Mopping up after the fact

[Jon L White <jonl@lucid.com>]

re: This example is, perhaps, a bit contrived. 

Certainly.

re: But I think it illustrates the point that make the extensible OO 
    protocol surrounding direct slot definition metaobjects back into 
    a non-extensible functional protocol is troubling.  

But does it?   The intent of this example would be more clearly covered
if the class metaobjects involved kept a slot for the common, defaulted
tail of a slot *specification*, which CANONICALIZE-SLOT-SPECIFICATION 
would look at.   Either way, of course, damages the referential 
transparancy of the specification.  So in a sense it might be better not 
to be led into a usage that uses the re-coding of the specifications 
purely in a way that demonstrates how a discrimination can be performed 
upon the induced class distinction.  


re: What I would rather do, actually, is change all the metaobjects 
    (direct and effective) associated with default initargs, into real 
    objects with a generic function based access protocol.  

The CLOS spec (88-002R and subsequent "cleanups")) leaves the content 
and type of the metaobjects unspecified; it uses "specification" or
"option" generally rather than implying a a subclassing of the resultant 
"effective" metaobjects.  So I would not suggest refining the concepts 
found in 88-002R except where it serves a real purpose.  Thus I am not 
now pushing for a distinction to be made for class :default-initargs 
specifications.   Someday, it might turn out to be a nice idea for some 
usage, but I don't feel strongly about it now.

At this time, none of the proposed nor contemplated metaobject protocols 
benefit from the re-coding of slot specifications into standard objects; 
and I don't think you even wanted to rebut the charge that the re-coding 
makes the code and design overly complex (when seen from the viewpoint 
of the proposed and contemplated protocols.)  So I'm only proposing the
application of Occam's razor.


-- JonL --

P.S.  [Gee, you've even gotten me saying "class metaobjects" now]