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bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in
From: |
Alan Mackenzie |
Subject: |
bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes |
Date: |
Fri, 6 Dec 2019 22:24:59 +0000 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
Hello, Eli.
On Fri, Dec 06, 2019 at 20:48:26 +0200, Eli Zaretskii wrote:
> > Date: Fri, 6 Dec 2019 18:28:42 +0000
> > Cc: yyoncho@gmail.com, 38406@debbugs.gnu.org
> > From: Alan Mackenzie <acm@muc.de>
> > > There might be a misunderstanding on my part here. Could you please
> > > explain how come electric-pair-post-self-insert-function is called
> > > twice if it isn't removed from the hook? where's the second (or the
> > > first) call?
> > The first call is an explicit call from c-electric-brace to
> > electric-pair-post-self-insert-function. Depending on the changes to the
> > buffer this call causes (amongst other things), differing electric
> > actions are performed by c-electric-brace. This call is itself a
> > workaround, there being no purpose designed function for this purpose in
> > elec-pair.el.
> > The second call happens when c-electric-brace run-hook's
> > post-self-insert-hook - _if_ electric-pair-post-self-insert-function
> > hasn't been filtered out of that hook.
> If you already call that particular function explicitly, then calling
> it one more time is indeed redundant.
No, it's not redundant. It's positively harmful.
> But is this the case with all the other functions that you suggest to
> filter from post-self-insert-hook?
No. They have individual reasons for being filtered out. Don't forget
that this is a particularly sensitive hook, allowing hook functions to
interfere in an unsynchronised way with partially complete command
processing.
Let's go through them again:
smie-blink-matching-open is inapplicable to CC Mode and just takes up
processor cycles.
electric-pair-post-self-insert-function we've already discussed.
blink-paren-post-self-insert-function would do nothing anyhow, since
blink-paren-function has been bound to nil - this is so that the actual
blinking doesn't occur until the newly inserted brace is at its final
position.
electric-indent-post-self-insert-function is redundant and possibly
harmful.
electric-layout-post-self-insert-function is undocumented, thus likely
to be harmful. Its name suggests it is redundant.
electric-quote-post-self-insert-function is undocumented, uncommented
and obscure. It is safer not to risk running it.
Given that the mechanism for filtering post-self-insert-hook is there,
why is there the resistance to filtering out redundant and effect-free
functions?
And how come functions without meaningful doc strings are allowed onto
Emacs hooks?
--
Alan Mackenzie (Nuremberg, Germany).
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, (continued)
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/05
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Alan Mackenzie, 2019/12/05
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/05
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Alan Mackenzie, 2019/12/05
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/06
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Alan Mackenzie, 2019/12/06
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/06
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes,
Alan Mackenzie <=
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/08
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Alan Mackenzie, 2019/12/07
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Eli Zaretskii, 2019/12/07
- bug#38406: 27.0.50; post-self-insert-hook does not hold its contract in cc-mode derived modes, Alan Mackenzie, 2019/12/07