#pragma once

#include "../utility/tmp_util/fundamental/eval_if.hpp"

#include "../utility/tmp_util/fundamental/is_same.hpp"

#include "../utility/tmp_util/fundamental/null_type.hpp"

#include <boost/optional.hpp>

#ifdef __has_include // Check if __has_include is present

# if __has_include(<optional>) // Check for a standard library

# include <optional>

# elif __has_include(<experimental/optional>) // Check for an experimental version

# include <experimental/optional>

# endif

#endif

namespace JSON

{

namespace Internal

{

template <typename T>

struct has_value_type {

};

template <typename T>

using has_value_type_t = typename has_value_type <T>::type;

struct get_value_type

};

template <typename T>

struct is_optional

};

template <typename T, bool _is_optional>

struct is_optional_set_impl

{

static inline bool isSet(T&&) noexcept { return true; }

};

template <typename T>

struct is_optional_set_impl <T, true>

{

static inline bool isSet(T&& t) noexcept { return t.operator bool(); }

};

template <typename T>

inline bool is_optional_set(T&& t) noexcept {

using decayed = typename std::decay <T>::type;

return is_optional_set_impl <T, is_optional <decayed>::value>::isSet(std::forward <T> (t));

}

}

}