The Art of C++ / Config is a C++ header-only library that reads config files based on JSON and JAXN and produces a single JSON Value as result.
- Version 1.x (requires C++17)
- JAXN syntax with extensions (backward compatible with JSON).
- JAXN data model (JSON extended with binary data and non-finites).
- Meta data, all sub-values are annotated with filename and position.
- Copy, reference, replace and delete anything in the JSON structure.
- Multiple ways to read and include other config and data files, and
- use environment variables and the output of arbitrary shell commands.
- The function
tao::config::parse_file()is all you need to get going.
This library is still under heavy development and not very well documented...
...however it generally works, and test coverage and error messages are not too bad.
To compile the tests and examples it requires taocpp/json checked out next to it.
The config parser is backward compatible with JSON; every JSON file with a top-level object can be used as config file.
{
"ip": "127.0.0.2",
"port": 27960,
"maps": [ "ztn", "dm13", "t9" ]
}
This small example can be rendered differently using some of the additional syntactic possibilities of the config file format.
#!/usr/local/bin/q3s
ip = "127.0.0.2"
port = 27960
maps = [ "ztn" "dm13" "t9" ] // Add dm6 or t4?
Semantic features like deleting and referencing values, or including files and reading environment variables, usually only make sense with larger, non-trivial real-world examples.
Parsing a config file generally entails nothing more than calling the appropriate parse_file() function with the filename.
#include <tao/config.hpp>
const tao::config::value config = tao::config::parse_file( "foo.cfg" );
The resulting value is nothing other but a JSON Value from The Art of C++ / JSON with a custom traits class. It can be inspected using all the facilities of that JSON library.
For questions and suggestions regarding The Art of C++ / Config, success or failure stories, and any other kind of feedback, please feel free to join our Discord server, open a discussion, an issue or a pull request on GitHub or contact the authors at taocpp(at)icemx.net.
The Art of C++ / Config is certified Open Source software. It may be used for any purpose, including commercial purposes, at absolutely no cost. It is distributed under the terms of the MIT license reproduced here.
Copyright (c) 2018-2021 Dr. Colin Hirsch and Daniel Frey
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