[Openmcl-devel] MOP errors

Gary Byers gb at clozure.com
Mon Feb 7 16:44:50 PST 2005

On Mon, 7 Feb 2005, [iso-8859-1] Tiarnán Ó Corráin wrote:

> Hello--
> I'm trying to use the BKNR datastore in openmcl
> (http://bknr.net). When I try to load the datastore application, I get
> the following error message:
> ,----
> | The class #<STANDARD-CLASS STANDARD-OBJECT> was specified as a
> | but the meta-classes #<STANDARD-CLASS STANDARD-CLASS> and
> |    [Condition of type SIMPLE-ERROR]
> `----
> Is this a problem with openmcl's incomplete implementation of the MOP,
> or should I look elsewhere?

Look to the definition of VALIDATE-SUPERCLASS in


The rationale for requiring that class implementors define
VALIDATE-SUPERCLASS methods (and for the implementation-provide primary
method being somewhat conservative) is described in the "Notes" section
of that dictionary entry.

This is a somewhat subtle and confusing issue.

Some implementations seem to have made a conscious decision to be
more lenient about this than the spec suggests.  I don't believe that
this reduces overall confusion.

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