svoid gazelle_splitMultiRule(S ruleID) {
  PairS p = dm_textAndCommentForRule(ruleID);
  if (p == null) ret;
  LPair<S> lines = ai_findDoubleArrowRulesAsPairs(p.a);
  S comment = "extracted from multi-rule " + ruleID;
  L<T3S> rules = dm_gazelle_allRulesWithComment(comment);
  Set<S> textsNeeded = asSet(mapPairsToList gazelle_constructRuleText(lines));
  for (T3S t : rules)
    if (!textsNeeded.remove(t.a))
      gazelle_deleteRule(t.c);
  for (S text : textsNeeded)
    dm_gazelle_addRuleWithComment(text, appendWithNewLine(p.b, comment));
}