[Python-Dev] python package

[Gordon McMillan]

On 14 Jul 2002 at 19:53, M.-A. Lemburg wrote:

> Gordon McMillan wrote:

> > ... But stuffing a __path__ attribute into
> > a module does *not* make the module a package.

> Hmm, I know that Python itself uses __path__ to
> tell whether it has a package or not, so I don't see
> why a
> module can't be regarded as package.

If you put on a Richard M. Nixon mask, you might
be mistaken for ("regarded as") Richard M. Nixon.
That doesn't make you Richard M. Nixon.

Stuffing __path__ into a module means that 
*most* of Python's runtime will regard your module as
a package. It doesn't make it a package.

In particular, most introspection tools and most
programmers will not recognize your module as
a package.

> Moving the module into a directory of the same name
> and then renaming it to __init__.py has the same
> effect. And in that case, hacking __path__ is
> perfectly legal. 

Yes, it now *is* a package. One which violates
recommended practice, which is to keep __init__.py
simple, but still a package.
 
> You haven't commented on the sys.modules trick yet.
> This one doesn't even use the __path__ hackery :-)
> 
> DateTime.py:
> import sys
> import mx.DateTime
> sys.modules[__name__] = mx.DateTime
[...]
> See: it's the same module :-)

Anytime x != sys.modules[x].__name__,
someone, sometime will suffer.

Installer and (I believe) py2exe have hooks
so that this gets analyzed properly. The hook
is keyed by "DateTime".

If you really find it intolerable to stick your
users with making a one line change in their
code, you might consider contributing hooks 
to Installer (or patches to py2exe).

Particularly for your non-free packages, since
I'm not going to download those and reverse-engineer 
them.

Or perhaps you could do like Pmw, and
include a "bundle" script.

-- Gordon
http://www.mcmillan-inc.com/