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Re: add-hook versus custom-set-variables
From: |
Bill Wohler |
Subject: |
Re: add-hook versus custom-set-variables |
Date: |
Thu, 29 Dec 2005 02:05:35 -0800 |
Stefan Monnier <address@hidden> wrote:
> >>> Two workarounds which aren't pretty are to insist that the user add a
> >>> defvar in .emacs for any hook he customizes
> >>
> >> I don't understand what you're suggesting here.
> >> How could a defvar in .emacs help?
>
> > Please read Luc's article where he describes the technique and why.
>
> > http://article.gmane.org/gmane.emacs.pretest.bugs/9993
>
> Oh, I see. It's not specific to defvar: setq works just as well.
>
> >>> ;; MH-E hooks
> >>> (eval-after-load 'mh-customize
> >>> (progn
> >>> (message "Adding mailcrypt hooks to MH-E...")
> >>> (add-hook 'mh-folder-mode-hook 'mc-install-read-mode)
> >>> (add-hook 'mh-letter-mode-hook 'mc-install-write-mode)))
> >>
> >> eval-after-load is a function, not a macro. I know it's counter
> >> intuitive.
>
> > I don't know enough about the internals to know why this would be
> > counter-intuitive. I read your answer as: macros do what you expect,
> > functions don't. Please elaborate if this is not what you mean. Why
> > doesn't eval-after-load do what I expect?
>
> The evaluation of a form (A B C) can follow the following two paths:
>
> - if it's a macro:
>
> (eval (macrocall A B C))
>
> - if it's a function
>
> (funcall A (eval B) (eval C))
>
> Note how the function cannot delay the evaluation of its arguments.
Thanks for the explanation. There's a lot of strange things in
elisp--mostly around compilation and evaluation--that I don't understand
and every little bit helps. Maybe another reading of these sections in
the elisp manual will make more sense now.
In any event, I think I get it now. To keep eval-after-load from being
completely useless, the idiom is to quote the form. Right?
This works:
(eval-after-load "mh-e"
'(progn
(add-hook 'mh-folder-mode-hook 'mc-install-read-mode)
(add-hook 'mh-letter-mode-hook 'mc-install-write-mode)))
BUT!
While coming up with a recipe to prove that the semantics had changed
between Emacs 21 and 22, I discovered I was inadvertently performing my
"site-init" *after* I ran custom-set-variables. (Recall that I'm
simulating the Debian site-init from my .emacs while using CVS Emacs.)
Normally, site-init is performed *before* one's .emacs is loaded. After
moving the site-init to the top of my .emacs file, I regained Emacs 21
semantics and all is well.
Sorry about the false alarm; at least I learned a few things.
--
Bill Wohler <address@hidden> http://www.newt.com/wohler/ GnuPG ID:610BD9AD
Maintainer of comp.mail.mh FAQ and MH-E. Vote Libertarian!
If you're passed on the right, you're in the wrong lane.
Re: add-hook versus custom-set-variables, Bill Wohler, 2005/12/30
- Re: add-hook versus custom-set-variables, Stefan Monnier, 2005/12/30
- Re: add-hook versus custom-set-variables, Richard M. Stallman, 2005/12/31
- Re: add-hook versus custom-set-variables, David Kastrup, 2005/12/31
- Re: add-hook versus custom-set-variables, Chong Yidong, 2005/12/31
- Re: add-hook versus custom-set-variables, David Kastrup, 2005/12/31