Release date: 2018-08-20 SHA-256: ce6b5610a051ec6795fa11c33854abebb086f0fd67c311f5921c3c07f9531b44 (json.hpp), 35ee642558b90e2f9bc758995c4788c4b4d4dec54eef95fb8f38cb4d49c8fc7c (include.zip)

Summary

This release introduces a SAX interface to the library. While this may be a very special feature used by only few people, it allowed to unify all functions that consumed input and created some kind of JSON value. Internally, now all existing functions like parse, accept, from_cbor, from_msgpack, and from_ubjson use the SAX interface with different event processors. This allowed to separate the input processing from the value generation. Furthermore, throwing an exception in case of a parse error is now optional and up to the event processor. Finally, the JSON parser is now non-recursive (meaning it does not use the call stack, but std::vector<bool> to track the hierarchy of structured values) which allows to process nested input more efficiently.

Furthermore, the library finally is able to parse from wide string types. This is the first step toward opening the library from UTF-8 to UTF-16 and UTF-32.

This release further fixes several bugs in the library. All changes are backward-compatible.

:sparkles: New Features

• added a parser with a SAX interface (#971, #1153)
• support to parse from wide string types std::wstring, std::u16string, and std::u32string; the input will be converted to UTF-8 (#1031)
• added support for std::string_view when using C++17 (#1028)
• allow to roundtrip std::map and std::unordered_map from JSON if key type is not convertible to string; in these cases, values are serialized to arrays of pairs (#1079, #1089, #1133, #1138)

:bug: Bug Fixes

• allow to create nullptr_t from JSON allowing to properly roundtrip null values (#1169)
• allow compare user-defined string types (#1130)
• better support for algorithms using iterators from items() (#1045, #1134)
• added parameter to avoid compilation error with MSVC 2015 debug builds (#1114)
• re-added accidentially skipped unit tests (#1176)
• fixed MSVC issue with std::swap (#1168)

:zap: Improvements

• key() function for iterators returns a const reference rather than a string copy (#1098)
• binary formats CBOR, MessagePack, and UBJSON now supports float as type for floating-point numbers (#1021)

:hammer: Further Changes

• changed issue templates
• improved continuous integration: added builders for Xcode 9.3 and 9.4, added builders for GCC 8 and Clang 6, added builder for MinGW, added builders for MSVC targeting x86
• required CMake version is now at least 3.8 (#1040)
• overworked CMake file wrt. packaging (#1048)
• added package managers: Spack (#1041) and CocoaPods (#1148)
• fixed Meson include directory (#1142)
• preprocessor macro JSON_SKIP_UNSUPPORTED_COMPILER_CHECK can skip the rejection of unsupported compilers - use at your own risk! (#1128)
• preprocessor macro JSON_INTERNAL_CATCH/JSON_INTERNAL_CATCH_USER allows to control the behavior of exception handling inside the library (#1187)
• added note on char to JSON conversion
• added note how to send security-related issue via encrypted email
• removed dependency to std::stringstream (#1117)
• added SPDX-License-Identifier
• added updated JSON Parsing Test Suite, described in Parsing JSON is a Minefield 💣
• updated to Catch 1.12.0

:fire: Deprecated functions

This release does not deprecate any functions. As an overview, the following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

• Function iterator_wrapper are deprecated. Please use the member function items() instead.
• Functions friend std::istream& operator<<(basic_json&, std::istream&) and friend std::ostream& operator>>(const basic_json&, std::ostream&) are deprecated. Please use friend std::istream& operator>>(std::istream&, basic_json&) and friend operator<<(std::ostream&, const basic_json&) instead.