Re: \if, \elseif, \else, \endif (was Re: PSQL commands: \quit_if, \quit_unless)

>> Maybe this can be a discussed in a follow-up patch and Corey should
>> proceed to finalize the if patch?
>
> In the event that we can leave prompting to a later patch, here are the v12
> highlights:

My 0.02€ about v12: Patch applies, make check ok, psql make check ok.

> - created conditional.h and conditional.c which contain the functions with
> stack-ish push/pop/peek/poke names

Why not.

> - now all non-test, non-doc changes are in src/bin/psql

Hmmm, see below.

> - moved conditional stack out of scan_state, stack state maintained by
> mainloop.c/startup.c, passed to HandleSlashCommands

ISTM that it is kind of a regression, because logically this is about the
scan state so it should be in the corresponding structure, and having two
structures to pass the scan state is not an improvement...

> - documentation encourages the user to employ ON_ERROR_STOP when using
> conditionals

Indeed. The paragraph explanations are clear enough to me.

I would suggest to also apply the advice to the example shown, including a
comment about why the variable is set on.

Also, the last element of the tap tests should be distinct: I suggest to
use 'if syntax error' and 'elif syntax error' in place of 'syntax error'
for the two first tests.

--
Fabien.