[Greg Ross]

I'm not sure I understand what you mean when you say undefine.

Of course you can delete variable definitions that you don't need. If you need a variable in one of your program slots that you don't need in another, then you'll need to be a little more creative.

We usually have a pool of temporary variables which may be used locally (within a subroutine or program slot) which may be used elsewhere with impunity.

These temp variables are named temp1, temp2, etc. We then either use those variables directly, or alias them to something like temp1_tableOffset, temp2_scaledY, etc.