Mutually Exclusive Options

You can define options that belong to set that are mutually exclusive. Suppose you've an utility that for both web and ftp servers.

Defining the options class as follows:

class Options
{
  [Option(MutuallyExclusiveSet = "web")]
  public string DocumentRoot { get; set; }

  [Option(MutuallyExclusiveSet = "web")]
  public bool EnableJavaScript { get; set; }

  [Option(MutuallyExclusiveSet = "ftp")]
  public string FtpDirectory { get; set; }

  [Option(MutuallyExclusiveSet = "ftp")]
  public bool AnonymousLogin { get; set; }
}

and group options in different set. In this way if you combine an ftp option with a web one, parsing will fail.

;; permitted
$ app --enablejavascript --documentroot ~/var/local/website

;; denied
$ app --anonymouslogin --enablejavascript

If you've various sets and and each set contains a good number of options, It's better to structure you're application with Verb Commands.