主题：请帮忙添加一些注释

lookbackdays:=min(lookbackdays,ceilingamt); // 取两个数中的较小值

lookbackdays:=max(lookbackdays,flooramt); // 取两个数中的较大值

mid:=ma(close,lookbackdays); //中线---收盘价的N--lookbackdays日移动平均
upband:=mid+bolbandtrig*std(close,lookbackdays);//上轨---中线加偏移值
dnband:=mid-bolbandtrig*std(close,lookbackdays);//下轨---中线减偏移值

buypoint:=ref(hhv(high,lookbackdays),1);//当前周期之前lookbackdays周期最高价
sellpoint:=ref(llv(low,lookbackdays),1);//当前周期之前lookbackdays周期最低价

longliqpoint:=ma(close,lookbackdays);//收盘价的N--lookbackdays日移动平均
shortliqpoint:=ma(close,lookbackdays);//同上一句