On Thu, Sep 8, 2011 at 3:55 AM, egbert <egber...@xs4all.nl> wrote:
> My classes correspond to sql tables.
> In these classes I want to have several class variables
> that refer to data that are common to all instances.
>
> The assignment statements for the class variables are the same
> in all classes, except that of these instructions needs the name
> of the class itself. That name is used to read a file with meta-data.
>
> So what I have now is something like this (simplified):
>
> class TableOne(object):
> m = Metadata('TableOne')
> m.do_something()
> def __init__(self):
> etc
>
> class TableTwo(object):
> m = Metadata('TableTwo')
> m.do_something()
> def __init__(self):
> etc
>
> I have tried:
> - to eliminate the class name argument, but in this phase of the
> object creation __class__ and __name__ are not available
> - to move the two statements to a superclass, but the class variables
> come in the superclass namespace, not in the subclass namespace.
>
> Any ideas ?
Definitely an interesting problem I've run into before. Here are two solutions:
1. in Python 3, use the metaclass __prepare__() (see
http://code.activestate.com/recipes/577813/);
2. in Python 2 or 3, use a descriptor to defer creating your Metadata
objects until after the class object is available (see
http://code.activestate.com/recipes/577745/).
HTH
-eric
> e
> --
> Egbert Bouwman - Keizersgracht 197 II - 1016 DS Amsterdam - 020 6257991
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