JSON for Modern C++ 1.1.0

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~basic_json
| template<template< typename U, typename V, typename...Args > class ObjectType = std::map, template< typename U, typename...Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = int64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator>
static basic_json nlohmann::basic_json::parse | ( | const string_t & | s,
|  | parser_callback_t | cb = `nullptr`
| ) |  |
| inline static
  Parameters
  [in] | s | string to read a serialized JSON value from
  [in] | cb | a parser callback function of type parser_callback_t which is used to control the deserialization by filtering unwanted values (optional)
  Returns result of the deserialization Complexity Linear in the length of the input. The parser is a predictive LL(1) parser. The complexity can be higher if the parser callback function cb has a super-linear complexity. Note A UTF-8 byte order mark is silently ignored. Example The example below demonstrates the parse function with and without callback function. 1 #include <json.hpp> 2 3 using namespace nlohmann; 4 5 int main() 6 { 7 // a JSON text 8 std::string text = R"( 9 { 10 "Image": { 11 "Width": 800, 12 "Height": 600, 13 "Title": "View from 15th Floor", 14 "Thumbnail": { 15 "Url": "http://www.example.com/image/481989943", 16 "Height": 125, 17 "Width": 100 18 }, 19 "Animated" : false, 20 "IDs": [116, 943, 234, 38793] 21 } 22 } 23 )"; 24 25 // parse and serialize JSON 26 json j_complete = json::parse(text); 27 std::cout << std::setw(4) << j_complete << "\n\n"; 28 29 30 // define parser callback 31 json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed) 32 { 33 // skip object elements with key "Thumbnail" 34 if (event == json::parse_event_t::key and parsed == json("Thumbnail")) 35 { 36 return false; 37 } 38 else 39 { 40 return true; 41 } 42 }; 43 44 // parse (with callback) and serialize JSON 45 json j_filtered = json::parse(text, cb); 46 std::cout << std::setw(4) << j_filtered << '\n'; 47 } nlohmann::json basic_json<> json default JSON class Definition: json.hpp:8170 nlohmann::basic_json a class to store JSON values Definition: json.hpp:191 nlohmann::basic_json::parser_callback_t std::function< bool(int depth, parse_event_t event, basic_json &parsed)> parser_callback_t per-element parser callback type Definition: json.hpp:829 nlohmann namespace for Niels Lohmann Definition: json.hpp:88 nlohmann::basic_json::parse_event_t::key the parser read a key of a value in an object nlohmann::basic_json::parse static basic_json parse(const string_t &s, parser_callback_t cb=nullptr) deserialize from string Definition: json.hpp:5210 nlohmann::basic_json::parse_event_t parse_event_t JSON callback events. Definition: json.hpp:764 Output (play with this example online):
      {
          "Image": {
              "Animated": false,
              "Height": 600,
              "IDs": [
                  116,
                  943,
                  234,
                  38793
              ],
              "Thumbnail": {
                  "Height": 125,
                  "Url": "http://www.example.com/image/481989943",
                  "Width": 100
              },
              "Title": "View from 15th Floor",
              "Width": 800
          }
      }

      {
          "Image": {
              "Animated": false,
              "Height": 600,
              "IDs": [
                  116,
                  943,
                  234,
                  38793
              ],
              "Title": "View from 15th Floor",
              "Width": 800
          }
      }
  The example code above can be translated with
      g++ -std=c++11 -Isrc doc/examples/parse__string__parser_callback_t.cpp -o parse__string__parser_callback_t
See also parse(std::istream&, parser_callback_t) for a version that reads from an input stream Since version 1.0.0 Definition at line 5210 of file json.hpp.