bug#48009: 28.0.50; Support query-regexp-replace using re-builder

[Stefan Kangas]

Phil Sainty <psainty@orcon.net.nz> writes:

> That could be very nice, although it feels like a pretty significant
> complication.  Also, re-builder's interactive updates can sometimes
> need a manual C-c C-u (`reb-force-update') if it gets confused (which
> I think occasionally happens when the regexp is invalid?), and that
> might not be great.

True, it would need to be robust enough to handle most of what you throw
at it.  But even with some warts, it would be a significant improvement,
I think.  If it is optional, users run less risk of being caught
unawares.

A naive approach would be to run something akin to `reb-force-update'
automatically after some delay, but I have no idea if that would work in
practice.

> Or did you mean to use the isearch highlighting code, which is perhaps
> more forgiving of temporary invalid states?

I'm not familiar with the code, so I can't help with ideas for how to
best implement something like this, unfortunately.