Re: [Chicken-users] New immediate values (was: DBI)

[felix winkelmann]

On Fri, Feb 29, 2008 at 1:41 PM, Tobia Conforto <address@hidden> wrote:
> felix winkelmann wrote:
>  >> (define sql-null (new-immediate-value))
>  >> (define (sql-null? x) (eq? x sql-null))
>  >>
>  >> With the certainty that sql-null won't be eq? to anything else at
>  >> all, won't be a list, a record, nothing at all except itself.  I
>  >> think this could have a few uses.
>  >
>
> > It would probably have uses, but what would you gain? All you need
>  > is a distinct unique object:
>  >
>  > (define sql-null (gensym 'sql-null))
>
>
>  This is still a symbol.
>
>  People are using (void) because it's nothing but (void), that is, all
>  standard predicates (symbol?, pair?, number?, string?...) return #f.
>  Only its own predicate returns #t.
>

Would a db interface include symbols as output?


cheers,
felix (who would like to keep the number of immediate types small)