detail namespace with internal helper functions More...

Namespaces
namespace	dtoa_impl
	implements the Grisu2 algorithm for binary to decimal floating-point conversion.

Classes
class	binary_reader
	deserialization of CBOR, MessagePack, and UBJSON values More...

struct	conjunction

struct	conjunction< B1 >

struct	conjunction< B1, Bn... >

struct	detector

struct	detector< Default, void_t< Op< Args... > >, Op, Args... >

class	exception
	general exception of the basic_json class More...

struct	external_constructor

struct	external_constructor< value_t::array >

struct	external_constructor< value_t::binary >

struct	external_constructor< value_t::boolean >

struct	external_constructor< value_t::number_float >

struct	external_constructor< value_t::number_integer >

struct	external_constructor< value_t::number_unsigned >

struct	external_constructor< value_t::object >

struct	external_constructor< value_t::string >

struct	from_json_fn

struct	has_from_json

struct	has_from_json< BasicJsonType, T, enable_if_t< !is_basic_json< T >::value > >

struct	has_non_default_from_json

struct	has_non_default_from_json< BasicJsonType, T, enable_if_t< !is_basic_json< T >::value > >

struct	has_to_json

struct	has_to_json< BasicJsonType, T, enable_if_t< !is_basic_json< T >::value > >

struct	internal_iterator
	an iterator value More...

class	invalid_iterator
	exception indicating errors with iterators More...

struct	is_basic_json

struct	is_basic_json< NLOHMANN_BASIC_JSON_TPL >

struct	is_compatible_array_type

struct	is_compatible_array_type_impl

struct	is_compatible_array_type_impl< BasicJsonType, CompatibleArrayType, enable_if_t< is_detected< value_type_t, CompatibleArrayType >::value &&is_detected< iterator_t, CompatibleArrayType >::value &&!is_iterator_traits< iterator_traits< CompatibleArrayType > >::value > >

struct	is_compatible_integer_type

struct	is_compatible_integer_type_impl

struct	is_compatible_integer_type_impl< RealIntegerType, CompatibleNumberIntegerType, enable_if_t< std::is_integral< RealIntegerType >::value &&std::is_integral< CompatibleNumberIntegerType >::value &&!std::is_same< bool, CompatibleNumberIntegerType >::value > >

struct	is_compatible_object_type

struct	is_compatible_object_type_impl

struct	is_compatible_object_type_impl< BasicJsonType, CompatibleObjectType, enable_if_t< is_detected< mapped_type_t, CompatibleObjectType >::value &&is_detected< key_type_t, CompatibleObjectType >::value > >

struct	is_compatible_string_type

struct	is_compatible_string_type_impl

struct	is_compatible_string_type_impl< BasicJsonType, CompatibleStringType, enable_if_t< is_detected_exact< typename BasicJsonType::string_t::value_type, value_type_t, CompatibleStringType >::value > >

struct	is_compatible_type

struct	is_compatible_type_impl

struct	is_compatible_type_impl< BasicJsonType, CompatibleType, enable_if_t< is_complete_type< CompatibleType >::value > >

struct	is_complete_type

struct	is_complete_type< T, decltype(void(sizeof(T)))>

struct	is_constructible_array_type

struct	is_constructible_array_type_impl

struct	is_constructible_array_type_impl< BasicJsonType, ConstructibleArrayType, enable_if_t< !std::is_same< ConstructibleArrayType, typename BasicJsonType::value_type >::value &&std::is_default_constructible< ConstructibleArrayType >::value &&(std::is_move_assignable< ConstructibleArrayType >::value\|\|std::is_copy_assignable< ConstructibleArrayType >::value)&&is_detected< value_type_t, ConstructibleArrayType >::value &&is_detected< iterator_t, ConstructibleArrayType >::value &&is_complete_type< detected_t< value_type_t, ConstructibleArrayType > >::value > >

struct	is_constructible_array_type_impl< BasicJsonType, ConstructibleArrayType, enable_if_t< std::is_same< ConstructibleArrayType, typename BasicJsonType::value_type >::value > >

