Re: Documentation of return values of range functions lower and upper

On Wed, Nov 1, 2023 at 09:40:43PM +0100, Laurenz Albe wrote:
> > Yes, I agree this documentation needs help.
> >
> > For upper/lower(), it is clear that the documentation is better saying
> > "unspecified" rather than infinite. The fact that upper/lower_inf()
> > returns false for +/-Infinity is quite odd, but should at least be
> > documented.
> >
> > Patch attached. It is odd that +Infinity (vs. Infinity) wasn't
> > supported for datetime input until PG 16, but I think we have to say
> > +/-infinity vs (blank)/-Infinity.
> >
> > Patch attached.
>
> I am unhappy with "unspecified". A NULL value as upper or lower bound has a very
> specific meaning, namely that the range is unbounded in that direction. This is
> a bit confusing, since NULL is typically used for unknown or undefined values.
>
> I think it would be better to say "returns NULL if the range is empty or unbounded"
> and "is the range unbounded on the upper end?".

I had to go with "Is the multirange's lower bound unbounded?" because
the surrounding items use that sentence structure. Patch attached.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

Only you can decide what is important to you.