🚀 go-pugleaf

re: (reference-p foo)  versus
    (defmethod reference-value ((reference reference))
	(reference-val reference))

Keep in mind that many Common Lisp implementations can "open-code"
the REFERENCE-P test, posibly into very few instructions; but the
generic-function dispatch step -- especially for an object not of
STANDARD-CLASS -- will likely cost a lot more time.

Of course, there is a trade-off point depending on how many methods
are written for the function REFERENCE-VALUE; typically the dispatch
time will be constant, and an in-line type test will be linear in
the number of cases.  I think you only have one case.


-- JonL --