anchor.diff:      | "--view" -> Some TokenOption.View
       | "--modified" -> Some TokenOption.Modified
       | "--html" -> Some TokenOption.Html
  -    | "--rc" -> Some TokenOption.Rc
  +    | "--alpha" -> Some TokenOption.Alpha
  +    | "--beta" -> Some TokenOption.Beta
       | _ -> None
   
   
  
positive.code:         MainCommand.Bind, "bind <projectId-wildcard>+ : update bindings"
          MainCommand.Clean, "clean : DANGER! reset and clean workspace (interactive command)"
          MainCommand.History, "history [--html] : display history since last baseline"
          MainCommand.Upgrade, "upgrade : upgrade full-build to latest available version"
          MainCommand.Unknown, ""
          MainCommand.UpdatePackage, "update package : update packages"
          MainCommand.OutdatedPackage, "outdated package : display outdated packages"
  
negative.code:     | View
      | Modified
      | Html
      | Alpha
      | Beta
  
  let private (|TokenOption|_|) (token : string) =
      match token with
  