Hi Éibhear, Thanks for sending the example. I think it is not expected to work going forward because the lisp block relies on being able to pick up the value of ‘params’, which will not be possible now that org is moving to lexical binding. In general, org-babel-execute:foo are internal functions, so trying to trick them int working properly in an elisp code block is a bad idea.
The emacs-lisp babel backend is special, so I can’t predict what the result would be of making it return the symbol nil instead of the string “nil.” (Though for the sake of consistency it ought to allow nil symbol returns.) On the balance, I recommend you do something like the following, using two code blocks (untested): ,---- | #+name: dot-code | #+begin_src emacs-lisp :results verbatim | (generate-dot-code) | #+end_src | | #+RESULTS: dot-code | : "your dot code will appear here" | | #+begin_src dot :file foo.png :var code=dot-code() | $code | #+end_src | | #+RESULTS: | [[file:foo.png]] `---- Hope this helps, -- Aaron Ecay
