static LS tok_autoLongConstants(LS tok) {
  int n = l(tok);
  for (int i = 1 ; i < n; i += 2) {
    S t = tok.get(i);
    if (isInteger(t) && !eq(get(tok, i+2), "L")
      && !eqOneOf(get(tok, i-2), /*"-",*/ /* huh? */ "." /* float/double */)
      && !longIsInt(parseLong(t)))
      tokAppend(tok, i, "L");
  }
  ret tok;
}