You keep mentioning G-code and I recently bought a 3D printer so I'm getting interested in it myself. Could you suggest a good reference for learning about G-code? I've done some web searches but haven't found one that describes all of the commands that my printer seems to use (a Printrbot Smalls). I'm assuming that G-code refers to the Gxxx commands but there also seem to be Mxxx commands and maybe others. I'd like to learn about all of them.
Also, it seems you've decided that it is impossible to create a G-code interpreter for P1. Why is that?