[Python-Dev] PEP 372 -- Adding an ordered directory to collections ready for pronouncement

[Hrvoje Niksic]

Steven D'Aprano wrote:
> Gisle Aas wrote:
> 
>> Instead of introducing a sorteddict I would instead suggest that the 
>> future should bring an odict with a sort method; possibly also 
>> keys_sorted and items_sorted methods.
> 
> Instead of odict.sorted(), that can be spelled:
> 
> sorted(odict)  # sort the keys
> sorted(odict.values())  # sort the items
> sorted(odict.items())  # sort the (key, value) pairs

All of these are useful, but not when you want to sort the odict 
in-place.  Since ordered dict is all about order, a method for changing 
the underlying key order seems quite useful.  An odict.sort() would be 
easy to implement both in the current code (where it would delegate to 
self._keys.sort()) and in an alternative implementation using a linked 
list of keys (variants of mergesort work very nicely with linked lists).

> The idea of a SortedDict is that it should be sorted at all times,

A SortedDict would be nice to have, but we might rather want to use a 
balanced tree for the its C implementation, i.e. not inherit from dict 
at all.