From: Eli Zaretskii <eliz@gnu.org>
To: Pip Cet <pipcet@gmail.com>
Cc: 36190@debbugs.gnu.org
Subject: bug#36190: 27.0.50; `put-text-property' etc. with buffer argument calls current buffer's `after-change-functions'
Date: Mon, 17 Jun 2019 18:59:05 +0300 [thread overview]
Message-ID: <83lfy0td86.fsf@gnu.org> (raw)
In-Reply-To: <CAOqdjBf4MhxGGPWe--bAp6qZSCFL9W9z4U+zABYyGyq_UYCbWw@mail.gmail.com> (message from Pip Cet on Mon, 17 Jun 2019 11:38:38 +0000)
> From: Pip Cet <pipcet@gmail.com>
> Date: Mon, 17 Jun 2019 11:38:38 +0000
> Cc: 36190@debbugs.gnu.org
>
> > Switching buffers means rebinding values of all the buffer-local
> > variables, of which there could be quite a few. Or am I missing
> > something?
>
> I just don't see how the requirement to switch buffers for modifying
> text properties is so different, performance-wise, from the case of
> modifying buffer text; in the latter case, we simply accept we can do
> so only for the current buffer.
It isn't different. It's just that (a) modifying another buffer's
text is relatively rare, and (b) this is one more such switch.
> In any case, the current code already switches buffers, it's just a
> question of doing so twice rather than once.
Yes. IOW, we get hit by that one more time.
> > > > I wish we had a better alternative.
> > >
> > > (Such as not calling regular modification hooks for text property changes?)
> >
> > I thought about that, but I don't think this would be acceptable.
>
> It's certainly not something to be done on the spur of the moment, but
> it is something I feel Emacs did wrongly, perhaps because XEmacs did
> things differently, if I understand correctly. I'm not sure I'm aware
> of even a single place where text properties are used for something
> that's integrally part of buffer text.
I don't think this i a part of the problem: applications that don't
want the side effects of text properties can use overlays instead.
> when someone has time to test things properly, is to rewrite all
> buffer-modifying functions to look like this:
>
> Lisp_Object hooks = run_before_change_hooks (...);
> modify_buffer ();
> run_after_change_hooks (hooks, ...);
I think that'd be a welcome refactoring, if indeed this paradigm
doesn't break in some subtle use case (Emacs internals are frequently
like that).
> > struct buffer *b;
> > if (NILP (object))
> > {
> > XSETBUFFER (object, current_buffer);
> > b = NULL;
> > }
> > else if (BUFFERP (object))
> > b = XBUFFER (object);
> > [...]
> > signal_after_change (b, ...);
>
> I find the above much less readable than the current version, I must say.
I guess we will have to disagree then, because this is boilerplate C
ion Emacs sources.
> > > It was out of genuine interest, because passing NULL to implicitly
> > > specify a default argument is something that people advocate against,
> >
> > Not to specify the default, but to indicate that no action is needed
> > at all wrt the buffer. It is similar to the last argument to
> > 'strtol', for example.
>
> The `base' argument, you mean?
Sorry, meant the penultimate argument, ENDPTR.
next prev parent reply other threads:[~2019-06-17 15:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 13:48 bug#36190: 27.0.50; `put-text-property' etc. with buffer argument calls current buffer's `after-change-functions' Pip Cet
2019-06-13 16:36 ` Eli Zaretskii
2019-06-13 18:48 ` Pip Cet
2019-06-13 19:05 ` Eli Zaretskii
2019-06-13 19:27 ` Eli Zaretskii
2019-06-13 19:42 ` Pip Cet
2019-06-13 20:01 ` Eli Zaretskii
2019-06-13 20:57 ` Pip Cet
2019-06-13 21:37 ` Pip Cet
2019-06-14 7:41 ` Eli Zaretskii
2019-06-14 11:14 ` Pip Cet
2019-06-14 12:10 ` Eli Zaretskii
2019-06-15 15:14 ` Pip Cet
2019-06-15 15:23 ` Eli Zaretskii
2019-06-15 19:27 ` Pip Cet
2019-07-06 8:08 ` Eli Zaretskii
2019-07-06 15:27 ` Pip Cet
2019-07-06 16:22 ` Eli Zaretskii
2019-06-14 7:36 ` Eli Zaretskii
2019-06-17 11:38 ` Pip Cet
2019-06-17 15:59 ` Eli Zaretskii [this message]
2019-06-18 17:14 ` Pip Cet
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