First, let me say that I'm only a novice elisp hacker...  That said after
spending some time debugging I think there may be a disconnect between the
example in the org-manual and the function org-entry-get-with-inheritance.
The manual shows an example in section 7.1 where a GENRES+ adds to a GENRES
property statement in a parent heading.   But the docs and code in the
org-entry-get-with-inheritance function seem to implement a model that only
looks up the outline if you don't find anything on the current heading,
even if it's a "+" property.

(defun org-entry-get-with-inheritance (property &optional literal-nil)
  "Get entry property, and search higher levels if not present.
The search will stop at the first ancestor which has the property defined.
If the value found is \"nil\", return nil to show that the property
should be considered as undefined (this is the meaning of nil here).
However, if LITERAL-NIL is set, return the string value \"nil\" instead."
  (move-marker org-entry-property-inherited-from nil)
  (let (tmp)
    (unless (org-before-first-heading-p)
      (save-excursion
    (save-restriction
      (widen)
      (catch 'ex
        (while t
          (when (setq tmp (org-entry-get nil property nil 'literal-nil))

>>> In my previous example when we get here org-entry-get returns the value
of the property GENRES which is "Baroque" and executes the following three
functions including the throw, which stops the loop.
>>> Based on the documentation I would think that this function should
check to see if the current property is a "GENRES+" vs. a "GENRES" property
and continue up the outline looking for more GENRES+ properties and only
stop when we find a plain GENRES or reach the top.  This looks like what
the (org-up-heading-safe) below is trying to do, but never gets executed
because org-entry-get returned a positive value of "Baroque" when searching
for GENRES on the current entry.

        (org-back-to-heading t)
        (move-marker org-entry-property-inherited-from (point))
        (throw 'ex tmp))
          (or (org-up-heading-safe) (throw 'ex nil)))))))
    (setq tmp (or tmp
          (cdr (assoc property org-file-properties))
          (cdr (assoc property org-global-properties))
          (cdr (assoc property org-global-properties-fixed))))
    (if literal-nil tmp (org-not-nil tmp))))

Thoughts?

~>Bill

On Wed, Apr 18, 2012 at 4:05 PM, Bill Wishon <bill@wishon.org> wrote:

> Hi Org-mode Community,
>
> I can't get the example in section 7.1 of the org-mode manual to work as I
> expect.  Perhaps someone can help me see what I'm doing wrong.
>
> I tried creating this buffer:
>
> * CD collection
> ** Classic
>  :PROPERTIES:
>  :GENRES: Classic
>  :END:
> *** Goldberg Variations
>  :PROPERTIES:
>  :Title:    Goldberg Variations
>  :Composer: J.S. Bach
>  :Artist:   Glen Gould
>  :Publisher: Deutsche Grammophon
>  :NDisks:   1
>  :GENRES+:   Baroque
>  :END:
>
> Then I set the org-use-property-inheritance variable to include GENRES.
>
> Then I wrote the following function
>
> (defun bill-test (property)
>   "print all inheirited properties"
>   (interactive "MProperty: ")
>   (message (concat property " = " (org-entry-get (point) property t))))
>
> Which prints "GENRES = Baroque" when I run it with the point on Goldberg
> Variations, based on the manual I expected this to print "GENRES = Classic
> Baroque”.
>
> While I think they should all do the same thing, I also tried the
> following ways of calling org-entry-get just in case all with the same
> result.
> (org-entry-get (point) property 'selective)
> (org-entry-get nil property t)
> (org-entry-get nil property 'selective)
>
> I'm using org-version 7.8.09 on Windows with emacs "GNU Emacs 23.3.1
> (i386-mingw-nt6.1.7601) of 2011-03-10 on 3249CTO".
>
> Any pointers about what I'm doing wrong would be great.
>
> Thanks,
> ~>Bill
>