multiple inheritance of a dynamic list of classes?

[devicerandom at gmail.com]

On 13 Feb, 09:14, Peter Otten <__pete... at web.de> wrote:
> deviceran... at gmail.com wrote:
> > Thanks both for suggestions. I still think that using inheritance is
> > somehow cleanest in this case (I always hear the mantra "avoid
> > multiple inheritance!", but this is one of the cases it seems to make
> > a lot of sense to me), but it's nice food for thought/code anyway.
>
> "Avoid inheritance" would be almost as justified :-)

Why?

> Problems that may arise with this case of multiple inheritance:
>
> - If you need initializers, ensure that they are all invoked

Yes, I figured it out. This should be easy in this case.

> - What would you do about name clashes? To avoid them your plugins need to
> know about each other.

Yes, I know, but I can't see any simple solution to this (if you can,
please share it with me!). The cmd module works by interpreting any
method starting with "do_" as a command, so "do_blah" becomes the
"blah" command. If two people write a "do_blah" command, and both
plugins are used, I see no easy way to solve the issue (apart
rewriting a cmd module).
Perhaps there can be some previous sanity check in each modules dict
to see if there are obvious namespace clashings, and in this case
issue a warning. I don't know.

> - State (instance attributes) is shared among all your plugins. Since you
> call all base classes Commands, Python's double-underscore hack won't work.

What double-underscore hack are you referring to? (sigh, my python
limits are all arising...) I can call all base classes
PluginNameCommand, however, this wouldn't break the thing (I'm still
at the very early planning stage) and would maybe work.

m.