JSON for Modern C++ 3.7.1

accept
accept
allocator_type
array
array_t
at
at
at
at
at
at
back
back
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
basic_json
begin
begin
boolean_t
cbegin
cend
clear
const_iterator
const_pointer
const_reference
const_reverse_iterator
contains
contains
count
crbegin
crend
detail::external_constructor
diff
difference_type
dump
emplace
emplace_back
empty
end
end
erase
erase
erase
erase
error_handler_t
exception
find
find
flatten
from_bson
from_bson
from_cbor
from_cbor
from_msgpack
from_msgpack
from_ubjson
from_ubjson
front
front
get
get
get
get
get
get
get_allocator
get_ptr
get_ptr
get_ref
get_ref
get_to
get_to
initializer_list_t
input_format_t
insert
insert
insert
insert
insert
insert
insert_iterator
invalid_iterator
is_array
is_boolean
is_discarded
is_null
is_number
is_number_float
is_number_integer
is_number_unsigned
is_object
is_primitive
is_string
is_structured
items
items
iterator
iterator_wrapper
iterator_wrapper
json_pointer
json_sax_t
json_serializer
max_size
merge_patch
meta
number_float_t
number_integer_t
number_unsigned_t
object
object_comparator_t
object_t
operator value_t
operator ValueType
operator!=
operator!=
operator!=
operator+=
operator+=
operator+=
operator+=
operator<
operator<
operator<
operator<<
operator<<
operator<=
operator<=
operator<=
operator=
operator==
operator==
operator==
operator>
operator>
operator>
operator>=
operator>=
operator>=
operator>>
operator>>
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
operator[]
other_error
out_of_range
parse
parse
parse_error
parse_event_t
parser_callback_t
patch
pointer
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rbegin
rbegin
reference
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sax_parse
sax_parse
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swap
to_bson
to_bson
to_bson
to_cbor
to_cbor
to_cbor
to_msgpack
to_msgpack
to_msgpack
to_ubjson
to_ubjson
to_ubjson
type
type_error
type_name
unflatten
update
update
value
value
value
value
value_t
value_type
~basic_json
| ## ◆ parse() [1/2] 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 = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
static basic_json nlohmann::basic_json::parse | ( | detail::input_adapter && | i,
|  | const parser_callback_t | cb = `nullptr`,
|  | const bool | allow_exceptions = `true`
| ) |  |
| inline static
  This function reads from a compatible input. Examples are: an array of 1-byte values strings with character/literal type with size of 1 byte input streams container with contiguous storage of 1-byte values. Compatible container types include `std::vector`, `std::string`, `std::array`, `std::valarray`, and `std::initializer_list`. Furthermore, C-style arrays can be used with `std::begin()`/`std::end()`. User-defined containers can be used as long as they implement random-access iterators and a contiguous storage. Precondition Each element of the container has a size of 1 byte. Violating this precondition yields undefined behavior. This precondition is enforced with a static assertion. The container storage is contiguous. Violating this precondition yields undefined behavior. This precondition is enforced with an assertion. Warning There is no way to enforce all preconditions at compile-time. If the function is called with a noncompliant container and with assertions switched off, the behavior is undefined and will most likely yield segmentation violation. Parameters
  [in] | i | input to read from
  [in] | cb | a parser callback function of type parser_callback_t which is used to control the deserialization by filtering unwanted values (optional)
  [in] | allow_exceptions | whether to throw exceptions in case of a parse error (optional, true by default)
  Returns deserialized JSON value; in case of a parse error and allow_exceptions set to `false`, the return value will be value_t::discarded. Exceptions
  parse_error.101 | if a parse error occurs; example: `""unexpected end of input; expected string literal""`
  parse_error.102 | if to_unicode fails or surrogate error
  parse_error.103 | if to_unicode fails
  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 reading from an array. 1 #include <iostream> 2 #include <iomanip> 3 #include <nlohmann/json.hpp> 4 5 using json = nlohmann::json; 6 7 int main() 8 { 9 // a JSON text 10 char text[] = R"( 11 { 12 "Image": { 13 "Width": 800, 14 "Height": 600, 15 "Title": "View from 15th Floor", 16 "Thumbnail": { 17 "Url": "http://www.example.com/image/481989943", 18 "Height": 125, 19 "Width": 100 20 }, 21 "Animated" : false, 22 "IDs": [116, 943, 234, 38793] 23 } 24 } 25 )"; 26 27 // parse and serialize JSON 28 json j_complete = json::parse(text); 29 std::cout << std::setw(4) << j_complete << "\n\n"; 30 } 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
