ANN: intervalset Was: Set type for datetime intervals

[Nagy László Zsolt]

>> How about creating two classes for this? One that supports zero sized
>> intervals, and another that doesn't?
> If you don't want zero sized intervals, just don't put any in it. You
> don't have a separate list type to support even integers vs one that
> supports all floats. What operations are made different in
> implementation by this restriction?
When you substract two sets, zero sized intervals may appear in the
result. It is not just a question of "putting or not putting them in".
Are zero sized intervals valid or not? In my particular application,
they are not. I think Michael was right: this cannot be generalized. It
is application dependent.