Re: [PATCH #8316] Variable Editor

[Daniel J Sebald]

On 02/24/2014 11:45 AM, John W. Eaton wrote:
> On 02/20/2014 02:00 AM, Daniel J Sebald wrote:

> How should functions called through this mechanism pass data? The
> natural thing for Octave is octave_value and octave_value_list. But that
> means passing these objects across threads, doesn't it? If so, is
> Michael Goffioul's reference counting change the best solution?
>
> Dan, now would probably be a good time to take another look at the
> changes you proposed last year. Can you tell me where they are again? I
> thought they were in the patch tracker but I don't see them now.

The patch with the sample background commands and data transfer via 
octave_value_list is this one:

http://savannah.gnu.org/patch/?8016

There are some verbose data printouts describing how passing data via 
octave_value does create the problem Michael describes (an octave_value 
copy occurs on the other side of the divide), but passing an 
octave_value_list doesn't create an octave_value copy so the GUI thread 
can access the data provided the worker process is suspended momentarily.


> > In the case of the variable editor, I think after the completion of a
> > command the editor just asks for the contents of the variable and
> > updates those that have changed, then that is all that is needed. But I
> > would suggest to do so efficiently. Rather than asking for all
> > variables, just ask for those displayed, e.g., x(6:30,17:25) if it is
> > only those that are displayed.
>
> Agreed, because you can only display a small segment of a Matrix at once
> on any display, no matter how large. But we would still like to be able
> to edit variables with millions of elements.

Yes, won't be easy.  That's why we need creative programmers.

Dan