From mboxrd@z Thu Jan  1 00:00:00 1970
From: Charles Berry <ccberry@ucsd.edu>
Subject: Re: macro expansion in source code
Date: Thu, 29 Aug 2013 15:15:08 +0000 (UTC)
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Johannes Rainer <johannes.rainer <at> gmail.com> writes:

> 
> 
> hi,
> I was just wondering if there is a way to use macro expansion also in 
> source code blocks or headers. I tried this, but the macro was never 
> expanded, but rather the {{{image_width}}} was exported. could the 
> expansion be done by calling the macro expansion before export 
> (e.g. using a hook)?
> 
> something like this:

[snip]

I think the answer is no. But you can accomplish much the same thing with
properties and/or noweb references. Like this

* header
  :PROPERTIES:
  :image_width: 16
  :END:

#+NAME: imwide
#+HEADER: :var iw=(org-entry-get (point) "image_width")
#+BEGIN_SRC R :results value
iw
#+END_SRC

#+RESULTS: imwide
: 16


#+BEGIN_SRC R :noweb yes :results output
image.width <- 
  <<imwide()>>
image.width
#+END_SRC

#+RESULTS:
: [1] 16