[Distutils] A prefix option?

[Phillip J. Eby]

At 03:45 PM 2/9/2006 -0600, Ian Bicking wrote:
>Phillip J. Eby wrote:
>>>I think we need a simple way to handle custom directories that is:
>>>
>>>- cross platform
>>>
>>>- doesn't require modifying the Python install
>>>
>>>- allows chained/multile custom directories, which means the trick
>>>  of putting eggs and scripts in the same directory doesn't work,
>>
>>PYTHONPATH-based installs allow all of this, as long as you add the 
>>setuptools .egg to PYTHONPATH.
>
>Would putting sys.path manipulations directly into the generated scripts 
>handle all these issues, then?  Including the Windows problem of 
>environmental variables being hard to access.

I've just posted an alternative idea for how to go about this, that would 
allow a "pure PYTHONPATH" (i.e., without needing a hard-coded setuptools 
.egg in it) to work.  Let me know what you think.


>>>It appears that this has something to do with your plugin proposal.
>>
>>Not that I'm aware of, actually.  The plugin facility is intended for an 
>>"application instance" path, distinct from a general/global installation 
>>location.
>
>Aren't we talking about setting up application instance paths here, except 
>where the application is Python itself?

Hm.  I was going to say no, that find_plugins() is something with much more 
restricted utility, but then it occurred to me that it certainly would make 
it possible to find the latest usable eggs that are installed and put them 
on sys.path.  :)  I don't think it's a good idea, though, because until 0.7 
there isn't a way to later change your mind and decide you'd like a 
different version of something.  And of course the cost to invoke 
find_plugins() is enormously higher than the cost of Python processing .pth 
entries at startup.

Anyway, I think the other idea ( 
http://mail.python.org/pipermail/distutils-sig/2006-February/006026.html ) 
may fix the issue a bit better.