pymc-devs/pymc — pull request #83 by takluyver (2012-01-14 01:06:11+00:00)
Title: Groundwork for Python 3 compatibility

*Not ready for merge*

This includes the groundwork for getting PyMC on Python 3. The diff is huge, but very little of it is real structural changes.

The current situation is that `import pymc` works on Python 2.7 and 3.2, but there are many test failures on both. I thought this was a good point to pause and discuss it with others, to check that you're happy with the approach.

It's using [six](http://packages.python.org/six/), to give one codebase that installs on recent versions of Python 2 and 3. This time, I'm not having 2to3 run at setup, so the Python code needs to be valid Python 2 and 3.

I've also found and fixed a couple of string exceptions (`raise "message"`), which are invalid on recent Python 2 versions as well.