On Tue, 20 Jan 2015, Marcin Borkowski wrote:

> Hello Orgers,
>
> assume that I have this in my Org file:
>
> #+BEGIN_FOO :bar baz qux
> whatever
> #+END_FOO
>
> and I want to extract the value of the header argument "bar" (i.e., the
> string "baz qux" in this case).  How do I do it?  (I'm writing – still –
> the custom exporter, and would like to be able to set something
> spearately for each special block of some kind.)

It will be easier to use a src block for a faux language (say FOO).

Customize `org-babel-execute:FOO' as needed and you should be set:

#+BEGIN_SRC emacs-lisp
   (defun org-babel-execute:FOO (body params &optional etc)
     (concat  body (format " %S" (assoc :bar params))))
#+END_SRC

#+RESULTS:
: org-babel-execute:FOO

#+NAME: example1
#+BEGIN_SRC FOO :bar baz qux :exports results
whatever
#+END_SRC

#+RESULTS: example1
: whatever (:bar . "baz qux")

HTH,

Chuck