anchor.diff:      Disallow: /pt/bin/
     '';
   
  +  options = {
  +
  +    dataDir = mkOption {
  +      example = "/data/wiki/data";
  +      description = "
  +        Path to the directory that holds the Wiki data.
  +      ";
  +    };
  +
  +    pubDir = mkOption {
  +      example = "/data/wiki/pub";
  +      description = "
  +        Path to the directory that holds uploaded files.
  +      ";
  +    };
  +
  +    twikiName = mkOption {
  +      default = "Wiki";
  +      example = "Foobar Wiki";
  +      description = "
  +        Name of this Wiki.
  +      ";
  +    };
  +
  +    registrationDomain = mkOption {
  +      example = "example.org";
  +      description = "
  +        Domain from which registrations are permitted.  Use `all' to
  +        permit registrations from anywhere.
  +      ";
  +    };
  +
  +  };  
  +
   }
positive.code:   dispScriptUrlPath = "";
    dispViewPath      = "";
  
    twikiName = "Program Transformation Wiki";
    startWeb = config.startWeb;
    registrationDomain = "ewi.tudelft.nl";
    defaultUrlHost = "";
  
    # Build the TWiki CGI and configuration files.
    twikiRoot = (import /etc/nixos/services/twiki/twiki-instance.nix).twiki {
      name = "pt-wiki";
      pubdir = pubDir;
      datadir = dataDir;
      inherit twikiName scriptUrlPath pubUrlPath absHostPath
        dispPubUrlPath dispScriptUrlPath dispViewPath
        registrationDomain defaultUrlHost;
    };
  
    plugins = import /etc/nixos/services/twiki/server-pkgs/twiki-plugins.nix;
  
negative.code: let
  
    inherit (pkgs.lib) mkOption;
  
    dataDir = config.dataDir; # "/data/pt-wiki/data";
    pubDir = config.pubDir; # "/data/pt-wiki/pub";
  
    scriptUrlPath = "/bin";
    pubUrlPath    = "/pub";
  