nixos-config/overlays/file-tree.nix

final: _: let
  inherit (final) lib;
  linkToPath = path: fileOrDir: (
    if final.lib.types.path.check fileOrDir
    then [
      {
        name = lib.concatStringsSep "/" path;
        path = fileOrDir;
      }
    ]
    else
      lib.concatLists (
        lib.mapAttrsToList
        (dirName: linkToPath (path ++ [dirName]))
        fileOrDir
      )
  );
in {
  recursiveLinkFarm = name: files: final.linkFarm name (linkToPath [] files);
}