knowing your template

Is there a way to find out for a smarty custom function which template it is 
called from ? I'd like to make a gettext translation function/modifier and a 
logical choice seemed to be to use the template names as domains, but the 
documentation and googling turned up nothing. I know I could assign it as a 
temp variable but it would not solve the problem of nested templates (include 
"inside.tpl").