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(at)momjian(dot)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(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

Only you can decide what is important to you.