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 begin begin boolean_t cbegin cend clear const_iterator const_pointer const_reference const_reverse_iterator count crbegin crend detail::external_constructor diff difference_type dump emplace emplace_back empty end end erase erase erase erase exception find find flatten from_cbor from_msgpack front front get get get get get get_allocator get_ptr get_ptr get_ref get_ref insert insert insert insert insert insert 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 iterator iterator_wrapper iterator_wrapper json_serializer max_size meta number_float_t number_integer_t number_unsigned_t object 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[] operator[] operator[] other_error out_of_range parse parse parse parse parse parse parse_error parse_event_t parser_callback_t patch pointer push_back push_back push_back push_back rbegin rbegin reference rend rend reverse_iterator size size_type string_t swap swap swap swap to_cbor to_msgpack type type_error type_name unflatten value value value value value_t value_type ~basic_json

parse() [2/6] 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> template<typename CharT , typename std::enable_if< std::is_pointer< CharT >::value and std::is_integral< typename std::remove_pointer< CharT >::type >::value and sizeof(typename std::remove_pointer< CharT >::type)==1, int >::type = 0> static basic_json nlohmann::basic_json::parse ( const CharT  s, const parser_callback_t  cb = nullptr  ) inlinestatic Template Parameters CharT character/literal type with size of 1 byte Parameters [in] s string literal 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 Exceptions parse_error.101 in case of an unexpected token 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. String containers like std::string or string_t can be parsed with parse(const ContiguousContainer&, const parser_callback_t) Example The example below demonstrates the parse() function with and without callback function. #include "json.hpp" #include <iomanip> // for std::setw using json = nlohmann::json; int main() { // a JSON text auto text = R"( { "Image": { "Width": 800, "Height": 600, "Title": "View from 15th Floor", "Thumbnail": { "Url": "http://www.example.com/image/481989943", "Height": 125, "Width": 100 }, "Animated" : false, "IDs": [116, 943, 234, 38793] } } )"; // parse and serialize JSON json j_complete = json::parse(text); std::cout << std::setw(4) << j_complete << "\n\n"; // define parser callback json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed) { // skip object elements with key "Thumbnail" if (event == json::parse_event_t::key and parsed == json("Thumbnail")) { return false; } else { return true; } }; // parse (with callback) and serialize JSON json j_filtered = json::parse(text, cb); std::cout << std::setw(4) << j_filtered << '\n'; } 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&, const parser_callback_t) for a version that reads from an input stream Since version 1.0.0 (originally for string_t) Definition at line 7331 of file json.hpp.