anchor.diff:  let
   
     inherit (pkgs) prayer;
  +
  +  cfg = config.services.prayer;
   
     stateDir = "/var/lib/prayer";
   
  
positive.code:       enable = mkOption {
          default = false;
          description = ''
            Whether to run the machine as a HTTP proxy server.
          '';
        };
  
        listenAddress = mkOption {
          default = "127.0.0.1:8118";
          description = ''
            Address the proxy server is listening to.
          '';
        };
  
        logDir = mkOption {
          default = "/var/log/prayer" ;
          description = ''
            Location for prayer log files.
          '';
        };
  
  
negative.code:     prayer_group = "${prayerGroup}"
      sendmail_path = "/var/setuid-wrappers/sendmail"
  
      use_http_port ${cfg.port}
  
      ${cfg.extraConfig}
    '';
  
    prayerCfg = pkgs.runCommand "prayer.cf" { } ''
  