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

>
> Patches do not apply cleanly.
> Part 1 gets:
> error: patch failed: src/test/regress/parallel_schedule:89
> error: src/test/regress/parallel_schedule: patch does not apply
>
> There is still the useless file, ok it is removed by part2. Could have
> been just one patch...
>

parallel_schedule failed because I hadn't rebased recently enough.

git format-patch did us no favors there. New patch is redone as one commit.

ISTM that PQExpBuffer is partially a memory leak. Something should need to
> be freed?
>

I copied that pattern from somewhere else, so yeah, I duplicated whatever
leak was there. Fixed.

> I think that you should use appendPQExpBufferChar and Str instead of
> relying on the format variant which is probably expensive. Something like:
>
> if (num_options > 0)
> append...Char(buf, ' ');
> append...Str(buf, ...);
>

All flavors of appendPQExpBuffer*() I can find have a const *char format
string, so no way to append a naked string. If you know differently, I'm
listening. Not fixed.

>
> is_true_boolean_expression: "return (success) ? tf : false;"
> Is this simply: "return success && tf;"?
>

Neat. Done.

>
> Some functions have opt1, opt2, but some start at opt0. This does not look
> too consistent, although the inconsistency may be preexisting from your
> patch. Basically, there is a need for some more restructuring in
> "command.c".

It is pre-existing. Maybe this patch will inspire someone else to make the
other more consistent.

v26 attached