anchor.diff:              documentRoot = "/data/webroot-bar";
             }
           ];
  +        type = with types; listOf optionSet;
           description = ''
             Specification of the virtual hosts served by Apache.  Each
             element should be an attribute set specifying the
  
positive.code:           are the non-global options permissible for the main host.
          '';
  
          # Add the default value for each function which is not defined.
          # This should be replaced by sub-modules.
          apply =
            map (vhost:
              addDefaultOptionValues vhostOptions vhost
            );
        };
  
      }
      // perServerOptions {forMainServer = true;}
      ;
    };
  }
negative.code: {config, pkgs, ...}:
  
  let
    inherit (pkgs.lib) mkOption addDefaultOptionValues types;
  
    perServerOptions = {forMainServer}: {
  
  