On Mon, Sep 05, 2022 at 12:16:31AM +0200, Alessandro Bertulli wrote:
> 
> Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> writes:
> 
> > `LaTeX-mode-map`, like most package variables, is only defined once
> > its package is actually loaded, which is done lazily in response to the
> > use of the package (e.g. opening a LaTeX file).
> >
> > So it's normal that `LaTeX-mode-map` is not defined when your init file
> > is loaded.  This is on purpose to try and speed up Emacs's startup.
> >
> > You can use things like:
> >
> >     (with-eval-after-load 'latex
> >       (define-key LaTeX-mode-map (kbd "C-c a") #'my-bar)
> >       (define-key LaTeX-mode-map (kbd "C-c b") #'my-foo))
> 
> You honestly opened a world to me. I have long wondered the difference
> between require and with-eval-after-load (of course I could have read
> the docs, but I never found time). :-)
> 
> > or
> >
> >     (defun my-latex-setup ()
> >       (define-key LaTeX-mode-map (kbd "C-c a") #'my-bar)
> >       (define-key LaTeX-mode-map (kbd "C-c b") #'my-foo))
> >     (add-hook 'LaTeX-mode-hook #'my-latex-setup)
> >
> > in order to delay the customization to after the variable is defined.
> 
> Isn't this redundant? You call the function every time a LaTeX file is
> loaded. The first method is preferrable, right?

I think they are doing different things. There are things you want to
happen on each buffer when and once it becomes a "LaTeX buffer". Setting
buffer-local variables comes to mind.

And to nitpick a bit more: it doesn't happen when a LaTeX file is loaded,
but when LaTeX mode is "switched on", that can happen in other occassions
too (when creating a new buffer you know it will be LaTeX, but you can
also switch the mode on and off; LaTeX isn't a good example for the second).

Cheers
-- 
t