iod json parsing of nested objects

json_nested.cc

#include <iostream>
#include <iod/json.hh>

// Run iod_generate_symbols test.cc symbols.hh
#include "symbols.hh"

int main()
{
  std::string str = R"({"name": "x", "position": { "x": 10, "y": 11, "z": 12}})";
  using namespace s;
  auto o = iod::D(_name = std::string(),
                  _position = iod::D(_x = int(), _y = int(), _z = int()));

  json_decode(o, str);

  assert(o.name == "x");
  assert(o.position.x == 10);
  assert(o.position.y == 11);
  assert(o.position.z == 12);
}