struct	is_constructible_object_type

struct	is_constructible_object_type_impl

struct	is_constructible_object_type_impl< BasicJsonType, ConstructibleObjectType, enable_if_t< is_detected< mapped_type_t, ConstructibleObjectType >::value &&is_detected< key_type_t, ConstructibleObjectType >::value > >

struct	is_constructible_string_type

struct	is_constructible_string_type_impl

struct	is_constructible_string_type_impl< BasicJsonType, ConstructibleStringType, enable_if_t< is_detected_exact< typename BasicJsonType::string_t::value_type, value_type_t, ConstructibleStringType >::value > >

struct	is_constructible_tuple

struct	is_constructible_tuple< T1, std::tuple< Args... > >

struct	is_getable

struct	is_iterator_traits

struct	is_iterator_traits< iterator_traits< T > >

struct	is_json_ref

struct	is_json_ref< json_ref< T > >

class	iter_impl
	a template for a bidirectional iterator for the basic_json class This class implements a both iterators (iterator and const_iterator) for the basic_json class. More...

class	iteration_proxy
	proxy class for the items() function More...

class	iteration_proxy_value

struct	iterator_traits

struct	iterator_traits< T *, enable_if_t< std::is_object< T >::value > >

struct	iterator_traits< T, enable_if_t< !std::is_pointer< T >::value > >

struct	iterator_types

struct	iterator_types< It, void_t< typename It::difference_type, typename It::value_type, typename It::pointer, typename It::reference, typename It::iterator_category > >

class	json_ref

class	json_sax_acceptor

class	json_sax_dom_callback_parser

class	json_sax_dom_parser
	SAX implementation to create a JSON value from SAX events. More...

class	lexer
	lexical analysis More...

class	lexer_base

struct	make_void

struct	nonesuch

class	other_error
	exception indicating other library errors More...

class	out_of_range
	exception indicating access out of the defined range More...

class	parse_error
	exception indicating a parse error More...

struct	position_t
	struct to capture the start position of the current token More...

class	serializer

struct	to_json_fn

class	type_error
	exception indicating executing a member function with a wrong type More...

Typedefs
template<typename ... Ts>
using	void_t = typename make_void< Ts... >::type

template<template< class... > class Op, class... Args>
using	is_detected = typename detector< nonesuch, void, Op, Args... >::value_t

template<template< class... > class Op, class... Args>
using	detected_t = typename detector< nonesuch, void, Op, Args... >::type

template<class Default , template< class... > class Op, class... Args>
using	detected_or = detector< Default, void, Op, Args... >

template<class Default , template< class... > class Op, class... Args>
using	detected_or_t = typename detected_or< Default, Op, Args... >::type

template<class Expected , template< class... > class Op, class... Args>
using	is_detected_exact = std::is_same< Expected, detected_t< Op, Args... > >

template<class To , template< class... > class Op, class... Args>
using	is_detected_convertible = std::is_convertible< detected_t< Op, Args... >, To >

template<typename T >
using	mapped_type_t = typename T::mapped_type

template<typename T >
using	key_type_t = typename T::key_type

template<typename T >
using	value_type_t = typename T::value_type

template<typename T >
using	difference_type_t = typename T::difference_type

template<typename T >
using	pointer_t = typename T::pointer

template<typename T >
using	reference_t = typename T::reference

template<typename T >
using	iterator_category_t = typename T::iterator_category

template<typename T >
using	iterator_t = typename T::iterator

template<typename T , typename... Args>
using	to_json_function = decltype(T::to_json(std::declval< Args >()...))

template<typename T , typename... Args>
using	from_json_function = decltype(T::from_json(std::declval< Args >()...))

template<typename T , typename U >
using	get_template_function = decltype(std::declval< T >().template get< U >())

Enumerations
enum class	value_t : std::uint8_t { null , object , array , string , boolean , number_integer , number_unsigned , number_float , binary , discarded }
	the JSON type enumeration More...

enum class	cbor_tag_handler_t { error , ignore }
	how to treat CBOR tags More...

enum class	error_handler_t { strict , replace , ignore }
	how to treat decoding errors More...

