This results in the following behavior.
#+property: var foo=1
#+property: var+ bar=2
#+begin_src emacs-lisp
(+ foo bar)
#+end_src
#+results:
: 3
#+begin_src emacs-lisp
(org-entry-get (point) "var" t)
#+end_src
#+results:
: foo=1 bar=2
* overwriting a file-wide property
:PROPERTIES:
:var: foo=7
:END:
#+begin_src emacs-lisp
foo
#+end_src
#+results:
: 7
#+begin_src emacs-lisp
(org-entry-get (point) "var" t)
#+end_src
#+results:
: foo=7
* appending to a file-wide property
:PROPERTIES:
:var+: baz=3
:END:
#+begin_src emacs-lisp
(+ foo bar baz)
#+end_src
#+results:
: 6
#+begin_src emacs-lisp
(org-entry-get (point) "var" t)
#+end_src
#+results:
: foo=1 bar=2 baz=3
* lisp/org.el (org-update-property-plist): Updates a given property
list with a property name and a property value.
(org-set-regexps-and-options): Use org-update-property-plist.
(org-entry-get): Use org-update-property-plist.
* testing/examples/property-inheritance.org: Example file for testing
appending property behavior.
* testing/lisp/test-property-inheritance.el: Tests of appending
property behavior.
* lisp/ob.el (org-babel-balanced-split): Allow splitting on single
characters as well as groups of two characters.
(org-babel-parse-multiple-vars): Split variables on single spaces.
Eric Schulte