DISPLACE

[JONL at MIT-MC (Jon L White)]

    Date: 20 March 1980 16:42-EST
    From: Daniel L. Weinreb <DLW at MIT-AI>
    The Lisp documentation in LISP NEWS is typically done without much
    thought; . . .  MACLISP does not need lots of
    little functions like (LAMBDA (X Y) (RPLACA X Y) (RPLACD X Y) X)
    . . .  						. . .  LISP NEWS
    was not handed down on engraved tablets--we should reason together
    about what the right thing is and what should be done about it.
Not to be picky about your conceptions of LISP NEWS, but this happens to 
be the entry in LISP NEWS for DISPLACE, dated 
"Sunday  Sept 17,1978   FM+11H.57M.58S.   LISP 1742  -HIC, JONL-"
"[5] DISPLACE now treats atomic arguments differently.
    Its definition is now like:
    (DEFUN DISPLACE (X Y)
           (AND (ATOM X) (ERROR '|-- not a list. (DISPLACE)| X))
           (COND ((ATOM Y)
    	      (RPLACA X 'PROGN)
    	      (RPLACD X (NCONS Y)))
    	     (T (RPLACA X (CAR Y))
    		(RPLACD X (CDR Y)))))"
By the bye, what prompted your comment?