It is possible to instrument a literate Org-mode configuration file with a backing Emacs Lisp file?

Question

It is a common practice to write Emacs configuration files using literate-programming style in Org mode.

Unfortunately, while improving readability, this comes with significant programming disadvantages. In particular, since there is no backing .el file, Emacs is only aware of the code in the current source block. This means that except for the currently-edited block, navigation, symbol definition, and flycheck are all unavailable.

#+BEGIN_SRC emacs-lisp
  (defun literate-but-invisible ()
    (interactive)
    (message "I close my eyes..."))
#+END_SRC

#+BEGIN_SRC emacs-lisp
  (defun humans-can-read-but-emacs-cannot ()
    (interactive)
    (literate-but-invisible) ; No navigation! Flycheck reports undefined symbol!
    (message "...so that the room will be empty"))
#+END_SRC

Is there any way to tell Emacs to tangle and use the generated .el file to provide these features in Org mode? Such a feature would improve the maintainability of literate Emacs Lisp code.

Note that while it would be a fantastic feature to see Flycheck working for Org and Emacs Lisp simultaneously in one buffer, I am only asking about how to instrument org-edit buffers (the environment you get when you invoke org-edit-special (usually C-c ')). This should be easier since there is only one active mode for the buffer.

I have opened a feature request on the Flycheck repository here, and there is some relevant research in another issue here. However, I am not yet able to construct a solution.

Answer 1

For navigation and symbol definition see https://github.com/jkitchin/scimax/blob/master/scimax-literate-programming.el

You can generate a TAGS file with M-x scimax-lp-generate-tags.

After this, I can navigate to function definitions with M-. and M-,. You need to refresh the TAGS file with that function as things move around and get added, but maybe that can be done in a save-buffer hook or something. Also note that this gives tags relative to the org-file, not to where the definitions are in the source files.

M-x scimax-lp-signature-doc will get some information about the symbol at point if it is defined in the org-file.

I worked out a conceptual way to get flycheck to work in src-blocks in org-files. The idea is to have a proxy file that has the tangled code in it, in exactly the same character positions (ie you change all the other characters to spaces). Then, let flycheck work on that file. Then, transfer the flycheck overlays from the proxy file to the original file. You setup a hook function to update the proxy file on saving, and then update the overlays. Surprisingly, this works pretty well.

You can see the code at https://github.com/jkitchin/scimax/blob/master/scimax-ob-flycheck.org.

This is what a bad bit of code usually looks like

After turning on scimax-ob-flycheck-mode it looks like:

Answer 2

 (defun org-literate-programming-eval-src-blocks ()
   "Auto evaluate Org buffer all source blocks to get a complete
 project environment when Literate Programming."
   (if (string= (buffer-name) "init.org")
       (org-babel-execute-buffer)))

 (add-hook 'find-file-hook #'org-literate-programming-eval-src-blocks :before)

The upper code add a function to evaluate all source blocks in buffer which matches your file "init.org". The filename can be modified as you needed.