Re: Code snippet for Message Sequence Diagram export

[Juan <Pechiar@computer.org>]

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

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