cerulean/nix/snow/flake/outputs/nixosConfigurations.nix

{lib, ...}: let
  inherit
    (lib)
    mkOption
    types
    literalExpression
    ;
in {
  options = {
    outputs.nixosConfigurations = mkOption {
      type = types.lazyAttrsOf types.raw;
      default = {};
      description = ''
        Instantiated NixOS configurations. Used by `nixos-rebuild`.

        `nixosConfigurations` is for specific machines. If you want to expose
        reusable configurations, add them to [`nixosModules`](#opt-flake.nixosModules)
        in the form of modules (no `lib.nixosSystem`), so that you can reference
        them in this or another flake's `nixosConfigurations`.
      '';
      example = literalExpression ''
        {
          my-machine = inputs.nixpkgs.lib.nixosSystem {
            # system is not needed with freshly generated hardware-configuration.nix
            # system = "x86_64-linux";  # or set nixpkgs.hostPlatform in a module.
            modules = [
              ./my-machine/nixos-configuration.nix
              config.nixosModules.my-module
            ];
          };
        }
      '';
    };
  };
}