{self, ...}: let
  version = self.shortRev or self.dirtyShortRev or "unknown";
in {
  flake.overlays.default = _: prev: {
    hello = prev.callPackage ./derivation.nix {inherit version;};
  };

  perSystem = {
    pkgs,
    self',
    ...
  }: {
    package = {
      hello = pkgs.callPackage ./derivation.nix {inherit version;};
      default = self'.packages.hello;
    };
  };
}