anchor.diff: -{ config, lib, pkgs, ... }:
  +{ config, lib, options, pkgs, ... }:
   
   with lib;
   
   let
     cfg = config.services.mpdscribble;
     mpdCfg = config.services.mpd;
  +  mpdOpt = options.services.mpd;
   
     endpointUrls = {
       "last.fm" = "http://post.audioscrobbler.com";
  
positive.code:         mpdCfg.network.listenAddress
        else
          "localhost");
        type = types.str;
        description = ''
          Host for the mpdscribble daemon to search for a mpd daemon on.
  
negative.code: 
      port = mkOption {
        default = mpdCfg.network.port;
        defaultText = literalExpression "config.${mpdOpt.network.port}";
        type = types.port;
        description = ''
          Port for the mpdscribble daemon to search for a mpd daemon on.
  