{
  sources ? import ./npins,
  pkgs ? import sources.nixpkgs { config.allowUnfree = true; },
  ...
}:

let
  inherit (pkgs.lib) callPackageWith;

  callPackage = callPackageWith (pkgs // self);

  listDirs =
    dir:
    let
      entries = builtins.readDir dir;
    in
    builtins.filter (n: entries.${n} == "directory") (builtins.attrNames entries);

  mkPackages =
    fun: dir:
    builtins.map (name: {
      inherit name;
      value = fun (dir + "/${name}") { };
    }) (listDirs dir);

  self = builtins.listToAttrs (mkPackages callPackage ./by-name);
in
self