[Python-Dev] New and Improved Import Hooks

[Gordon McMillan]

On 5 Dec 2002 at 11:51, M.-A. Lemburg wrote:

> Here's a sketch:
> 
> 1. User programs register import hooks based on REs
> which are
>     used to match the entries in sys.path, e.g.
>     ".*\.zip" for ZIP importers (caching could help in
>     improving the mapping performance).
> 
> 2. When Python sees an import request, it scans
> sys.path and
>     creates hook objects for each entry which it then
>     calls to say "go look and check whether you have
>     module X" until one of the hooks succeeds.
> 
> 3. Python then uses the hook object to complete the
> import
>     in much a similar way as e.g. SAX parsers call out
>     to event handlers.

Except for where the policy that associates a
"hook object" with an element of sys.path resides,
this is what iu.py does. In your case, you've got it
in the manager. In iu.py, each importer is given
a chance, until one says "yes, I can handle this".

I base this design choice on the observation that
managers, no matter how smart they are to start
with, tend to become very stupid over time <wink>.

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