- Release date: 2016-06-24
- SHA-256: ac9e1fb25c2ac9ca5fc501fcd2fe3281fe04f07018a1b48820e7b1b11491bb6c
This release adds several features such as JSON Pointers, JSON Patch, or support for 64 bit unsigned integers. Furthermore, several (subtle) bugs have been fixed.
As `noexcept` and `constexpr` specifier have been added to several functions, the public API has effectively been changed in a (potential) non-backwards compatible manner. As we adhere to [Semantic Versioning](http://semver.org), this calls for a new major version, so say hello to 2️⃣.0️⃣.0️⃣.
- 🔟 A JSON value now uses `uint64_t` (default value for template parameter `NumberUnsignedType`) as data type for **unsigned integer** values. This type is used automatically when an unsigned number is parsed. Furthermore, constructors, conversion operators and an `is_number_unsigned()` test have been added.
- 👉 **JSON Pointer** ([RFC 6901](https://tools.ietf.org/html/rfc6901)) support: A JSON Pointer is a string (similar to an XPath expression) to address a value inside a structured JSON value. JSON Pointers can be used in `at()` and `operator[]` functions. Furthermore, JSON values can be “flattened” to key/value pairs using `flatten()` where each key is a JSON Pointer. The original value can be restored by “unflattening” the flattened value using `unflatten()`.
- 🏥 **JSON Patch** ([RFC 6902](https://tools.ietf.org/html/rfc6902)) support. A JSON Patch is a JSON value that describes the required edit operations (add, change, remove, …) to transform a JSON value into another one. A JSON Patch can be created with function `diff(const basic_json&)` and applied with `patch(const basic_json&)`. Note the created patches use a rather primitive algorithm so far and leave room for improvement.
- 🇪🇺 The code is now **locale-independent**: Floating-point numbers are always serialized with a period (`.`) as decimal separator and ignores different settings from the locale.
- 🍺 **Homebrew** support: Install the library with `brew tap nlohmann/json && brew install nlohmann_json`.
- Added constructor to create a JSON value by parsing a `std::istream` (e.g., `std::stringstream` or `std::ifstream`).
- Added **`noexcept`** specifier to `basic_json(boolean_t)`, `basic_json(const number_integer_t)`, `basic_json(const int)`, `basic_json(const number_float_t)`, iterator functions (`begin()`, `end()`, etc.)
- When parsing numbers, the sign of `0.0` (vs. `-0.0`) is preserved.
- Improved MSVC 2015, Android, and MinGW support. See [README](https://github.com/nlohmann/json#supported-compilers) for more information.
- Improved test coverage (added 2,225,386 tests).
- Removed some misuses of `std::move`.
- Fixed several compiler warnings.
- Improved error messages from JSON parser.
- Updated to [`re2c`](http://re2c.org) to version 0.16 to use a minimal DFAs for the lexer.
- Updated test suite to use [Catch](https://github.com/philsquared/Catch) version 1.5.6.
- Made type getters (`is_number`, etc.) and const value access `constexpr`.
- Functions `push_back` and `operator+=` now work with key/value pairs passed as initializer list, e.g. `j_object += {"key", 1}`.
- Overworked `CMakeLists.txt` to make it easier to integrate the library into other projects.
- Parser error messages are still very vague and contain no information on the error location.
- The implemented `diff` function is rather primitive and does not create minimal diffs.
- The name of function `iteration_wrapper` may change in the future and the function will be deprecated in the next release.
- Roundtripping (i.e., parsing a JSON value from a string, serializing it, and comparing the strings) of floating-point numbers is not 100% accurate. Note that [RFC 7159](https://tools.ietf.org/html/rfc7159) defines no format to internally represent numbers and states not requirement for roundtripping. Nevertheless, benchmarks like [Native JSON Benchmark](https://github.com/miloyip/nativejson-benchmark) treat roundtripping deviations as conformance errors.