@Override
  public String toString() {
    String delimiter = myOp.toString();
    if (myOp == LongRangeBinOp.PLUS && myRight instanceof DfaTypeValue) {
      long value = extractLong((DfaTypeValue)myRight);
      if (value < 0) {
        delimiter = "";
      }
    }
    return myLeft + delimiter + myRight;
  }
@Override
  public String toString()