Command Line Parser Library 3 pre-release for .Net.

The Command Line Parser Library offers .Net applications a clean and concise API for handling command line arguments, detecting errors in the command line, and displaying help screens. Parsing command line arguments should be as simple as defining a data structure that contains the required data. This library provides hassle free command line parsing.

This library was inspired by the CommandLine and CommandLine2 projects. Unfortunately the former hasn't seen much development and the latter has a number of egregious bugs. This library is a complete rewrite, preserving a very similar API to CommandLine2.

Compatibility:

• .NET Framework 3.5+

Current Release:

• This code is currently pre-release, a significant amount of documentation, testing, and packaging still needs to be done.

At glance:

• One line parsing using default singleton: CommandLine.Parser.Default.ParseArguments(...).
• One line help screen generator: HelpText.AutoBuild(...).
• Map command line arguments to sequences (IEnumerable<T>), enum or standard scalar types.
• Extensible argument deserialization and validation.
• Define verb based commands (i.e. git commit or git push) (see Parser.ParseMultiVerbArguments)
• Mutually exclusive parameter sets
• Flexible command line argument style (i.e. /F <file> or --file=<file> or -File <file>) (see ParserSettings)

To install:

• Currently the only way to install this package is to build from source and manually copy binary. Nuget package comming soon.

Sample:

Define a class to receive command line values:

class Options {
  [Option('r', "read", Required = true,
    HelpText = "Input files to be processed.")]
  public IEnumerable<string> InputFiles { get; set; }
    
  // omitting long name, default --verbose
  [Option(DefaultValue = true,
    HelpText = "Prints all messages to standard output.")]
  public bool Verbose { get; set; }

  // a position parameter may be referenced by name, or used in the appropriate position
  [Option('o', 0)]
  public int Offset { get; set;}
  }
}

Parse the command line and consume the resulting obejct:

static void Main(string[] args) {
  var result = CommandLine.Parser.Default.ParseArguments<Options>(args);
  if (!result.Errors.Any()) {
    // Values are available here
    if (result.Value.Verbose) Console.WriteLine("Filenames: {0}", string.Join(",", result.Value.InputFiles.ToArray()));
  }
}

Known Issues:

• OptionsAttribute needs a position only constructor and a parameterless constructor
• VerbAttribute shouldn't be strictly required
• Parameter validation is Not Yet Implemented
• Default value assignment is Not Yet Implemented

Acknowledgements:

Thanks to Giacomo Stelluti Scala (@gsscoder) for prior work on CommandLine which was the inspiration for this library. Thanks to Thomas (@cosmo0) for prior work on CommandLine2 which was also inspirational for this library.

Main Contributors (alphabetical order):

• Paul Wheeler (@paulwh)

Resources for newcomers:

• Quickstart - TODO
• Wiki - TODO

Latest Changes:

• Minor changes to improve consistency with existing CommandLine package. (@paulwh)

Contacts:

Paul Wheeler

• paul.wheeler AT appature DOT com