Re: -I switch to ls and dired.

[Luc Teirlinck]

Richard Stallman wrote:

   The code that removes -R could be made smarter so that it detects
   R as an option, but not R as an argument.  The rules for options
   are not that complicated.

I believe that would be possible.  However, it would seem that this
would not be the end of the problems with options that take arguments
(I believe that this just covers -I and nothing else.)  Indeed, these
arguments are not processed the way the shell does.  Instead, they are
just split at spaces.  Quoting is ignored, shell variables are not
expanded and so on.

As a result, for instance, -I '* *', to exclude file names containing
a space, will lead to an error.

Also, R is by no means the _only_ problem and arguments are not the
only problem either.

For instance, trying `C-u i --ignore-backups' on some listed directory
yields an error:

Can't have dirs with and without -b switches together.

Of course, there is a b in backups.

There seem to be other examples all over dired and dired-aux. 

Dired seems to _systematically_ make two assumptions:

1.  No options take arguments.  Equivalently (or so I believe), -I is
    not used.

2.  No long options are used.

We can either just document those two assumptions or try to
systematically get rid of them.  I have the impression that the second
possibility will require many changes in dired and dired-aux (and
probably in dired-x), all well as changes in `insert-directory' in
files.el.

Sincerely,

Luc.