Re: warn when core functions are shadowed

[John W. Eaton]

On  1-Feb-2010, Jaroslav Hajek wrote:

| Well, the shadowing isn't disabled, you just get a warning. When doing
| power-user tricks, you probably don't mind ignoring a few warnings.
| The problem with configuration is that it should probably be done
| through a command-line switch, because some of these warnings will
| occur prior to reading your octaverc.

It would probably be good to go ahead and use warning_with_id
("Octave:shadow", ...) or similar even if some warnings could occur
before the user has a chance to set the warning state in their
.octaverc file.  I expect the normal thing would be that there would
be no warnings because of functions found in ".", so Octave would get
to the .octaverc file without warnings.  Then the user could have

  warning ("off", "Octave:shadow");
  addpath ("/my/directory/which/shadows/functions/from/octave");

If we do want to add a command-line option, then we can make it work for
all warning flags:

  --warning ID      set warning state for ID to "on"
  --no-warning ID   set warning state for ID to "off"

jwe