Re: A question about overlays and performance.

[Jeff Norden <jnorden@tntech.edu>]

> I am currently working on re-implementing org-mode folding from using
> overlays to text-properties.

It's interesting that you are working to change org's overlays back to
text properties, while I'm considering doing exactly the opposite for
the project that I've been playing with.  Do org buffers routinely wind
up with thousands of overlays?

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>> ...
>> And the way I recommend to avoid this problem is to stay clear of
>> indirect buffers (which I consider as an attractive nuisance).

From what little I've seen of them, I'm quite inclined to agree with
Stefan's opinion about indirect buffers.  Is their main use in org to
provide multiple views of a buffer with different foldings?

I wonder if it might be possible to implement a "window-invisibility-spec",
that would override the buffer-spec when set.  It would have to be done
in C, not lisp.  You might even want to add a new field in the window
structure.  I have no real clue as to whether this is possible, feasible,
or a good idea.  But it might provide a nice way to display a single buffer
in two different windows with different levels of hidden text.  It seems
like it would be a lot simpler than using indirect buffers, but I'm
certainly no expert on this.

Regards,
-Jeff