[amibroker] AFL code question to retrieve the barindex when two MA are crossing

[atlas190]

Lol !!

I tried to build a custom indicator .
I want to retrieve the bar's number as soon as two  moving average are
crossing , or the index number at the point of intersection  . I
wished to spy the value by using "filter = 1 ;"
As soon as I have caught this number I can to compute a second number
80 bar ago .
With that I have a time interval and I can plot this interval at the
screen .


Here is my code 


Curve1= 0 ;
Curve2 = 0;
Curve1 = Cross(WMA(C,150),MA(C,150));
Curve2= Ref(Cross(WMA(C,150),MA(C,150)),80);
a = 0 ;
b = 0 ;

a = ValueWhen(Curve1,MA(C,150));
b= ValueWhen(Curve2,MA(C,150));

Refindex1 = Curve1[0];//Here I trie to catch the bar' number without
success
Refindex2 = Curve2[0];

numdesbarres =BarIndex();  

Plot(IIf(BarIndex() >= Refindex2 AND BarIndex() <= Ref
index1,a,Null),"TEST",colorBlack,1);
Plot(IIf(BarIndex() >= Refindex2 AND BarIndex() <=
Refindex1,b,Null),"TEST",colorRed,1);

Filter = 1;
AddColumn(numdesbarres,"bar's number");
AddColumn(Refindex1,"index number");
AddColumn(Refindex2,"index number 80 bars ago");