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

On Mon, Feb 13, 2017 at 3:40 PM, Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> wrote:

>
> Hello Robert,
>
> [...] I think we should try to make this REALLY simple. We don't really
>> want to have everybody have to change their PROMPT1 and PROMPT2 strings for
>> this one feature.
>>
>
> Ok. I think that we agree that the stack was too much details.
>
> How about just introducing a new value for %R?
>>
>
> Yes. That is indeed one of the idea being discussed.
>
> [...] , or @ if commands are currently being ignored because of the result
>> of an \if test.
>>
>
,-or-@ has one advantage over t/f/z: we cannot infer the 'z' state purely
from pset.active_state, and the if-stack itself is sequestered in
scan_state, which is not visible to the get_prompt() function.

I suppose if somebody wanted it, a separate slash command that does a
verbose printing of the current if-stack would be nice, but mostly just to
explain to people how the if-stack works.

> If I can find some simple mnemonic for "," vs "@" for being executed vs
> ignored, I could live with that, but nothing obvious comes to my mind.
>

@in't gonna execute it?

I'm here all week, try the veal.

To sum up your points: just update %R (ok), keep it simple/short (ok... but
> how simple [2 vs 3 states] and short [1 or 2 chars]), and no real need to
> be too nice with the user beyond the vital (ok, that significantly
> simplifies things).

I'd be fine with either of these on aesthetic grounds. On technical
grounds, 'z' is harder to show.