anchor.diff:          ExecStart = "${pkgs.nginx}/bin/nginx -c ${configFile} -p ${cfg.stateDir}";
         };
       };
  - 
  +
       users.extraUsers.nginx = {
         group = "nginx";
       };
  - 
  +
       users.extraGroups.nginx = {};
     };
   }
  
positive.code: { config, pkgs, ... }:
   
  with pkgs.lib;
   
  let
    cfg = config.services.nginx;
    configFile = pkgs.writeText "nginx.conf" ''
      ${cfg.config}
    '';
  in
   
  {
    options = {
      services.nginx = {
  
negative.code:         ";
        };
      };
  
    };
  
    config = mkIf cfg.enable {
      environment.systemPackages = [ pkgs.nginx ];
  
      # TODO: test user supplied config file pases syntax test
  
      systemd.services.nginx = {
        description = "Nginx Web Server";
        after = [ "network.target" ];
  