static BasicLogicRule<S> ai_sharedPhrasesIntoDollarVars(BasicLogicRule<S> r) {
  LLS splits = stringsToLineCompSplits_wordMode(r.lhs, r.rhs);
  ifdef ai_sharedPhrasesIntoDollarVars_debug
    print(+splits);
  endifdef
  LS phrases = antiFilter isDollarVar(intersectCISets(splits));
  SS map = ciMapWithUnusedCountingDollarVars(phrases, linesLL(r.lhs, r.rhs));
  LLS splits2 = map(splits, l -> replaceElementsUsingMap(l, map));
  ret listToBasicLogicRule(lambdaMap nlJoin(splits2));
}