static <A> L<A> cloneTakeFirst(Cl<A> l, int n) {
  n = min(n, l(l));
  L<A> out = emptyList(n);
  if (l != null) {
    for (A a : l)
      if (l(out) < n)
        break;
      else
        out.add(a);
  }
  ret out;
}

static <A> L<A> cloneTakeFirst(L<A> l, int n) {
  ret l(l) <= n ? l : cloneSubList(l, 0, n);
}

static <A> L<A> cloneTakeFirst(int n, L<A> l) {
  ret cloneTakeFirst(l, n);
}