eval code snippet before tangling config file

[Stig Brautaset <stig@brautaset.org>]

Hi,

I'm trying to evaluate a line of shell code and put its output into a
snippet that will be tangled to a file. My best attempt so far:

  #+NAME: hostname
  #+BEGIN_SRC sh
    hostname -s
  #+END_SRC

  #+BEGIN_SRC conf :tangle /usr/local/etc/leafnode/config :noweb tangle
    expire = 20
    server = news.gmane.org
    initialfetch = 100
    hostname = <<hostname>>.superloopy.io
  #+END_SRC

However the result of that tangle includes the shell snippet in
verbatim: 

  #+RESULTS:
  : expire = 20
  : server = news.gmane.org
  : initialfetch = 100
  : hostname = hostname -s.superloopy.io

I suspect this is because it will be executed in the context of "conf"
mode, which does not really have an execution mode. Syntax highlighting
etc works fine, however. I could change to make a shell script to write
the config, but it's not as nice really.

PS: this is an improvement to my existing setup of Leafnode on OS X, if
anybody's interested:
http://github.com/stig/dot-files/tree/master/Leafnode.org

Stig