assumes scope is set up in the topmost environment. if scope=group it assumes group_id is set in the topmost environment, if scope=user it assumes that user_id is set in topmost environment and if scope=table it assumes on_which_table and on_what_id are set in topmost environment. this procedure operates in the same manner as export_form_vars except that it automatically figures out and sets appropriate scope variables. (e.g. for scope=group_id, export_form_scope_vars return_url would return the following string