help-gnu-emacs
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: How to exclude a major mode from a hook


From: Nicolas Richard
Subject: Re: How to exclude a major mode from a hook
Date: Wed, 11 Feb 2015 11:15:01 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux)

Hi,

Cecil Westerhof <address@hidden> writes:
> I had the following in my .emacs:
>     (add-hook 'before-save-hook 'delete-trailing-whitespace)

IMO this is not the right thing to do, because one day you'll want to
edit a file in which trailing white spaces are important and you'll
wonder why it's all screwed up.

I would suggest to use a function that checks for trailing whitespaces
(with exceptions, such as the signature delimiter in message-mode) and
(interactievly) prompts if there is something to fix. I don't know if
such a function exists.

> So I rewrote it to:
>     (add-hook 'before-save-hook (lambda () (when (not (string= major-mode 
> "message-mode"))
>                                              'delete-trailing-whitespace)))

The condition
    (string= major-mode "message-mode")
can be written as
    (eq major-mode 'message-mode)
and would be better written as
    (derived-mode-p 'message-mode)

-- 
Nicolas



reply via email to

[Prev in Thread] Current Thread [Next in Thread]