From: Tom Lane <tgl@sss.pgh.pa.us>
To: Corey Huinker <corey.huinker@gmail.com>
cc: 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
Subject: Re: \if, \elseif, \else, \endif (was Re: PSQL commands: \quit_if,
 \quit_unless)
In-reply-to: 
 <CADkLM=c=8i8sB9Ua2fxWxWdDsgAT87Xo+X1s+R7iAtk2fdXABA@mail.gmail.com>
References: 
 <CADkLM=dcMHeSOQZv0Dd8AO4cM+OzADg7u8PcA7d8pNezmLDo=g@mail.gmail.com>
 <24063.1486671184@sss.pgh.pa.us> <5095.1486674948@sss.pgh.pa.us>
 <4fb8635d88c7dc907d069e15fdd1ab94@xs4all.nl>
 <CADkLM=fbsnkWUWOKz8JiU5hN-8mKDm7MgsuAq6pHk-22eqJ3xA@mail.gmail.com>
 <alpine.DEB.2.20.1702100847180.27011@lancre>
 <CADkLM=dXgQTRDsyjCUZCh9LGKbNAnxM2weVq9uO4E7LfJg5P2Q@mail.gmail.com>
 <alpine.DEB.2.20.1702102217390.26448@lancre>
 <CAM-w4HMRumvzES_PaBD8b84b_LdhTyH__FAK6xwFBgwkTzvOsw@mail.gmail.com>
 <CADkLM=f4cDjWgq_JxMhf_NS0PG-xYuL5rhVpxth2zYxpu_fMhQ@mail.gmail.com>
 <CAM-w4HNhWn=suYQfhPOHyrg4_ub1OtT+oogfRNPnacWEBa6Ugw@mail.gmail.com>
 <alpine.DEB.2.20.1702120823010.26448@lancre>
 <CADkLM=fj9EOqCB89nJ7Qm9OKdrF9xL0qqaRq3VFa5=vO4faUzg@mail.gmail.com>
 <CADkLM=dZJ77XF=0pZMeQQkLYgHyXPs=bAg4+K0W+d-U5SbwAeg@mail.gmail.com>
 <CADkLM=decErx7iFyzxuPMQ5DNd6dearn+VuE1ajWKA_NaaMtug@mail.gmail.com>
 <28640.1487108678@sss.pgh.pa.us> <alpine.DEB.2.20.1702142349280.16120@lancre>
 <16856.1487797250@sss.pgh.pa.us> !
 <CADkLM=cxaB-GjPScrhSqcTfwEHD5JLtOOQ6PRqv8dWBY1q0c0Q@mail.gmail.com>
 <18672.1487799954@sss.pgh.pa.us>
 <CADkLM=c0h5V+H9aLOjEmc=6naRS2+W6ajZtENy+b3JpkOHZJ+w@mail.gmail.com>
 <CADkLM=c=8i8sB9Ua2fxWxWdDsgAT87Xo+X1s+R7iAtk2fdXABA@mail.gmail.com>
Comments: In-reply-to Corey Huinker <corey.huinker@gmail.com>
	message dated "Wed, 22 Feb 2017 17:52:28 -0500"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <21887.1487804399.1@sss.pgh.pa.us>
Date: Wed, 22 Feb 2017 17:59:59 -0500
Message-ID: <21888.1487804399@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Corey Huinker <corey.huinker@gmail.com> writes:
> After some research, GetVariable is called by psql_get_variable, which is
> one of the callback functions passed to psql_scan_create(). So passing a
> state variable around probably isn't going to work and PsqlFileState now
> looks like the best option.

Ah, I see why *that* wants to know about it ... I think.  I suppose you're
arguing that variable expansion shouldn't be able to insert, say, an \else
in a non-active branch?  Maybe, but if it can insert an \else in an active
branch, then why not non-active too?  Seems a bit inconsistent.

Anyway, what this seems to point up is that maybe we should've allowed
for a passthrough "void *" argument to the psqlscan callback functions.
There wasn't one in the original design but it's a fairly standard part
of our usual approach to callback functions, so it's hard to see an
objection to adding one now.

			regards, tom lane


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers