redefining Common Lisp functions

[edsel!bhopal!jonl@navajo.stanford.edu (Jon L White)]

Unfortunately, it is hard for an implementation to determine when a user 
is truly "redefining" a function, or merely changing it's symbol-function
cell in a way compatible with portable Common Lisp.  The most obvious case 
in point is the need to install "wrapper-like" function in order to do 
traceing.  A user ought to be able to implement his own monitoring scheme, 
which would involve changing the contents of the symbol-function cell of 
an arbitrary Common Lisp function (name), without bumping into some kind 
of hard barrier.

-- JonL --