karl wrote:

> 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
>
>
So how do you properly use Morphic to display the intermediate results 
of a long-running, computationally-intensive process? This code could 
not be runing in the step method, otherwise the display would never update.

Would you have your computationally-intensive process running in a 
forked thread, and the implementor of "step" then alters the values 
underlying the morph objects?

-- kurt