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As I say, there is no API documented for the facility of subclassing brought to VPython through the Boost implementation.

And I suspect not as much attention was given to developing this as an intuitive API as there might have been, and wouldn't be surprised if

Arthur: there

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is no intention of the VPython project to document it. Or at least to give documentation of it any priority.

These go together. By not documenting any API, they're free to give more thought to changing it later. Once documented, it's harder to keep revamping it.

I hope that is the direction they are going. Just don't know. Bruce has disappointed me before. He tends to like to control the flow of information in ways that I am not totally comfortable with. There are smart guys who know there are plenty of other smart (and smarter) guys out there. And then there are the guys who *always* seem to worry about talking over peoples heads. One of the things I love about the Open Source community is the struggle to keep up.

Until there's some documentation, I guess it's very unsafe (in the sense of future code breakage) to build any real codebase on the new subclassing features.

I wouldn't worry about it too much. I don't see much changing other than possibly the initialization routine. With modern text editors... Art