anchor.diff:  { config, lib, pkgs, ... }:
  +
   with lib;
  +
   let
  +
     cfg = config.services.redshift;
   
   in {
  -  options = {
  -    services.redshift.enable = mkOption {
  +
  +  options.services.redshift = {
  +    enable = mkOption {
         type = types.bool;
         default = false;
         example = true;
  -      description = "Enable Redshift to change your screen's colour temperature depending on the time of day";
  +      description = ''
  +        Enable Redshift to change your screen's colour temperature depending on
  +        the time of day.
  +      '';
       };
   
  -    services.redshift.latitude = mkOption {
  -      description = "Your current latitude";
  +    latitude = mkOption {
         type = types.str;
  +      description = ''
  +        Your current latitude.
  +      '';
       };
   
  -    services.redshift.longitude = mkOption {
  -      description = "Your current longitude";
  +    longitude = mkOption {
         type = types.str;
  +      description = ''
  +        Your current longitude.
  +      '';
       };
   
  -    services.redshift.temperature = {
  +    temperature = {
         day = mkOption {
  -        description = "Colour temperature to use during day time";
  +        type = types.int;
           default = 5500;
  -        type = types.int;
  +        description = ''
  +          Colour temperature to use during the day.
  +        '';
         };
         night = mkOption {
  -        description = "Colour temperature to use during night time";
  +        type = types.int;
           default = 3700;
  -        type = types.int;
  +        description = ''
  +          Colour temperature to use at night.
  +        '';
         };
       };
   
  -    services.redshift.brightness = {
  +    brightness = {
         day = mkOption {
  -        description = "Screen brightness to apply during the day (between 0.1 and 1.0)";
  +        type = types.str;
           default = "1";
  -        type = types.str;
  +        description = ''
  +          Screen brightness to apply during the day,
  +          between <literal>0.1</literal> and <literal>1.0</literal>.
  +        '';
         };
         night = mkOption {
  -        description = "Screen brightness to apply during the night (between 0.1 and 1.0)";
  +        type = types.str;
           default = "1";
  -        type = types.str;
  +        description = ''
  +          Screen brightness to apply during the night,
  +          between <literal>0.1</literal> and <literal>1.0</literal>.
  +        '';
         };
       };
   
  -    services.redshift.extraOptions = mkOption {
  +    package = mkOption {
  +      type = types.package;
  +      default = pkgs.redshift;
  +      description = ''
  +        redshift derivation to use.
  +      '';
  +    };
  +
  +    extraOptions = mkOption {
         type = types.listOf types.str;
         default = [];
         example = [ "-v" "-m randr" ];
  -      description = "Additional command-line arguments to pass to the redshift(1) command";
  +      description = ''
  +        Additional command-line arguments to pass to
  +        <command>redshift</command>.
  +      '';
       };
     };
   
  
positive.code:       serviceConfig.Restart = "always";
      };
    };
  }
  
negative.code:       after = [ "display-manager.service" ];
        wantedBy = [ "graphical.target" ];
        serviceConfig.ExecStart = ''
          ${cfg.package}/bin/redshift \
            -l ${cfg.latitude}:${cfg.longitude} \
            -t ${toString cfg.temperature.day}:${toString cfg.temperature.night} \
            -b ${toString cfg.brightness.day}:${toString cfg.brightness.night} \
  