svoid surroundTokenRangeWithRoundBrackets(LS tok, IntRange r) {
  if (r != null) surroundTokenRangeWithRoundBrackets(tok, r.start, r.end);
}

svoid surroundTokenRangeWithRoundBrackets(LS tok, int i, int j) {
  tokPrepend(tok, i | 1, "(");
  tokAppend(tok, j & ~1, ")");
}