Re: [Babel] Coding system of tangled files?

From: "Sébastien Vauban" <wxhgmqzgwmuf-geNee64TY+gS+FvcfC7Uqw@public.gmane.org>
To: emacs-orgmode-mXXj517/zsQ@public.gmane.org
Subject: Re: [Babel] Coding system of tangled files?
Date: Mon, 22 Nov 2010 13:41:40 +0100	[thread overview]
Message-ID: <80tyj9wmwr.fsf@missioncriticalit.com> (raw)
In-Reply-To: 87tyjeheqt.fsf@gmail.com

Hi Eric,

"Eric Schulte" wrote:
> I think this should be possible using the `org-babel-post-tangle-hook' to
> re-save the file with a specified encoding. After looking into this a little
> bit it appears that you should be able to add a function to this hook which
> will update the `save-buffer-coding-system' variable and then re-save the
> buffer. This should allow you to save tangled files in arbitrary code
> systems.

#+TITLE:     Format for tangling files
#+DATE:      2010-11-22

#+BABEL: :comments yes

* Bug report

** Script

#+begin_src sh :tangle doit.sh
#!/bin/bash
# L'élève est là-bas...

ls
date
#+end_src

** Execute it in a Bash shell

The tangled file, when launched from withing a Bash shell, returns errors:

#+begin_src sh
sva@MEDIACENTER:.../Accounting/dev 0$ ./doit.sh 
./doit.sh: line 4: $'\r': command not found
./doit.sh: line 5: $'ls\r': command not found
./doit.sh: line 6: $'date\r': command not found
#+end_src

The reason is that the tangled file is saved as UTF-8-dos (being under
Windows). It should be saved in unix format. Is there a way to impose this?

* Answer from Eric

#+begin_example
I think this should be possible using the `org-babel-post-tangle-hook' to
re-save the file with a specified encoding. After looking into this a little
bit it appears that you should be able to add a function to this hook which
will update the `save-buffer-coding-system' variable and then re-save the
buffer.
#+end_example

* Tests

** One

Evaluate this:

#+begin_src emacs-lisp :results silent :tangle no
(add-hook 'org-babel-pre-tangle-hook
          (lambda ()
            (setq save-buffer-coding-system 'iso-latin-9-unix)))
#+end_src

Instead of setting the variable in *post* hook (and saving the tangled file --
for which I did not know how to procede: what's the argument to give to
save?), I wondered if it shouldn't be easier to set it in the *pre* hook...

Though, the above does not work as I would expect.

** Two

After different trials, I came up with the following which works for me...

Evaluate this:

#+begin_src emacs-lisp :results silent :tangle no
(add-hook 'org-babel-pre-tangle-hook
          (lambda ()
            (setq coding-system-for-write 'iso-latin-9-unix)))
#+end_src

It's not clear to me what's the exact difference between the 2 variables
(=save-buffer-coding-system= and =coding-system-for-write=). But that works:

#+begin_src sh
sva@MEDIACENTER:.../Accounting/dev 0$ doit.sh
accountlog.csv  csv2ledger.sh  doit.sh  ecm-tangle.txt  my-csv2ledger.html  my-csv2ledger.txt
Mon Nov 22 13:30:12     2010
#+end_src

Best regards,
  Seb

-- 
Sébastien Vauban

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