docs: function notifyExpression(expression) {
                  var len = 0, childGroup = null;
                  if (!expression) {
                      return;
                  }
                  if (expression.getType() === GTYPE.EXP) {
                      for (var i = 0, len = expression.getChildren().length; i < len; i++) {
                          notifyExpression(expression.getChild(i));
                      }
                  } else if (expression.getType() === GTYPE.COMPOUND_EXP) {
                      // 操作数处理
                      for (var i = 0, len = expression.getOperands().length; i < len; i++) {
                          notifyExpression(expression.getOperand(i));
                      }
                      // 处理操作符
                      notifyExpression(expression.getOperator());
                  }
                  expression.addedCall && expression.addedCall();
              }