ChaiScript/include/chaiscript/utility/json_wrap.hpp

#ifndef CHAISCRIPT_SIMPLEJSON_WRAP_HPP
#define CHAISCRIPT_SIMPLEJSON_WRAP_HPP

#include "json.hpp"
#include "../dispatchkit/dynamic_object.hpp"

namespace chaiscript {
  class json_wrap {
  public:
    static Module &library(Module &m) {
      m.add(chaiscript::fun([](const std::string &t_str) { return from_json(t_str); }), "from_json");
      m.add(chaiscript::fun([](const std::string &t_str) { return object_from_json(t_str); }), "object_from_json");
      m.add(chaiscript::fun(&json_wrap::to_json), "to_json");
      m.add(chaiscript::fun(&json_wrap::map_to_object), "map_to_object");
      m.add(chaiscript::fun(&json_wrap::object_to_map), "object_to_map");

      return m;
    }

  private:
    static Boxed_Value from_json(const json::JSON &t_json) {
      switch (t_json.JSONType()) {
        case json::JSON::Class::Null:
          return Boxed_Value();
        case json::JSON::Class::Object: {
          std::map<std::string, Boxed_Value> m;

          for (const auto &p : t_json.object_range()) {
            m.insert(std::make_pair(p.first, from_json(p.second)));
          }

          return Boxed_Value(m);
        }
        case json::JSON::Class::Array: {
          std::vector<Boxed_Value> vec;

          for (const auto &p : t_json.array_range()) {
            vec.emplace_back(from_json(p));
          }

          return Boxed_Value(vec);
        }
        case json::JSON::Class::String:
          return Boxed_Value(t_json.to_string());
        case json::JSON::Class::Floating:
          return Boxed_Value(t_json.to_float());
        case json::JSON::Class::Integral:
          return Boxed_Value(t_json.to_int());
        case json::JSON::Class::Boolean:
          return Boxed_Value(t_json.to_bool());
      }

      throw std::runtime_error("Unknown JSON type");
    }

    static Boxed_Value from_json(const std::string &t_json) {
      try {
        return from_json(json::JSON::Load(t_json));
      } catch (const std::out_of_range &) {
        throw std::runtime_error("Unparsed JSON input");
      }
    }

    static Boxed_Value object_from_json(const json::JSON &t_json) {
      switch (t_json.JSONType()) {
        case json::JSON::Class::Null:
          return Boxed_Value();
        case json::JSON::Class::Object: {
          auto obj = dispatch::Dynamic_Object("JSON_Object");

          for (const auto &p : t_json.object_range()) {
            obj.get_attr(p.first) = object_from_json(p.second);
          }

          return Boxed_Value(std::move(obj));
        }
        case json::JSON::Class::Array: {
          std::vector<Boxed_Value> vec;

          for (const auto &p : t_json.array_range()) {
            vec.emplace_back(object_from_json(p));
          }

          return Boxed_Value(vec);
        }
        case json::JSON::Class::String:
          return Boxed_Value(t_json.to_string());
        case json::JSON::Class::Floating:
          return Boxed_Value(t_json.to_float());
        case json::JSON::Class::Integral:
          return Boxed_Value(t_json.to_int());
        case json::JSON::Class::Boolean:
          return Boxed_Value(t_json.to_bool());
      }

      throw std::runtime_error("Unknown JSON type");
    }

    static Boxed_Value object_from_json(const std::string &t_json) {
      try {
        return object_from_json(json::JSON::Load(t_json));
      } catch (const std::out_of_range &) {
        throw std::runtime_error("Unparsed JSON input");
      }
    }

    static Boxed_Value map_to_object(const std::map<std::string, Boxed_Value> &t_map) {
      auto obj = dispatch::Dynamic_Object("JSON_Object");

      for (const auto &p : t_map) {
        obj.get_attr(p.first) = p.second;
      }

      return Boxed_Value(std::move(obj));
    }

    static std::map<std::string, Boxed_Value> object_to_map(const dispatch::Dynamic_Object &t_obj) {
      return t_obj.get_attrs();
    }

    static std::string to_json(const Boxed_Value &t_bv) { return to_json_object(t_bv).dump(); }

    static json::JSON to_json_object(const Boxed_Value &t_bv) {
      try {
        const std::map<std::string, Boxed_Value> m = chaiscript::boxed_cast<const std::map<std::string, Boxed_Value> &>(t_bv);

        json::JSON obj(json::JSON::Class::Object);
        for (const auto &o : m) {
          obj[o.first] = to_json_object(o.second);
        }
        return obj;
      } catch (const chaiscript::exception::bad_boxed_cast &) {
        // not a map
      }

      try {
        const std::vector<Boxed_Value> v = chaiscript::boxed_cast<const std::vector<Boxed_Value> &>(t_bv);

        json::JSON obj(json::JSON::Class::Array);
        for (size_t i = 0; i < v.size(); ++i) {
          obj[i] = to_json_object(v[i]);
        }
        return obj;
      } catch (const chaiscript::exception::bad_boxed_cast &) {
        // not a vector
      }

      try {
        Boxed_Number bn(t_bv);
        if (Boxed_Number::is_floating_point(t_bv)) {
          return json::JSON(bn.get_as<double>());
        } else {
          return json::JSON(bn.get_as<std::int64_t>());
        }
      } catch (const chaiscript::detail::exception::bad_any_cast &) {
        // not a number
      }

      try {
        return json::JSON(boxed_cast<bool>(t_bv));
      } catch (const chaiscript::exception::bad_boxed_cast &) {
        // not a bool
      }

      try {
        return json::JSON(boxed_cast<std::string>(t_bv));
      } catch (const chaiscript::exception::bad_boxed_cast &) {
        // not a string
      }

      try {
        const chaiscript::dispatch::Dynamic_Object &o = boxed_cast<const dispatch::Dynamic_Object &>(t_bv);

        json::JSON obj(json::JSON::Class::Object);
        for (const auto &attr : o.get_attrs()) {
          obj[attr.first] = to_json_object(attr.second);
        }
        return obj;
      } catch (const chaiscript::exception::bad_boxed_cast &) {
        // not a dynamic object
      }

      if (t_bv.is_null())
        return json::JSON(); // a null value

      throw std::runtime_error("Unknown object type to convert to JSON");
    }
  };

} // namespace chaiscript

#endif