Copy constructors

[Neil Schemenauer]

Alex Martelli wrote:
> > Zope's persistency support manages this without assignment to
> > __class__.  A persistent object has three states: ghost, valid, and
> 
> Yes, and AMK has, it seems to me, posted eloquently as to
> how and why this is a kludge (or at least that's how I
> read AMK's posts on this thread), made necessary by the
> extension-class disabling (effectively) __class__ changes.

You can have the ability to efficiently subclass builtin
types or the ability to assign to __class__.  Pick one.  I would choose
the first any day.  The effect of second can usually be achieved in some
other way.

Regarding Andrew's problem with extension-class disabling __class__
changes: I worked around it.  It wasn't too bad.

  Neil