Re: setnu-mode and Emacs 21.

[Miles Bader]

Juanma Barranquero <address@hidden> writes:
> If creating hundreds or thousands of overlays does not work
> (performance-wise), then other features that could profit from it
> working right will also be slow, and won't be "fixed" by the
> line-numbering-specific change you're suggesting.

I think working hard to speed up overlays is the wrong approach,
because it will always fail as soon as the file gets big enough, and
because speed is almost always at odds with flexibility.

Perhaps the right thing to do is to have an interface that lets user
code create overlays only for parts of the buffer that are displayed
(and allows undisplayed overlays to eventually go away).  The
`jit-lock' font-lock mode does something similar (I think), but I don't
know enough about it to say whether it could be used for other purposes.
If not, then maybe the mechanism it uses could be extended.

-Miles
-- 
`Life is a boundless sea of bitterness'