[amibroker] TS to AFL

[Ara Kaloustian]

Does anyone know the AFL equivalent of CurrentBar from Trade Station.

I am trying to translate what seem to be a simple code ... but results dont 
match TS image.

Code is:
PctK=IFF(CurrentBar=1,Ratio,PctK[1]+(.5*(Ratio-PctK[1])));

I have tried:
PCtK = iif(bi == LastValue(BarIndex()), ....

Thanks

Ara