This patch adds two very simple psql commands: \quit_if and \quit_unless.
A few comments about the feature design:
I'm unsure about the name, esp with '_'. There are some \lo_* commands, but others rely on pasted words (\crosstabview, \errverbose, ...).
I'm completely flexible with regard to the names.
I'm wondering if an simplistic interpreted \if \elsif/\else \fi would make more sense:
The problem is that \if \elsif \else \fi is anything but simplistic, and would be a vastly bigger change. Detecting nested if-thens, detecting un-matched if-thens, etc.
Quitting seems a little bit definitive, and means that if I have some alternatives then I have to have something that relaunch another script outside...
When \includes are process, does \quit stop the include or the full script. I'm afraid it is the script.
It behaves exactly as if the script contained \quit at that location.
Now probably an \if... would have also some drawbacks, but ISTM that there could be less of them.
It'd be nice, but I'm trying to keep things simple.
There is no test provided with the patch.
Indeed, but testing such a feature is hard within our current test harness. I welcome suggestions for how to convert the example script in my first email to tests.