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MACROEXPANDED not working with SETF (??)

    Date: 29 OCT 1980 1004-EST
    From: JONL at MIT-MC (Jon L White)
    To:   GJC
    cc:   (BUG LISP)
    Re:   MACROEXPANDED not working with SETF (??)

    The subject line of this note is not the right characterization of the 
    problem -- what's going wrong here is that any macro-expansion which
    has been "memoized" one way or other may need to be invalidated
    by operations other than that of merely redefining the macro.
     ; ? I think you mean `(FIND-PROJECTION ,X ,MAIN-AXIS) ?

In fact, it is exactly the correct characterization of THE PROBLEM.
If the user defines a macro such as PROJECT-IT, then he is well
aware of the fact that the expansion depends on the value of
a global variable which may change. SETF is not a user
defined macro, therefore, why should it be his responsiblity
to make up for its deficiencies with respect to the attempt
at memoization? 

       But as Alfred E. Neuman used to say, "Not to worry . . ."

Sure, whatever you say.