Python blocks evaled; elisp blocks not: org-babel export to latex

Question

I need to have automatic evaluation turned on for elisp (or emacs-lisp) because I have huge documents that I export to PDF with batch scripts, and it's intolerable to have to go in and manually evaluate elisp blocks. Here is an MVE:

Consider the following org-babel file

#+BEGIN_SRC elisp :exports both
(+ 1 41)
#+END_SRC

#+BEGIN_SRC python :exports both :results output
print 'only python, no lisp for y00'
#+END_SRC

I can evaluate either code block by placing point in them and typing C-c C-c. In each block, I get an interactive security question Evaluate this (elisp / python) code block on your system? Great, no problem. Doing that for both, I get

#+BEGIN_SRC elisp :exports both
(+ 1 41)
#+END_SRC

#+RESULTS:
: 42

#+BEGIN_SRC python :exports both :results output
print 'only python, no lisp for y00'
#+END_SRC

#+RESULTS:
: only python, no lisp for y00

Ok, I now remove the #+RESULTS blocks and type M-x org-babel-export-to-pdf. I only get the security question for the python block, and not for the elisp block. The PDF output only has the results for the python block and not for the elisp block.

Looks like some setting has auto-evaluation-on-export or some such turned off for elisp. Changing the code type to emacs-lisp for the elisp block does not fix it.

Answer 1

After some investigation it seems like the condition for being able to evaluate the code block by pressing C-c C-c is that a function with the name org-babel-execute:<type> where <type> is the mode / language of the source block, be defined, while executing Babel source block during exporting will also look into the contents of org-babel-load-languages to decide whether to execute it. This is apart from the header arguments, which instruct Babel to take certain action during export.

In the OP's case, evaluation via C-c C-c works whether the header arguments specify language elisp or emacs-lisp, but evaluation via export only works if the header arguments specify language emacs-lisp, which alone matches the language specified in org-babel-load-languages. elisp is not recognized as a valid language for export purposes in org-babel-load-languages; specifying it there results in an error.