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

>
> Hmmm. ISTM that control-c must at least reset the stack, otherwise their
> is not easy way to get out. What can be left to another patch is doing a
> control-C for contents and then another one for the stack when there is no
> content.
>

And so it shall be.

> - put Fabien's tap test in place verbatim
>>
>
> Hmmm. That was really just a POC... I would suggest some more tests, eg:
>
> # elif error
> "\\if false\n\\elif error\n\\endif\n"
>
> # ignore commands on error (stdout must be empty)
> "\\if error\n\\echo NO\n\\else\n\\echo NO\n\\endif\n"
>

Those are already in the regression (around line 2763 of
expected/psql.out), are you saying we should have them in TAP as well?
Should we only do TAP tests?

Anyway, here's the Ctrl-C behavior:

# \if true
new \if is true, executing commands
# \echo msg
msg
# ^C
escaped \if, executing commands
# \if false
new \if is false, ignoring commands until next \elif, \else, or \endif
# \echo msg
inside inactive branch, command ignored.
# ^C
escaped \if, executing commands
# \echo msg
msg
# \endif
encountered un-matched \endif
#

Ctrl-C exits do the same before/after state checks that \endif does, the
lone difference being that it "escaped" the \if rather than "exited" the
\if. Thanks to Daniel for pointing out where it should be handled, because
I wasn't going to figure that out on my own.

v7's only major difference from v6 is the Ctrl-C branch escaping.