Re: How to reliably edit a file from within Emacs Lisp and return a string?

[Jean Louis]

* Eli Zaretskii <eliz@gnu.org> [2019-08-24 15:18]:
> What do you mean by "disturbing"?  If the problem is that you are
> using recursive-edit, and you exit recursive-edit with C-M-c, then I
> specifically did NOT suggest to use recursive-edit.  You shouldn't
> need it, AFAIU.  You need a simple editing of a buffer, that's all.

I am listening to your advice.

> You could, but I don't see how this is going to solve your problem any
> better than installing a kill-buffer-hook.  After all, if you are
> afraid that the user might kill the buffer when they shouldn't, then
> your reliability issue is not solved by using the kill-buffer as a
> trigger for feeding the stuff back to the database?

Yes, I tried before with kill-buffer-hook and I was doing something
wrong.

With those advises, I made the below function, which does mostly what
I want.

Thank you, it is solved!

Jean

(defun edit-db-field-value (table field type id value file)
  (string-to-file-force value file)
  (let* ((buffer (create-file-buffer file)))
    (switch-to-buffer buffer)
    (set-visited-file-name file)
    (insert value)
    (add-hook 'kill-buffer-hook `(lambda ()
                                  (let ((new-value (file-to-string ,file)))
                                    (rcd-db-update-entry ,table ,field ,type 
,id new-value)))
              0 t)))