[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Last use of defadvice in Emacs
From: |
Stefan Monnier |
Subject: |
Re: Last use of defadvice in Emacs |
Date: |
Wed, 06 Apr 2022 17:08:21 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) |
>> The patch below replaces the last remaining use of `defadvice` in Emacs
>> (well, except for Org where this has already been fixed upstream but
>> we're waiting for the change to trickle down to `master`).
>
> Why would we want to replace defadvice with advice-add?
> Don't all the objections to advice apply equally to both forms?
Both should be avoided, indeed. But `defadvice` is slowly being
replaced because it cannot obey `lexical-binding` (along with a bunch
of more minor annoyances) so it gets a few more objections.
> I've spent an hour trying various combinations of eval-when-compile and
> (boundp 'font-lock-extend-after-change-region-function), to try and get
> the stuff compiled or ignored based on the presence/absence of that
> variable. Something like C's #ifdef. I didn't manage it, and don't
> think it's possible. That's another C facility Emacs Lisp seems to be
> missing.
I thought the code was written specifically to perform the test at
runtime, so that the code compiled on Emacs-21 would still skip the
advice when run on Emacsā„22 (and also so code compiled on Emacs-28 would
still activate the advice when run on some hypothetical future Emacs
where `font-lock-extend-after-change-region-function` has been removed).
If you want to perform the test at compile time then I think something
like the following should work.
Stefan
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 957a0b8a7c5..05da61dbb2f 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -2565,18 +2565,18 @@
;; Emacs < 22 and XEmacs
(defmacro c-advise-fl-for-region (function)
(declare (debug t))
+ (unless (boundp 'font-lock-extend-after-change-region-function)
`(defadvice ,function (before get-awk-region activate)
;; Make sure that any string/regexp is completely font-locked.
(when c-buffer-is-cc-mode
(save-excursion
(ad-set-arg 1 c-new-END) ; end
- (ad-set-arg 0 c-new-BEG))))) ; beg
+ (ad-set-arg 0 c-new-BEG)))))) ; beg
-(unless (boundp 'font-lock-extend-after-change-region-function)
- (c-advise-fl-for-region font-lock-after-change-function)
- (c-advise-fl-for-region jit-lock-after-change)
- (c-advise-fl-for-region lazy-lock-defer-rest-after-change)
- (c-advise-fl-for-region lazy-lock-defer-line-after-change))
+(c-advise-fl-for-region font-lock-after-change-function)
+(c-advise-fl-for-region jit-lock-after-change)
+(c-advise-fl-for-region lazy-lock-defer-rest-after-change)
+(c-advise-fl-for-region lazy-lock-defer-line-after-change)
;; Connect up to `electric-indent-mode' (Emacs 24.4 and later).
(defun c-electric-indent-mode-hook ()
- Last use of defadvice in Emacs, Stefan Monnier, 2022/04/04
- Re: Last use of defadvice in Emacs, T.V Raman, 2022/04/04
- Re: Last use of defadvice in Emacs, Richard Stallman, 2022/04/05
- Re: Last use of defadvice in Emacs, Alan Mackenzie, 2022/04/06
- Re: Last use of defadvice in Emacs,
Stefan Monnier <=
- Re: Last use of defadvice in Emacs, T.V Raman, 2022/04/06
- Re: Last use of defadvice in Emacs, Stefan Monnier, 2022/04/06
- Re: Last use of defadvice in Emacs, Eli Zaretskii, 2022/04/07
- Re: Last use of defadvice in Emacs, Stefan Monnier, 2022/04/07
- Re: Last use of defadvice in Emacs, T.V Raman, 2022/04/07
- Re: Last use of defadvice in Emacs, Stefan Monnier, 2022/04/07
- Re: Last use of defadvice in Emacs, T.V Raman, 2022/04/08
- Re: Last use of defadvice in Emacs, Eli Zaretskii, 2022/04/08
- Re: Last use of defadvice in Emacs, Alan Mackenzie, 2022/04/07
- Re: Last use of defadvice in Emacs, Stefan Monnier, 2022/04/07