Re: redisplay-dont-pause does not work

[David Kastrup <dak@gnu.org>]

storm@cua.dk (Kim F. Storm) writes:

> Richard Stallman <rms@gnu.org> writes:
>
>> 	  You can request a display update, but only if no input is pending,
>> 	with @code{(sit-for 0)}.  To force a display update even when input is
>> 	pending, do this:
>>
>> 	@example
>> 	(let ((redisplay-dont-pause t))
>> 	  (sit-for 0))
>> 	@end example
>>
>>     Yes, I see a contradiction here.  Setting `redisplay-dont-pause' does
>>     not have the declared effect, to wit "to force a display update even
>>     when input is pending".
>>
>> I think that text in the manual is mistaken.  `redisplay-dont-pause'
>> only affects redisplay itself.  It has no effect on sit-for, which
>> isn't (strictly speaking) redisplay.
>>
>> We could change the code, or change the manual.
>> I am not sure which is better.
>
> Here is a fix for the code.
>
> *** dispnew.c	01 May 2006 10:07:42 +0200	1.363
> --- dispnew.c	27 May 2006 22:53:42 +0200	
> ***************
> *** 6406,6412 ****
>     swallow_events (display);
>   
>     if (detect_input_pending_run_timers (display) || !NILP (Vexecuting_kbd_macro))
> !     return Qnil;
>   
>     if (initial_display)
>       redisplay_preserve_echo_area (2);
> --- 6406,6415 ----
>     swallow_events (display);
>   
>     if (detect_input_pending_run_timers (display) || !NILP (Vexecuting_kbd_macro))
> !     {
> !       if (!redisplay_dont_pause || sec || usec)
> ! 	return Qnil;
> !     }
>   
>     if (initial_display)
>       redisplay_preserve_echo_area (2);

Is there a particular reason that you used " || sec || usec" here?  It
makes (sit-for 0) a special case, and I am not sure why.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum