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@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.