Horton

Re: Variable substitution in psql backtick expansion

Corey Huinker <corey.huinker@gmail.com>

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From: Corey Huinker <corey.huinker@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Date: 2017-03-31T11:50:44Z
Lists: pgsql-hackers 
On Thu, Mar 30, 2017 at 1:33 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> single-quoted according to Unix shell conventions.  (So the
> processing would be a bit different from what it is for the
> same notation in SQL contexts.)
>

+1
Having been bit by format '%L' prepending an 'E' to any string that happens
to have a backslash in it, I'm in favor of this difference.

Any reason we wouldn't do :"VARIABLE" as well? People might expect it given
its use elsewhere, and it would make possible things like

SELECT '$HOME/lamentable application name dir/bin/myprog' as myprog \gset
`:"myprog" arg1 arg2`


both for expanding $HOME and keeping the lamentable dir path as one arg.

Commits

  1. Add psql variables showing server version and psql version.

  2. Reformat psql's --help=variables output.

  3. Remove reinvention of stringify macro.

  4. Allow psql variable substitution to occur in backtick command strings.