[Python-Dev] PEP 455: TransformDict

[Antoine Pitrou]

On Fri, 13 Sep 2013 23:18:39 +0300
Serhiy Storchaka <storchaka at gmail.com> wrote:
> 13.09.13 23:02, Antoine Pitrou написав(ла):
> > On Fri, 13 Sep 2013 16:54:01 -0300
> > "Joao S. O. Bueno" <jsbueno at python.org.br> wrote:
> >> I see the PEP does not contemplate a way to retrieve the original key
> >> - like we've talked about somewhere along the thread.
> >
> > Indeed. If that's important I can add it. I was hoping to keep very
> > close to the MutableMapping API, to make the PEP as few
> > controversial as possible.
> 
> I think that's important. As OrderectDict has additional methods besides 
> the MutableMapping API, so TransformDict should provide useful 
> specialized methods.

Ok, I have a better (IMO) proposal:

    >>> d = TransformDict(str.casefold, {'Foo': 1})
    >>> d.getitem('foo')
    ('Foo', 1)
    >>> d.getitem('bar')
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    KeyError: 'bar'

Regards

Antoine.