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

Hello,

> We could just issue interactive-only warnings when:
> - A user types a branching condition command which sets the branch inactive
> - A user types a command or query when the current branch is inactive.
>
> The warnings could be specific about state, something like:
>
> psql session is now in an inactive \if branch. No queries will be executed
> and only branching commands (\if, \elif, \else, \endif) will be evaluated.
> [...]

My 0.02€: it looks too verbose, should stay on one short line. Maybe:

(in|)active (\if|\elif|\else), (execut|ignor)ing commands

Although there is some redundancy...

calvin=> \if true
active \if: executing commands
calvin=(t)> \echo ok
ok
calvin=(t)> \else
inactive \else: skipping commands
calvin=(f)> ...

Maybe it could be controlled, say based on VERBOSITY setting (which really
controls verbosity of error reports) or some other.

I'm unsure whether it is a good idea, I like terse interfaces, but this is
just an opinion.

--
Fabien.