请问老师怎么取得开仓时k线的最低价？就以下面公式为例。
n:=barslast(barpos=1)+1;
hh:=if(barpos=1,o,ref(hhv(h,n),1));
ll:=if(barpos=1,o,ref(llv(l,n),1));
entertime:=time<closetime(0);
exittime:=time=closetime(0);
enterlong:c>hh and entertime,tfilter;
exitlong:c<ll or exittime,tfilter;
entershort:c<ll and entertime,tfilter;
exitshort:c>hh or exittime,tfilter;