cpp_argument_parser

A robust command-line argument parser written in C++20.

• Cross-platform; tested on Windows, Mac, and Linux.
  • Correctly handles Windows-specific text encodings of command-line arguments
• Supports single and double-dashed arguments with arbitrary names and types
  • Supports optional = signs (so cmd --max-depth=5 and cmd --max-depth 5 both work)
• Supports option bundling: combining multiple single-character boolean options with a single dash (e.g. cmd -abcd rather than cmd -a -b -c -d)

General Usage

Say you wanted a command to support the following options:

• max_threads (aka m): The maximum number of threads to use for the hypothetical command
• quiet (aka q): Whether or not to suppress compiler output
• outfile (aka o): The file path of the output file
• log-errors (aka l): Whether to write error messages to the output file
• fail-on-warning: Whether or not to abort if the system generates a warning

To have your command support these options, you would simply

1. Add the fields to the CommandLineOptions class (you would not need to change anything else), so it would look like

class CommandLineOptions {
    ...
public:
    /* List options here as fields */
    int max_threads = 0;
    bool quiet = false;
    std::string outfile = "output.txt";
    bool log_errors = false;
    bool fail_on_warning = false;

    ...
};

2. Then, for each option name, add one line to CommandLineOptions::try_processing().
3. Finally add the fields corresponding to your options to std::formatter<CommandLineOptions>::format().

Afterwards, you would be able to execute your program, passing your options to the executable. For example, cpp_argument_parser would correctly handle all of the following:

• ./cmd --max_threads 5 -ql --outfile=log.txt
• ./cmd -m=5 -l=false --fail-on-warning
• ./cmd -q=1 --max_threads=20 -fl -o log.txt

The command-line arguments are directly accessible from the fields of CommandLineOptions, which are set in its constructor.

How to Build

1. git clone this repo.
2. After git cloneing, cd to the top directory of cpp_argument_parser, and create a build directory (e.g. mkdir build).
3. cd into the build directory and run cmake ...
4. Build the project (run make if the previous step generated Makefiles).

How to Run Tests

From the build directory, give executable permissions to the test script first using chmod +x ./../scripts/run_tests.sh (if on Linux). Then, use the command ./../scripts/run_tests.sh.