You might find a function like this one: https://github.com/jkitchin/techela-emacs/blob/master/techela-grade.el#L149 

helpful. There are some variations that do similar things.

John

-----------------------------------
Professor John Kitchin 
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803


On Tue, Mar 5, 2019 at 1:51 AM Nik Clayton <nik@ngo.org.uk> wrote:
Hoi,

Is there an API for manipulating properties that are set in #+PROPERTY lines before the first headline of a file (i.e., not in a property drawer)?

I've got some properties that (a) make sense when set for the whole file, and (b) the file contains multiple first level headings (which isn't going to change).

Using org-entry-put when point is before the first headline throws a "Before first headline" error (when when the #+PROPERTY line already exists and I want to update an existing entry).

N