nixos/fn.nix

{ lib }:

with builtins;
with lib;

rec {
  ifelse = a: b: c: if a then b else c;
  fileContentsOr = a: b: (ifelse
    (pathIsRegularFile a)
    a b);
  cwd = toString ./.;
  lst = { p ? cwd, t ? "regular", b ? false }: (lists.forEach
    (attrNames
      (filterAttrs (n: v: v == t)
        (readDir p)))
    (v: ((optionalString b "${p}/")  + v)));
  lsf = p: (lst { p = p; });
  lsd = p: (lst { p = p; t = "directory"; b = true; });
  lsfRec = p: b: flatten ((map (np: lsfRec np b) (lsd p)) ++ (lst { p = p; b = b; }));
}