主题：求助,这个简单公识不知道那里错了.求指导.

IF  cross(Value1,Value2)  THEN
BEGIN
longLine = high;
shortLine = 0;
END

IF  cross(Value2,Value1)  THEN
BEGIN
longLine =0;
shortLine =low;
END

if longLine<>0 then begin
buy(HOLDING=0,1,THISCLOSE);
end;

if shortLine<>0 then begin
sell(HOLDING=0,1,THISCLOSE);
end;

不知怎么错了.图表上没交易信号望指导.