Why are there no ordered dictionaries?

[Christoph Zwerschke]

> d1[0:0] + d1[2:2] ==> OrderedDict( (1, 11), (3, 13) )

Oops, sorry, that was nonsense again. I meant
d1[0:1] + d1[1:2] ==> OrderedDict( (1, 11), (3, 13) )

> Ordered dictionaries could allow slicing and concatenation.

Some operations such as concatenation need of course special 
considerations, since the keys must stay unique. A concatenation of 
ordered dicts with overlapping keys should probably give an IndexError.

-- Christoph