Re: INDIRECT and real-time question

[Jody Goldberg <jody gnome org>]

On Fri, Oct 11, 2002 at 01:30:02PM -0400, Pavel Shevchenko wrote:
> 1. High performance real-time interfaces should be area-based, so real time call
> should looks like RTS(<symbol_range>, <field_range>, "<out_cell_name>")
> for example: RTS(A1:A101, B1:F1, "A2") to insert 100x5 = 500 real-time values
> into cell range A2:F101. 

Area based is definitely a requirement, my initial thought was an
array formula based approach.

    with record ids in A2:A101
    with field ids in B1:F1
    select B2:F101
    =ReadFromFeed(feedID,A2:A101,B1:B1)<Ctrl-Shift-Enter>
 
On the positive side you get appropriate permisioning on the cells.
They would not be individually editable, and the recalc would be
enmass.

There are 2 downsides
1) Changing the size of the array is cumbersome.
2) With a naive approach when one of the values change, anything
   depending on all of them would recalc.  However, that can be
   circumvented by being a touch smarte w.r.t. how to handle the
   updates.  If we change the corner cell value directly and queue
   the individual update cells directly things will work nicely.

Update interval
    The current approach of recalculating as updates come in
    is destined for starvation.  A better approach would be to
    queue the changes for an interval, then commit in a block
    and recalc.  This should be simple to implement, all that would
    be required would be an interface to control frequency