Functions
bool	operator< (const value_t lhs, const value_t rhs) noexcept
	comparison operator for JSON types

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename std::nullptr_t &n)

template<typename BasicJsonType , typename ArithmeticType , enable_if_t< std::is_arithmetic< ArithmeticType >::value &&!std::is_same< ArithmeticType, typename BasicJsonType::boolean_t >::value, int > = 0>
void	get_arithmetic_value (const BasicJsonType &j, ArithmeticType &val)

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::boolean_t &b)

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::string_t &s)

template<typename BasicJsonType , typename ConstructibleStringType , enable_if_t< is_constructible_string_type< BasicJsonType, ConstructibleStringType >::value &&!std::is_same< typename BasicJsonType::string_t, ConstructibleStringType >::value, int > = 0>
void	from_json (const BasicJsonType &j, ConstructibleStringType &s)

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::number_float_t &val)

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::number_unsigned_t &val)

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::number_integer_t &val)

template<typename BasicJsonType , typename EnumType , enable_if_t< std::is_enum< EnumType >::value, int > = 0>
void	from_json (const BasicJsonType &j, EnumType &e)

template<typename BasicJsonType , typename T , typename Allocator , enable_if_t< is_getable< BasicJsonType, T >::value, int > = 0>
void	from_json (const BasicJsonType &j, std::forward_list< T, Allocator > &l)

template<typename BasicJsonType , typename T , enable_if_t< is_getable< BasicJsonType, T >::value, int > = 0>
void	from_json (const BasicJsonType &j, std::valarray< T > &l)

template<typename BasicJsonType , typename T , std::size_t N>
auto	from_json (const BasicJsonType &j, T(&arr)[N]) -> decltype(j.template get< T >(), void())

template<typename BasicJsonType >
void	from_json_array_impl (const BasicJsonType &j, typename BasicJsonType::array_t &arr, priority_tag< 3 >)

template<typename BasicJsonType , typename T , std::size_t N>
auto	from_json_array_impl (const BasicJsonType &j, std::array< T, N > &arr, priority_tag< 2 >) -> decltype(j.template get< T >(), void())

template<typename BasicJsonType , typename ConstructibleArrayType >
auto	from_json_array_impl (const BasicJsonType &j, ConstructibleArrayType &arr, priority_tag< 1 >) -> decltype(arr.reserve(std::declval< typename ConstructibleArrayType::size_type >()), j.template get< typename ConstructibleArrayType::value_type >(), void())

template<typename BasicJsonType , typename ConstructibleArrayType >
void	from_json_array_impl (const BasicJsonType &j, ConstructibleArrayType &arr, priority_tag< 0 >)

template<typename BasicJsonType , typename ConstructibleArrayType , enable_if_t< is_constructible_array_type< BasicJsonType, ConstructibleArrayType >::value &&!is_constructible_object_type< BasicJsonType, ConstructibleArrayType >::value &&!is_constructible_string_type< BasicJsonType, ConstructibleArrayType >::value &&!std::is_same< ConstructibleArrayType, typename BasicJsonType::binary_t >::value &&!is_basic_json< ConstructibleArrayType >::value, int > = 0>
auto	from_json (const BasicJsonType &j, ConstructibleArrayType &arr) -> decltype(from_json_array_impl(j, arr, priority_tag< 3 > {}), j.template get< typename ConstructibleArrayType::value_type >(), void())

template<typename BasicJsonType >
void	from_json (const BasicJsonType &j, typename BasicJsonType::binary_t &bin)

template<typename BasicJsonType , typename ConstructibleObjectType , enable_if_t< is_constructible_object_type< BasicJsonType, ConstructibleObjectType >::value, int > = 0>
void	from_json (const BasicJsonType &j, ConstructibleObjectType &obj)

template<typename BasicJsonType , typename ArithmeticType , enable_if_t< std::is_arithmetic< ArithmeticType >::value &&!std::is_same< ArithmeticType, typename BasicJsonType::number_unsigned_t >::value &&!std::is_same< ArithmeticType, typename BasicJsonType::number_integer_t >::value &&!std::is_same< ArithmeticType, typename BasicJsonType::number_float_t >::value &&!std::is_same< ArithmeticType, typename BasicJsonType::boolean_t >::value, int > = 0>
void	from_json (const BasicJsonType &j, ArithmeticType &val)

