"Thomas Heller" <thomas.heller@ion-tof.com> wrote,
> > >>>>> "GvR" == Guido van Rossum <guido@digicool.com> writes:
> >
> > GvR> Let x be an object, C its class, and M C's class. So,
> >
> > | x.__class__ is C
> > | C.__class__ is M
> >
> > GvR> Then x's methods are described in C.__dict__, and C's methods
> > GvR> are described in M.__dict__.
> >
> > GvR> The problem is that if you write C.spam, there could be two
> > GvR> spams: one in C.__dict__, one in M.__dict__. Which one to
> > GvR> use?
In my 'objectmodule' I adopted a concept which I refer to as the
"unbound instance". That is, I invented an object which is used as a
proxy for accessing instance attributes. It looks like an instance
but only for the purposes of attribute access. Now, since this object
will only return "unbound method objects" when accessing a method (as
opposed to the "bound method object" you would get when accessing a
method from a real instance) I thought the name was at least slightly
appropriate. In short, each class defined by the objectmodule has a
special attribute '_' which is the "unbound instance" for that class.
This unbound instance is used to resolve the name ambiguity. Now,
consider this:
import object
class foo(object.base):
def frob(self):
print "I've been frobbed", self
class __class__:
def frob(cl):
print "No, I've been frobbed", cl
>>> f = foo()
>>> x = f.frob
>>> # x is the instance frob method bound to f
>>> y = foo.frob
>>> # y is the class frob method bound to foo
>>> z = foo._.frob
>>> # z is the instance frob method but is not bound to any instance
>>> huh = foo.__class__._.frob
>>> # huh is the class frob method but is not bound to any class
>>>
> Thin ice again I'm on here (even more), but I have the impression
> that creating a class Point in Smalltalk _automatically_ creates two
> classes: Point and PointClass. The latter is normally hidden (but
> contains the class methods of Point as instance methods).
That's the way I remember it too. And, (if I recall correctly) in
SmallTalk (unlike CLOS), you have no control over the meta-class. In
the example above, like in SmallTalk, the name of foo.__class__ is
determined automatically. In this case it is 'foo_class'. However,
unlike SmallTalk, the above example could be extended to include a
'class __class__:' definition under the existing 'class __class__:'.
The name generated by this construct would, of course, be
'foo_class_class'. Lather, Rinse, repeat...
--
Donald Beaudry Ab Initio Software Corp.
201 Spring Street
donb@init.com Lexington, MA 02421
...Will hack for sushi...
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