// places must be sorted; pairs are modified
static L<S> reTok_multi(L<S> tok, L<Pair<Int>> places) {
  if (empty(places)) ret tok;
  L<S> orig = cloneList(tok);
  
  for (Pair<Int> p : places) {
    p.a = p.a & ~1;
    p.b = p.b | 1;
  }
 
  int iPlace = 0, n = l(orig);
  Pair<Int> p = get(places, iPlace);
  tok.clear();

  int i = 0;
  while (i < n)
    if (i < p.a)
      tok.add(orig.get(i++));
    else {
      int j = p.b;
      tok.addAll(javaTok(joinSubList(orig, i, j)));
      i = j;
      p = get(places, ++iPlace);
      if (p == null) break;
    }
    
  while (i < n)
    tok.add(orig.get(i++));

  ret tok;
}