template<typename BasicJsonType , typename A1 , typename A2 >
void	from_json (const BasicJsonType &j, std::pair< A1, A2 > &p)

template<typename BasicJsonType , typename Tuple , std::size_t... Idx>
void	from_json_tuple_impl (const BasicJsonType &j, Tuple &t, index_sequence< Idx... >)

template<typename BasicJsonType , typename... Args>
void	from_json (const BasicJsonType &j, std::tuple< Args... > &t)

template<typename BasicJsonType , typename Key , typename Value , typename Compare , typename Allocator , typename = enable_if_t < !std::is_constructible < typename BasicJsonType::string_t, Key >::value >>
void	from_json (const BasicJsonType &j, std::map< Key, Value, Compare, Allocator > &m)

template<typename BasicJsonType , typename Key , typename Value , typename Hash , typename KeyEqual , typename Allocator , typename = enable_if_t < !std::is_constructible < typename BasicJsonType::string_t, Key >::value >>
void	from_json (const BasicJsonType &j, std::unordered_map< Key, Value, Hash, KeyEqual, Allocator > &m)

template<typename string_type >
void	int_to_string (string_type &target, std::size_t value)

template<std::size_t N, typename IteratorType , enable_if_t< N==0, int > = 0>
auto	get (const nlohmann::detail::iteration_proxy_value< IteratorType > &i) -> decltype(i.key())

template<typename BasicJsonType , typename T , enable_if_t< std::is_same< T, typename BasicJsonType::boolean_t >::value, int > = 0>
void	to_json (BasicJsonType &j, T b) noexcept

template<typename BasicJsonType , typename CompatibleString , enable_if_t< std::is_constructible< typename BasicJsonType::string_t, CompatibleString >::value, int > = 0>
void	to_json (BasicJsonType &j, const CompatibleString &s)

template<typename BasicJsonType >
void	to_json (BasicJsonType &j, typename BasicJsonType::string_t &&s)

template<typename BasicJsonType , typename FloatType , enable_if_t< std::is_floating_point< FloatType >::value, int > = 0>
void	to_json (BasicJsonType &j, FloatType val) noexcept

template<typename BasicJsonType , typename CompatibleNumberUnsignedType , enable_if_t< is_compatible_integer_type< typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType >::value, int > = 0>
void	to_json (BasicJsonType &j, CompatibleNumberUnsignedType val) noexcept

template<typename BasicJsonType , typename CompatibleNumberIntegerType , enable_if_t< is_compatible_integer_type< typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType >::value, int > = 0>
void	to_json (BasicJsonType &j, CompatibleNumberIntegerType val) noexcept

template<typename BasicJsonType , typename EnumType , enable_if_t< std::is_enum< EnumType >::value, int > = 0>
void	to_json (BasicJsonType &j, EnumType e) noexcept

template<typename BasicJsonType >
void	to_json (BasicJsonType &j, const std::vector< bool > &e)

template<typename BasicJsonType , typename CompatibleArrayType , enable_if_t< is_compatible_array_type< BasicJsonType, CompatibleArrayType >::value &&!is_compatible_object_type< BasicJsonType, CompatibleArrayType >::value &&!is_compatible_string_type< BasicJsonType, CompatibleArrayType >::value &&!std::is_same< typename BasicJsonType::binary_t, CompatibleArrayType >::value &&!is_basic_json< CompatibleArrayType >::value, int > = 0>
void	to_json (BasicJsonType &j, const CompatibleArrayType &arr)

template<typename BasicJsonType >
void	to_json (BasicJsonType &j, const typename BasicJsonType::binary_t &bin)

template<typename BasicJsonType , typename T , enable_if_t< std::is_convertible< T, BasicJsonType >::value, int > = 0>
void	to_json (BasicJsonType &j, const std::valarray< T > &arr)

template<typename BasicJsonType >
void	to_json (BasicJsonType &j, typename BasicJsonType::array_t &&arr)

