What is the general goal of the feature?
Current behavior
Using pulldata() on itemsets.csv (generated by the external_choices worksheet of an XLSForm) does not appear to work.
Expected behavior
Using pulldata() on itemsets.csv (generated by the external_choices worksheet of an XLSForm) should be able to work just as for any other csv file.
What are some example use cases for this feature?
One might be more comfortable with encapsulating the whole form in one xlsx workbook. In that case, they might want to use additional columns in external_choices. They might be confused that pulldata() works for normal CSV files, but not for itemsets.csv. At the very least, there should be some sort of warning in ODK validate saying not to use pulldata() on itemsets.csv if it is not supported (I'm not sure if something like that exists already; I'm just posting this on behalf of a colleague).
What can you contribute to making this feature a reality?
If there is any related JavaRosa code to be done, with some guidance I may be able to help, now that I am more familiar with that codebase.