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* Review and extend the documentation, and check it in CI A review of all documentation pages found factual errors, dead links, missing cross-references, and gaps in examples. This fixes them and adds checks so the same problems are caught automatically. Fixes: - wrong signatures and version histories (operator!= C++20 member, binary() subtype type, get<PointerType>(), JSON_NO_THREAD_LOCAL, ...) - stale descriptions (number parsing since #5283, UBJSON table, SAX example that no longer compiled, tsl::ordered_map advice) - dead internal and external links; repology.org badges (the domain is suspended) replaced by badges that query the registries directly - deprecation notes link the migration guide; the guide itself fixed Additions: - "See also" sections, cross-references, 25 runnable examples, 12 Mermaid diagrams, new API pages for json_pointer::operator<=> and byte_container_with_subtype::operator==/!= - landing page, guides for untrusted input and performance - "unreleased" badge after versions newer than the latest release Checks: - strict documentation build (broken links/anchors fail it); CI and the publish workflow fetch the full history the build needs - weekly external link check, Mermaid syntax check in CI - check_structure.py: example titles, heading levels, alt texts, header links, docset index coverage; its unused-example check works again - all examples produce the same output on every platform Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Keep the customer links that could not be fixed A dead link on the customers page is still the evidence of where the use of the library was documented. Keep the original URLs of the entries without a working replacement (Marne, Cisco Webex Desk Camera, Philips Hue, CyberArk) and exclude exactly these URLs from the link check. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct the duplicate-key recipe's claim about SAX positions The SAX interface's key() receives no position either; only parse_error() does. Also note that the recipe does not report the path to the repeated key (see discussion #5085). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Say the library is available as a single header and mention json_fwd.hpp Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct documentation errors found while hunting for bugs - patch/patch_inplace: list the JSON pointer errors parse_error.106-109 and out_of_range.402/404, and quote the actual parse_error.105 message. - unflatten: list parse_error.106/107/108 and out_of_range.404. - to_bson: list out_of_range.415 (binary subtype above 255) and note that 412 and 415 are new in 3.13.0. - to_string: state that string_t must be convertible to std::string, also in the StringType requirements table. - JSON Lines: a `while (input >> j)` loop also throws after the last value for concatenated JSON values; show a loop that works for both. - BON8: a string gets 0xFF only if nothing follows it in the message; a string at the end of an array or object is ended by 0xFE. - custom_string_type.hpp: add operator+=(char), which the "Always required" list asks for (json_pointer::to_string, flatten, unflatten, and diff did not compile), and an ADL int_to_string for diff and items. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Cache the release headers with functools.lru_cache Codacy (Pylint) flagged the mutable default argument that header() used as its cache. functools.lru_cache keeps the same memoization without it. The script's output is unchanged. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2.8 KiB
2.8 KiB
nlohmann::basic_json::operator<=
// until C++20
bool operator<=(const_reference lhs, const_reference rhs) noexcept; // (1)
template<typename ScalarType>
bool operator<=(const_reference lhs, const ScalarType rhs) noexcept; // (2)
template<typename ScalarType>
bool operator<=(ScalarType lhs, const const_reference rhs) noexcept; // (2)
-
Compares whether one JSON value
lhsis less than or equal to another JSON valuerhsaccording to the following rules:- The comparison always yields
#!cpp falseif (1) either operand is discarded, or (2) either operand isNaNand the other operand is eitherNaNor any other number. - Otherwise, returns the result of
#!cpp !(rhs < lhs)(see operator<).
- The comparison always yields
-
Compares whether a JSON value is less than or equal to a scalar or a scalar is less than or equal to a JSON value by converting the scalar to a JSON value and comparing both JSON values according to 1.
Template parameters
ScalarType- a scalar type according to
std::is_scalar<ScalarType>::value
Parameters
lhs(in)- first value to consider
rhs(in)- second value to consider
Return value
whether lhs is less than or equal to rhs
Exception safety
No-throw guarantee: this function never throws exceptions.
Complexity
Linear.
Notes
!!! note "Comparing NaN"
`NaN` values are unordered within the domain of numbers.
The following comparisons all yield `#!cpp false`:
1. Comparing a `NaN` with itself.
2. Comparing a `NaN` with another `NaN`.
3. Comparing a `NaN` and any other number.
!!! note "Operator overload resolution"
Since C++20 overload resolution will consider the _rewritten candidate_ generated from
[`operator<=>`](operator_spaceship.md).
!!! warning "Deprecation"
If [`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../macros/json_use_legacy_discarded_value_comparison.md) is
defined to `1`, the library declares a member `#!cpp bool operator<=(const_reference rhs) const noexcept` in
C++20 mode to emulate the legacy comparison of discarded values. This member is deprecated since version 3.11.0,
together with the legacy comparison behavior.
See the [migration guide](../../integration/migration_guide.md#miscellaneous-functions) for how to update existing
code.
Examples
??? example
The example demonstrates comparing several JSON types.
```cpp
--8<-- "examples/operator__lessequal.cpp"
```
Output:
```json
--8<-- "examples/operator__lessequal.output"
```
See also
- operator<=> comparison: 3-way
Version history
- Added in version 1.0.0. Conditionally removed since C++20 in version 3.11.0.
- Added in version 1.0.0. Conditionally removed since C++20 in version 3.11.0.