[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: constant folding/smashing

    Date: Thu, 9 Jun 88 14:59:16 PDT
    From: Jon L White <edsel!jonl@labrea.stanford.edu>
    re: My point is that in the form
	the quoted object is no more or less "constant" than in the form
	   (SETF (FIRST (QUOTE (A B C))) 1)
	So why does QUOTE make the components of the list (1 2 3)
	unmodifiable but not the components of X?
    Because the semantic model of symbols doesn't consider them to have 
    modifiable components; they are "atomic".  In fact, several implementations 
    I'm familiar do a "spaghetti-stack" lookup for the SYMBOL-VALUE function  -- 
    not a structure-component fetch.  And there have been serious suggestions for
    flushing the symbol-plist notion in favor of hashtables, or at least
    encouraging one to use hashtable entries rather than plist entries.