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constexpr double DOUBLE_NULL    =    -std::numeric_limits<double>::infinity();
constexpr float FLOAT_NULL    =    -std::numeric_limits<float>::infinity();

class Nuller {
public:
	operator int() const                { return INT_NULL; }
	operator int64() const              { return INT64_NULL; }
	operator double() const             { return DOUBLE_NULL; }
	operator float() const              { return FLOAT_NULL; }
	operator bool() const               { return false; }

	Nuller() {}
};

extern const Nuller Null;

template <class T> void SetNull(T& x) { x = Null; }

template <class T> bool IsNull(const T& x)       { return x.IsNullInstance(); }

template<> inline bool  IsNull(const int& i)     { return i == INT_NULL; }
template<> inline bool  IsNull(const int64& i)   { return i == INT64_NULL; }
template<> inline bool  IsNull(const double& r)  { return !(std::abs(r) < std::numeric_limits<double>::infinity()); }
template<> inline bool  IsNull(const float& r)   { return !(std::abs(r) < std::numeric_limits<float>::infinity()); }
template<> inline bool  IsNull(const bool& r  )  { return false; }
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