[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Random metaclasses for CL types

re: > As I've previously argued, the only utility of BUILT-IN-CLASS is 
    > taxonomic and this capability can just as easily and naturally be 
    > provided by a list  of all such classes.

    No, having a list doesn't give you the ability to write methods
    specialized on that group of things.

Hey, did you forget we are talking about BUILT-IN-CLASS (and not about
any particular built-in class such as INTEGER or VECTOR)?   User's can't 
write methods for BUILT-IN-CLASS.  Since my previous arguments about the 
artificial similarities among the built-in classes haven't been rebutted, 
then I don't see much to be gained by trying to let them write methods for 
such an ad-hoc construct.  

In your "portable INSPECTOR" project, for example, you need to make a 
decision as to whether to call the built-in DESCRIBE-OBJECT, or to fall 
into some code written in CLOS.  I claim there is no conceptual
disadvantage to making that decision by doing a MEMBER down a system
supplied list.   Furthermore I claim that creating an abstract metaclass 
for some totally disconnected set of classes has the _disadvantage_ of 
adding confusion, because the observer of the abstraction must think 
that there is an underlying similarity in the base elements.  [The 
offending abstraction is BUILT-IN-CLASS because it's only portable
use is taxonomic.]

-- JonL --