static bool matchWordSequence(O _pat, O _real, IMatchF matchF, Map map) {
  if (!(_pat << WordSequence && _real << WordSequence)) false;
  WordSequence pat = cast _pat;
  WordSequence real = cast _real;
  int n = l(pat.l);
  if (n != l(real.l)) false;
  for i to n:
    if (!matchF.get(pat.l.get(i), real.l.get(i), map)) false;
  true;
}