Horton

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

Corey Huinker <corey.huinker@gmail.com>

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From: Corey Huinker <corey.huinker@gmail.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Fabien COELHO <coelho@cri.ensmp.fr>, Greg Stark <stark@mit.edu>, Erik Rijkers <er@xs4all.nl>, Robert Haas <robertmhaas@gmail.com>, Daniel Verite <daniel@manitou-mail.org>, Jim Nasby <Jim.Nasby@bluetreble.com>, PostgreSQL <pgsql-hackers@postgresql.org>, pgsql-hackers-owner@postgresql.org
Date: 2017-03-12T17:12:49Z
Lists: pgsql-hackers 
On Sun, Mar 12, 2017 at 1:52 AM, David G. Johnston <
david.g.johnston@gmail.com> wrote:
>
> Oddly, Corey was using you as support for this position...though without
an actual quote:
>
> """

Reading this, I started to wonder "so how did I get that impression?" and I
found this from Feb 9:

IMO, an erroneous backslash command should have no effect, period.
"It failed but we'll treat it as if it were valid" is a rathole
I don't want to descend into.  It's particularly bad in interactive
mode, because the most natural thing to do is correct your spelling
and issue the command again --- but if psql already decided to do
something on the strength of the mistaken command, that doesn't work,
and you'll have to do something or other to unwind the unwanted
control state before you can get back to what you meant to do.

Commits

  1. Support \if ... \elif ... \else ... \endif in psql scripting.

  2. Add a "void *" passthrough pointer for psqlscan.l's callback functions.