[Python-ideas] Add a site.cfg to keep a persistent list of paths (original) (raw)

Ron Adam rrr at ronadam.com
Wed Oct 20 20:46:42 CEST 2010

On 10/20/2010 08:38 AM, Nick Coghlan wrote:

On Wed, Oct 20, 2010 at 7:57 PM, Paul Moore<p.f.moore at gmail.com> wrote:

On 19 October 2010 22:26, Tarek Ziadé<ziade.tarek at gmail.com> wrote:

There's one feature I want to add in distutils2: the develop command setuptools provides. Basically it adds a "link" file into site-packages, and does some magic at startup to load the path that is contained in the link file. The use case is to be able to have a project added in the python path without installing it.

Can you explain the requirement in more detail? I don't use the setuptools develop command, so I don't have the background, but it seems to me that what you're proposing can be done simply by adding the relevant directory to PYTHONPATH. That's all I ever do when developing (but my needs are pretty simple, so there may well be subtle problems with that approach). A different idea along these lines that I've been pondering is an actual -p path option for the interpreter command line, that allowed a sequence of directories to be provided that would be prepended to PYTHONPATH (and hence included in sys.path). So if you're wanting to test two different versions of a module (from a parent directory containing the two versions in separate subdirectories): python -p versionA runtests.py python -p versionB runtests.py For more permanent additions to sys.path, PYTHONPATH (possibly in conjunction with virtualenv) is reasonable answer. Zipfile and directory execution covers execution of more complex applications containing multiple files as if they were simple scripts. The main piece I see missing from the puzzle is the ability to easily switch back and forth between multiple versions of a support package or library without mucking with persistent state like the environment variables or the filesystem.

Yes, I don't like changing the system wide environment variables and file system options. It's too easy to break other things that depend on them.

How about adding the ability to use a .pth file from the current program directory?

Ron

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