{ inputs, lib, pkgs, ... }:

let
  inherit (lib) makeExtensible attrValues foldr;
  inherit (modules) mapModules;

  # We define modules, so we can use mapModules
  modules = import ./modules.nix {
    inherit lib;
    self.attrs = import ./attrs.nix { inherit lib; self = {}; };
  };

  # mylib = {
  #   "attrs" = import "attrs.nix" { selg lib pkgs inputs };
  #   "options" = import "options.nix" { selg lib pkgs inputs };
  #   ...
  #   "extend": <<lambda>>;    # from makeExtensible
  #   "__unfix__": <<lambda>>; # from makeExtensible
  #   }
  mylib = makeExtensible (self:
    with self; mapModules ./.
      (file: import file { inherit self lib pkgs inputs; }));
in
# We have
#   (attrValues super) = [ (import "attrs.nix" {...}) (import "options.nix" {...}) ... ]
# And thus
#   mylib.extend(...) = (import "attrs.nix" {...}) // (import "options.nix" {...}) // ...
# Which is what we want, default.nix returns all modules merged (and extensible)
mylib.extend
  (self: super:
    foldr (a: b: a // b) {} (attrValues super))