Re: Wrong results from in_range() tests with infinite offset

Dean Rasheed <dean.a.rasheed@gmail.com> writes:
>     if (isinf(base) && isinf(offset))
>     {
>         if ((base > 0 && sub) || (base < 0 && !sub))
>             PG_RETURN_BOOL(true);
>     }

Yeah, I'd experimented with more-or-less that logic before arriving at
my v2 patch.  I didn't like the outcome that "inf both infinitely precedes
and infinitely follows itself".  Still, it is nicely simple.

To make sense of this behavior, you have to argue that +/-inf are not
in any way concrete values, but represent some sort of infinite ranges;
then there could be some members of the class "inf" that infinitely
precede other members.  I thought that was bending the mathematical
concept a bit too far.  However, this isn't an area of math that I've
studied in any detail, so maybe it's a standard interpretation.

Still, I think the results my v2 patch gets make more sense than these.

            regards, tom lane