Private data on parsing

[TerensTare]

• Describe what you want to achieve.
  I was reading about overloading nllohman::adl_serializer<>.
  Wanted to know how to do that with classes that have protected/private data members.

• Describe what you tried.

• Describe which system (OS, compiler) you are using.
  Visual Studio 2019, Windows 10 Home

• Describe which version of the library you are using (release version, develop branch).
  vcpkg latest release

[nlohmann]

This works:

#include <iostream>
#include "json.hpp"

using json = nlohmann::json;

class Foo
{
  public:
    Foo(int x_, int y_) : x(x_), y(y_) {}

  private:
    int x;
    int y;
  
    // to allow access to private members
    friend void to_json(json& j, const Foo& f);
};

void to_json(json& j, const Foo& f)
{
    j["x"] = f.x;
    j["y"] = f.y;
}

int main() {
    Foo f(1,2);
    
    json j(f);
    std::cout << j << std::endl;
}

[TerensTare]

Thank you for everything.
I wish you happy coding.