bug#64185: proposal for new function: copy-line

[Eli Zaretskii]

> Cc: 64185@debbugs.gnu.org
> From: Zachary Kanfer <zkanfer@gmail.com>
> Date: Mon, 26 Jun 2023 15:18:19 -0400
> 
> > > The code becomes slightly more verbose this way, but is far easier to read
> > > and comprehend. It seems an extremely worthwhile tradeoff to me.
> > 
> > Not sure how often users will read the code of duplicate-line.
> 
> Developers will. And it's easier to read with symbols.

The advantage of symbols for reading the code is very minor, so the
other considerations, in particular the ease of changing the value
interactively, prevail.