sbool nlLogic_stringFunction(S f, Func e, SS matches) {
  L<S> l = tok_splitAtComma(javaTokWithBrackets(nlLogic_text(e.arg)));
  if (l(l) != 2) false;
  l = mapReplaceVars2(l, matches);
  if (isDollarVar(second(l)) && !isDollarVar(first(l)))
    ret strictPutIC(matches, second(l), str(callAndMake(f, first(l))));
  ret eqic(second(l), first(l));
}