sS gazelle_processSquareBracketAnnotations(S ruleText, LS comments) {
  LS lines = tlft(ruleText);
  for i over lines: {
    S s = lines.get(i);
    PairS p = splitTrailingSquareBracketStuff(s);
    if (nempty(p.b))
      comments.add("in " + (i+1) + " = " + p.b);
    lines.set(i, p.a);
  }
  ret lines_rtrim(lines);
}