// f: A -> Comparable
static <A> L<A> sortedByCalculatedFieldDesc(Collection<A> c, fO f) {
  ret sortByCalculatedFieldDesc(c, f);
}



static <A> L<A> mapLike sortedByCalculatedFieldDesc(O f, Collection<A> c) {
  ret sortByCalculatedFieldDesc(f, c);
}

static <A, B> L<A> sortedByCalculatedFieldDesc(Iterable<A> c, IF1<A, B> f) {
  L<A> l = cloneList(c);
  sort(l, new Comparator<A>() {
    public int compare(A a, A b) {
      ret stdcompare(f.get(b), f.get(a));
    }
  });
  ret l;
}