[amibroker] Retrieve the bar's value to the intersection point of 2 moving averages (AFL)

[atlas190]

Every body hello ; french beginner with Amibroker , I seek your help .

For example ,

I tried to retrieve  the bar's value and the date to the
intersection's point of 2 moving averages .

Curve1 = Cross(WMA(C,30),MA(C,150));
Curve2= Ref(Cross(WMA(C,30),MA(C,150)),80);  
a = 0 ;
b = 0 ;

a = ValueWhen(Curve1,MA(C,260));
b= ValueWhen(Curve2,MA(C,260));

x = ValueWhen(BarIndex(),a);  //to retrieve the bar's number (failed!)
y =valueWhen(date(),a);  //to retrieve the date at the intersection
point (failed too!!)

What is the solution to type ?