[Python-Dev] More flexible namespaces.

[Christian Tismer]

David Ascher wrote:
[Marc:> 
> > Since you put out to objectives, I'd like to propose a little
> > different approach...
> >
> > 1. Have eval/exec accept any mapping object as input
> >
> > 2. Make those two copy the content of the mapping object into real
> >    dictionaries
> >
> > 3. Provide a hook into the dictionary implementation that can be
> >    used to redirect KeyErrors and use that redirection to forward
> >    the request to the original mapping objects

I don't think that this proposal would give so much new
value. Since a mapping can also be implemented in arbitrary
ways, say by functions, a mapping is not necessarily finite
and might not be changeable into a dict.

[David:>
> Interesting counterproposal.  I'm not sure whether any of the proposals on
> the table really do what's needed for e.g. case-insensitive namespace
> handling.  I can see how all of the proposals so far allow
> case-insensitive reference name handling in the global namespace, but
> don't we also need to hook into the local-namespace creation process to
> allow case-insensitivity to work throughout?

Case-independant namespaces seem to be a minor point,
nice to have for interfacing to other products, but then,
in a function, I see no benefit in changing the semantics
of function locals? The lookup of foreign symbols would 
always be through a mapping object. If you take COM for 
instance, your access to a COM wrapper for an arbitrary
object would be through properties of this object. After
assignment to a local function variable, why should we
support case-insensitivity at all?

I would think mapping objects would be a great 
simplification of lazy imports in COM, where
we would like to avoid to import really huge
namespaces in one big slurp. Also the wrapper code
could be made quite a lot easier and faster without
so much getattr/setattr trapping.

Does btw. anybody really want to see case-insensitivity
in Python programs? I'm quite happy with it as it is,
and I would even force the use to always use the same
case style after he has touched an external property
once. Example for Excel: You may write "xl.workbooks"
in lowercase, but then you have to stay with it.
This would keep Python source clean for, say, PyLint.

my 0.02 Euro - chris

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