Do symbols need to be EQ?

[Anton Vodonosov]

I think the most confusing part is what you mean by "same" symbols.

03.07.2015, 10:10, "Edi Weitz" <edi at weitz.de>:
> Just out of curiosity and without any relevance in practise:
>
> Is there one place in the standard where it is explicitly said that
> two symbols which are the "same" symbol must be "identical"? I know
> that there are a couple of examples where this is implied, but
> formally the examples aren't part of the standard, right?
>
> The EQ dictionary entry for example shows this example:
>
>   (eq 'a 'a) => true
>
> and then it continues with this note (emphasis mine): "Symbols that
> print the same USUALLY are EQ to each other because of the use of the
> INTERN function."
>
> And the entry for INTERN is actually the closest I could find in terms
> of clarification because it says that if a symbol of a specified name
> is already accessible, _IT_ is returned -- which sounds like object
> identity to me.
>
> But how does this fit into the picture?
>
>   CL-USER 1 > (defparameter *s* 'foo)
>   *S*
>   CL-USER 2 > (unintern 'foo)
>   T
>   CL-USER 3 > (defparameter *s2* 'foo)
>   *S2*
>   CL-USER 4 > (eq *s* *s2*)
>   NIL
>
> *S* has lost its home package and is thus not EQ to *S2*, sure, but
> how do we explain this in terms of object identity? Has the UNINTERN
> operation changed the identity of *S* which once was the one and only
> CL-USER::FOO but can't be anymore because this role is now occupied by
> *S2*?
>
> Did I miss some clarifying words in the standard? Did I just manage
> to confuse myself?
>
> Thanks,
> Edi.
>
> PS: The UNINTERN entry warns about side effects which could harm
> consistency, so maybe this is what they meant?