public static void printInterval(PrintableStringWriter stream, Stella_Object lower, boolean strictLowerP, Stella_Object upper, boolean strictUpperP) {
    if (strictLowerP) {
      stream.print("(");
    }
    else {
      stream.print("[");
    }
    if (lower != null) {
      stream.print(lower);
    }
    else {
      stream.print("?");
    }
    stream.print(",");
    if (upper != null) {
      stream.print(upper);
    }
    else {
      stream.print("?");
    }
    if (strictUpperP) {
      stream.print(")");
    }
    else {
      stream.print("]");
    }
  }