static Matches getMatches(S pat, S input) {
  new Matches m;
  ret match(pat, input, m) ? m : null;
}

static Matches getMatches(S pat, LS input) {
  new Matches m;
  ret match(pat, input, m) ? m : null;
}

static Matches getMatches(LS pat, LS input) {
  new Matches m;
  ret match3(pat, input, m) ? m : null;
}