dynamic modules

[Jeff Shannon]

Werner Schiendl wrote:

> Hi,
>
> you can create a type (a class) instead of a plain module.
>
> When the reference count drops to zero, the instance will then be deleted.
>
> It is probably possibly to create a singleton class, that always returns one
> single instance if there is one instead of creating a new one every time.
> But I never tried that.
>
> hth
> Werner

ActiveState's Python cookbook has a Singleton recipe at

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52558

and also the even-better Borg pattern from Alex Martelli:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66531

Though, if the intent is to be able to clear out a large chunk of memory, I'm
not positive that either of these patterns will work.  In both cases, even if
you delete all the instances of your singleton/borg class, the class object
itself may still hold a reference to the shared data.  I suppose that, if you're
confident that you're done with it, perhaps you could delete the class object as
well....   something to look into, anyhow.

Jeff Shannon
Technician/Programmer
Credit International