static <A> A[] dropLast(A[] a, int n default 1) {
  if (a == null) null;
  n = Math.min(n, a.length);
  A[] b = arrayOfSameType(a, a.length-n);
  System.arraycopy(a, 0, b, 0, b.length);
  ret b;
}

static <A> L<A> dropLast(L<A> l) {
  ret subList(l, 0, l(l)-1);
}

static <A> L<A> dropLast(int n, L<A> l) {
  ret subList(l, 0, l(l)-n);
}

static <A> L<A> dropLast(Iterable<A> l) {
  ret dropLast(asList(l));
}

static S dropLast(S s) {
  ret substring(s, 0, l(s)-1);
}

static S dropLast(S s, int n) {
  ret substring(s, 0, l(s)-n);
}

static S dropLast(int n, S s) {
  ret dropLast(s, n);
}