I would like to emphasize the bit "once that is working"... it can be a bit much to get the whole mechanism working at the same time as developing the macro. So get the flow going from a text file being read in to the correct function being called for that shape and maybe do a few shapes until you are sure the beast is about right, then do the macrology. Especially if a macro is in a separate file (as it should be) and you are not reloading the whole shebang each time you run, you'll go nuts running old code even after changing the macro if you just reload the macro-defining file. Add to that the fact that the mechanism itself will be a moving target... well, I like to divide and conquer these deals.
