bug#30085: 25.2: Documentation for cua-rectangle-mark-mode

[Kim Storm]

On 2018-01-12 10:22, Eli Zaretskii wrote:
> > Date: Fri, 12 Jan 2018 02:14:26 -0500
> > From: Boruch Baum <boruch_baum@gmx.com>
> >
> > File `cua-rect.el' list its author as Kim F. Storm <storm@cua.dk>, so
> > I've taken the liberty of cc'ing the author on the bug report. @Kim:
> > Your work seems like a great improvement over emacs' documented
> > rectangle support, but seems to have remained relatively unknown due to
> > lack of documentation. It should be front and center in any search for
> > emacs rectangle support.
> Thanks for the comments.  Yes, cua-rect facilities are notoriously
> under-documented.  I would suggest that you (or someone else who uses
> cua-rect) propose specific patches to fix that, based on your
> experimenting with the facility and code reading.  IME, this will
> allow us to fill this gap much faster than any other alternative.
>
> Of course, Kim's contributions to this effort will also be very
> welcome.
Just a little history here:

In the original cua-mode file, everything was stashed together in
the same file, so I had to refactor the code before it wasincludedinEmacs 22.1So I ended up adding three files: cua-base.el 
cua-gmrk.eland cua-rect.elknowing that documentation for some of the 
more advanced stuff still needed some improvements. However, the other 
emacs maintainers insisted that the cua-rect.el stuff didn't really have 
anything to do with cua-mode as such, but rather should be merged into 
the existing rect.el code. I agreed in principle, but didn't know how to 
accomplish that, so I left it for someone else to do - and continued to 
work on other stuff. Obviously, that merge never happened, and 
therefore, the more advanced rectangle support in cua-rect stays 
inaccessible for those who don't use cua-mode, and even for cua-mode 
users, some features are probably not widely used due to lack of 
documentation. So there are really two issues here: - merge cua-rect and 
rect code - complete documentation for the combined package I might be 
able to contribute on the second item, but I still don't know how to 
accomplish the first.