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Replies to Extension to MAP

    Date: Wed, 25 Mar 1987  20:03 EST
    From: "Scott E. Fahlman" <Fahlman@c.cs.cmu.edu>

	How about, if the first arg to MAP is an integer, it specifies
	which argument should be clobbered?  This doesn't allow an
	unrelated sequence to be be clobbered, of course, but it does
	allow the common case of an in-place MAP operation.

    This is a joke, right?  

(defmacro --Quux () ':-)


    The idea of extending MAP in a compatible way was cute, but dangerous:
    it is usually a mistake to overload the same function to do two
    fundamentally different things depending on some subtle type
    distinction.  If you want a destructive operation, you should ask for it
    by name.  Then if a sequence gets clobbered mysteriously, you have some
    hope of finding the code responsible.

"The jam so disgusting, you can't say it on television.  Ask for it by name!"
			-- Fluckers Jam Commercial, Saturday Night Live