static <A, B> int generalizedBinarySearch(L<A> l, B key, IF2<A, B, Int> cmp) {
  ret generalizedBinarySearch(l, 0, l(l), key, cmp);
}

static <A, B> int generalizedBinarySearch(L<A> l, int fromIndex, int toIndex, B key, IF2<A, B, Int> cmp) {
  int low = fromIndex;
  int high = toIndex - 1;

  while (low <= high) {
    int mid = (low + high) >>> 1;
    A midVal = l.get(mid);

    int c = cmp.get(midVal, key);
    if (c < 0)
      low = mid + 1;
    else if (c > 0)
      high = mid - 1;
    else
      ret mid; // key found
  }
  ret -(low + 1);  // key not found.
}