          }
      }
  The example code above can be translated with
      g++ -std=c++11 -Isingle_include doc/examples/parse__array__parser_callback_t.cpp -o parse__array__parser_callback_t
  Example The example below demonstrates the `parse()` function with and without callback function. 1 #include <iostream> 2 #include <iomanip> 3 #include <nlohmann/json.hpp> 4 5 using json = nlohmann::json; 6 7 int main() 8 { 9 // a JSON text 10 auto text = R"( 11 { 12 "Image": { 13 "Width": 800, 14 "Height": 600, 15 "Title": "View from 15th Floor", 16 "Thumbnail": { 17 "Url": "http://www.example.com/image/481989943", 18 "Height": 125, 19 "Width": 100 20 }, 21 "Animated" : false, 22 "IDs": [116, 943, 234, 38793] 23 } 24 } 25 )"; 26 27 // parse and serialize JSON 28 json j_complete = json::parse(text); 29 std::cout << std::setw(4) << j_complete << "\n\n"; 30 31 32 // define parser callback 33 json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed) 34 { 35 // skip object elements with key "Thumbnail" 36 if (event == json::parse_event_t::key and parsed == json("Thumbnail")) 37 { 38 return false; 39 } 40 else 41 { 42 return true; 43 } 44 }; 45 46 // parse (with callback) and serialize JSON 47 json j_filtered = json::parse(text, cb); 48 std::cout << std::setw(4) << j_filtered << '\n'; 49 } 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 -Isingle_include doc/examples/parse__string__parser_callback_t.cpp -o parse__string__parser_callback_t
  Example The example below demonstrates the `parse()` function with and without callback function. 1 #include <iostream> 2 #include <iomanip> 3 #include <sstream> 4 #include <nlohmann/json.hpp> 5 6 using json = nlohmann::json; 7 8 int main() 9 { 10 // a JSON text 11 auto text = R"( 12 { 13 "Image": { 14 "Width": 800, 15 "Height": 600, 16 "Title": "View from 15th Floor", 17 "Thumbnail": { 18 "Url": "http://www.example.com/image/481989943", 19 "Height": 125, 20 "Width": 100 21 }, 22 "Animated" : false, 23 "IDs": [116, 943, 234, 38793] 24 } 25 } 26 )"; 27 28 // fill a stream with JSON text 29 std::stringstream ss; 30 ss << text; 31 32 // parse and serialize JSON 33 json j_complete = json::parse(ss); 34 std::cout << std::setw(4) << j_complete << "\n\n"; 35 36 37 // define parser callback 38 json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed) 39 { 40 // skip object elements with key "Thumbnail" 41 if (event == json::parse_event_t::key and parsed == json("Thumbnail")) 42 { 43 return false; 44 } 45 else 46 { 47 return true; 48 } 49 }; 50 51 // fill a stream with JSON text 52 ss.clear(); 53 ss << text; 54 55 // parse (with callback) and serialize JSON 56 json j_filtered = json::parse(ss, cb); 57 std::cout << std::setw(4) << j_filtered << '\n'; 58 } 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 -Isingle_include doc/examples/parse__istream__parser_callback_t.cpp -o parse__istream__parser_callback_t
  Example The example below demonstrates the `parse()` function reading from a contiguous container. 1 #include <iostream> 2 #include <iomanip> 3 #include <nlohmann/json.hpp> 4 5 using json = nlohmann::json; 6 7 int main() 8 { 9 // a JSON text given as std::vector 10 std::vector<uint8_t> text = {'[', '1', ',', '2', ',', '3', ']', '\0'}; 11 12 // parse and serialize JSON 13 json j_complete = json::parse(text); 14 std::cout << std::setw(4) << j_complete << "\n\n"; 15 } Output (play with this example online):
      [
          1,
          2,
          3
      ]
  The example code above can be translated with
      g++ -std=c++11 -Isingle_include doc/examples/parse__contiguouscontainer__parser_callback_t.cpp -o parse__contiguouscontainer__parser_callback_t
Since version 2.0.3 (contiguous containers) Definition at line 20708 of file json.hpp.

nlohmann::basic_json::parser_callback_t
typename parser::parser_callback_t parser_callback_t
per-element parser callback type
Definition: json.hpp:15665
nlohmann::basic_json::parse_event_t
typename parser::parse_event_t parse_event_t
parser event types
Definition: json.hpp:15614
nlohmann::basic_json::parse
static basic_json parse(detail::input_adapter &&i, const parser_callback_t cb=nullptr, const bool allow_exceptions=true)
deserialize from a compatible input
Definition: json.hpp:20708
nlohmann::json
basic_json<> json
default JSON class
Definition: json.hpp:2445