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MACROEXPANDED not working with SETF (??)
- To: JONL at MIT-MC
- Subject: MACROEXPANDED not working with SETF (??)
- From: George J. Carrette <GJC at MIT-MC>
- Date: Wed, 29 Oct 80 18:25:00 GMT
- Cc: BUG-LISP at MIT-MC
- Original-date: 29 October 1980 13:25-EST
Date: 29 OCT 1980 1004-EST
From: JONL at MIT-MC (Jon L White)
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.
(DEFMACRO PROJECT-IT (X) `(FIND-PROJECTION ,x MAIN-AXIS))
; ? 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
But as Alfred E. Neuman used to say, "Not to worry . . ."
Sure, whatever you say.