Run code in orgmode source blocks

emacs orgmode

With Babel you can easily execute code for a variety of languages from within orgmode.

To configure Babel for the languages I wanted to execute, I put the following in my .emacs.d/init.el config.

;; Configure babel for these languages
(org-babel-do-load-languages
  'org-babel-load-languages
  '((python . t)
    (shell . t)
    (dot . t)
    (org . t)
    (scheme . t)
    ))

;; run code blocks without prompting first
(setq org-confirm-babel-evaluate nil)

Then make a new .org file and try running a snippet in the file. 

#+BEGIN_SRC python :results output
for x in range(0,3):
  print("Hello world")
#+END_SRC

Execute the code using C-c C-c (Control-c Control-c) with the cursor in the SRC block.

The results are included in the file like magic. 

#+RESULTS:
: Hello world
: Hello world
: Hello world

Graphviz

It's particularly handy for Graphviz. You get a nicely interactive way to draw Graphs.

Execute the block the same way with C-c C-c and you get a link to the graph.

#+BEGIN_SRC dot :file graphviz.png

digraph architecture {
node [color=green] [shape=box]; "A"
node [color=blue] [shape=oval]; "B", "C"
"A" -> "B";
"B" -> "C";
"C" -> "A";
"C" -> "D";
"D" -> "E";
"E" -> "B";
}

#+END_SRC

#+RESULTS:
[[file:graphviz.png]]

/posts/graphviz.png

/posts/orgmode-babel-graphviz.png

References