template<typename BasicJsonType , typename CompatibleObjectType , enable_if_t< is_compatible_object_type< BasicJsonType, CompatibleObjectType >::value &&!is_basic_json< CompatibleObjectType >::value, int > = 0>
void	to_json (BasicJsonType &j, const CompatibleObjectType &obj)

template<typename BasicJsonType >
void	to_json (BasicJsonType &j, typename BasicJsonType::object_t &&obj)

template<typename BasicJsonType , typename T , std::size_t N, enable_if_t< !std::is_constructible< typename BasicJsonType::string_t, const T(&)[N]>::value, int > = 0>
void	to_json (BasicJsonType &j, const T(&arr)[N])

template<typename BasicJsonType , typename T1 , typename T2 , enable_if_t< std::is_constructible< BasicJsonType, T1 >::value &&std::is_constructible< BasicJsonType, T2 >::value, int > = 0>
void	to_json (BasicJsonType &j, const std::pair< T1, T2 > &p)

template<typename BasicJsonType , typename T , enable_if_t< std::is_same< T, iteration_proxy_value< typename BasicJsonType::iterator > >::value, int > = 0>
void	to_json (BasicJsonType &j, const T &b)

template<typename BasicJsonType , typename Tuple , std::size_t... Idx>
void	to_json_tuple_impl (BasicJsonType &j, const Tuple &t, index_sequence< Idx... >)

Detailed Description

detail namespace with internal helper functions

This namespace collects functions that should not be exposed, implementations of some basic_json methods, and meta-programming helpers.

Since: version 2.1.0

Enumeration Type Documentation

◆ cbor_tag_handler_t

enum class nlohmann::detail::cbor_tag_handler_t

strong

how to treat CBOR tags

Enumerator
error	throw a parse_error exception in case of a tag
ignore	ignore tags

◆ error_handler_t

enum class nlohmann::detail::error_handler_t

strong

how to treat decoding errors

Enumerator
strict	throw a type_error exception in case of invalid UTF-8
replace	replace invalid UTF-8 sequences with U+FFFD
ignore	ignore invalid UTF-8 sequences

◆ value_t

enum class nlohmann::detail::value_t : std::uint8_t

strong

the JSON type enumeration

This enumeration collects the different JSON types. It is internally used to distinguish the stored values, and the functions basic_json::is_null(), basic_json::is_object(), basic_json::is_array(), basic_json::is_string(), basic_json::is_boolean(), basic_json::is_number() (with basic_json::is_number_integer(), basic_json::is_number_unsigned(), and basic_json::is_number_float()), basic_json::is_discarded(), basic_json::is_primitive(), and basic_json::is_structured() rely on it.

Note: There are three enumeration entries (number_integer, number_unsigned, and number_float), because the library distinguishes these three types for numbers: basic_json::number_unsigned_t is used for unsigned integers, basic_json::number_integer_t is used for signed integers, and basic_json::number_float_t is used for floating-point numbers or to approximate integers which do not fit in the limits of their respective type.

See also: basic_json::basic_json(const value_t value_type) – create a JSON value with the default value for a given type

Since: version 1.0.0

Enumerator
null	null value
object	object (unordered set of name/value pairs)
array	array (ordered collection of values)
string	string value
boolean	boolean value
number_integer	number value (signed integer)
number_unsigned	number value (unsigned integer)
number_float	number value (floating-point)
binary	binary array (ordered collection of bytes)
discarded	discarded by the parser callback function

Function Documentation

◆ operator<()

bool nlohmann::detail::operator<	(	const value_t	lhs,
		const value_t	rhs
	)

inlinenoexcept

comparison operator for JSON types

Returns an ordering that is similar to Python:

order: null < boolean < number < object < array < string < binary
furthermore, each type is not smaller than itself
discarded values are not comparable
binary is represented as a b"" string in python and directly comparable to a string; however, making a binary array directly comparable with a string would be surprising behavior in a JSON file.

Since: version 1.0.0

Namespaces

Classes

Typedefs

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ cbor_tag_handler_t

◆ error_handler_t

◆ value_t

Function Documentation

◆ operator<()