[ZODB-Dev] BTrees and setdefault

[Tim Peters]

[Ruslan Spivak]
>> I'd like to implement 'setdefault' method for BTrees. For me it seems
>> like lacking feature of mapping protocol. It can be of course easily
>> emulated, but "Readability counts."(C) :)
>>
>> If there won't be objections regarding this method then i'll try to make
>> this excercise on the branch.

[Dmitry Vasiliev]
> See:
>
> http://mail.zope.org/pipermail/zodb-dev/2004-September/008034.html
> http://mail.zope.org/pipermail/zodb-dev/2004-October/008040.html

Dmitry, it's nearly a year since you first suggested this.  Have you missed
these methods in practice (i.e., do you have use cases), or it still just a
matter of making BTrees formally "more like" newer Python dictionaries?

Ruslan, don't forget to change BTrees/Interfaces.py.  I find that hard to
follow:  defining 14 interfaces to describe the BTree types makes it quite a
maze to traverse.  If setdefault() is added, it probably belongs in
IDictionaryIsh.