Re: Nested sit-for's

[Richard Stallman <rms@gnu.org>]

    I think we could clean up the code even more by extending
    run-with-idle-timer as follows:

      (run-with-idle-timer SECS REPEAT FUNCTION &rest ARGS)

       Perform an action the next time Emacs is idle for SECS seconds.
       The action is to call function with arguments ARGS.
       SECS may be an integer or a floating point number.

       If REPEAT is non-nil, do the action each time Emacs has been idle for
       exactly SECS seconds (that is, only once for each time Emacs becomes idle).

       Additionally, if REPEAT is a number, repeat the action every REPEAT
       seconds as long as Emacs stays idle.

That feature could be useful for some cases, but unconditional
repetition isn't quite what we want for the jit-lock case.

So let's not add it now.