[Tutor] Default class in module

Kent Johnson kent37 at tds.net
Thu Aug 11 14:27:18 CEST 2005

Jan Eden wrote:
> Hi,
> I'd like to pack some modules in a package. Each module contains a single class, which forces me to
> from Pythonsite.Show import Page
> page = Page()
> ...
> class Page(Site.DB): #class DB from module Site in package Pythonsite
>     ...
> Is there a way to define a default class for a module which would me allow to
> from Pythonsite import Show
> page = Show() #page as an instance of default class in Show
> class Page(Site): #Page as a subclass of default class in Site

I don't know of any way to do exactly what you ask. However you can use the __init__.py module of the package to promote classes to package level visibility.

For example suppose you have
  __init__.py - empty
  myclass.py - defines MyClass
  myotherclass.py - defines MyOtherClass

To use this you would for example
from mypackage.myclass import MyClass
mc = MyClass()

But if you put these lines in __init__.py:

from mypackage.myclass import MyClass
from mypackage.myotherclassimport MyOtherClass

this brings the class names into the module namespace. Now you can say
from mypackage import MyClass
mc = MyClass()

I suppose you could do your example by including this line in __init__.py:
from Pythonsite import Show
Show = Show.Page

Then clients that say
from Pythonsite import Show

will actually get Show.Page which is what Pythonsite.Show is now bound to, but that seems unneccesarily twisted and obscure to me.


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