Re: Using babel to generate a commit log

[Nick Dokos <nicholas.dokos@hp.com>]

Luke Crook <luke@balooga.com> wrote:

> 
> I have written the following code that uses the Emacs vc-* commands to generate 
> a commit log. I would like the output of this code to be included when my file 
> is exported.
> 
> 
> ;; Most of this code is copied from vc.el vc-print-log
> (when (vc-find-backend-function (vc-backend (buffer-file-name (current-buffer)))
>   				                'print-log)
>       (let* ((limit (if (numberp limit) limit vc-log-show-limit))
> 	         (vc-fileset (vc-deduce-fileset t)) ;FIXME: Why t? --Stef
> 	         (backend (car vc-fileset))
> 	         (files (cadr vc-fileset)))
> 	  (with-temp-buffer 
>           (vc-call-backend backend
> 	      		       'print-log
> 	      		       files
> 	      		       (current-buffer))
>           (sit-for 5 t)          
>           (buffer-string))))
> #+end_src
> 
> What is happening is; 
> 
>   1) The code between #+begin_src and #+end_src is exported and not the result 
> of evaluating the code (the commit log).

Try using

--8<---------------cut here---------------start------------->8---
#+begin_src emacs-lisp :var limit="" :exports results
--8<---------------cut here---------------end--------------->8---

>   2) I have to add at delay of at least 5 seconds (set-for 5 t) as vc-git calls 
> "git log" as an asynchronous process. If not for the delay then babel 
> immediately returns an empty buffer and the "vc-call-backend" process never 
> completes.
> 

A quick look didn't produce much enlightenment: the standard way is to set
a process sentinel, but this is commented out in vc-do-command. There is also
a hook that is run at the end of the function:

,----
| 	(vc-exec-after
| 	 `(run-hook-with-args 'vc-post-command-functions
| 			      ',command ',file-or-list ',flags))
`----

but I think you need the process in order to set a sentinel (see sec. 37.10 of
the Elisp manual for info on sentinels).

Nick