Class Json

python-package/compile/include/LightGBM/json11.hpp:67–197

class JsonValue;

class Json final {
 public:
    // Types
    enum Type {
        NUL, NUMBER, BOOL, STRING, ARRAY, OBJECT
    };

    // Array and object typedefs
    typedef std::vector<Json> array;
    typedef std::map<std::string, Json> object;

    // Constructors for the various types of JSON value.
    Json() noexcept;                 // NUL
    Json(std::nullptr_t) noexcept;   // NUL
    Json(double value);              // NUMBER
    Json(int value);                 // NUMBER
    Json(bool value);                // BOOL
    Json(const std::string &value);  // STRING
    Json(std::string &&value);       // STRING
    Json(const char * value);        // STRING
    Json(const array &values);       // ARRAY
    Json(array &&values);            // ARRAY
    Json(const object &values);      // OBJECT
    Json(object &&values);           // OBJECT

    // Implicit constructor: anything with a to_json() function.
    template <class T, class = decltype(&T::to_json)>
    Json(const T & t) : Json(t.to_json()) {}

    // Implicit constructor: map-like objects (std::map, std::unordered_map, etc)
    template <class M, typename std::enable_if<
        std::is_constructible<std::string, decltype(std::declval<M>().begin()->first)>::value
        && std::is_constructible<Json, decltype(std::declval<M>().begin()->second)>::value,
            int>::type = 0>
    Json(const M & m) : Json(object(m.begin(), m.end())) {}

    // Implicit constructor: vector-like objects (std::list, std::vector, std::set, etc)
    template <class V, typename std::enable_if<
        std::is_constructible<Json, decltype(*std::declval<V>().begin())>::value,
            int>::type = 0>
    Json(const V & v) : Json(array(v.begin(), v.end())) {}

    // This prevents Json(some_pointer) from accidentally producing a bool. Use
    // Json(bool(some_pointer)) if that behavior is desired.
    Json(void *) = delete;

    // Accessors
    Type type() const;

    bool is_null()   const { return type() == NUL; }
    bool is_number() const { return type() == NUMBER; }
    bool is_bool()   const { return type() == BOOL; }
    bool is_string() const { return type() == STRING; }
    bool is_array()  const { return type() == ARRAY; }
    bool is_object() const { return type() == OBJECT; }

    // Return the enclosed value if this is a number, 0 otherwise. Note that json11 does not
    // distinguish between integer and non-integer numbers - number_value() and int_value()