static L<S> javaTokNPunctuation(S s) {
  L<S> tok = javaTok(s);
  for (int i = 1; i < l(tok); i += 2) {
    int j = i;
    S t;
    while (j < l(tok) && l(t = tok.get(j)) == 1
      && !Character.isLetterOrDigit(t.charAt(0)))
        j += 2;
    if (j > i)
      // j points to next C token after mergeable stuff
      replaceSubList(tok, i-1, j, ll(joinSubList(tok, i-1, j)));
  }
  ret tok;
}