{
  description = "";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-unstable";
  };

  outputs = {
    self,
    nixpkgs,
    ...
  }: let
    systems = [
      "x86_64-linux"
      "aarch64-linux"
      "x86_64-darwin"
      "aarch64-darwin"
    ];

    forAllSystems = fn: nixpkgs.lib.genAttrs systems (sys: fn nixpkgs.legacyPackages.${sys});
    version = self.shortRev or self.dirtyShortRev or "unknown";
  in {
    devShells = forAllSystems ({
      pkgs,
      system,
      ...
    }: {
      default = pkgs.mkShell {
        packages = with pkgs; [
          bash
        ];

        inputsFrom = [self.packages.${system}.hello];
      };
    });

    formatter = forAllSystems (pkgs: pkgs.alejandra);

    packages = forAllSystems ({
      pkgs,
      system,
      ...
    }: {
      hello = pkgs.callPackage ./. {inherit version;};
      default = self.packages.${system}.hello;
    });

    overlays.default = _: prev: {
      hello = prev.callPackage ./. {inherit version;};
    };
  };
}