holger krekel pyth at
Wed Jun 5 12:30:55 EDT 2002

Steve Holden wrote:
> "Vojin Jovanovic" <vjovanov at> wrote ...
> [...]
> >
> > > Well, good luck with your project -- and don't spring any more
> > > requirements on us, it's getting harder each time to solve your problem.
> >
> > Sorry, but it is not that my problem is hard.  It is that the concept of
> > having
> > to reference instance variables always through self. is making it hard and
> > inconvenient which was my point in my original post.
> > My opinion is that those points explained in FAQ are irrelevant.  The only
> > one relevant is .....
> >
> [...]
> Could you maybe use self.__dict__ as a namespace argument to the eval()?

no his questions go deeper :-)

the problem is that the values in the dict have to be 'evaluated' if accessed. 
For every name in such a value you need to evaluate its value again.
IOW it's recursive. The obvious solution is to intercept the namevalue-lookups 
during evaluation of an equation. But this doesn't work for exec/eval:
They ignore the interception points. 

IOW you cannot successfully wrap or inherit a dictionary type and pass it 
to exec/eval :-(

The next best solution IMO is to preprend a namescope like 'self.' 
to every name in an expression. But you may have to parse the expression to 
do this. Maybe fixing exec/eval behaviour is a better idea?



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