Hello Bob,
On Thu, May 1, 2008 at 5:52 PM, Robert Brown <brown(a)google.com> wrote:
> I tried to get CLPython up and running on the latest SBCL. The diff below
> contains a couple of easy fixes. SBCL wants BREAK's argument to be a
> string
> and SBCL's LOOP does not like a negative loop increment.
Thanks for the patches!
> The real porting problem right now is CLOS related. SBCL does not like
> the
> following code in core/classes.lisp:
>
> ;; Fix superclass and metaclass of PY-DICT.
> (ensure-class 'py-dict
> :direct-superclasses (list 'py-core-object)
> :metaclass 'py-core-type)
>
> I get the following error:
>
> debugger invoked on a SB-PCL::METAOBJECT-INITIALIZATION-VIOLATION in
> thread
> #<THREAD "initial thread" {11701A79}>:
> Cannot CHANGE-CLASS objects into CLASS metaobjects.
> See also:
> AMOP, Initialization of Class Metaobjects
>
> I think the problem is that PY-DICT is a normal class and the ENSURE-CLASS
> call tries to turn it into a metaclass. Anyway, I'm far from a CLOS
> expert.
Well, class py-dict is not turned into a metaclass here, at least that's not
the intention. :) The superclass and metaclass of it are changed but py-dict
remains a non-metaclass class. So I think the actual error message is
incorrect, but something else is wrong.
The problem might be that you can not change the metaclasses of a class
using ensure-class. Could you please check if the call to ensure-class
without the metaclass change is accepted?
(ensure-class 'py-dict
:direct-superclasses (list 'py-core-object))
Thanks,
- Willem
