json_view: enable_if_not_view_t instead of '!' in the from_json() templates

astyle spaces out the template argument list when it contains a negation;
the alias spells the condition with negation<> and leaves the lines alone.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/conversions/from_json.hpp

@@ -50,8 +50,13 @@ namespace detail
 // json_type_of_t<BasicJsonType> its basic_json type). The helpers below are
 // the accesses that differ between the two.
 
+// the enable_if parameter of the overloads that read basic_json values (written
+// with negation<> because astyle spaces out a template argument list with '!')
+template<typename T>
+using enable_if_not_view_t = enable_if_t<negation<is_json_view<T>>::value, int>;
+
 // the boolean of j, a boolean
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 typename BasicJsonType::boolean_t boolean_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
@@ -64,7 +69,7 @@ bool boolean_value(const View& v)
 }
 
 // the string of j, a string
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::string_t& string_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::string_t*>();
@@ -79,7 +84,7 @@ typename View::string_t string_value(const View& v)
 
 // the binary value of j, a binary value (never a view: a view of a JSON text
 // holds no binary values)
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::binary_t& binary_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::binary_t*>();
@@ -92,7 +97,7 @@ typename View::basic_json_type::binary_t binary_value(const View& /*unused*/)
 }
 
 // the elements of j, an array, for a range-based for loop
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::array_t& array_elements(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -132,7 +137,7 @@ void from_json(const BasicJsonType& j, std::optional<T>& opt)
 
 // read a number value of any of the three number types into val;
 // returns false (leaving val untouched) if j is not a number
-template < typename BasicJsonType, typename ArithmeticType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename ArithmeticType, enable_if_not_view_t<BasicJsonType> = 0 >
 bool get_number_value(const BasicJsonType& j, ArithmeticType& val)
 {
     switch (static_cast<value_t>(j))
@@ -324,7 +329,7 @@ auto from_json(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines
 }
 
 // (for a view, array_t is read element by element below)
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 inline void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
 {
     arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -333,7 +338,7 @@ inline void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType:
 // fill a std::array from the JSON array j: the size is checked once and the
 // elements are read in order, so a short array converts the elements it has and
 // then throws the out_of_range error at() would throw for the first missing one
-template < typename BasicJsonType, typename T, std::size_t N, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename T, std::size_t N, enable_if_not_view_t<BasicJsonType> = 0 >
 void from_json_std_array(const BasicJsonType& j, std::array<T, N>& arr)
 {
     const auto& inner_array = *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -556,7 +561,7 @@ void from_json_object_assign(ConstructibleObjectType& obj, Key&& key, Value&& va
     obj.emplace(std::forward<Key>(key), std::forward<Value>(value));
 }
 
-template < typename BasicJsonType, typename ConstructibleObjectType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename ConstructibleObjectType, enable_if_not_view_t<BasicJsonType> = 0 >
 void from_json_object_impl(const BasicJsonType& j, ConstructibleObjectType& ret)
 {
     const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
@@ -715,7 +720,7 @@ void from_json_pair_array_to_map(const BasicJsonType& j, MapType& m)
 // read a map with enum keys from an object, using the enum's own from_json for
 // the keys (e.g., from NLOHMANN_JSON_SERIALIZE_ENUM); this is the form written
 // with JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
-template < typename BasicJsonType, typename Map, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename Map, enable_if_not_view_t<BasicJsonType> = 0 >
 inline bool from_json_enum_keyed_object(const BasicJsonType& j, Map& m, std::true_type /*key is enum*/)
 {
     if (!j.is_object())

single_include/nlohmann/json.hpp

@@ -6173,8 +6173,13 @@ namespace detail
 // json_type_of_t<BasicJsonType> its basic_json type). The helpers below are
 // the accesses that differ between the two.
 
+// the enable_if parameter of the overloads that read basic_json values (written
+// with negation<> because astyle spaces out a template argument list with '!')
+template<typename T>
+using enable_if_not_view_t = enable_if_t<negation<is_json_view<T>>::value, int>;
+
 // the boolean of j, a boolean
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 typename BasicJsonType::boolean_t boolean_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::boolean_t*>();
@@ -6187,7 +6192,7 @@ bool boolean_value(const View& v)
 }
 
 // the string of j, a string
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::string_t& string_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::string_t*>();
@@ -6202,7 +6207,7 @@ typename View::string_t string_value(const View& v)
 
 // the binary value of j, a binary value (never a view: a view of a JSON text
 // holds no binary values)
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::binary_t& binary_value(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::binary_t*>();
@@ -6215,7 +6220,7 @@ typename View::basic_json_type::binary_t binary_value(const View& /*unused*/)
 }
 
 // the elements of j, an array, for a range-based for loop
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 const typename BasicJsonType::array_t& array_elements(const BasicJsonType& j)
 {
     return *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -6255,7 +6260,7 @@ void from_json(const BasicJsonType& j, std::optional<T>& opt)
 
 // read a number value of any of the three number types into val;
 // returns false (leaving val untouched) if j is not a number
-template < typename BasicJsonType, typename ArithmeticType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename ArithmeticType, enable_if_not_view_t<BasicJsonType> = 0 >
 bool get_number_value(const BasicJsonType& j, ArithmeticType& val)
 {
     switch (static_cast<value_t>(j))
@@ -6447,7 +6452,7 @@ auto from_json(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines
 }
 
 // (for a view, array_t is read element by element below)
-template < typename BasicJsonType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, enable_if_not_view_t<BasicJsonType> = 0 >
 inline void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType::array_t& arr, priority_tag<3> /*unused*/)
 {
     arr = *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -6456,7 +6461,7 @@ inline void from_json_array_impl(const BasicJsonType& j, typename BasicJsonType:
 // fill a std::array from the JSON array j: the size is checked once and the
 // elements are read in order, so a short array converts the elements it has and
 // then throws the out_of_range error at() would throw for the first missing one
-template < typename BasicJsonType, typename T, std::size_t N, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename T, std::size_t N, enable_if_not_view_t<BasicJsonType> = 0 >
 void from_json_std_array(const BasicJsonType& j, std::array<T, N>& arr)
 {
     const auto& inner_array = *j.template get_ptr<const typename BasicJsonType::array_t*>();
@@ -6679,7 +6684,7 @@ void from_json_object_assign(ConstructibleObjectType& obj, Key&& key, Value&& va
     obj.emplace(std::forward<Key>(key), std::forward<Value>(value));
 }
 
-template < typename BasicJsonType, typename ConstructibleObjectType, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename ConstructibleObjectType, enable_if_not_view_t<BasicJsonType> = 0 >
 void from_json_object_impl(const BasicJsonType& j, ConstructibleObjectType& ret)
 {
     const auto* inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
@@ -6838,7 +6843,7 @@ void from_json_pair_array_to_map(const BasicJsonType& j, MapType& m)
 // read a map with enum keys from an object, using the enum's own from_json for
 // the keys (e.g., from NLOHMANN_JSON_SERIALIZE_ENUM); this is the form written
 // with JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
-template < typename BasicJsonType, typename Map, enable_if_t < !is_json_view<BasicJsonType>::value, int > = 0 >
+template < typename BasicJsonType, typename Map, enable_if_not_view_t<BasicJsonType> = 0 >
 inline bool from_json_enum_keyed_object(const BasicJsonType& j, Map& m, std::true_type /*key is enum*/)
 {
     if (!j.is_object())