labelInterpolationFnc only takes one argument - is it posible to pass the name or index of the specific bar ?

[michmosh]

i need to display a diferent simbol ( $ , @ ) for each bar but labelInterpolationFnc only takes one argument (text) .
is there a way to pass an index for this function ?

I also think this is required. I've already sent a pull request #10
Don't know why it's not merged.