json_type

template<typename J, typename T>
concept json_type = std::disjunction_v<
    std::is_same<T, typename J::Nul>,
    std::is_same<T, typename J::Bol>,
    std::is_same<T, typename J::Num>,
    std::is_same<T, typename J::Str>,
    std::is_same<T, typename J::Arr>,
    std::is_same<T, typename J::Obj>
>;

In mysvac:: json namespace, it is used to determine whether a type T is a subtype within J. J must be an instantiated type of the json:: Json class template.

As json::Json is a class template, its inner types differ based on the template arguments. Hence, the concept must consider both the type T to be checked and the container type J as input.

The template supports only the six JSON data types and does not account for the JSON container type J.

Example

using namespace mysvac;

...

if constexpr (json_type<Json, T>) {
    std::cout << "T is a JSON object." << std::endl;
} else {
    std::cout << "T is not a JSON object." << std::endl;
}

Version

Since v3.0.0 .