--- /dev/null
+## Copyright (C) 2012 John W. Eaton
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING. If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} ispref (@var{group}, @var{pref})
+## Return true if the named preference @var{pref} exists in the
+## preference group @var{group}.
+##
+## The named preference group must be a character string.
+##
+## The preference @var{pref} may be a character string or a cell array
+## of character strings.
+##
+## If @var{pref} is not specified, return true if the preference
+## group @var{group} exists.
+## @seealso{getpref, addpref, setpref, rmpref}
+## @end deftypefn
+
+## Author: jwe
+
+function retval = ispref (group, pref)
+
+ if (nargin == 1)
+ retval = isfield (loadprefs (), group);
+ elseif (nargin == 2)
+ prefs = loadprefs ();
+ if (isfield (prefs, group))
+ grp = prefs.(group);
+ if (ischar (pref) || iscellstr (pref))
+ retval = isfield (grp, pref);
+ else
+ retval = false;
+ endif
+ else
+ retval = false;
+ endif
+ else
+ print_usage ();
+ endif
+
+endfunction
+
+%% Testing these functions will require some care to avoid wiping out
+%% existing (or creating unwanted) preferences for the user running the
+%% tests.