Grid2d -- A 2d container class for agents.
Grid2d is a generic container class to represent agent position on a 2d lattice. It gets most of its behaviour from Discrete2d, adding extra code to check that you don't overwrite things by accident. Grid2d is pretty primitive: only one object can be stored at a site, no boundary conditions are implied, etc.
If set to true, then if you try to store something at a site that doesn't have 0x0 there, a warning will be generated.
- putObject: anObject atX:
Replaces the Discrete2d method. First check to see if it should do overwrite warnings, and if so if you're going to overwrite: if both conditions are true, print out a warning message. Regardless of the check, it writes the new object in.