(no)) };
};
 
template <typename T, typename Arg = T>
struct greaterExists {
    enum { value = (sizeof(check(*(T *)(0) > *(Arg *)(0))) != sizeof(no)) };
};
} // namespace types
} // namespace core
} // namespace z
 
#pragma GCC diagnostic pop