> Hi Éibhear,
>
> I'm afraid I don't understand the problem the patch is trying to fix.
> Can you provide a MWE (minimal working example) that illustrates the bug
> you're observing?
>
> Thanks,
>
> --
> Aaron Ecay
>
Hi Aaron,
Thanks for getting back to me.
Prerequisites:
- The dot utility from graphvis is available
- org-babel-load-languages includes '(dot . t)
See below for a sample org file.
For org-mode 8.2.10, invoking C-c C-c on the #+BEGIN_SRC line produces a
file called sample-flow.png, representing a simple flow from a "Start"
node to an "End" node.
In org-mode 8.3.1 and 8.3.2, sample-flow.png contains only the text "nil".
I believe the bug to be in `org-babel-execute:emacs-lisp', when the second
parameter to `org-babel-result-cond' is being evaluated. When `result' is
nil, it is converted to "nil", and this is being written into the
sample-flow.png file, overwriting the contents that the dot utility had
created.
My patch prevents a nil result being converted into a text string when
calling `org-babel-result-cond'. I believe this is an appropriate change.
Éibhear
---------------------->8==========================
* Charts
** Chart from flows
#+name: chart-from-flows
#+HEADER: :var nodes=sample-elements graph=sample-connections
ranks=sample-ranks
#+BEGIN_SRC emacs-lisp :file ./sample-flow.png :colnames yes :exports
results
(org-babel-execute:dot
(concat
"digraph {\n"
"//rankdir=LR;\n" ;; remove comment characters '//' for
horizontal layout; add for vertical layout
(mapconcat
(lambda (x)
(format "%s [label=\"%s\" shape=%s style=\"filled\"
fillcolor=\"%s\"]"
(car x)
(nth 1 x)
(if (string= "" (nth 2 x)) "box" (nth 2 x))
(if (string= "" (nth 3 x)) "none" (nth 3 x))
)) nodes "\n")
"\n"
(mapconcat
(lambda (x)
(format "%s -> %s [taillabel=\"%s\" color=\"%s\" style=\"%s\"]"
(car x)
(nth 1 x)
(nth 2 x)
(if (string= "" (nth 3 x)) "black" (nth 3 x))
(if (string= "" (nth 4 x)) "solid" (nth 4 x))
)) graph "\n")
"\n"
(mapconcat
(lambda (x)
(format "{rank=%s %s}"
(if (or (string= "min" (car x)) (string=
"max" (car x))) (car x) (concat "same; " (car
x))) (nth 1 x))) ranks "\n")
"}\n") params)
#+END_SRC
#+RESULTS: chart-from-flows
[[file:./sample-flow.png]]
** Development process flow
*** Flow elements
#+name: sample-elements
| *node* | *label* | *shape* | *fillcolor* |
|--------+---------+---------+-------------|
| start | Start | ellipse | |
| end | End | ellipse | |
*** Flow connections
#+name: sample-connections
| from | to | label | colour | style |
|-------+-----+-------+--------+-------|
| start | end | | | |
*** Flow ranks
#+name: sample-ranks
| anchor | node |
|--------+-------|
| min | start |
| start | end |
---------------------->8==========================
--
Éibhear Ó hAnluain,
Dublin, Ireland
+-------------------------------+--------------------------------+
| e-mail: eibhear....@gmail.com | Web: [http://www.gibiris.org/] |
| Twitter: @eibhear | Google+: +Éibhear Ó hAnluain |
| Mobile: +353 86 856 5666 | VoIP: sip:eibh...@linphone.org |
+-------------------------------+--------------------------------+
