[Python-Dev] [Visualpython-users] How VPython 6 differs from VPython 5 (original) (raw)

Mark Janssen dreamingforward at gmail.com
Mon Jan 14 02:41:34 CET 2013

On Sun, Jan 13, 2013 at 12:14 PM, Bruce Sherwood <Bruce_Sherwood at ncsu.edu> wrote:

For the record, I do not know of any evidence whatsoever for a supposed "split" between the tiny VPython community and the huge Python community concerning floating point variables. Nor do I see anything in Python that needs to be "fixed".

Well it was bit enough that the python community created a brand-new language construct called import future -- something never considered before then and which actually changes the behavior of python unlike any other module. And perhaps I've just felt it more because I was a big proponent of both 3-d graphics as a way to keep python a draw for beginning programmers and also a big fan of scientific simulation. No one had anything near vpython back then. (But ultimately I need to stop mentioning this issue to this vpython list because it's really the Python group which need to get back in sync.)

The new (currently experimental) version of VPython based on wxPython must, in order to run in a Cocoa environment on the Mac, make the interact loop be the primary thread, with the user's Python calculations at worst a secondary thread, which is the opposite of the older VPython, where the interval-driven rendering thread was secondary to the user's calculations. By the unusual stratagem of having VPython import the user's program it has been possible to make this work, and at the same time greatly simplify the C++ component of VPython by eliminating threading, with additional important simplification from eliminating essentially all platform-dependent code thanks to the multiplatform character of wxPython. The result is that nearly all existing VPython programs will work without change, at the very small cost of a few marginal cases requiring minor tweaking. I should alter the documentation to make this important property of the new version more salient.

I need to analyze this more carefully before commenting further....

mark

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