static Matches ai_matchPattern(S pat, S input) {
  pat = quoteUnlessQuoted(pat);
  S function = ai_forward(pat, "can be matched with");
  function = "get" + firstToUpper(function);
  if (!has_verified(function, "is", "a safe function to call")) fail("no mama: " + function);
  ret (Matches) quickImport(callAndMake(function, unquote(pat), input));
}