Here are my two tables, one for nodes and one for edges (the real ones are longer, with something like 30 or 40 nodes):
#+name: students-table
| *node* | *label* | *shape* | *fillcolor* |
|--------+-----------+---------+-------------|
| a | Omar | ellipse | green |
| b | Hindia | ellipse | orange |
| c | Yuvrai | ellipse | purple |
#+name: students-graph
| a | b |
| a | c |
| b | c |
I can generate my table using these two code blocks:
#+name: make-dot
#+BEGIN_SRC emacs-lisp :var table=students-table graph=students-graph :results output :exports none
(mapcar #'(lambda (x)
(princ (format "%s [label=\"%s\" shape=%s style=\"filled\" fillcolor=\"%s\"];\n"
(car x) (second x) (nth 2 x) (nth 3 x) ))) table)
(mapcar #'(lambda (x)
(princ (format "%s -- %s;\n"
(first x) (second x)))) graph)
#+END_SRC
#+BEGIN_SRC dot :file Images/test-dot.png :var input=make-dot :exports results
graph {
rankdir=TB
$input
}
#+END_SRC
I would, however, like to avoid the clumsy intermediate step and use something like this instead:
#+name: graph-from-tables
#+HEADER: :var nodes=students-table graph=students-graph horiz='t
#+BEGIN_SRC emacs-lisp :file ~/example-diagram.png :colnames yes :exports results
(org-babel-execute:dot
(concat
"graph {\n"
(when horiz "rankdir=LR;\n") ;up-down or left-right
(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;"
(car x) (nth 1 x) )) graph "\n")
"}\n") params)
#+END_SRC
However, this just creates a file ~/example-diagram.png whose content is "nil%". I'm not sure how to debug the problem. Any suggestions? Does this code work for you guys? I am using an uptodate arch linux, emacs 25, and a recent graphviz.
thanks as always for the help.
Also -- WISHLIST: instead of a manually-entered list of edges, I'd like to randomly create a random set of connections between the nodes. I can easily create a list of nodes:
(let ((names () ))
(dolist (x nodes)
(push (nth 1 x ) names)
)
... do some stuff here)
but generating a list of unique edges -- that is, node pairs where
(a . b) and (b . a) are considered equivalent -- is somewhat beyond me.
Again, many thanks,
Matt