[O] org-edit-src-code outside of org

[Jorge A. Alfaro-Murillo]

Hi, I would like to use org-edit-src-code outside of org, I think it
would be very handy in Message mode, to send messages that contain code
and edit that code in the proper mode.

I put something like this

     #+BEGIN_SRC emacs-lisp
       (defun mm-org-try-structure-completion ()
         (interactive)
         (if (not (org-try-structure-completion))
             (message-tab)))
       (eval-after-load "message"
         '(progn
            (define-key message-mode-map (kbd "<tab>")
            'mm-org-try-structure-completion)))
     #+END_SRC

which allows me now to do <'a letter' and hit <tab> and get a the proper
source block just as in org.

I can enter the editing of the source block without problems with
org-edit-src-code (which I plan to bind to C-c ', just as in org),
however when I am want to close the editing and go back to the message
buffer it fails, specifically the part of org-edit-src-exit that says:

     #+BEGIN_SRC emacs-lisp
       (unless (org-bound-and-true-p org-edit-src-from-org-mode)
          (error "This is not a sub-editing buffer, something is wrong"))
     #+END_SRC
          
Is there a particular reason why the code has to check to see if it is
coming from org-mode? Shouldn't it be enough that already the
org-in-block-p was passed?

If I evaluate the function definition of org-edit-src-exit without the
last part everything works as expect, I can exit with C-c ' and the code
is there. Even doing C-x C-s before exiting works as well.

Best,

Jorge.

PS: What is the alternative when you write messages with code, do you
guys first write it in org and then copy and yank it?