Re: Terminology: Shared versus class; local versus instance

[Danny Bobrow <Bobrow.pa@Xerox.COM>]

    Note that by recourse to old documents you can discover that
    the term "local slot" was introduced to cover both ":allocation
    :instance" and ":allocation :dynamic" slots.  No doubt the
    existence of :dynamic meant that it would have been confusing to
    call these "instance slots". Now that :dynamic is gone, it would be
    okay with me to simplify things by calling the two kinds of slots
    "instance" and "class".  Do you think that this terminological
    change might cause trouble for implementations that experiment with
    extensions, such as dynamic slots?  

No, because one could use "instance or dynamic" to cover the union.  The
name now is specific to the specified allocation rather than to a
property of that allocation.  

    (Of course one might wonder in this connection why no one ever
    proposed dynamic class slots, in other words, why the
    static/dynamic distinction was thought to be on the same axis as
    the local/shared distinction.)
Dynamic slots were proposed as an efficiency measure for slots that were
seldom used, the argument was that it was better not to allocate space
in each instance.  For class slots, allocation is only once per class. 
 
  danny