Replace usage of boost::program_option with ini-cpp

[tan2]

Currently, our codebase relies on boost::program_options for parameter parsing. While powerful, Boost is a massive dependency that bloats our build times, complicates our CI/CD pipelines, and feels unnecessarily heavy since we only need to parse INI-format configuration files.

I propose replacing boost::program_options with ini-cpp (specifically the C++17 wrapper: SSARCandy/ini-cpp). It provides a modern, header-only implementation that perfectly meets our strict requirements:

• Native support for default values.
• Native support for extracting vectors (GetVector<T>).
• Built-in capabilities to dump/write the configuration back to a file.

Pros of switching to ini-cpp:

• Faster Compile Times: ini-cpp is a lightweight, header-only library. It removes the need to build and link against compiled Boost libraries.
• Cleaner Syntax: It leverages modern C++17, replacing Boost's verbose macro-like option declarations with a very clean, straightforward reader.Get<T>() API.
• Simplified Dependency Management: We can drop the heavy Boost requirement from our CMake/vcpkg setups, shrinking our project footprint.

GitHub Repository: https://github.com/SSARCandy/ini-cpp

Official Documentation: https://ssarcandy.tw/ini-cpp/index.html

API Reference (inih namespace): https://ssarcandy.tw/ini-cpp/namespaceinih.html

[chaseshyu]

Currently, the only library we need to manually install for DES compilation is Boost on Linux. It’s a good idea to make the user experience as smooth as possible when starting with DES. But it seems like the cpp-ini doesn’t support the -h option. We might need to make a helper for -h if we want to keep the -h function.

[tan2]

You are right, ini-cpp does not support option registry, which is required to print the usage help.

Another option is to use CLI11 (https://github.com/cliutils/cli11).

CLI11 supports all three of those features natively. In fact, its architecture is much closer to boost::program_options than ini-cpp is, making it the ideal drop-in replacement if we want an all-in-one solution.

Here is how CLI11 handles our specific requirements:

• Registry & -h Support: The CLI::App object acts as your central registry. It automatically catches the -h or --help flag and prints a beautifully formatted doc-string screen containing all parameters, descriptions, and types.

• Defaults: You just assign a default value to your standard C++ variable before registering it. If you chain ->capture_default_str(), CLI11 will automatically print that default value on the help screen.

• Vectors: It natively supports std::vector. If a user passes multiple values on the command line or comma-separated values in an INI file, it parses them directly into the vector.