[Python-Dev] Alternative Approach to Relative Imports

M.-A. Lemburg mal@lemburg.com
Mon, 27 Sep 1999 12:19:25 +0200

M.-A. Lemburg wrote:
> BTW, while hacking along I found a few things that might be worth
> discussing w/r to a general import hook scheme:
> Currently, the imputil apporach uses a simple chaining technique.
> Unfortunately, it doesn't allow inspecting the chain for already
> loaded hooks, so the same type of hook could be loaded more than
> once.
> Also, there are at least two types of hooks:
> 1. hooks that redirect the import to some other data source
> 2. hooks that modify the way modules are searched
> Since the first variant may well also be suited to used by
> the second, the simple chaining method probably won't be
> powerful enough to handle it.
> I think what we really need is a set of register/deregister
> APIs + some framework to differentiate between the two
> hook types (and possibly other variants).

Another quirk that I think needs fixing:

When I issues an import:

	import mx.DateTime

the whole import is handled by the importer installed at
the start of the import. It is not possible to install a different
importer e.g. in mx/__init__.py to handle the rest of the
import (in this case the import of subpackage DateTime).
I think that the importer should honor the __importer__ function
(this is set by imputil) if present to let it continue the
import of subsequent elements in the dotted name.

Aside: Perhaps this is getting too technical for this list... should
I start an egroups mailing list for defining a new and more
flexible import mechanism ?

Marc-Andre Lemburg
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