boost variant defines JSON Wrapper

Note operator JSONValue&() const meant  jw.operator const JSONValue&() the same as jw as in
cout<<render_json_value(jw)<<endl;

#include <vector>
#include <map>
#include <boost\variant.hpp>

typedef decltype(nullptr) nullptr_t;
struct JSONWrapper;
using JSONArray = std::vector<JSONWrapper>;
typedef std::map<std::string, JSONArray> JSONObject;
using JSONValue = boost::variant<bool, double, std::string, nullptr_t, JSONArray, JSONObject>;

struct JSONWrapper {
 JSONValue value;
 operator JSONValue&() { return value; }
 operator const JSONValue&() const { return value; }
};