Re: Code snippet for Message Sequence Diagram export

[Dan Davison <davison@stats.ox.ac.uk>]

Juan <Pechiar@computer.org> writes:

> Below goes code snippet using org-babel instead of org-export.

Hi Juan,

Thanks, we'd be pleased to include this in org-babel. First question is:
if you haven't already, can you sign FSF copyright transfer forms for
Emacs / Org-mode?

http://orgmode.org/worg/org-contribute.php

And a couple of little questions:

- I think I'd prefer to get rid of the org-mscgen-path variable, and
  simply require that mscgen is on the user's $PATH. Is that OK or am I
  missing a reason for doing it differently?
- Is it definitely correct to automatically wrap the user's code in msg
  { ... }? I initially fell into the trap of including that inside my
  code block. I do not know the language; are there situations where the
  desired mscgen code will not be generated by wrapping everything in a
  msg { ... } block?
- If you are feeling energetic, it would be really nice to check the
  exit code from the shell-command and use org-babel-error-notify if
  necessary, similar to this fragment from org-babel-python

		     (setq exit-code (org-babel-shell-command-on-region
				      (point-min) (point-max) "python" nil 'replace (current-buffer)))
		     (buffer-string))))
	     (if (> exit-code 0) (org-babel-error-notify exit-code stderr))

  (Looks like we should be doing this in org-babel-ditaa also)

Thanks again,

Dan


>
> On Mon, May 17, 2010 at 09:13:29AM +0100, Eric S Fraga wrote:
>> On Sun, 16 May 2010 17:18:39 -0300, Juan <pechiar@computer.org> wrote:
>> > The following code adds an export block of type 'mscgen'. The block
>> > body will be processed by the mscgen application. Sort of works, not
>> > very tested yet.
>>
>> [...]
>>
>> Juan,
>>
>> this could be very useful.  Thanks!  I do wonder, however, whether it
>> would make sense to have this as a org-babel language?  It would be
>> nice to have the images generated appear in the org file directly...
>>
>> Thanks again,
>> eric
>
> ;;; org-babel-mscgen.el --- org-babel functions for mscgen evaluation
>
> ;;; TODO insert GPL header here
>
> ;;; Commentary:
> ;;
> ;; This software provides EMACS org-babel export support for message
> ;; sequence charts. The mscgen utility is used for processing the
> ;; sequence definition, and must therefore be installed in the system.
> ;;
> ;; The code is a direct modification of org-babel-ditaa
> ;; from the org-mode distribution.
> ;;
> ;; Mscgen is available and documented at http://www.mcternan.me.uk/mscgen/index.html
> ;;
> ;; Customize path to mscgen utility with org-mscgen-path variable
> ;;
> ;; Example:
> ;;
> ;; #+begin_src mscgen :file example.png
> ;;  A,B;
> ;;  A -> B [ label = "send message" ];
> ;;  B <: A [ label = "get answer" ];
> ;; #+end_src
>
> ;;; Code:
> (require 'org-babel)
>
> (defvar org-mscgen-path
>   "/opt/local/bin/mscgen"
>   "Complete path to the mscgen executable")
>
> (org-babel-add-interpreter "mscgen")
>
> (add-to-list 'org-babel-tangle-langs '("mscgen" "mscgen"))
>
> (defvar org-babel-default-header-args:mscgen
>   '((:results . "file") (:exports . "results"))
>   "Default arguments to use when evaluating a mscgen source block.")
>
> (defun org-babel-expand-body:mscgen (body params &optional processed-params) body)
>
> (defun org-babel-execute:mscgen (body params)
>   "Execute a block of Mscgen code with org-babel.  This function is
> called by `org-babel-execute-src-block'."
>   (message "executing Mscgen source code block")
>   (let ((result-params (split-string (or (cdr (assoc :results params)) "")))
>         (out-file (cdr (assoc :file params)))
>         (cmdline (cdr (assoc :cmdline params)))
>         (in-file (make-temp-file "org-babel-mscgen")))
>     (unless (file-exists-p org-mscgen-path)
>       (error (format "Could not find mscgen at %s" org-mscgen-path)))
>     (with-temp-file in-file (insert (concat "msc {\n" body "\n}\n")))
>     (message (concat org-mscgen-path " -T png  -o " out-file " -i " in-file))
>     (shell-command (concat org-mscgen-path " -T png  -o " out-file " -i " in-file))
>     out-file))
>
> (defun org-babel-prep-session:mscgen (session params)
>   (error "Mscgen does not support sessions"))
>
> (provide 'org-babel-mscgen)
> ;;; org-babel-mscgen.el ends here
>
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