On 2024-09-18 We 4:23 AM, Peter Eisentraut wrote:
On 17.09.24 21:16, David E. Wheeler wrote:
On Sep 17, 2024, at 15:03, Florents Tselai
<florents.tse...@gmail.com> wrote:
Fallback scenario: make this an extension, but in a first pass I
didn’t find any convenient hooks.
One has to create a whole new scanner, grammar etc.
Yeah, it got me thinking about the RFC-9535 JSONPath "Function
Extension" feature[1], which allows users to add functions. Would be
cool to have a way to register jsonpath functions somehow, but I
would imagine it’d need quite a bit of specification similar to
RFC-9535. Wouldn’t surprise me to see something like that appear in a
future version of the spec, with an interface something like CREATE
OPERATOR.
Why can't we "just" call any suitable pg_proc-registered function from
JSON path? The proposed patch routes the example
'$.replace("hello","bye")' internally to the internal implementation
of the SQL function replace(..., 'hello', 'bye'). Why can't we do this
automatically for any function call in a JSON path expression?
That might work. The thing that bothers me about the original proposal
is this: what if we add a new non-spec jsonpath method and then a new
version of the spec adds a method with the same name, but not compatible
with our method? We'll be in a nasty place. At the very least I think we
need to try hard to avoid that. Maybe we should prefix non-spec method
names with "pg_", or maybe use an initial capital letter.
cheers
andrew
--
Andrew Dunstan
EDB: https://www.enterprisedb.com
