[Pythonmac-SIG] Multiple version of the same module

[Christopher Barker]

Pierre-Alain Dorange wrote:
> How to manage a module with several versions on MacOS X ?

Unfortunately, the Python core developers have never seen the need to do 
this -- I still don't know why.

A number of packages have developed their own systems (wx.version, for 
wxPython, for instance) -- you might see if pygame has one.

> I've installed the stableone from source and i go into a
> "pygame-1.8.0release-py2.5-macosx-10.3-i386.egg" directory.

setuptools supposedly can do this for you too, if things are installed 
as eggs -- I think pkg_resources.require() is what you need -- take a 
look at the setuptools docs.

> I just install the 1.9 (for test) and it go into "pygame" directory

Ahh -so it's not an egg? If you want setuptools to help you out, you'll 
have to install the dev version as an egg, too.

> When i import "pygame" from python, the 1.8.0 is imported only and 1.9.0
> is complely ignored... How do python choose from several package ? Do
> package register them elsewhere ?

no --- python looks in sys.path, and uses the first one it finds.

So, the way folks have done this in the past, pre-setuptools is 
manipulate sys,path in various ways -- a script that moves *.pth files 
around, or python code that directly manipulates sys.path (that's what 
wx.version does)

easy_install creates a easy-install.pth file that adds the paths to eggs 
that it has installed -- it puts everything before site-packages, which 
is probably why your python is finding the 1.8 egg.

I know I haven't really given you the answer, but hopefully some hints 
to so you can figure out your options.

-Chris




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