Which constants must be quoted?

[CPH%OZ.AI.MIT.EDU@XX.LCS.MIT.EDU]

I would like to suggest: quoting should be necessary only for symbols
and lists (including the empty list.)  My reasoning:

1. Only symbols and lists can represent non-constant s-expressions.
Therefore it is not necessary to quote other objects.

2. While there is definitely a split of opinion on whether or not the
remaining objects should require quoting (i.e. should we try to be
more like 3-lisp or not,) I favor not requiring quoting since this is
traditional lisp practice.  I don't see that such a decision affects
the semantics of the language much, so there seems little reason to
break with tradition here (not to mention the fact that I have a
considerable investment in this tradition!)

3. I favor quoting the empty list, because I don't think that it
should be distinguished from lists in general.  As RRRS states, the
unquoted empty list represents an empty combination, and should be
considered an error.