jsonpp

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jsonpp

jsonpp is a header-only JSON parser and writer that is currently in development. It is a semi-strict parser that throws exceptions for errors.

jsonpp is licensed with the MIT license.

Features

• Easy to use with a simple API.
• No special null, array, or object types.
  • json::null is a type alias to std::nullptr_t.
  • json::array is std::vector<json::value>.
  • json::object is std::map<std::string, json::value>.
• Decently fast.
• No dependencies, only the standard library and a C++11 compiler.

Documentation

Documentation is an on going process and can be found here. Amongst documentation you can also find examples.

Example usage

Parsing

#include <jsonpp/parser.hpp>
#include <iostream>

int main() {
    json::parser p;
    json::value v;
    try {
        p.parse("[null, \"hello\", 10.0]", v);
        if(v.is<json::array>()) {
            for(auto&& val : v.as<json::array>()) {
                std::cout << val.as<std::string>("stuff");
            }
        }
    }
    catch(const std::exception& e) {
        std::cerr << e.what() << '\n';
    }
}

Output:

stuff hello stuff

Writing

#include <jsonpp/value.hpp>
#include <iostream>

int main() {
    json::value v = { nullptr, "hello", 10 };
    json::object o = {
        { "key", "value" },
        { "key2", 2 },
        { "key3", nullptr }
    };
    json::dump(std::cout, o);
}

Output:

{
    "key": "value",
    "key2": 2,
    "key3": null
}

Quirks and Specification

• NaN and inf are currently allowed.
• Comments, e.g. // stuff is planned to be supported in the future.
• The parser is not destructive.
• The parser is recursive descent.
• Numbers are stored in a double just like JSON but v.as<int> and friends work with caution.
• String is expected to be in UTF-8.
• Some errors are not caught but effort has been made to catch a lot of errors.