svoid tok_forUnnull(LS tok) {
  jreplace(tok, "fOr (", "for unnull (");
  
  int i = -1;
  while ((i = jfind(tok, i+1, "for unnull (")) >= 0) {
    int argsFrom = i+4;
    int iColon = indexOf(tok, i, ":");
    int iClosing = tok_findEndOfForExpression(tok, iColon+2);
    ifdef tok_forUnnull_debug
      print("Found for unnull: " + joinSubList(tok, i, iClosing+1));
    endifdef
    clearTokens(tok, i+2, i+4);
    tokPrepend(tok, iColon+2, "unnullForIteration(");
    tokPrepend(tok, iClosing, ")");
    reTok(tok, i+2, iClosing+1);
    ifdef tok_forUnnull_debug
      print("for unnull => " + joinSubList(tok, i, iClosing+1));
    endifdef
  }
}

Began life as a copy of #1013206