static ItIt<Matches> flexMatchIC_iterator(S pat, S input) {
  L<S> tokPat = javaTokNPunctuation_plusAsterisk(pat), tokInput = javaTokNPunctuation_plusAsterisk(input);
  ret flexMatchIC_iterator(pat, tokPat, tokInput);
}
  
static ItIt<Matches> flexMatchIC_iterator(S pat, LS tokPat, LS tokInput) {
  L<Int> varIndices = flexMatchIC_getVarIndices(tokPat, tokInput);
  if (varIndices == null) ret emptyItIt();

  ItIt<LS> spreadInputs = ai_spreadCertainIndices_2_iterator(tokPat, tokInput, varIndices);
  
  ret mapI_notNulls(spreadInputs, tok -> {
    new Matches m;
    ret match(pat, tok, m) ? m : null;
  });
}