std::tuple mapping to object instead of json::value_t::array

[jacobschloss]

Hi,

I'm having an issue where a function taking parameters of int, std::tuple<double, double, double> seems like it is getting detected as int, json-object instead of int, json-array.

nlohmann-json maps std::pair and std::tuple to json-array.

Example:

When sending a jsonrpc request like
{"jsonrpc":"2.0","id":1,"method":"method","params":{"x":0, "y":[1.0, 2.0, 3.0]}}

to a C++ method with signature
bool method(const int x, const std::tuple<double, double, double>& y);

I get an error:

{"error":{"code":-32602,"message":"invalid parameter: must be object, but is array for parameter \"y\""},"id":1,"jsonrpc":"2.0"}

Adding this to typemapper.hpp to map std::tuples to json::value_t::array

template <typename... T>
constexpr json::value_t GetType(type<std::tuple<T...>>) {
  return json::value_t::array;
}

Seemed to work, and the call was accepted.

[cinemast]

Yes, you already found the solution to that. However, I will not add more custom type mappings built in, since there are just too many.