josiest / konbu

An modern-cpp parsing interface with yaml-cpp

Konbu

Konbu is a parsing utility library built on top of yaml-cpp. The motivation behind it to provide a reasonable way to read data with default values, while still being able to keep track of any parsing failures that happen along the way.

Requirements

• C++23 compiler
• yaml-cpp

As mentioned before, konbu is built on top of yaml-cpp, so you'll need to have yaml-cpp installed on your system. The interface also plans to use std::expected, which is a library feature from the C++23 standard. So you'll also need a C++ compiler that supports this standard or higher.

Installation

So far konbu is a single-include header library, so feel free to just copy it directly into your project. Alternatively, if you want to use cmake, you can also run the following commands

git clone https://github.com/josiest/konbu.git
cd konbu
mkdir build
cd build
cmake ..
cmake --install . --prefix <path/to/your/project>

You can then add this to your project's CMakeLists.txt

find_package(konbu 0.1.0 EXACT REQUIRED PATHS lib/cmake)
target_link_libraries(<your-project> INTERFACE konbu::konbu)

Note that this example uses the --prefix option for installing via cmake, and that find_package uses the exact version number. Because konbu is in its early stages of development, its interface is fairly volatile. So I'd highly recommend that you install it on a per-project basis with a specific version. This way, if breaking changes are introduced to the interface, your project isn't broken along with it.

Usage

So far this library is fairly small in scope. There are only a few template concepts and utility functions in the library. However, when using konbu, it's implied that you'll be writing read function overloads with a specific interface. This looks like

namespace konbu {
template<std::ranges::output_range<YAML::Exception> error_output>
void read(YAML::Node const & config, your_class & value, error_output & errors)
{
    // ... parse your_class ...
}
}

This interface has some expectations:

• error_output is an allocator-aware container
• any errors encountered while parsing should be written to errors via an insert_iterator
• your_class should be default-constructable so that if any errors happen along the way, the value that already exists will be used.

You can then use the function somewhat like this:

void print_error(std::string const & error)
{
    std::cout << error << "\n\n";
}

int main()
{
    auto const config = YAML::LoadFile("path/to/your/asset.yaml");
    std::vector<YAML::Exception> errors;
    
    your_class value;
    konbu::read(config, value, errors);
    
    ranges::for_each(errors | views::transform(&YAML::Exception::what),
                     print_error);
}

Examples

For more details and examples of how to use te library, see examples/sketch.cpp for a data interface for a prototype UI library