Extract value from org-babel-get-src-block-info

Question

I have this elisp code:

#+BEGIN_SRC emacs-lisp :dir ~/org/test

(defun test ()
  (setq args '(org-babel-get-src-block-info))
  (cdr (assoc ':dir args)))
(test)

#+END_SRC

But when I execute the code block, I get a message saying that no output was produced... what am I doing wrong?

Answer 1

You should:

1. Unquote '(org-babel-get-src-block-info) and
2. Replace (cdr (assoc ':dir args)) with (assoc-default :dir (nth 2 args))

That is:

#+BEGIN_SRC emacs-lisp :dir ~/org/test
(defun test ()
  (setq args (org-babel-get-src-block-info))
  (assoc-default :dir (nth 2 args)))
(test)
#+END_SRC

Or:

#+BEGIN_SRC emacs-lisp :dir ~/org/test
(let* ((info (org-babel-get-src-block-info))
       (params (nth 2 info)))
  (assoc-default :dir params))
#+END_SRC

Answer 2

For a start, you are quoting the call to org-babel-get-src-block-info, so the function is never called. Second, you probably want to change the test function to something like this:

(defun test()
   (let ((args (org-babel-get-src-block-info)))
      args))

until you understand what the call to org-babel-get-src-block-info returns. In fact, it would be a good idea to try doing M-: (org-babel-get-src-block-info) RET, so you can see clearly what the function returns. Third, babel has strange ideas about what to do with the output. In this particular case, you might want to set :results raw (despite the disadvantage that you have to delete the results by hand every time), so as to avoid the strange interpretation.