Re: A proposal for the future of open-paren-in-column-0-is-defun-start.

[Alan Mackenzie]

Hello, Stefan.

On Sun, Apr 05, 2020 at 10:33:17 -0400, Stefan Monnier wrote:
> > With this mechanism in place, o-p-i-c-0-i-d-s could safely be left
> > enabled, for speed's sake,

> FWIW setting `comment-use-syntax-ppss` to nil is likely make things
> *slower* in many cases.

Anyhow, the problem with using syntax-ppss here is it involves lots and
lots of scanning over large buffer portions in certain circumstances.
The o-p-i-c-0-i-d-s approach wouldn't.

Also, syntax-ppss doesn't (necessarily) do the right thing on narrowed
buffers, thus potentially leading to errors.  Why don't you make sure
the buffer is widened before using syntax-ppss?

> This "newish" variable was only introduced so as to have an escape hatch
> if it turned out that the new functionality of relying on syntax-ppss
> proved problematic.

Why is the o-p-i-c-0-i-d-s mechanism made dependent on
comment-use-syntax-ppss being nil?

> Given that I haven't seen a single incident reported since that fateful
> Dec 12 2017 night, I think we'd be better off removing
> `comment-use-syntax-ppss` altogether.

Er, Martin reported a delay of 10 seconds when scrolling a buffer with
the mouse wheel.  How does that not cound as an "incident"?

What you mean by your suggestion is to remove
open-paren-in-column-0-is-defun start altogether.

Both Martin and Richard, who have less powerful machines than we do, are
unhappy about this.

Anyway, what exactly happened on 2017-12-12 that qualifies as a fateful
incident?

Also, you haven't commented on my proposal.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).