sS renderLineCompedSingleWithBrackets(LineCompedSingle<Char> lc) {
  new StringBuilder buf;
  renderLineCompedSingleWithBrackets_step(lc, buf, lc.main);
  ret str(buf);
}
  
svoid renderLineCompedSingleWithBrackets_step(LineCompedSingle<Char> lc, StringBuilder buf, L<Int> chunks) {
  for (int idx : chunks)
    if (idx < l(lc.literals))
      buf.append(lc.literals.get(idx));
    else {
      buf.append("(");
      renderLineCompedSingleWithBrackets_step(lc, buf, intPairToList(lc.pairs.get(idx-l(lc.literals))));
      buf.append(")");
    }
}

Began life as a copy of #1028479