Re: sit-for

[Chong Yidong]

> Since we have the new sit-for implementation, I have a lot of times
> when Emacs just pauses in busy waiting for input.  This happens
> spontaneously.  One situation where it happens frequently is when
> reading news with gnus.

Another possibility just occurred to me.  Unlike the old sit-for, the
new sit-for is not interrupted by input coming from processes (as
opposed to user input).  If gnus (or some other package) relies on
this behavior, a bug will arise.

The question is: is this a bug of the new sit-for?  If sit-for is
changed to interrupt due to processes, we have the same problem as
before: input coming from miscellaneous async processes will interfere
with towers of hanoi (or other animation code).

One possibility is to bring back the old sit-for with its warts
(interruptable even if no new input events are available) and change
the animation code to use `read-event' with its new timeout argument.

Another possibility is to leave sit-for as it is, try to find code
that relies on sit-for returning due to process output, and fix it.