static ItIt<SS> arbitraryVarsFlexFindIC_iterator_withPreAndPost(Set<S> vars, S pat, S input) {
  LS usedVars = ll("$_pre");
  S starsPat = arbitraryVarsToStars(pat, vars, usedVars);
  usedVars.add("$_post");
  ret mapI(flexMatchIC_iterator("* " + starsPat + " *", input), m -> matchesToMapUsingVarList_ciMap(m, usedVars));
}