Generating a flow chart in org-mode

flow-charts-in-org-mode

;; Using org-mode to describe state transitions with embedded elisp to 
;; emit those state transitions as a graphical flow-chart via dot
;;
;; Modified with minor improvements from https://orgmode.org/worg/org-tutorials/org-dot-diagrams.html
;;
;; Place cursor in elisp code-block, eval with `C-c C-c`.

#+NAME: nodes
| *node*                      | *label*                            | *shape* | *fillcolor*    | fg    |
|-----------------------------+------------------------------------+---------+----------------+-------|
| get_user                    | get_user                           |         | cornflowerblue |       |
| resolve_or_create_user      | resolve-or-create-user             |         | cornflowerblue |       |
| user_in_datomic             | is user in datomic?                | diamond | yellow         |       |
| return_eid                  | return user EID                    |         |                |       |
| return_follows              | return follow info                 | circle  | green          |       |
| upsert_editor_api_user      | upsert-editor-api-user             |         | cornflowerblue |       |
| call_editor_api             | call-editor-api                    |         | cornflowerblue |       |
| editor_api_response_anomaly | editor-api response is anomaly?    | diamond | yellow         |       |
| return_anomaly              | return editor-api response anomaly | plain   | firebrick1     | white |
| import_user                 | import-entity-tx-entity            |         | cornflowerblue |       |
| import_anomaly              | datomic response is anomaly?       | diamond | yellow         |       |
| return_anomaly2             | return anomaly tx-result           | plain   | firebrick1     | white |

#+NAME: edges
| From                        | To                          | label |
|-----------------------------+-----------------------------+-------|
| get_user                    | resolve_or_create_user      |       |
| resolve_or_create_user      | user_in_datomic             |       |
| user_in_datomic             | return_eid                  | Y     |
| return_eid                  | return_follows              |       |
| user_in_datomic             | upsert_editor_api_user      | N     |
| upsert_editor_api_user      | call_editor_api             |       |
| call_editor_api             | editor_api_response_anomaly |       |
| editor_api_response_anomaly | return_anomaly              | Y     |
| editor_api_response_anomaly | import_user                 | N     |
| import_user                 | import_anomaly              |       |
| import_anomaly              | return_anomaly2             | Y     |
| import_anomaly              | return_eid                  | N     |

#+BEGIN_SRC elisp :imagename ~/get-user.png :results output raw :var nodes=nodes edges=edges
  (defun write_nodes(x)
    (format "%s [label=\"%s\" shape=%s style=\"filled\" fillcolor=\"%s\" fontcolor=\"%s\"]"
    (nth 0 x)
    (nth 1 x)
    (if (string= "" (nth 2 x)) "box"   (nth 2 x))
    (if (string= "" (nth 3 x)) "none"  (nth 3 x))
    (if (string= "" (nth 4 x)) "black" (nth 4 x))))

  (defun write_edges(x)
    (format "%s -> %s [taillabel=\"%s\"]"
    (nth 0 x)
    (nth 1 x)
    (nth 2 x)))

  (defun dotgen(nodes edges)
    (let ((dotbegin "digraph {\n")
          (dotend "\n}"))
      (concat dotbegin
              (mapconcat #'write_nodes nodes "\n")
              (mapconcat #'write_edges edges "\n")
              dotend)))

  (let* ((params (nth 2 (org-babel-get-src-block-info)))
         (imagename (cdr (assq :imagename params))))
    (assq-delete-all :imagename params)
    (push `(:file . ,imagename) params)
(message "vvv")
(message (dotgen nodes edges))
(message "^^^")
    (org-babel-execute:dot (dotgen nodes edges) params)
    (princ (format "[[./%s]]" imagename)))
#+END_SRC