Re: Should we document how column DEFAULT expressions work?

On Fri, Jul  5, 2024 at 05:03:35PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > Well, 'now()' certainly _looks_ like a function call, though it isn't. 
> > The fact that 'now()'::timestamptz and 'now'::timestamptz generate
> > volatile results via a function call was my point.
> 
> The only reason 'now()'::timestamptz works is that timestamptz_in
> ignores irrelevant punctuation (or what it thinks is irrelevant,
> anyway).  I do not think we should include examples that look like
> that, because it will further confuse readers who don't already
> have a solid grasp of how this works.

Wow, I see that now:

    test=> SELECT 'now('::timestamptz;
              timestamptz
    -------------------------------
     2024-07-05 17:04:33.457915-04

If I remove the 'now()' mention in the docs, patch attached, I am
concerned people will be confused whether it is the removal of the
single quotes or the use of "()" which causes insert-time evaluation,
and they might try 'now()'.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.