On 2008 Feb 27, at 19:17, John Cowan wrote, quoting me:
alternatively, an object called the-SQL-null-object could be created
(perhaps as a record type value).
That is a priori reasonable, but it won't work with eq?, whereas the
unspecified value will.
I fail to understand why eq? compatibility is significant, one provides
a predicate to test SQL null-ness.
In order to sort out this farrago of nothingness, let me suggest the
following:
a. '() is just right for a multivalued field that happens to contain no
values, but is unsuitable for indicating SQL null.
b. (the-SQL-null-object) returns an SQL null value, and (SQL-null? x)
tells you whether x is an SQL null. (I'm not wedded to those names,
just using them as an example.)
c. Whether (the-SQL-null-object) returns a value of a disjoint type
from that returned by (void) is theoretically unimportant, but
it would be more elegant and explainable if the return value
behaves in a manner that's consistent with #!eof.
-- vincent
_______________________________________________
Chicken-users mailing list
Chicken-users@nongnu.org
http://lists.nongnu.org/mailman/listinfo/chicken-users
