{ config, lib, pkgs, ... }: with lib; let cfg = config.programs.test.meow; in { options = { programs.test.meow = { enable = mkEnableOption "meow"; name = mkOption { type = types.str; default = "cat"; }; }; }; config = mkIf cfg.enable { environment.systemPackages = [ pkgs.meow ]; environment.etc."meow".text = cfg.name; }; }