Re: Proposal to improve the nomenclature of scrolling directions

[Nix <nix@esperi.org.uk>]

On 10 Nov 2012, Eli Zaretskii verbalised:

>> Date: Sat, 10 Nov 2012 12:09:59 +0100
>> From: martin rudalics <rudalics@gmx.at>
>> CC: rms@gnu.org, dan@haxney.org, eli@barzilay.org, emacs-devel@gnu.org, 
>>  nix@esperi.org.uk, monnier@iro.umontreal.ca, dmoncayo@gmail.com, 
>>  stephen@xemacs.org
>> 
>>  > Meanwhile, it turned out that what's requested is something else: when
>>  > the user or a Lisp program deliberately scrolls the text, leave point
>>  > where it was, instead of moving it to be visible in the new contents
>>  > of the window.  This would need changes to window-scrolling code in
>>  > window.c, to avoid moving point.
>> 
>> Not necessarily.  We can always move point lazily, that is, whenever it
>> is requested.
>
> That requires changes to window-scrolling functions, since currently
> they do move point, and they do it non-lazily.  See
> window_scroll_pixel_based, where it calls SET_PT_BOTH etc.

Well, yes. That's the whole reason we started talking about it when we
were talking about scroll-in-place, which wraps the window-scrolling
functions :)

> And what does "whenever it is requested" means, anyway, in practical
> terms?  Those "other editors" that allow point to stay out of the
> window will scroll the display back to show point when some command is
> invoked that modifies the buffer text.

Exactly that.

>                                         Given that the modification
> commands don't require moving point, and C-v/M-v won't either (as this
> is the main justification for the feature we are discussing), what
> will?

Normally, in the Other Editors, PgUp/PgDn do move point: it's things
like scrolling using the scroll bars that does not. I'm not sure this is
so useful in Emacs -- when was the last time you used the scroll bars?
When was the last time you noticed they existed? I could have had this
feature on for the last six months and never triggered it once. :)

-- 
NULL && (void)