stream_parser example with fstream?

[sinall]

Since file.hpp is not part of this library, it's not convenient to be used.

[grisumbras]

I'm not sure if I understand your issue correctly. Are you asking for an example of using the library for parsing from std::fstream?

[oxygene]

I'm not the original poster, but I assume I have the same "problem". It's very convenient to parse a whole std::string. And if I want to parse the contents of an std::ifstream, the easiest approach would be to slurp in the contents of the whole file into a std::string std::string{istreambuf_iterator{file}, {}} and use boost::json::parse again.

However, if I don't want to first read the contents of the whole file into memory, I need a streaming parser. This is where the stream_parser example comes into play. I assume the OP wanted to apply this example to a standard std::ifstream because this is a very common use-case.

I agree that having an example just based on std::ifstream would be better because people usually don't invent their own file io classes. Additionally, having convenience functions for streaming to and from std::ostream and std::istream would be great and would take the burden from the users to write the boilerplate "pumping" code to/from the streams.

[grisumbras]

Since version 1.81.0, the simplest (and, for most cases, the best) way to parse an std::istream is operator>>.

E.g.

std::ifstream is(filename);
boost::json::value jv;
is >> jv;

operator<< for value also exists.