bug#20992: 25.0.50; `virtual-dired': (1) doc typo, (2) unclear

[Drew Adams <drew.adams@oracle.com>]

> > 4. It's not clear from the doc just how `virtual-dired' changes
> > Dired mode.  It doesn't seem particularly "virtual", but it's not
> > clear what is meant by that word here.
> >
> > Seems that this is in fact just Dired mode, and that it is the
> > opposite of a virtual Dired mode: it puts an ordinary `ls'
> > listing into Dired mode, no?
> 
> More or less yes, I guess.  My impression after reading the available
> docs, and when trying to use it, is that the purpose is to get a dired
> like listing from somewhere else, e.g. an external source, or from a
> saved file (e.g. a dired buffer from a later Emacs session saved to a
> file) into a dired-like mode to have access to some of its commands.

That's what I understood too.

> It is virtual in the sense that the contents do not necessarily need to
> reflect the contents of an existing directory.  This is only checked if
> you switch to the real dired mode.

Dired contents do not, anyway, need to reflect the
contents of an existing directory.  A Dired buffer
can show an arbitrary list of files and directories.

E.g., this opens a Dired buffer named `foobar', with 3
entries: files bookmark+.el and dired+.el, and directory
THROW.  (Well, any of those 3 could be a directory or a
file name.)

(dired '("foobar"
         "~/somedir/THROW"
         "~/somedir/bookmark+.el"
         "~/somedir/dired+.el")
       nil)

The difference, I think, is how the listing is generated.
Instead of passing a list of file/dir names (possibly
absolute) and `ls' switches to `dired', for virtual-dired
you pass a "rendered" listing (I guess).

> A better wording might have been
> "offline" dired mode or so.

That's not a great word for this, IMO.

I don't have a good idea either, though.  Is the listing
essentially pre-rendered?  If so, then that term might
be OK.  I really don't know.

(I have nothing to say about the rest of your message.
I know nothing about that.)