test and rework org-babel configuration

init.org

@@ -1,5 +1,5 @@
 #+TITLE: My Emacs Configuration
-#+PROPERTY: header-args :tangle yes
+#+PROPERTY: header-args:emacs-lisp :tangle yes :lexical yes
 
 * Literate Configuration for Emacs
 ** Goals
@@ -101,6 +101,36 @@ then load it.
     (load custom-file nil :nomessage))
 #+END_SRC
 
+** Utility Functions
+
+** Get latest version of a github released project
+
+Many projects nowadays use github to release their software. However
+there is no easy way to get the latest version of a project
+provided. This functions uses the releases API to get the latest
+metadata and get the version number from the JSON.
+
+#+BEGIN_SRC emacs-lisp 
+  (defun pti-with-latest-github-version (repo f)
+    "Return the latest version of the releases for REPO.
+
+              The repo should be in the form of 'owner/repo'. The function F
+  will be called with the version in format 'vX.Y.Z' as the only argument."
+    (url-retrieve
+     (format "https://api.github.com/repos/%s/releases/latest" repo)
+     (lambda (events)
+       (message "Events: %s" events)
+       (goto-char url-http-end-of-headers)
+       (let ((json-object-type 'plist)
+             (json-key-type 'symbol)
+             (json-array-type 'vector))
+         (let ((result (json-read)))
+           (message "Latest version: %s" (plist-get result 'name))
+           (funcall f (plist-get result 'name))
+           )))))
+#+END_SRC
+
+
 * Crafted Emacs
 
 When I could not solve the persistent slowness I experienced on
@@ -722,6 +752,12 @@ This enables direnv globally.
 #+RESULTS:
 
 *** Org Babel Support
+
+I have a test file which has samples of babel features for easy
+testing in my [[file:~/org/snamellit/testfile.org::*User Journey Graph][org babel test file.]]
+
+**** Support REST calls in Babel Blocks
+
 #+BEGIN_SRC emacs-lisp
   ;; enable verb package to do REST calls
   (use-package verb
@@ -734,22 +770,90 @@ This enables direnv globally.
   (use-package ob-verb
     :after verb
     :defer 3)
-  ;; configure babel languages
+    #+END_SRC
+**** Support Mermaid Diagrams in Babel Blocks
 
-  (use-package org-babel
+#+BEGIN_SRC emacs-lisp
-    :no-require
+  ;; enable mermaid for org-babel
-    :after '(ob-verb)
+  (use-package ob-mermaid
-    :config
+    :ensure t
-    (org-babel-do-load-languages
+    :defer 3)
-     'org-babel-load-languages
+  #+END_SRC
-     '((emacs-lisp . t)
-       (shell . t)
-       (python . t)
-       (latex . t)
-       (verb . t)
-       (scheme . t)
-       (plantuml . t))))
 
+  Mermaid needs support of the mermaid-cli which is a node package. It
+  can be installed with
+
+#+BEGIN_SRC shell :tangle no
+npm install -g @mermaid-js/mermaid-cli
+#+END_SRC
+
+#+RESULTS:
+|         |          |          |         |         |         |
+| changed | 194      | packages | in      | 6s      |         |
+|         |          |          |         |         |         |
+| 39      | packages | are      | looking | for     | funding |
+| run     | `npm     | fund`    | for     | details |         |
+
+**** Support PlantUML Diagrams in Babel Blocks
+
+Requires nothing special, other than *plantuml.jar* archive installed.
+
+#+BEGIN_SRC emacs-lisp :lexical t
+      (defun pti-download-latest-plantuml ()
+        "Download the latest version of PlantUML.
+
+        This function is interactive to make it easy to upgrade to
+      the latest, current version with `M-x pti-download-latest-plantuml'."
+        (interactive)
+        (pti-with-latest-github-version
+         "plantuml/plantuml"
+         
+         
+         (lambda (version)
+           (let ((url (format
+                       "https://github.com/plantuml/plantuml/releases/download/%s/plantuml-%s.jar"
+                       version (substring version 1))))
+             (message "Downloading PlantUML version %s from %s" version url)
+             (url-copy-file
+              url
+              (concat  user-emacs-directory "plantuml.jar")
+              ))))
+        )
+
+      (let ((plantuml-jar (concat user-emacs-directory "plantuml.jar")))
+        (if (not (file-exists-p plantuml-jar))
+            (pti-download-latest-plantuml))
+
+        (setq org-plantuml-jar-path plantuml-jar))
+#+END_SRC
+
+#+RESULTS:
+: /home/pti/.config/emacs/plantuml.jar
+
+****  Configure Babel Languages
+#+BEGIN_SRC emacs-lisp
+    ;; configure babel languages
+    (use-package org-babel
+      :no-require
+      :after '(ob-verb ob-mermaid)
+      :config
+      (org-babel-do-load-languages
+       'org-babel-load-languages
+       '((emacs-lisp . t)
+         (shell . t)
+         (python . t)
+         (latex . t)
+         (verb . t)
+         (scheme . t)
+         (plantuml . t)
+         (mermaid . t)
+         (dot . t))))
+#+END_SRC
+
+**** Temporary Patches for Org Babel
+
+***** Fix Scheme Babel Bug
+#+BEGIN_SRC emacs-lisp
   ;; fix a bug in ob-scheme which causes an error to be thrown when evaluating
   ;; a cons cell or improper list
   ;; see https://list.orgmode.org/87bkk3x1bu.fsf@gajsin.name/T/
@@ -770,6 +874,12 @@ This enables direnv globally.
 #+RESULTS:
 : org-babel-scheme--table-or-string
 
+**** TODO Move babel test file to emacs config folder
+
+Alternatively I might add a sample after each configured block to keep
+it in the same context. Hmmm....  sounds even better.
+
+
 *** Org Export
 #+BEGIN_SRC emacs-lisp
     (use-package ox