Parse command line arguments for C++ programs. Boost has a more robust library for parsing command line options, but this lighter-weight argparse can be used without using the boost library.

Usage

See main.cpp for an example of how to use argparse. In short:

• First create argument specifications using the Argument class.
• Then add those argument specifications to an ArgumentParser object.
• Parse the command line arguments with ArgumentParser::parse.
• Finally, retrieve argument values with ArgumentParser::get<t>.

Argument Specification

The Argument class specifies how a command line argument is to be interpreted. Its member variables include:

• name. Determines whether the argument is an option, beginning with "--" or "-", or a positional argument. Options must appear before positional arguments: programName [optional arguments] [positional arguments].
• shortName. A shorter name for an option to appear on the command line. Must begin with '-'. Ignored for positional arguments.
• nargs. The number of sub-arguments expected for this argument. (Defaults to 1.) Set this to 0 to make this a boolean flag (i.e., if this argument is present, then its value is true, and if not, then its value is false). Special constant values NARGS_AT_LEAST_ZERO and NARGS_AT_LEAST_ONE specify that the parser is to consume as many arguments as possible.
• required. Must this argument be provided on the command line? (Defaults to false for options and true for positionals.)
• defaultValue. The default value for if this argument doesn't appear. This can be a single string (for nargs=1) or a vector of strings (for nargs>1). If nargs is 0, then defaultValue becomes "false".
• help. The help description printed if the user specifies the --help or -h option.
• metavar. The name that represents this argument's sub-arguments in the help message. (Defaults to name for positionals and all-caps name for options.)
• choices. If specified, the value(s) for this argument must be among the elements of the choices vector.

Roadmap

As my leisure time permits, I intend to make the following changes:

• Improve error messages.
• Improve documentation, comments, and code organization.
• Write comprehensive tests.