Access document title, author, date with elisp

Question

The beginning of my document looks like this

#+TITLE: this is the document title
#+AUTHOR: R. Wiggum
#+DATE: 2018-09-12

How can I access these properties with LISP?

Answer 1

Org is not great at exposing interfaces for this kind of thing, but reading through the source leads me to:

 (plist-get (org-export-get-environment) :title)