static S dollarVarsToStars_underscores(S s) {
  ret dollarVarsToStars_underscores(s, null);
}

static S dollarVarsToStars_underscores(S s, L<S> varNames_out) {
  ret join(dollarVarsToStars_underscores(javaTok(s), varNames_out));
}

static L<S> dollarVarsToStars_underscores(L<S> tok, L<S> varNames_out) {
  for (int i = 1; i < l(tok); i += 2) {
    S t = tok.get(i);
    if (isDollarVar(t)) {
      listAdd(varNames_out, t);
      tok.set(i, joinWithSpace(rep("*", underscoreWordCount(t))));
    } else if (eq(t, "*"))
      listAdd(varNames_out, "*");
  }
  ret tok;
}

Began life as a copy of #1010854