Mail for the std-proposals forum

proposal-discussion.txt

Hi there,

I am wondering whether JSON [RFC7159] support would be a helpful extension to the C++ standard library (pure library extension), including, but not limited to, the following aspects:

1. A variant-like container type (for this mail, let's call it "std::json") that combines C++ types for the JSON value types [RFC7159, chapter 3]:
  - string (e.g. std::string),
  - number (e.g., double or int64_t),
  - boolean (e.g., bool),
  - array (e.g., std::vector), and
  - object (e.g., std::map).
This type should have an intuitive API (i.e., all expected container methods), but also use as much syntactic sugar as possible (e.g., using initializer lists to express arrays like "std::json my_array = {"a string", 17, 42.12};".

2. A serialization function to create a textual representation (called "JSON text" in [RFC7159]) from a std::json value that conforms to the JSON grammar [RFC7159, chapter 2-7].

3. A deserialization function (i.e., a parser) [RFC7159, chapter 9] to create a std::json value from a JSON text.

There are currently dozens of libraries [json.org] written in C or C++ solving these aspects. However, it would be of great convenience to have JSON be part of the C++ standard library. In particular, the wide use of JSON as exchange format for structured data as well as to express simple configuration data would could solve a lot of use cases within the C++ standard library.

I would be willing to draft a proposal based on the experience I made with my C++ JSON library [nlohmann/json]. Of course, I would be interested in your thoughts on this.

All the best,
Niels

References

[RFC7159] https://tools.ietf.org/html/rfc7159.html
[json.org] http://json.org
[nlohmann/json] https://github.com/nlohmann/json

Great!

JSONPath (http://jsonpath.com), yes this was it. I remember people asking for this on reddit.