Python 3.0 to be backwards incompatible

The Python development community is working towards a new, backwards incompatible version of the language, version 3.0, which is slated for release in early 2009.

"We are going to break pretty much all the code. Pretty much every program will need changes," said Anthony Baxter, release manager for Python and a senior software engineer at Google Australia. Any extension modules, including proprietary vendor ones, will also need to be rewritten.

Python is an open source language which is used by a number of institutions including Google. While not elaborating on how much Python code is in use at Google, Baxter estimated that Python accounts for around 15 percent of Google's code base.

Python 3.0 will be the first version to break backwards compatibility. The program developers, led by language creator Guido Van Rossum, had elected to rewrite the language to remove accumulated "cruft", to simplify the language to make it easier to teach and use.

3.0 will solve a number of problems including the current "shambles" when mixing unicode and non-unicode strings in the current version of the language, said Baxter.

The Python development community was committed to providing a smooth upgrade path and will build a number of forwards-compatible new features into the next release of the current version of the language, version 2.6. This release is expected to come out around the same time as the release of 3.0, said Baxter.

"2.x is not going away. I'm happy to do a 2.7 if it's needed. We're not expecting everyone to rewrite all their code the day after 3.0 comes out, that would be very foolish," Baxter said.

Anthony Baxter is a senior software engineer at Google Australia. He has been the release manager for Python for over four years. His "Two Snake Enter, One Snake Leave" talk was the only Australian keynote at the conference, which closes today.

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