settingsnode

settingsnode is a small convenience C++ wrapper for reading nested settings without tying the rest of a program to one configuration backend.

The public API is a SettingsNode: you can ask whether a node is present, read typed scalar values, walk maps and sequences, and get useful path information in exceptions. The repository currently includes adapters for yaml-cpp and pybind11 objects.

Basic use

#include <fstream>
#include <memory>
#include <settingsnode.h>
#include <settingsnode/yaml.h>

int main() {
    std::ifstream stream("config.yaml");
    settings::SettingsNode config(std::make_unique<settings::YAML>(stream));

    const auto host = config["server"]["host"].as<std::string>("127.0.0.1");
    const auto port = config["server"]["port"].as<int>(8080);

    for (const auto& item : config["plugins"].as_sequence()) {
        const auto name = item["name"].as<std::string>();
        const auto enabled = item["enabled"].as<bool>(true);
    }
}

Missing required values throw settings::exception with the path that failed. Fallback overloads such as as<int>(8080) return the fallback only when the node is missing; type errors still come from the backend.

Maps and sequences

for (const auto& entry : config["limits"].as_map()) {
    const std::string& key = entry.first;
    const settings::SettingsNode& value = entry.second;
}

std::vector<int> ports = config["ports"].to_vector<int>();
std::unordered_map<std::string, double> weights = config["weights"].to_map<double>();

The iterators are single-pass input iterators. They are meant for direct iteration, not for storing and revisiting later.

CMake

Include settingsnode.cmake and link the interface target:

include(path/to/settingsnode/settingsnode.cmake)
target_link_libraries(my_target PRIVATE settingsnode)

There is also a compatibility helper:

include_settingsnode(my_target)

Backend libraries are still your responsibility. For YAML support, link yaml-cpp; for Python object support, include and link pybind11 as usual for your project.

Backends

YAML:

#include <settingsnode/yaml.h>

settings::SettingsNode config(std::make_unique<settings::YAML>(stream));

Python objects through pybind11:

#include <settingsnode/pybind.h>

settings::SettingsNode config(std::make_unique<settings::PyNode>(python_object));