CASE: access the number of a bookyear

From now on you can access the number of a bookyear by this code:

{{ period.bookyear_index }}

For Belgium tax calculations, this can be used as we sometimes need to know if the bookyear is part of the first 3 years of a company.

The index depends on the enddate of the very first book year (that’s defined in the panel Company Information of a company file)!
If you are in the fourth bookyear, the output will be:

4