主题：ext全局变量的疑惑！觉得很大的bug

以下内容为程序代码:

1 ma1:ma(close,10);
2 bt:=ref(ma1,1)＞ref(ma1,2);
3 dt:=ref(ma1,1)＜ref(ma1,2);
4 if bt and holding=0 then BEGIN
5     buy(1,1,limitr,open);
6     EXTGBDATAset('tt',date);
7     EXTGBSTRINGSET('趋势','向上');
8 end
9
10 if dt and holding＞0 then begin
11     EXTGBDATASET('tt',date);
12     EXTGBSTRINGSET('趋势','向下');
13     sell(1,1,limitr,open);
14
15 end