Enforcing fields to be filled in [closed]

edit

I am creating a template with several text fields. Just to be clear I am not using Base: this are fields in Writer unconnected to any database. I would like to use a macro to validate field contents (and check certain fields have been filled in) before the document is saved or exported. I have already worked out how to connect macros to the right events. But, if my macro returns False, the action (save/e-mail/whatever) still goes ahead. Is there anyway to prevent a Save from a macro event handler?