Programming Python, 3rd Edition

Coming Attractions

What developments can Python users expect to see in the coming years? Python 3000, which is referred to in the foreword to the second edition as “intentionally vaporware,” will see the light of day after all as Python 3.0. After half a decade of talk, it’s finally time to start doing something about it. I’ve created a branch of the 2.5 source tree, and, along with a handful of developers, I’m working on transforming the code base into my vision for Python 3000. At the same time, I’m working with the community on a detailed definition of Python 3000; there’s a new mailing dedicated to Python 3000 and a series of PEPs, starting with PEP 3000.

This work is still in the early stages. Some changes, such as removing classic classes and string exceptions, adopting Unicode as the only character type, and changing integer division so that 1/2 returns 0.5 instead of truncating toward zero, have been planned for years. But many other changes are still being hotly debated, and new features are being proposed almost daily.

I see my own role in this debate as a force of moderation: there are many more good ideas than could possibly be implemented in the given time, and, taken together, they would change the language so much that it would be unrecognizable. My goal for Python 3000 is to fix some of my oldest design mistakes, especially the ones that can’t be fixed without breaking backward compatibility. That alone will be a huge task. For example, a consequence of the choice ...