The idea is that we want to do the following:

1. We have a data import

2. Function is executed for each record in the import

3. Function gets a Contact_ID based on a different field (our own user_id that the incoming records will have)

4. Function returns the Contact_ID

5. Imported record is updated with Contact_ID

I created the function but I can't return any data (says it's impossible with void functions but I can't change it). 

And in the workflow rules how can I use whatever function returns to update the record that was just inserted. We have a custom module called "Skills" and every time we import data we need to find the Contact_ID for that user, the Contact module already has user_id and that's the field that's coming in the data.

For some reason I can't even find relevant docs to get this going (it takes me to Creator docs for Forms etc.), anybody knows how to tackle this?