Re: Highlighting parentheses when matching parentheses resides outside visible window

[Heime]

------- Original Message -------
On Wednesday, October 26th, 2022 at 11:09 AM, Eli Zaretskii <eliz@gnu.org> 
wrote:


> > Date: Tue, 25 Oct 2022 22:41:33 +0000
> > From: Heime heimeborgia@protonmail.com
> > Cc: help-gnu-emacs@gnu.org
> > 
> > Have spent some serious time scrutinising show-paren-style.
> > 
> > I will explain the problem. Suppose your function is longer than your emacs 
> > window.
> > Use "expression" as "show-paren-style", then go just after the last closing 
> > parenthesis.
> > You get the associated region highlighted. BUT, try to scroll up the code, 
> > the highlighting
> > get recomputed as the point moves across the window. Thus highlighting 
> > capability becomes
> > useless when the part does not fit in the emacs window pane.
> 
> 
> I'm sorry, but this doesn't explain your problem in enough detail.
> 
> First, what exactly do you mean by "scroll up the code"? which Emacs
> commands did you use to scroll? At least some ways of scrolling don't
> move point.

I use the arrow keys do a mouse scroll up.  With mouse scroll up, the
position of the cursor moves as the window gets updated.
 
> And when you say "point moves across the window", do you mean that
> point moves with the text or that the text moves, but point stays at
> the same screen coordinates? Depending on how you scroll, it could be
> one or the other.

If the point stays at same screen coordinates, or moves with the text;
the point still moves from its original position (originally positioned
after parenthesis of interest).  Have noticed that when I scroll, the 
cursor point always shown up in the window.
 
> Next, what do you mean by "highlighting get recomputed as the point
> moves across the window"? What happens with highlighting as you
> "scroll" that you don't like?

Let there be a long function, and you put the cursor at the point following
the last parenthesis.  With "show-paren-style" being expression, the function 
code get highlighted.  Suppose I want to go to the beginning of the function
which resides outside the window pane.  The highlighting is disabled as I go
to the beginning of the function.

> And finally, what would you like to happen instead in this case?

I would like the possibility of freezing the highlighting (not only when using
'expression put also for 'parenthesis).  Currently I loose all the parenthesis
or expression highlighting when I need to move through the code.