svoid tok_questionDot(LS tok) {

  jreplace_dyn(tok, "->?.", -> {

    S var = makeVar();

    ret var + " -> " + var + "?.";

  });

  jreplace(tok, "if (<id> ?. <id)", "if ($3 != null && $3.$6)");

  int i;

  while ((i = jfind(tok, "<id> ?.")) >= 0) {

    S var = tok.get(i);

    bool isExpression = eqGetOneOf(tok, i-2, "ret", "return", ",", "=", "(", "?", "+", ">"); // too few

    if (!isExpression) {

      int j = tok_findEndOfStatement(tok, i)-1;

      tokAppend_reTok(tok, j, " }");

      tokReplace_reTok(tok, i, i+6, "{ if (\*var*/ != null) \*var*/.");

    } else {

      S expr = "\*var*/ == null ? null : \*var*/.";

      bool needBrackets = eqGet(tok, i-2, "+");

      if (needBrackets) {

        expr = "(" + expr;

        int j = tok_endOfExpression(tok, i)-1;

        tokPrepend_reTok(tok, j, ")");

      }

      tokReplace_reTok(tok, i, i+6, expr);

    }

  }

  jreplace_dyn(tok, "<id>()?.",

    func(LS tok, int i) -> S {

      int iQ = indexOf(tok, i, "?");

      S expr = joinSubList(tok, i, iQ-1);

      bool isExpression = eqGetOneOf(tok, i-2, "ret", "return", ",", "=", "(", "?"); // too few

      S var = makeVar();

      if (!isExpression) {

        int j = tok_findEndOfStatement(tok, i)-1;

        tokAppend_reTok(tok, j, " }");

        ret "{ var \*var*/ = \*expr*/; if (\*var*/ != null) \*var*/.";

      } else {  // experimental

        int j = tok_findEndOfExpression(tok, i)-1;

        tokAppend_reTok(tok, j, ")");

        ret "rCallF(\*expr*/, \*var*/ -> \*var*/ == null ?: \*var*/.";

      }

    });

}