[Python-Dev] Python 2.3a1's mandatory use of cyclic GC causes existing applications to fail

[Guido van Rossum]

> On Thu, 6 Feb 2003, Guido van Rossum wrote:
> > Can you suggest a concrete syntax to do this?  Maybe setting __slots__
> > to a dictionary mapping names to type specifiers would do it -- and it
> > would even be backwards compatible: currently, if __slots__ is a dict,
> > its keys are used as slot names and its values are ignored, by virtue
> > of the way the type constructor iterates over __slots__.
> 
> I already use __slots__ assigned to dictionaries where the values are not
> ignored.  They are interpreted by a metaclass to apply type conversion
> operators and type/value enforcement predicates to slots.  I hope that
> future versions of Python will not tread on this feature.  (Though I'd
> happily trade in this feature in exchange for having __slots__ be immutable)

Hm...  Given this feedback, it sounds like the only way to implement
Christian's suggestion in a backwards-compatible way would be to use a
different __xxx__ name, e.g. __fields__.  I also like the suggestion
of allowing control over the order as well.

--Guido van Rossum (home page: http://www.python.org/~guido/)