Kurt Thams wrote:

> I wrote a program to solve Sudoku puzzles, and when I run it I get a 
> problem... various submorphs stop drawing (and get rendered as a red 
> box with a yellow cross through it), and a walkback comes up with 
> "Error: Error: Instances of UndefinedObject are not indexable" (in 
> WorldState>>displayWorldSafely)
>
> Not sure if I'm doing something wrong with my program or if it is an 
> error in Morphic.
>
> Essentially, I fork a process and set a morph to step while the forked 
> process updates the model that the morph is drawing from.
>
Don't fork off a process. Morphic runs in a single thread and a you will 
get errors like this if you
try using other processes. Use morphics step mechanism or if you 
_really_ have to use a seperate process
use WorldState>>addDeferredUIMessage:
Karl

> The code can be downloaded from here: 
> http://thams.com/Kurt-Sudoku-ktt.2.mcz
>
> and executed with 'Kudoku example1'
>
> Any help appreciated.
>
> -- kurt
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