static L<S> tok_combineRoundOrCurlyBrackets_keep_strict(L<S> tok) {
  new L<S> l;
  for i over tok: {
    S t = tok.get(i);
    if (odd(i) && eqOneOf(t, "{", "(")) {
      int j = findEndOfBracketPart_strict(tok, i);
      l.add(joinSubList(tok, i, j));
      i = j-1;
    } else
      l.add(t);
  }
  ret l;
}

Began life as a copy of #1013160