* preamble
#+TITLE:     businessprocess.org
#+AUTHOR:    Eric S Fraga
#+EMAIL:     e.fraga@ucl.ac.uk
#+DATE:      2010-11-15 Mon
#+DESCRIPTION: cf. 
#+KEYWORDS: 
#+LANGUAGE:  en
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#+EXPORT_SELECT_TAGS: export
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* The problem

Look at [[gnus:nnmaildir%2BUCL:lists#87bp5sacnf.fsf@bunting.net.au][this email]].

* the table

#+tblname: processtable 
| Step        | Description                                                             | Next Steps  |       |
|-------------+-------------------------------------------------------------------------+-------------+-------|
| Begin       | Begin the process                                                       | Choice1     |       |
| Choice1     | Decide if we are big or small.                                          | Big         | Small |
| Big         | If we are big then do big things                                        | End         |       |
| Small       | If we are small then figure out if we are really small or possibly big. | ReallySmall | Big   |
| ReallySmall | Yes we are really small                                                 | End         |       |
| End         | The end.                                                                |             |       |
|-------------+-------------------------------------------------------------------------+-------------+-------|

* the elisp code

#+source: esf/business-process
#+begin_src emacs-lisp :results value raw :exports results
(defun esf/generate-business-process-graph (table name file)
  (let ((entries (nthcdr 2 table))
	(output (format "digraph %s {" name))
	)
    (message "Initial: %s\n" table)
    (message "Entries: %s\n" entries)
    ;; we need to do two iterations through the table, one to define
    ;; the nodes and then one to connect them.
    (setq savedentries entries)		;for second iteration
    (while entries
      (let ((entry (first entries)))
	(if (listp entry)
	    (let ((step (first entry))
		  (description (nth 1 entry)) )
	      (setq output  (format "%s\n  %s [label=\"%s\"];" output step description))
	      )
	  )
	(setq entries (cdr entries))
	)
      )
    (setq entries savedentries)
    (while entries
      (let ((entry (first entries)))
	(if (listp entry)
	    (let ((from (first entry))
		  (nextsteps (cdr (cdr entry))) )
	      (message "Nextsteps: %s\n" nextsteps)
	      (while nextsteps
		(let ((to (first nextsteps)))
		  (if to 
		      (if (not (string= to ""))
			  (setq output (format "%s\n  %s -> %s;" output from to))))
		  (setq nextsteps (cdr nextsteps))
		  )
		)
	      )
	  )
	(setq entries (cdr entries))
	)
      ) ; end while entries left
    (format "#+begin_src dot :results file :file %s :exports results
%s
}
,#+end_src\n" file output)
    )
  )
(esf/generate-business-process-graph table name file)
#+end_src

* the graph
#+call: esf/business-process(table=processtable, file="business.pdf", name="process")

#+results: esf/business-process(table=processtable, file="business.pdf", name="process")
#+begin_src dot :results file :file business.pdf :exports results
digraph process {
  Begin [label="Begin the process"];
  Choice1 [label="Decide if we are big or small."];
  Big [label="If we are big then do big things"];
  Small [label="If we are small then figure out if we are really small or possibly big."];
  ReallySmall [label="Yes we are really small"];
  End [label="The end."];
  Begin -> Choice1;
  Choice1 -> Big;
  Choice1 -> Small;
  Big -> End;
  Small -> ReallySmall;
  Small -> Big;
  ReallySmall -> End;
}
#+end_src