best way to share an instance of a class among modules?

c chaelon at gmail.com
Thu Feb 7 01:43:14 CET 2013


On Feb 6, 7:03 pm, Michael Torrie <torr... at gmail.com> wrote:
> On 02/06/2013 03:41 PM, CM wrote:
>
> > Thank you.  But, I'm sorry, I'm not following this enough to get it to
> > work.  Shouldn't it be a little more like this:
>
> No, not exactly.
>
>
>
> > # in utilities module
> > shared_cursor =  DatabaseAccess_instance  #but how? see my question
> > below...
>
> How what?
>
> > # in importer
> > import utilities
> > self.shared_cursor = utilities.shared_cursor  ("self" is here to make
> > cursor available to all functions in importer
>
> Umm no.  For one you're using self incorrectly.  For two, it already is
> visible to all functions in the module.  You just have to refer to it as
> "utilities.shared_cursor."

I was using self correctly, I think; but I should have said that the
code in the importing module would be within a class, so self there
refers to that class.  But that's a side point.

I agree that utilities.shared_cursor is visible within the importing
module.  But the problem below remains for me...

> > My only problem, then, is I create the shared_cursor from within a
> > function within the instance of DatabaseAccess().  How then do I pass
> > it from within the function's namespace to the module's namespace so
> > that I can do that first line?
>
> Every function in a module has access to the module's global namespace.
>  And your shared_cursor is there, inside of the utilities reference,
> since utilities was imported into your module, "importer."

But the function in the module is also within a *class* so I don't
think the function does have access to the module's global namespace.
Here's the hierarchy:

-- Module namespace....
    ---- class namespace (DatabaseAccess is the name of the class)
         ---- function namespace
              This is where the cursor is created.  How do I get it
into the module namespace?

Che



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