When one exports from org to, say, latex the resulting *.tex file includes
a comment at the top indicating the time of creation. This is useful in
part because it lets the user know that the *.tex file isn't the original
source.
The same isn't true of tangled code from a source block, and I've been
repeatedly bitten by editing a file of python code that was tangled from a
source org file.
I'd like to deal with this by making tangle emit a comment with
information about the org-source file. The :prologue header argument is
well suited to this; e.g.,
#+begin_src python :tangle /tmp/test.py :prologue (format "# Tangled from
%s on %s" (buffer-file-name) (current-time-string))
print "Hello, world!"
#+end_src
produces what one would want.
I'd like to make this header argument be applied automatically. The
variable org-babel-default-header-args looks like just the ticket, but my
lame efforts to write the necessary emacs-lisp aren't working:
#+BEGIN_SRC emacs-lisp
(add-to-list 'org-babel-default-header-args:python
'((:prologue . (format "# Tangled from %s on %s" (buffer-
file-name) (current-time-string)))))
#+END_SRC
What am I doing wrong?
Thanks for any help,
-Ethan
