static L<IntRange> findNonStreaks(L l, O pred) {
  new L<IntRange> out;
  int i = 0, n = l(l);
  while (i < n) {
    int j = i;
    while (j < n && !isTrue(callF(pred, l.get(j)))) ++j;
    if (j > i)
      out.add(intRange(i, j));
    i = j+1;
  }
  ret out;
}

static L<IntRange> findNonStreaks(O pred, L l) {
  ret findNonStreaks(l, pred);
}