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add static_asserts

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remove some useless trailing return types and && to help MSVC
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Théo DELRIEU 2017-01-12 22:52:00 +01:00 committed by Théo DELRIEU
parent e678c075dd
commit d0d8070422
1 changed files with 58 additions and 5 deletions
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63
src/json.hpp
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@ -715,27 +715,81 @@ void from_json(Json const &j, ArithmeticType &val)
throw std::domain_error("type must be number, but is " + type_name(j)); throw std::domain_error("type must be number, but is " + type_name(j));
} }
template <typename Json, typename T>
constexpr auto has_adl_from_json(int) -> decltype(from_json(std::declval<Json const&>(), std::declval<T&>()), true)
{
return true;
}
template <typename, typename>
constexpr bool has_adl_from_json(long)
{
return false;
}
template <typename Json, typename T>
constexpr auto has_adl_to_json(int) -> decltype(to_json(std::declval<Json&>(), std::declval<T const&>()), true)
{
return true;
}
template <typename, typename>
constexpr bool has_adl_to_json(long)
{
return false;
}
struct to_json_fn struct to_json_fn
{ {
template <typename Json, typename T> private:
constexpr auto operator()(Json&& j, T&& val) const template <typename Json, typename T, enable_if_t<has_adl_to_json<Json, T>(0), int> = 0>
auto operator()(Json&& j, T&& val) const
noexcept(noexcept(to_json(std::forward<Json>(j), std::forward<T>(val)))) noexcept(noexcept(to_json(std::forward<Json>(j), std::forward<T>(val))))
-> decltype(to_json(std::forward<Json>(j), std::forward<T>(val)), -> decltype(to_json(std::forward<Json>(j), std::forward<T>(val)),
void()) void())
{ {
return to_json(std::forward<Json>(j), std::forward<T>(val)); return to_json(std::forward<Json>(j), std::forward<T>(val));
} }
template <typename Json, typename T, enable_if_t<not has_adl_to_json<Json, T>(0), int> = 0>
void operator()(Json&&, T&&) const noexcept
{
static_assert(has_adl_to_json<Json, T>(0), "to_json method in T's namespace can not be called");
}
public:
template <typename Json, typename T>
void operator()(Json &j, T &&val) const
noexcept(noexcept(std::declval<to_json_fn>().call(0, j, std::forward<T>(val))))
{
return call(0, j, std::forward<T>(val));
}
}; };
struct from_json_fn struct from_json_fn
{ {
template <typename Json, typename T> private:
constexpr auto operator()(Json&& j, T& val) const template <typename Json, typename T, enable_if_t<has_adl_from_json<Json, T>(0), int> = 0>
auto operator()(Json&& j, T& val) const
noexcept(noexcept(from_json(std::forward<Json>(j), val))) noexcept(noexcept(from_json(std::forward<Json>(j), val)))
-> decltype(from_json(std::forward<Json>(j), val), void()) -> decltype(from_json(std::forward<Json>(j), val), void())
{ {
return from_json(std::forward<Json>(j), val); return from_json(std::forward<Json>(j), val);
} }
template <typename Json, typename T, enable_if_t<not has_adl_from_json<Json, T>(0), int> = 0>
void operator()(Json&&, T&) const noexcept
{
static_assert(has_adl_from_json<Json, T>(0), "from_json method in T's namespace can not be called");
}
public:
template <typename Json, typename T>
void operator()(Json const &j, T &val) const
noexcept(noexcept(std::declval<from_json_fn>().call(0, j, val)))
{
return call(0, j, val);
}
}; };
/*! /*!
@ -757,7 +811,6 @@ struct DecimalSeparator : std::numpunct<char>
return '.'; return '.';
} }
}; };
} }
// taken from ranges-v3 // taken from ranges-v3