@Override
  public ASTNode findChildByRole(int role) {
    LOG.assertTrue(ChildRole.isUnique(role));
    switch(role){
      case ChildRole.LPARENTH:
        return findChildByType(LPARENTH);

      case ChildRole.TYPE:
        return findChildByType(TYPE);

      case ChildRole.RPARENTH:
        return findChildByType(RPARENTH);

      case ChildRole.OPERAND:
        return findChildByType(EXPRESSION_BIT_SET);

      default:
        return null;
    }
  }
@Override
  public ASTNode findChildByRole(int role)