cereal と boost::variant で何でもほいほい入れてシリアライズする例 ref: http://qiita.com/usagi/items/497a07909069187cd045

file0.txt

#include <cereal/cereal.hpp>
#include <cereal/archives/json.hpp>
#include <cereal/types/vector.hpp>
#include <cereal/types/unordered_map.hpp>
#include <cereal/types/string.hpp>
#include <cereal/types/boost_variant.hpp>

using variant_data_type = boost::make_recursive_variant
< std::string
, std::uint8_t, std::uint16_t, std::uint32_t, std::uint64_t
, std::int8_t, std::int16_t, std::int32_t, std::int64_t
, float, double, long double
, bool
, std::vector< boost::recursive_variant_ >
, std::unordered_map< std::string, boost::recursive_variant_ >
>::type;

using variant_array_type = std::vector< variant_data_type >;
using variant_map_type   = std::unordered_map< std::string, variant_data_type >;

auto main() -> int
{
  using namespace std::literals::string_literals;

  variant_array_type array{ "hoge"s, true, false, 0x12345678 };
  variant_map_type   map{ { "key-1"s, "value"s }, { "key-2"s, 3.14f }, { "key-3"s, array } };
  variant_data_type  data = map;
  cereal::JSONOutputArchive( std::cout )( data );
}

file1.txt

{
    "value0": {
        "which": 14,
        "data": [
            {
                "key": "key-3",
                "value": {
                    "which": 13,
                    "data": [
                        {
                            "which": 0,
                            "data": "hoge"
                        },
                        {
                            "which": 12,
                            "data": true
                        },
                        {
                            "which": 12,
                            "data": false
                        },
                        {
                            "which": 7,
                            "data": 305419896
                        }
                    ]
                }
            },
            {
                "key": "key-1",
                "value": {
                    "which": 0,
                    "data": "value"
                }
            },
            {
                "key": "key-2",
                "value": {
                    "which": 9,
                    "data": 3.1400001049041748
                }
            }
        ]
    }
}