From mboxrd@z Thu Jan  1 00:00:00 1970
From: Charles Berry <ccberry@ucsd.edu>
Subject: Re: org babel before excute hook
Date: Sat, 12 Oct 2013 02:28:20 +0000 (UTC)
Message-ID: <loom.20131012T040759-761@post.gmane.org>
References: <CAO8D54wYb88EBLUPK7HjMRE5=H1Kpe-zxibkYoVRvxiV2obaEw@mail.gmail.com>
	<CAJ51ETpqTsHmeLatSx4bp_vW3+cT+a2QcJgQWbHew1fxcMOwiA@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Return-path: <emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org>
Received: from eggs.gnu.org ([2001:4830:134:3::10]:37743)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <geo-emacs-orgmode@m.gmane.org>) id 1VUowi-0008Ub-TN
	for emacs-orgmode@gnu.org; Fri, 11 Oct 2013 22:28:54 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <geo-emacs-orgmode@m.gmane.org>) id 1VUowc-0006Hs-Kk
	for emacs-orgmode@gnu.org; Fri, 11 Oct 2013 22:28:48 -0400
Received: from plane.gmane.org ([80.91.229.3]:51540)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <geo-emacs-orgmode@m.gmane.org>) id 1VUowc-0006Hi-Dk
	for emacs-orgmode@gnu.org; Fri, 11 Oct 2013 22:28:42 -0400
Received: from list by plane.gmane.org with local (Exim 4.69)
	(envelope-from <geo-emacs-orgmode@m.gmane.org>) id 1VUowa-0003YS-8Z
	for emacs-orgmode@gnu.org; Sat, 12 Oct 2013 04:28:40 +0200
Received: from 137.110.34.64 ([137.110.34.64])
	by main.gmane.org with esmtp (Gmexim 0.1 (Debian))
	id 1AlnuQ-0007hv-00
	for <emacs-orgmode@gnu.org>; Sat, 12 Oct 2013 04:28:40 +0200
Received: from ccberry by 137.110.34.64 with local (Gmexim 0.1 (Debian))
	id 1AlnuQ-0007hv-00
	for <emacs-orgmode@gnu.org>; Sat, 12 Oct 2013 04:28:40 +0200
List-Id: "General discussions about Org-mode." <emacs-orgmode.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/emacs-orgmode>
List-Post: <mailto:emacs-orgmode@gnu.org>
List-Help: <mailto:emacs-orgmode-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/emacs-orgmode>,
	<mailto:emacs-orgmode-request@gnu.org?subject=subscribe>
Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org
Sender: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org
To: emacs-orgmode@gnu.org

John Kitchin <jkitchin <at> andrew.cmu.edu> writes:

> 
> 
> 
> I have a related kind of problem. When preparing notes 
> for a class, I may end up with 70 code blocks in an org file, many of 
> which create graphics. I am always worried about accidentally using the 
> same filename and overwriting a graphic from an earlier block. A unique,
>  but reproducible filename would be sufficient for my needs.
> 

Header arg values can be elisp calls. You can use `make-temp-file'.

So every time this block is executed, a new file is created and the 
file link is added to the results.

#+BEGIN_SRC R :results output append :file (make-temp-file "temp")
cat(date(),"\n")
#+END_SRC

#+RESULTS:
[[file:/var/folders/kb/2hchpbyj7lb6z76l0q73w_fh0000gn/T/temp302IjV]]
[[file:/var/folders/kb/2hchpbyj7lb6z76l0q73w_fh0000gn/T/temp3028Lu]]

See `temporary-file-directory', too, if you want to use this, as the
default may not be what you intend.


You might want to use this:

#+BEGIN_SRC emacs-lisp
  (defun local-tfile (file) 
    (let ((temporary-file-directory "."))
      (make-temp-file file)))
#+END_SRC

Then the files go in the local directory when this is executed:

#+BEGIN_SRC R :file (local-tfile "tfile") :results output append 
cat(date(),"\n")
#+END_SRC

You might not want `append' in this case.


HTH,

Chuck

[rest deleted]