static L<GazelleTree> gazelle_reason_repeat(S input, O... _) {
  new L<GazelleTree> out;
  
  int steps = 0, max = 10;
  while (steps++ < max) {
    L<GazelleTree> l = gazelle_reasonWithPreAndPost(input, _);
    
    // commit to one entry
    
    if (empty(l)) ret l;
    GazelleTree t = first(l);

    LS lines = tok_splitAtPlusAtBeginningOfLine(t.line);
    if (l(lines) == 2 && t.rule() != null && contains(t.rule().comments, "out 2 = process")) {
      print("splitting!");
      t.line = first(lines);
      out.add(t);
      input = second(lines);
      continue;
    }
    
    out.addAll(l);
    break;
  }
  
  ret out;
}