delete-trailing-whitespace on save

[j***@gmail.com]

I would like to automatically call delete-trailing-whitespace in
python-mode when I execute save-buffer. I assume there is some way
using advice, but my emacs lisp skills are very rusty! At first I
thought I could use an after-save-hook


(add-hook 'python-mode-hook
(lambda ()
(setq show-trailing-whitespace t)
(make-local-hook 'after-save-hook)
(add-hook 'after-save-hook 'delete-trailing-whitespace)))

but that deletes the whitespace *after* saving. I need something like
a before-save-hook. I googled before-save-hook and it appears there
was once such a beast, but it does not appear to be a variable in my
version of emacs (GNU Emacs 21.3.1)

Thanks,
JDH

[Joost Kremers]

Post by j***@gmail.com
thought I could use an after-save-hook
but that deletes the whitespace *after* saving.

as the name implies... ;-)

Post by j***@gmail.com
I need something like
a before-save-hook. I googled before-save-hook and it appears there
was once such a beast, but it does not appear to be a variable in my
version of emacs (GNU Emacs 21.3.1)

there is in my version (GNU Emacs 23.0.0.1), so i find it odd that you
don't have it. have you tried <C-h v before-save-hook RET>?

[j***@gmail.com]

Post by Joost Kremers
there is in my version (GNU Emacs 23.0.0.1), so i find it odd that you
don't have it. have you tried <C-h v before-save-hook RET>?

Yes, and it is not there... Unfortunately, upgrading is probably not
an option for me.

JDH

[Will Parsons]

Post by j***@gmail.com
I would like to automatically call delete-trailing-whitespace in
python-mode when I execute save-buffer. I assume there is some way
using advice, but my emacs lisp skills are very rusty! At first I
thought I could use an after-save-hook
(add-hook 'python-mode-hook
(lambda ()
(setq show-trailing-whitespace t)
(make-local-hook 'after-save-hook)
(add-hook 'after-save-hook 'delete-trailing-whitespace)))
but that deletes the whitespace *after* saving. I need something like
a before-save-hook. I googled before-save-hook and it appears there
was once such a beast, but it does not appear to be a variable in my
version of emacs (GNU Emacs 21.3.1)

Try 'write-file-hooks.

- Will