[Python-Dev] RE: Comparing heterogeneous types

[Robert Brewer]

Aahz wrote:
> On Mon, May 31, 2004, Robert Brewer wrote:
> >
> > Quite similar to my current "pet peeve":
> > 
> > >>> None > 3
> > False
> > >>> None > 'hoopy'
> > False
> > >>> None > True
> > False
> > >>> None > datetime.date(2004, 5, 31)
> > Traceback (most recent call last):
> >   File "<interactive input>", line 1, in ?
> > TypeError: can't compare datetime.date to NoneType
> > 
> > ...writing an O-R mapper, this particular hobgoblin bites 
> me rather often ;)
> 
> Time for you to bite the bullet.  Guido has all-but-decreed that the
> future of comparisons is that TypeError will be raised for 
> all operators
> other than == and <> for types that have no appropriate relationship
> system.

...which is fine. I'll end up either disallowing None as a legal value,
or making a NO_VALUE singleton for which I can customize comparisons.
Either is a better design choice IMO; I just haven't been forced into
the choice yet. ;)


Robert Brewer
MIS
Amor Ministries
fumanchu at amor.org