Hello,
>> I think it's really time we seriously considered adding some flow
>> control logic, though.
>
> Yeah, maybe. I'd be interested to see a fully worked out proposal
> for that.
I agree that designing a fuller proposal before including individual parts
would be great and result in a more consistent result.
In order to bootstrap the discussion, I suggest the following:
- boolexpr is a simple "boolean" (t, non 0 int, non empty string.. as proposed by Corey and Pavel) or !/not boolexp
;it could be extended if necessary, but I would try to avoid that, as
- actual more complex expressions could be left to the server through SQL which simplifies the client a lot by
avoidingan expression language altogether
- then having a conditional block is very versatile and can be adapted to many use cases... maybe all
- \quit CODE, or I would prefer \exit CODE, could be used to exit while controlling the status
It could look like (although I do not like gset in this context, but
anyway):
SELECT ... AS has_foo_extension \gset SELECT ... AS has_bla_extension \gset \if :has_foo_extension ... \elif
:has_bla_extension ... \else -- no foo nor bla extension \echo please install foo or bla extension \exit 1 \fi --
extension... SELECT ... AS has_xxx_feature \gset \if ! :has_xxx_feature \echo "feature xxx is needed, aborting" \exit
2\fi ...
--
Fabien