spyder ports and python

[mark brethen]

I see recently that a couple of new keywords have been added to the spyder ports: python.versions and python.default_version. How do these work? 

As a side question, I've been reading about keeping project code in a virtual environment to maintain a clean python Installation. The virtualenv and virtualenvwrapper ports are a means to that end, and switching between environments looks pretty easy. Have any macports users out there tried this? And which python ports would be considered a pure python installation (everything else being installed in the virtual env)? In the write up, it was suggested to prepend your path with, for example, '/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin'. Is this recommended?

Thanks.

-Mark