Horton

Re: Invisible PROMPT2

Chapman Flack <chap@anastigmatix.net>

View thread View on postgr.es
From: Chapman Flack <chap@anastigmatix.net>
To: David Fetter <david@fetter.org>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, Thomas Munro <thomas.munro@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-11-13T18:03:08Z
Lists: pgsql-hackers 
On 11/13/19 12:49 PM, David Fetter wrote:
>> Or just define %w as meaning "whitespace of the same width as
>> PROMPT1".  You couldn't use it *in* PROMPT1, then, but I see
>> no use-case for that anyway.
> 
> +1 for doing it this way.  Would it make more sense to error out if
> somebody tried to set that in PROMPT1, or ignore it, or...?

Define it as "difference between PROMPT1's width and the total width
of non-%w elements in this prompt". Then it has a defined meaning in
PROMPT1 too (which could be arbitrary if it appears only once, but
has to be zero in case it appears more than once).

Easter egg: expand it to backspaces if used in PROMPT2 among other
stuff that's already wider than PROMPT1. ;)

Regards,
-Chap

Commits

  1. psql: Fix %w length in PROMPT2 when PROMPT1 contains a newline.

  2. Allow invisible PROMPT2 in psql.