Lists in Swarm

[Matthew Mitchell]

Hi, I am a student a Monash working with Bodan Durnota.

I am implementing some simulations in Swarm that were originally 
implemented in Star-logo and have experienced a problem when using lists.

Using both the Heatbug and Mousetrap examples as a base, I want to add 
new objects to the simulation as it runs.  The objects occupy a location 
in the 2D grid and are referenced using a list.  However, I tried a 
number of different ways to add to the grid and list as the simulation was 
running only to continually get segmentation errors.  

In the end I was using the following ActionGroup:

simActions = [ActionGroup create: aZone];
      [simActions createActionTo: aGroup message:M(addOne)];
      [simActions createActionTo: aGroup message:M(moveAll)];

The object aGroup simply adds an object the list (which it contains) when 
sent the message addOne.  On receiving the  message moveAll, aGroup will 
send a message to each object in the list making it move.  Although I 
could not get this to work using lists, it does work when I implement it 
using an array I developed based on the Grid2D class in Mousetrap. 

Is this due to insufficient knowledge of Swarm classes or should it be OK?

By the way, I am using swarm-951209, so I do not know whether the new 
version is the same. 

Regards

Matt