{ pkgs, lib ? pkgs.lib, unitDir ? "unit", packageFun ? "package.nix", root ? "${./pkgs}/${unitDir}" }:
let
  shards = lib.attrNames (builtins.readDir root);
  namesForShard = shard: lib.mapAttrs'
    (name: _: { inherit name; value = "${root}/${shard}/${name}"; })
    (builtins.readDir "${root}/${shard}");
  namesToPath = lib.foldl' lib.recursiveUpdate { } (map namesForShard shards);
  units = lib.mapAttrs (_: path: pkgs.callPackage "${path}/${packageFun}" { }) namesToPath;
in
units