At 01:51 PM 7/22/2010 +0100, Martin v. Löwis wrote:
At EuroPython, I sat down with Brett and we propose an approach
how namespace packages get along with import hooks. I reshuffled
the order in which things get done a little bit, and added a
section that elaborates on the hooks.
Basically, a finder will need to support a find_path method,
return all .pth files, and a loader will need to support a
load_module_with_path method, to initialize __path__.
Please comment if you think that this needs further changes;
I'm not certain I understand it precisely. There seem to be some
ambiguities in the spec, e.g.:
"If fullname is not found, is not a package, or does not have any
*.pth files, None must be returned."
What does "is not a package" actually mean in that context? What
happens if an empty list is returned - does that mean the importer is
saying, "this is a package, whether it has an __init__.py or not?"
As for the "list of strings" returned, is each string the entire
contents of the .pth file? Is it to be \n-separated, or is any
universal-newlines-compatible string accepted? Is there a particular
order in which .pth file contents are to be returned?
Regarding load_module_with_path(), how does its specification differ
from simply creating a module in sys.modules, setting its __path__,
and then invoking the standard load_module()? (i.e., is this method
actually needed, since a correct PEP 302 loader *must* reuse an
existing module object in sys.modules)
I'll hope to start implementing it soon.
Am I correct in understanding that, as written, one would have to
redefine __import__ to implement this in a library for older Python
versions? Or is it implementable as a meta_path importer?
Regards,
Martin
Thanks for your work on this, I was just thinking about pinging to
see how it was going. ;-)
(I want setuptools 0.7 to be able to supply an add-on module for
supporting this PEP in older Pythons, so that its current .pth hacks
for implementing namespace packages can be dropped.)
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