static LS ai_turnCertainWordsIntoUniqueDollarVarsai_turnWordsIntoUniqueDollarVars(LS tok, Set<S> wordsToTransform) {
  MultiSet<S> ms = ciSet();
  ret mapWithIndex(tok, (t, i) ->
    odd(i) && contains(wordsToTransform, t) ? "$" + t + emptyIfOne(ms.add(t)) : t);
}

sS ai_turnCertainWordsIntoUniqueDollarVars(S s, Set<S> wordsToTransform) {
  ret join(ai_turnWordsIntoUniqueDollarVars(javaTokWithBrackets(s), wordsToTransform));
}