How do I auto save evil buffers for specific file types?

Question

I'm a new Doom Emacs user that can't get used to having to save files manually.

I found a way to auto save evil buffers, but the problem with this approach is that I'm not able step out of vterm (an Emacs terminal emulator) without Emacs prompting me to save the vterm buffer, which obviously doesn't make any sense.

(add-hook 'evil-insert-state-exit-hook
      (lambda ()
        (call-interactively #'save-buffer)))

I was thinking maybe I could save specific file types only, so Emacs doesn't try to save the vterm buffer, how would I modify the above elisp to auto save files only for specific file types?

Answer 1

You may want to try the package super-save, which auto saves files when idle or Emacs lose focus.

My own auto save function saving when idle or lose focus, built from Emacs built-ins (github link in case I'm missing anything):

(defvar jester-auto-save-idle 1 "Time in seconds before auto-saving all buffers.")
(run-with-idle-timer jester-auto-save-idle t #'jester/save-all-buffers)
;; (cancel-function-timers 'jester/save-all-buffers) ; for debugging
(add-hook 'focus-out-hook #'jester/save-all-buffers)

(defun jester/save-all-buffers ()
  "Save all buffers."
  ;; yas overlay and company-select-next has problem with this.
  (when (and (not yas--active-snippets)
             (not company-candidates)
             (not (eq major-mode 'snippet-mode)))
    ;; https://github.com/manateelazycat/lazycat-emacs/commit/da13a688ef89f8ab2c577a3e9d2a7bcf0ef9b71d
    ;; https://emacs-china.org/t/topic/7687/30?u=jjpandari
    ;; this prevents blink of eldoc
    (with-temp-message
        (with-current-buffer " *Minibuf-0*" (buffer-string))
      ;; this prevents blink of ivy
      (let ((inhibit-message t))
        (save-some-buffers t #'(lambda () (and (buffer-file-name) (buffer-modified-p))))))))

Answer 2

Emacs has some built in functionality for this already, so there is no need to write your own function. In case you do want to use your function, I would suggest adding a check for 'prog-mode. Programming modes should all be derived from prog-mode, so:

(when (derived-mode-p 'prog-mode)
  ;; Do stuff
  )

or, to include text-mode (org-mode, md, etc.):

(when (or (derived-mode-p 'prog-mode)
          (derived-mode-p 'text-mode))
  ;; Do stuff)

The built in way (I would recommend this) is using auto-save-mode. Let's say you're working on test.py; auto-save-mode will automatically save a copy of the buffer as #test.py# which will then be removed when you manually save the file. To auto save over test.py directly, use auto-save-visited-mode.

Something like this will work:

(add-hook 'prog-mode-hook
  (auto-save-visited-mode))