[Python-Dev] PEP 382: Namespace Packages (original) (raw)

Brett Cannon brett at python.org
Sat Apr 4 01:37:06 CEST 2009

On Fri, Apr 3, 2009 at 13:15, "Martin v. Löwis" <martin at v.loewis.de> wrote:

> Note that there is no such thing as a "defining namespace package" -- > namespace package contents are symmetrical peers.

With the PEP, a "defining package" becomes possible - at most one portion can define an init.py. I know that the current mechanisms don't support it, and it might not be useful in general, but now there is a clean way of doing it, so I wouldn't exclude it. Distribution-wise, all distributions relying on the defining package would need to require (or installrequire, or depend on) it. > The above are also true for using only a '*' in .pkg files -- in that > event there are no sys.path changes. (Frankly, I'm doubtful that > anybody is using extendpath and .pkg files to begin with, so I'd be > fine with a proposal that instead used something like '.nsp' files that > didn't even need to be opened and read -- which would let the directory > scan stop at the first .nsp file found. That would work for me as well. Nobody at PyCon could remember where .pkg files came from. > I believe the PEP does this as well, IIUC. Correct. >> * It's possible to have a defining package dir and add-one package >> dirs. > > Also possible in the PEP, although the init.py must be in the first > such directory on sys.path. I should make it clear that this is not the case. I envision it to work this way: import zope - searches sys.path, until finding either a directory zope, or a file zope.{py,pyc,pyd,...} - if it is a directory, it checks for .pkg files. If it finds any, it processes them, extending path. - it then checks for init.py, taking the first hit anywhere on path (just like any module import would)

Just so people know how this init search could be done such that path is set from the .pkg is to treat it as a reload (assuming .pkg files can only be found off of sys.path).

-Brett

- if no .pkg was found, nor an init.py, it proceeds with the next sys.path item (skipping the directory entirely) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20090403/32f2ecb2/attachment-0001.htm>

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