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

>> I would suggest to assume false on everything else, and/or maybe to ignore
>> the whole if/endif section in such cases.
>
> +1, it also halves the number of values we have to support later.

After giving it some thought, I revise a little bit my opinion:

I think that if the value is evaluated to TRUE or FALSE, then fine. If it 
is anything else, then an error is raised (error message shown), which 
should also stop the script on "ON_ERROR_STOP", and if not the script 
continues with assuming the value was FALSE.

-- 
Fabien.