Re: SQL/JSON query functions context_item doc entry and type requirement

Hi,

On 06/17/24 02:43, Amit Langote wrote:
> <replaceable>context_item</replaceable> expression can be a value of
> any type that can be cast to <type>jsonb</type>. This includes types
> such as <type>char</type>, <type>text</type>, <type>bpchar</type>,
> <type>character varying</type>, and <type>bytea</type> (with
> <code>ENCODING UTF8</code>), as well as any domains over these types.

Reading this message in conjunction with [0] makes me think that we are
really talking about a function that takes a first parameter of type jsonb,
and behaves exactly that way (so any cast required is applied by the system
ahead of the call). Under those conditions, this seems like an unusual
sentence to add in the docs, at least until we have also documented that
tan's argument can be of any type that can be cast to double precision.

On the other hand, if the behavior of the functions were to be changed
(perhaps using prosupport rewriting as suggested in [1]?) so that it was
not purely describable as a function accepting exactly jsonb with a
possible system-applied cast in front, then in that case such an added
explanation in the docs might be very fitting.

Regards,
-Chap

[0]
https://www.postgresql.org/message-id/CA%2BHiwqGuqLfAEP-FwW3QHByfQOoUpyj6YZG6R6bScpQswvNYDA%40mail.gmail.com
[1] https://www.postgresql.org/message-id/66703054.6040109%40acm.org