issue QUOTE-MAY-COPY, version 2

[Jon L White <jonl@lucid.com>]

A few little points:


re: QUOTE-MAY-COPY:ALWAYS

To me, the choice of names for this alternative is somewhat loaded; it
seems to imply "excesssive, copying work must ALWAYS take place".  How
about a name like EXPLICITLY-VAGUE?  At issue is not the requirement
to do copying at all, but merely the prohibition from depending on the 
address of the constant obtained from the special form (QUOTE <foo>).


re:   If an implementation chooses to copy constants, the copying may only
      happen once each time the form containing the constant is processed
      with COMPILE or EVAL (see examples below).

This seems a bit fuzzy to me.  Why not simply say that successive
evaluations of a form (QUOTE <foo>) must all be EQL?  then you could
point out in an implementational note that this means you are restricted
to copying a given instance of a constant at most once.


I'd like to see a bit more of the burden laid on the feet of those who
feel that it is so important to retain EQ-semantics for quoted constants.
That is _definitely_ not the current practice for compiled files; so
how can reasonable, portable programs depend on this mistaken notion?
True, no current EVAL implementation goes to the effort to do anything
other than return a piece of the encoded program; but slightly more
clever interpreters/compilers could do so.  An EXPLICITLY-VAGUE proposal
simply gives an implementor the license to do the same tricks for EVAL
that so many do for COMPILE-FILE.


-- JonL --