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 (string PATH) (string FILETYPE) (bool RETURNFULLPATH)
  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; }));
  hasAttrs = aList: d: (map
    (a:
      (ifelse (isList a)
        (hasAttrByPath a d)
        (hasAttr a d)))
    aList);
  deps = p: ifelse (isAttrs p) (filter (p: isAttrs p)
    (p.buildInputs ++ p.nativeBuildInputs ++ p.propagatedBuildInputs ++ p.propagatedNativeBuildInputs)
  ) [];
  importFilter = l: p: filter (n: elem (nameFromURL (toString n) ".") l) p;
  depsRec = ld: ifelse (ld == []) [] ((toList ld) ++ (depsRec (lists.unique (lists.flatten (map (d: deps d) (toList ld))))));
  isBroken = p: ifelse ((elem true (hasAttrs [["meta" "broken"]] p)) && (p.meta.broken == true))
    (warn "Package ${p.name} is marked as broken." true)
    false;
  depsBroken = p: lists.any (p: (isBroken p)) (deps p);
  # Those two lines are quite magical 🧙
  depsBrokenRec = p: (b: b == true) (ifelse (depsBroken p) true
    (map (p: depsBrokenRec p) (deps p)));
  pkgFilter = ld: (filter
    (p: (
      ifelse (isBroken p)
        false
        (ifelse (depsBrokenRec p)
          (warn "Dependency of ${p.name} is marked as broken." false)
          true)
    ))
    ld);
}