// returns L<S|L>
static L recursiveJavaTok(S s) {
  L tok = cloneList(javaTokWithBrackets(s));
  for (int i = 1; i < l(tok); i += 2) {
    S t = cast tok.get(i);
    if (startsWithOneOf(t, "(", "{")) {
      L sub = recursiveJavaTok(dropFirstAndLast(t));
      
      // add brackets to inner N tokens
      sub.set(0, first(sub) + takeFirst(1, t));
      sub.set(l(sub)-1, takeLast(1, t) + last(sub));
      
      tok.set(i, sub);
    }
  }
  ret tok;
}